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Editorials

Chest. 1994;106(5):1313. doi:10.1378/chest.106.5.1313
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Abstract
Chest. 1994;106(5):1313-1315. doi:10.1378/chest.106.5.1313b
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Chest. 1994;106(5):1315-1316. doi:10.1378/chest.106.5.1315
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Abstract
Chest. 1994;106(5):1316-1317. doi:10.1378/chest.106.5.1316
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Abstract
Topics: ecg abnormal
Chest. 1994;106(5):1317-1318. doi:10.1378/chest.106.5.1317
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Articles

Chest. 1994;106(5):1319-1325. doi:10.1378/chest.106.5.1319
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We developed an automated method to recognize the lung in a computed tomographic (CT) image. With computer-assisted analysis, we were able to describe the continuous low attenuation (less than -960 Hounsfield units) areas (CLA) on chest CT scans. The size (CLAs) and number (CLAn) of the CLA and the percentage of total lung area occupied by low attenuation area (LAA%) were measured using CT scans obtained from 24 patients with chronic pulmonary emphysema (CPE) and 13 control patients. The automated algorithm recognized the lung areas successfully in all patients. The CLAs and LAA% were significantly higher, and CLAn was significantly lower in patients with CPE than in controls. There was a significant correlation between CT parameters and pulmonary function test results. The histograms of the size of CLA could be represented as a power function in each patient. This automated method should be useful in objectively defining the affected areas in the lungs of patients with CPE.

Chest. 1994;106(5):1326-1328. doi:10.1378/chest.106.5.1326
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As only peripheral subpleural lesions can be visualized at thoracoscopy, deep nonpałpable pulmonary nodules have to be identified before performing wedge resections. We evaluate the efficiency of computed tomographic (CT) guided methylene blue injections to localize these nodules before their thoracoscopic resection. Twenty-three nodules in 21 patients were preoperatively localized under CT guidance and marked with methylene blue injections. The localizations under CT guidance of the 23 nodules were successful in all cases. The surgeon confirmed accurate localization of 22 nodules. In one case, the injected methylene blue could not be identified during thoracoscopy. Complications of this technique included six cases of asymptomatic pneumothorax, four cases of local and asymptomatic pulmonary hemorrhage, and two cases of fit of coughing. Because of this technique, 22 thoracotomies could be avoided and the duration of the hospital stay was then reduced. Computed tomographic-guided localization with methylene blue injection is a simple, effective, and rapid technique enabling good thoracoscopic surgery results.

Chest. 1994;106(5):1329-1332. doi:10.1378/chest.106.5.1329
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Twenty-two patients with mediastinal tuberculosis were reviewed. The most common symptoms were chest pain, cough, fever, and weight loss. Results of the physical examination were unremarkable. The chest radiographs of all 22 patients showed abnormal mediastinum with no evidence of extramediastinal disease. Most (62%) had right-sided paratracheal lymphadenopathy. Mantoux skin test was positive (>15 mm) in all patients, whereas sputum smears and cultures for acid-fast bacilli were negative. Computed tomographic (CT) guided fine needle aspiration biopsies (FNAB) were performed in 12 patients using 22- to 25-gauge needles. Ten patients had fiberoptic bronchoscopic (FOB) examination with brushings and biopsies. Mediastinoscopy (n=8) or thoracotomy (n=6) was performed in patients where either FNAB or FOB was not diagnostic or where lymphoma was suspected clinically. The rates of true-positive diagnoses were 20%, 66%, 75%, and 100% for FOB, FNAB, mediastinoscopy, and thoracotomy, respectively. The rate of false-negative for FNAB was 34%. Only one patient developed nonsignificant pneumothorax after FNAB. These findings suggest that CT-guided FNAB is a useful and safe procedure and should be considered in the initial evaluation of patients suspected of having mediastinal tuberculosis.

Chest. 1994;106(5):1333-1338. doi:10.1378/chest.106.5.1333
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Objective: The purpose of our study was to establish magnetic resonance imaging (MRI) criteria for the diagnosis of pulmonary vascular malformations (PVMs).

Materials and methods: Since 1987, 11 patients have been referred for chest MRI at our institution because of findings suggestive of a PVM. They were evaluated with a 1.5-T MRI system, incorporating a combination of spin-echo, gradient-recalled echo (GRE) cine, and 2-D phase contrast (PC) cine sequences. We used the following MRI criteria to diagnose PVM: (1) flow void or intermediate gray signal on spin-echo sequences; (2) bright signal on GRE cine sequences; and (3) bright signal consistent with flow detected on PC cine sequences using relatively low velocity ranges. Twelve patients not suspected of having a PVM served as controls; all had both MRI and pulmonary angiography to evaluate for central pulmonary embolus.

Results: Eight patients in the study group had PVM as determined with MRI using these criteria. In four of these patients, a PVM was confirmed by subsequent pulmonary angiography. Three patients did not have PVM utilizing these criteria; two had neoplasms and one had presumed mucus plugging and/or atelectasis that resolved spontaneously. The smallest vascular malformation detected by MRI was 1 cm. None of the control patients had PVM by MRI or pulmonary angiography.

Conclusion: Utilizing these criteria, we believe that MRI is potentially an excellent noninvasive modality to evaluate PVM, and we stress that some form of PC cine sequence must be performed to determine if indeed there is blood flow within a suspicious lesion.

Chest. 1994;106(5):1339-1342. doi:10.1378/chest.106.5.1339
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Study objectives: To assess whether (1) there is an increased incidence of sternal fractures associated with internal mammary artery (IMA) revascularization in open heart surgery and (2) there is a higher incidence of pain in postoperative patients with sternal fractures.

Methods: Two hundred eighty-eight consecutive adult patients who had undergone cardiac surgery underwent median sternotomy from 1989 to 1991. IMA revascularization was used in 94 patients. The remainder underwent conventional saphenous vein graft (SVG) revascularization or other open cardiac procedure. The sternum was checked for fracture at the time of chest-wall closure. Lung volumes, arterial blood gases, respiratory rate, and oxygen requirements were measured before and after pain relief by intravenous or epidural analgesia.

Results: Of 288 consecutive median sternotomies, there were a total of 24 sternal fractures. IMA harvesting was associated with a significantly greater incidence of sternal fractures. In the 94 patients in whom IMA mobilization was used, there were 16 fractures; in the remaining 194 cases, there were 8 fractures (p<0.007). Twenty-one of 24 patients were not seriously affected by their sternal fractures, whereas 3 patients suffered major respiratory compromise due to postoperative pain. Epidural analgesia was effective treatment for these three cases of severe sternal fracture pain and was not associated with any adverse consequences. All three patients had significant improvement in their respiratory condition after epidural analgesia was instituted. Respiratory rate decreased from 27±3 to 18±0.3 breaths/min (p<0.00l) and end maximum inspired volume increased from 700±1 mL to 1,525±275 mL.

Conclusions: The use of sternal retraction devices for IMA harvesting in coronary bypass procedures results in an increased incidence of sternal fractures when compared with conventional SVG bypass procedures. Although most sternal fractures are well tolerated, some patients with fractures can become a significant pain management problem. Epidural analgesia is a safe and effective treatment for severe pain associated with sternal fractures and provides improved postoperative pulmonary function.

Chest. 1994;106(5):1343-1348. doi:10.1378/chest.106.5.1343
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The efficacy of transcutaneous electrical nerve stimulation (TENS) as an adjunct to narcotic medications for the management of postoperative pain was assessed in a prospective, randomized, controlled study of patients following coronary artery bypass graft (CABG) surgery with the right or left internal thoracic artery (ITA). Forty-five male patients (mean age, 57±6 years) were randomly assigned to (1) TENS, (2) placebo TENS, or (3) control treatments (n=15 each), following extubation and during the 24- to 72-h postoperative period. Twoway analysis of variance tests indicated no significant differences among treatment groups for (1) pain with cough, (2) narcotic medication intake, (3) FVC, (4) FEV1, and (5) PEFR (p>0.05). However, pain at rest reported by the TENS group was significantly lower than that reported by the control group (treatment main effect; p< 0.04), although no significant differences were observed between the TENS and placebo or between the placebo and control groups (p>0.05). All six criterion measures were characterized by significant changes over time for the entire group (n=45; time main effect; p<0.01), as follows: pain and medication intake were similar on days 1 and 2, but were significantly less on day 3, and pulmonary functions were significantly lower than preoperatively on day 1, decreased further on day 2, and despite an improvement on day 3, remained significantly lower than preoperative values (p<0.01). This study suggests that the addition of TENS, applied continuously during the immediate postoperative period following CABG with ITA, may not be advantageous in pain management or the prevention of pulmonary dysfunction.

Chest. 1994;106(5):1349-1357. doi:10.1378/chest.106.5.1349
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Between January 1980 and December 1992, 3% (210/6,862) of our patients undergoing myocardial revascularization (CABG) had high grade (>80%) internal carotid stenosis (CS). One hundred seventy-five of these patients with complete follow up for a minimum of 18 months were studied. Bilateral internal CS was present in 60%, and 75%, had other vascular lesions, mainly as peripheral vascular disease (PVD) of the lower limb (50.8%). All patients underwent CAE (carotid endarterectomy) followed by CABG under the same anesthesia. Peripheral vascular lesions, contralateral internal CS and recurrent (n=43) and progressive vascular lesions (n=50), were subsequently treated as staged procedures. Hospital mortality was 3.42%. By univariate analysis significant predictors of late mortality were congestive heart failure, COPD, PVD, postoperative myocardial infarction, postoperative stroke, and ischemic cardiomyopathy. Only the latter two were also significant by multivariate analysis. At 12 years, actuarial survival in the presence of these risk factors were 46%, 49%, 22%, 37%, 53%, and 27% respectively. All are significantly lower as compared with the corresponding subsets of patients with the risk factor absent. At 12 years, actuarial survival for the entire series was 65%. Cumulative incidence of postoperative strokes was higher in patients with bilateral internal CS than in patients with unilateral internal CS (p<0.07) and in patients with neurologic symptoms than asymptomatic patients. At 12 years, actuarial freedom from all cardiac related events, postoperative stroke, and symptomatic PVD were 49%, 82%, and 76% respectively. After successful revascularization these patients should be carefully followed for recurrent and progressive vascular lesions.

Chest. 1994;106(5):1358-1363. doi:10.1378/chest.106.5.1358
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Study objective: To assess the effect of cardiopulmonary bypass (CPB) on muscle blood flow (MBF) when measured in the forearm by venous occlusion plethysmography.

Design: This was a prospective study.

Setting: Operating room area of a tertiary care university medical center.

Participants: Twenty-seven patients (25 men and 2 women), aged 62±1.5 years, undergoing elective coronary bypass grafting.

Interventions: Measurements were made during the surgical procedure: before, during cold and warm, and after discontinuation of CPB.

Measurements and results: Changes in forearm blood flow (FBF), derived forearm vascular resistance (FVR), mean arterial pressure (MAP), and cardiac output (CO) were evaluated by repeated measures analysis of variance. The control FBF (measured before CPB) was found to be approximately 50 percent lower than that previously reported for awake volunteers and patients. The FVR was similarly higher. From these low values, the FBF increased significantly (p<0.001) during normothermic bypass and after CPB. Forearm vascular resistance decreased significantly (p<0.001) throughout the cold, warm, and postbypass periods. Only during the warm and the postbypass periods did FBF and FVR reach normal values. Mean arterial pressure decreased significantly (p<0.01) throughout. There was no statistically significant association between any of the variables and FBF or FVR. After correcting for patient and surgical phase variability, only MAP had a statistically significant effect (p=0.042) on FVR; blood temperature, skin temperature, hematocrit level, PaCO2, serum potassium, and systemic vascular resistance (SVR) had no effect on either FBF or FVR when tested singly or in combination. When correction for multiple comparisons was applied, the lowest probability value became greater than 0.25. There was no correlation between combinations of covariates and FBF or FVR after adjustments for the surgical phase of the study either.

Conclusion: These findings indicate that the increase in MBF seen during warm and the post-CPB periods is only a recovery toward normal blood flow. The role of this change in the low SVR that usually accompanies CPB is equivocal.

Chest. 1994;106(5):1364-1369. doi:10.1378/chest.106.5.1364
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To assess the potential effects of coronary artery bypass surgery on left ventricular diastolic filling, 12 patients, aged 65±11 years, were studied by serial transesophageal Doppler echocardiograms. Doppler measures of mitral inflow velocity were made before, immediately after, 4 h after, and 20 h after cardiopulmonary bypass (CPB). Left atrial pressure was directly measured and controlled at 10±2 mm Hg for each study period. Mitral maximal early inflow velocity (E)/maximal atrial velocity (A) ratios and atrial filling fractions were calculated as indexes of diastolic function from maximal E and A velocities and their time velocity integrals, respectively. Data sets were available for serial comparison in 11 patients and were also compared with an age-matched control group of normal values. The results of E/A ratios were as follows: control group—1.4±0.2; before CPB— 1.7±0.6; immediately after CPB—1.0±0.2 (p <0.05 vs control group, before CPB, and 20 h after CPB values); 4 h after CPB—0.8±0.2 (p <0.05 vs control group, before CPB, and 20 h after CPB values); and 20 h after CPB— 1.3±0.4. Atrial filling fractions were as follows: control group—0.29±0.05; before CPB—0.25±0.06; immediately after CPB—0.43±0.07 (p <0.05 vs control group, before CPB, and 20 h after CPB values); 4 h after CPB, 0.46±0.07 (p <0.05 vs control group, before CPB, and 20 h after CPB values); and 20 h after CPB—0.35±0.06. Alterations in Doppler indexes of left ventricular filling occurred immediately after CPB and persisted 4 h after CPB. These indexes returned to baseline values by 20 h after CPB. This suggests reversible diastolic dysfunction in patients after coronary artery bypass surgery.

Chest. 1994;106(5):1370-1375. doi:10.1378/chest.106.5.1370
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Study design: Aprotinin has recently been shown to reduce postoperative bleeding and transfusion requirements associated with coronary artery bypass grafting. One concern with its use, however, is that it may have a deleterious effect on graft patency because it promotes hemostasis. Forty-seven patients undergoing coronary artery bypass grafting were enrolled in a prospective, randomized double-blind trial of aprotinin to determine the effect of this agent on postoperative bleeding, transfusion requirements, renal function, and graft patency. The study group was comprised of the 32 patients who underwent technically adequate ultrafast CT scans 6 to 8 weeks postoperatively to determine graft patency. Sixteen patients received aprotinin (aprotinin group) and 16 received placebo (control group).

Results: Demographic and operative descriptors were comparable between groups. Postoperative mediastinal and chest tube drainage in the aprotinin group was significantly less than that in the control group (722 vs 1,540 mL; p=0.0006) and the mean blood transfusion requirements were less, but this did not reach significance (125 vs 297 mL; p=0.42). Analysis of graft patency by patients revealed that 5 patients in the aprotinin group (31%) had at least one occluded graft, while none of the patients in the control group had an occluded graft (p=0.04). Analysis by graft revealed that 38 of 43 grafts placed in the aprotinin group were patent, while all 38 grafts placed in the placebo group were patent (88.4 vs 100%; p=0.057). There was no difference in the incidence of myocardial infarction, renal dysfunction or hematologic indexes at discharge between the groups, or evidence of other thrombotic complications.

Conclusion: We conclude that high-dose aprotinin is effective in reducing hemorrhage after coronary artery bypass grafting. However, its routine use should be approached cautiously due to its possible adverse effects on graft patency.

Chest. 1994;106(5):1376-1380. doi:10.1378/chest.106.5.1376
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The effect of on-site extracorporeal membrane oxygenation (OS-ECMO) and selection criteria on the utilization rate of this technology is unknown. We retrospectively studied 55 neonates who were admitted to Arkansas Children's Hospital from 1985 to 1993. We compared the ECMO utilization, mortality, and morbidity rates for outborn neonates with moderate and severe persistent pulmonary hypertension (PPHN) before and after the establishment of an ECMO program with guidelines for its use at our institution. The rate of ECMO use was three times higher and the mortality rate was 13 times lower in the period after OS-ECMO compared with the period when ECMO was available only at other institutions. No differences were observed in the morbidity rates between the two periods. Physician decisions to initiate ECMO involved more than guidelines, since 37% of the increased ECMO use was not associated with use of the guidelines. Possible reasons for noncompliance with the guidelines are discussed. Neonates who had received medical therapy only and who had an oxygenation index ≥30 and <40 had no mortality. Our findings suggest that the need for ECMO in this group of neonates is low.

Chest. 1994;106(5):1381-1386. doi:10.1378/chest.106.5.1381
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To test the hypothesis that neural mechanisms evoked by unilateral pulmonary artery occlusion (UPAO) affect the release of atrial natriuretic peptides (ANP) from the heart, hemodynamics and levels of plasma ANP and cyclic guanosine monophosphate (c-GMP) were studied in 11 patients with lung cancer. The UPAO induced a significant rise in heart rate by 5.3 percent, increased mean pulmonary artery pressure by 31 percent without affecting right atrial pressure, and decreased plasma ANP levels in the coronary sinus by 17.4 percent (p<0.05) from 202.5±27.1 pg/ml to 167.2±27.4 pg/ml. Atropine sulfate (0.04 mg/kg) injection increased the heart rate by 38.2 percent (p<0.01), reduced the stroke volume index by 25.1 percent, decreased coronary sinus ANP levels from 198.5±16.4 pg/ml to 124.8±19.6 pg/ml (p<0.01), and decreased coronary sinus plasma c-GMP levels from 4.6±0.5 pmol/ml to 3.1±0.4 pmol/ml (p<0.05). After atropine pretreatment, UPAO induced a significant (p<0.05) increase of 34.8 percent in the coronary sinus ANP level. Thus, it is concluded that in UPAO, the secretion of ANP from the heart is modulated partly by the autonomic nervous system.

Chest. 1994;106(5):1387-1390. doi:10.1378/chest.106.5.1387
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The occurrence of significant pulmonary hemorrhage associated with pulmonary arteriovenous malformations (PAVMs) and hereditary hemorrhagic telangiectasia (HHT) and the incidence of PAVMs in family members of patients with PAVMs and HHT are poorly defined. We reviewed our experience in 143 patients with PAVMs and HHT. Eleven (8 percent) of the 143 patients with HHT and PAVMs had a history of either massive hemoptysis or of hemothorax which required hospitalization. One patient died directly related to the pulmonary hemorrhage. There were four men and seven women. Three of the seven women experienced pulmonary hemorrhage during pregnancy. Seven of the 11 families participated in screening for PAVMs. Thirty-six (80 percent) of the 45 screened family members were found to have HHT. Thirteen (36 percent) of the 36 family members with HHT were proven to have PAVMs by pulmonary angiography. Pulmonary hemorrhage due to spontaneous rupture of the PAVM is a potentially life-threatening complication that should be treated aggressively with transcatheter embolotherapy. It occurs more frequently than previously recognized in patients with PAVMs and HHT. In addition, because of the increased incidence of PAVMs in family members of patients with HHT and PAVM, screening of family members with HHT is recommended especially in women of childbearing age.

Chest. 1994;106(5):1391-1395. doi:10.1378/chest.106.5.1391
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To compare the effects of posture on bronchial reactivity in 12 patients with mitral valve stenosis (MS) and 10 with bronchial asthma (BA), a methacholine inhalation test was performed 2 h after being in either a supine or sitting position. All patients showed bronchial hyperreactivity to inhaled methacholine before the study. In MS patients, logarithmic values of the cumulative dose producing a 35 percent decrease in respiratory conductance (log PD35Grs) were significantly lower 2 h after being in a supine position than in those after being in a sitting position (0.71±0.78, 1.02±0.53 log units, respectively, p<0.05). In BA patients, however, log PD35Grs did not show significant changes (0.42±0.51, 0.58±0.48 log units, respectively). Variables of pulmonary function tests showed no significant differences between the two positions in both patients with MS and BA. We conclude that the bronchial hyperreactivity in MS is enhanced after the supine position for 2 h and that the supine posture may play an important role in the pathogenesis of cardiac asthma.

Chest. 1994;106(5):1396-1400. doi:10.1378/chest.106.5.1396
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As previous studies have suggested that inhaled furosemide may have a protective effect against certain types of provocative challenges in asthmatic subjects, we investigated the role of furosemide in treating acute asthma exacerbations. Twenty-four patients (n=24) with acute asthma were entered into the study on presenting to the emergency department. They were blindly randomized to receive one of three drug regimens: (1) inhaled furosemide (40 mg) (n=8); (2) inhaled metaproterenol (15 mg) (n=7); or (3) the combination of furosemide (40 mg) and metaproterenol (15 mg) (n=9). We measured FEV1 at entry (time 0) and 15, 30, 45, and 60 min after inhalation of the individual drugs or the combination from a face mask nebulizer. At entry, the three groups did not differ significantly in age (mean± SEM= 37.6±3.6, 38.5±3.6, and 41.0 years, respectively; p=0.770), baseline FEV1 (1.01±0.27, 1.04±0.27, and 1.25±0.14 L, respectively; p=0.620), or theophylline levels (2.87±1.8, 7.39±2.8, and 5.29±2.6, µg/ml, respectively; p=0.498). Pretreatment and posttreatment potassium levels were similar among the three groups. Inhalation of furosemide alone resulted in a 14.9±10.5 percent change in FEV1 percent from baseline, which was not statistically significant. In contrast, metaproterenol alone resulted in a 42.9±15.2 percent increase in FEV1 percent (F ratio= 6.226; p=0.0028). The combination of furosemide and metaproterenol resulted in a change in FEV1 percent that was not statistically different compared with metaproterenol alone (FEV1 percent= 41.9±12 percent). No significant adverse effects occurred in any of the groups.

Chest. 1994;106(5):1401-1406. doi:10.1378/chest.106.5.1401
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The incidence and severity of bronchial asthma has increased considerably in recent years. As a result, the number of patients requiring mechanical ventilation and more intensive medical therapy for treatment of refractory asthma has also increased. Despite this, available information concerning the quantitative changes in respiratory mechanics and the response to treatment that occur in such patients is limited. The present study describes the abnormalities in respiratory mechanics and the response to isoflurane anesthesia observed in three adults mechanically ventilated for treatment of status asthmaticus. Airway pressure, flow, and volume were measured during controlled mechanical ventilation in which the airway was periodically occluded in order to determine respiratory system mechanics. In two patients, the volume of hyperinflation and expiratory volume-flow relationship were also obtained. Inspiratory and expiratory indices of respiratory resistance were markedly abnormal. These abnormalities were associated with significant dynamic hyperinflation and high levels of intrinsic PEEP. Expiratory flow limitation was also identified in two patients by failure of low levels of applied positive end-expiratory pressure (PEEP) to alter the expiratory volume-flow relationship. Indices of respiratory resistance as well as the magnitude of dynamic hyperinflation and intrinsic PEEP improved considerably with isoflurane administration, after having been refractory to intensive conventional bronchodilator therapy. In summary, these results demonstrate the severity of abnormalities in respiratory mechanics present in ventilated patients with status asthmaticus and the potential therapeutic efficacy of inhalational anesthesia in this setting.

Chest. 1994;106(5):1407-1413. doi:10.1378/chest.106.5.1407
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Background: Enprofylline is a new xanthine derivative that shares theophylline's bronchodilator properties but is free of theophylline's adenosine receptor antagonist activity. We compared the long-term efficacy and tolerability of enprofylline and theophylline given over a 1-year period to adults with asthma.

Methods: Patients were recruited from 18 centers and 4 countries to participate in a 1-month double-blind comparison of enprofylline or theophylline in the treatment of asthma and were subsequently maintained on a regimen with the assigned medication for a further 11 months. The dosage of each xanthine was incremented from 150 mg twice daily at initiation to 300 and later 450 mg twice daily depending on the patient's tolerance and, in the case of theophylline, the rapidly assayed serum theophylline level. Patients kept a diary in which they recorded peak expiratory flow rate (PEFR) measured morning and evening, asthma symptom score, and the number of β2-agonists taken. Spirometry was checked at clinic visits at 3, 6, 9, and 12 months following randomization.

Results: Three-hundred forty-eight patients (174 enprofylline, 174 theophylline) participated in the trial. For both drugs there were significant improvements in PEFR and FEV1 during the first month of treatment with no significant difference between drugs (0.25 L for enprofylline vs 0.30 L for theophylline). Similarly, there were no differences in clinical outcome such as asthma exacerbations or β2-agonist usage between the two groups over follow-up. However, inhaled steroid dosage was more likely to have been incremented in theophylline-treated than enprofylline-treated patients (18% vs 8%, p=0.025). Both drugs produced a modest increase in heart rate throughout the trial (approximately 5 beats/min). In 31 patients (26 enprofylline, 5 theophylline), asymptomatic elevations in aspartate aminotransferase and/or alanine aminotransferase occurred at least once during the study. In five patients (four enprofylline, one theophylline), the increase exceeded three times the upper limit of the normal range. In some subjects receiving enprofylline, serum enprofylline levels rose progressively despite constant oral dosage of the drug.

Conclusions: Long-term xanthine therapy is well-tolerated by most adult asthmatics. However, long-term enprofylline administration may be associated with elevation in liver enzyme levels and unpredictable blood levels, thereby limiting its clinical usefulness.

Chest. 1994;106(5):1414-1418. doi:10.1378/chest.106.5.1414
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We recently reported that inhaled acetaldehyde causes bronchoconstriction indirectly via histamine release in patients with asthma. The purpose of this study was to investigate a role of thromboxane A2 in acetaldehydeinduced bronchoconstriction in asthmatic airways. We investigated the bronchial response to inhalation of ascending doses (5, 10, 20, and 40 mg/ml) of acetaldehyde in nine asthmatic subjects who were treated with placebo or OKY-046, a selective thromboxane A2 synthetase inhibitor, of 200 mg twice a day for 3 days, and 200 mg on the fourth day (test day) in a double-blind, randomized, placebo-controlled, crossover fashion. Percentage decreases in FEV1 caused by 20 and 40 mg/ml of acetaldehyde inhalation were significantly (p<0.05 and p<0.01, respectively) prevented by the pretreatment with OKY-046. Geometric mean value (geometric standard error of the mean) of acetaldehyde concentration producing a 20 percent fall in FEV1 (PC20-Ac-CHO) was significantly (p<0.01) greater with the OKY-046 pretreatment (72.2 [1.1] mg/ml) than with the placebo pretreatment (19.8 [1.2] mg/ml). We conclude that thromboxane A2 is one of contributors to acetaldehyde-induced bronchoconstriction in asthmatic subjects. It suggests that thromboxane A2 may play an important role in endogenous histamine-induced bronchoconstriction caused by acetaldehyde in asthmatic airways. We believe that this is a first report on the interaction between endogenous histamine and thromboxane A2 in asthmatic subjects.

Chest. 1994;106(5):1419-1426. doi:10.1378/chest.106.5.1419
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Peak expiratory flow rate (PEFR) monitoring is often used alone in evaluating bronchial caliber and the response to a bronchodilator in the assessment of asthmatic subjects. A 15% change in airway caliber has been proposed as the criteria for modifying treatment. Our aim was to determine if changes in PEFR from one visit to the next can adequately evaluate changes in airway caliber as assessed by FEV1, which is considered the gold standard, and to identify the characteristics of subjects whose evaluations were inadequate. This was a retrospective study of 197 asthmatic subjects seen regularly at an outpatient clinic for whom FEV1 and PEFR assessments, prebronchodilator and postbronchodilator, were available for two visits. There was a high correlation between PEFR and FEV1 (in absolute value or percent predicted) (r=0.83 and r=0.75). However, 24 of 56 (43%) of those who had a change in FEV1 of 15% or more between two visits (mean change [%]±SD, range [best-lowest/best]=20.9±5.1%, 15 to 36%) showed changes in PEFR of less than 15% (6.7±6.5%, 8.0 to 13.9%). On the other hand, 14 of 42 (33%) subjects with changes in FEV1 of less than 15% (9.8±3.2%, 1.1 to 13.8%) had changes in PEFR of 15% or more (22.2±10.9%, 16 to 35%). This discrepancy was not related to differences in baseline FEV1, control status, or the relationship between changes in FEV1 and PEFR in response to a bronchodilator. In conclusion, assessment of airway caliber through PEFR monitoring may not be valid in some asthmatic subjects and can often lead to underestimation or overestimation of changes in FEV1. None of the explanations considered made it possible to identify these subjects.

Chest. 1994;106(5):1427-1431. doi:10.1378/chest.106.5.1427
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Objective: We measured the ability of the medical history, physical examination, and peak flowmeter in diagnosing any degree of obstructive airways disease (OAD).

Design: Prospective comparison of historical and physical findings with independently measured spirometry.

Setting: University outpatient clinic.

Patients: Ninety-two adult consecutive outpatient volunteers with a self-reported history of smoking, asthma, chronic bronchitis, or emphysema.

Measurements: All subjects completed a pulmonary history questionnaire and received peak flow (PF) and spirometric testing. The subjects were independently examined for 12 pulmonary physical signs by four internists blinded to all other results. Multivariable analysis was used to create a diagnostic model to predict OAD as diagnosed by spirometry (FEV1 <80 percent of predicted not secondary to restrictive disease, or FEV1/ FVC less than 0.7).

Results: The best model diagnosed OAD when any of three variables were present—a history of smoking more than 30 pack-years, diminished breath sounds, or peak flow less than 350 L/min. This model had a sensitivity of 98 percent and specificity of 46 percent. In addition, the model detected all subjects with probable restrictive lung disease. Thirty-one percent of subjects had none of these variables and were at very low (3 percent) risk of OAD. Fifty percent of subjects with one or more abnormal variables had OAD.

Conclusions: The history, physical examination, and peak flowmeter can be used to screen high-risk patients for OAD. Using this diagnostic model, 31 percent of subjects could be classified at very low risk of OAD while half of those referred for spirometry would have abnormal results.

Chest. 1994;106(5):1432-1437. doi:10.1378/chest.106.5.1432
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To evaluate possible autonomic nervous system (ANS) dysfunction in patients with chronic obstructive pulmonary disease (COPD) in the absence of any hypoxic neuronal damage, we studied 31 patients with COPD patients aged 31 to 68 years (55±10) and 32 age-matched healthy subjects (control). Respiratory function in the patients was as follows: FEV1=52±8 percent; PaO2= 71±14 mm Hg; and PaCO2=40±10 mm Hg. The ANS was assessed by heart rate variability (HRV) in the time domain (SD of mean RR interval) and frequency domain (autoregressive spectral analysis recognizing low [LF] and high [HF] frequency components, vagal and sympathetic related, respectively). Patients and controls were evaluated at rest and during vagal (controlled breathing [CB]) and sympathetic (passive head-up tilt) maneuvers. Patients with COPD showed a depressed global HRV (rest SD=34±20 ms vs 45±15 ms, p<0.05; tilt SD=28±14 ms vs 38±13, p<0.01) with a predominant respiratory drive (rest HF=44±28 vs 28±18, p<0.05; tilt HF 42±28 vs 16±12, p<0.01) as compared with normal subjects. In the control group, vagal and sympathetic responses were in opposite directions following a stimulus, whereas there was no significant HRV response in the COPD group. We conclude that patients with COPD have abnormalities of ANS function, with in particular a depressed HRV response to sympathetic and vagal stimuli.

Chest. 1994;106(5):1438-1442. doi:10.1378/chest.106.5.1438
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A miniature flexible fiberoptic bronchoscope (FFB) (Olympus BF-N20) (2.2 mm diameter) was applied to 53 children (20 female subjects) ranging in age from 3 months to 15 years (mean, 4.19 years). Most common indications for bronchoscopy included stridor or weak cry and persistent wheezing or cough unresponsive to inhaled bronchodilators, chest physiotherapy, steroids, and antimicrobial agents. There were no complications. In 38 children (71.6 percent) it was diagnostically useful, particularly for the investigations of upper airway obstruction (66 percent). In 22 children (41.5 percent) it provided guidance for surgical interventions. The instrument was particularly useful during its application in infants with severe upper airway obstruction who otherwise would require open rigid-tube bronchoscopy in the operating room. It was of limited value when excessive bronchial secretions obstructed the view of the working field for which a bronchoscope with a built-in suction channel was needed. It is concluded that this miniature FFB is a useful diagnostic tool in infants and children particularly for obstructed upper airways but has limited applications in children with peripheral airway disease. The 2.2-mm bronchoscope may have its greatest advantage in preterm neonates and intubated infants, where the small glottic or endotracheal tube size renders the 3.5-mm bronchoscope useless.

Chest. 1994;106(5):1443-1447. doi:10.1378/chest.106.5.1443
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We developed a new type of bronchoscope (BF-2.7T) and cytology brush (BC-0.7T) that permit collection of pulmonary cells during direct observation of the small airways. This kind of cell collection has been previously impossible. With our cytology brush, 3.58±2.76x 104 cells were collected from small airways. The rate of living cells was 33.13±3.61 percent from the small airways. Analysis of endoscopic findings and investigation of pulmonary cells are very important for elucidating the pathophysiologic state of the small airways. The use of the BF-2.7T allowed collection of cancer cells under direct endoscopic vision in all five patients with peripheral lung cancer. They also contribute to our understanding of the relationship between exogenous factors and cells that compose the lung, and will provide means for treatment and prevention of diseases.

Chest. 1994;106(5):1448-1450. doi:10.1378/chest.106.5.1448
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We describe findings in 34 cases of lung cancer with skin metastases. In 24 men and 10 women, ages ranged from 32 to 85 years (mean, 61 years). In five, a skin lesion was the first manifestation of the underlying cancer; in another four, it was found coincidentally with detection of the lung mass. Pathologic findings included adenocarcinoma in 18 patients, large-cell carcinoma in 9, squamous cell carcinoma in 5, and small-cell carcinoma in 2. Among 87 patients with large-cell carcinoma, 9 (10.3 percent) developed cutaneous metastases. A review of 510 autopsies of primary lung cancer at Keio University from 1958 to 1992 showed 25 cases with skin metastases (4.9 percent), adenocarcinoma in 13 cases, large-cell carcinoma in 6, squamous cell carcinoma in 4, and small-cell carcinoma in 2. Skin metastases were proven in 15.4 percent of autopsy cases of large-cell carcinoma of the lung. Mean survival time from diagnosis of lung cancer was 10.3 months and that from diagnosis of skin metastasis was 4.9 months. The prognosis for patients having lung cancer with skin metastasis is thus very poor. In the review of 34 patients and 25 autopsies of lung cancer with skin metastasis, we conclude that the incidence of cutaneous metastasis is high for large-cell carcinoma and low for squamous and small-cell carcinoma.

Chest. 1994;106(5):1451-1455. doi:10.1378/chest.106.5.1451
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Thirty-three patients with T3, N2, M0 or T4, N2, M0, nonsmall-cell lung cancer (NSCLC) took part in a phase 2 study in an attempt to evaluate the feasability of neoadjuvant chemotherapy followed by surgery and thoracic radiotherapy. Chemotherapy consisted of daily administration of the following treatment: etoposide, 100 mg/m2; cisplatin, 25 mg/m2; ifosfamide, 1.5 g/m2; and mesna, 1.8 g/m2 for 4 days. Three cycles were planned starting every 21 days. Responding patients underwent a thoracotomy in order to attempt a resection and then received a 45 Gy of thoracic radiotherapy. The results of response and resection rates have been published and the present final report deals with the longterm results. Chemotherapy induced a 55 percent partial response rate and a 15 percent complete response rate allowing a complete resection in 55 percent of the patients. Complete remission was histologically confirmed for the five complete responders. Although the median survival was short (10 months), six patients were long-term survivors (3-year survival rate: 19 percent). Survival was significantly influenced by the type of resection: patients for whom a complete resection was possible survived the longest with a median survival three times that of the other patients. Modalities of relapses differed according to the results of surgery: 8 of the 15 patients who did not undergo a complete surgical resection experienced a local relapse during the first 18 months of follow-up whereas in the complete resection group, central nervous system metastasis was the main site of relapse. We conclude that the neoadjuvants ifosfamide, cisplatin, and etoposide in patients with locally advanced NSCLC are feasible to use and allow a 19 percent 3-year survival rate. These results are the rationale of an ongoing randomized study comparing neoadjuvant chemotherapy followed by surgery and surgery alone. This study is designed to test whether neoadjuvant chemotherapy improves survival of patients with locally advanced NSCLC.

Chest. 1994;106(5):1456-1459. doi:10.1378/chest.106.5.1456
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Objective: To describe changes in incidence and outcome of acute respiratory failure (ARF) due to AIDS-related Pneumocystis carinii pneumonia (PCP) at a tertiary care center over the 4-year period starting April 1, 1987 with reference to previously reported data from the preceding 6 years.

Methods: All patients admitted to St. Paul's hospital with a diagnosis of AIDS-related PCP during the study period were reviewed with regard to diagnostic, clinical, therapeutic, and outcome variables.

Results: A total of 456 episodes of PCP were diagnosed during the study period. These were compared against 127 cases diagnosed between 1981 and 1987. The frequency of hospitalization for PCP decreased to 78% in 1987 to 1991 from 100% in 1981 to 1987 (p≤0.001). A similar decreasing trend was observed with regard to the incidence of PCP-related ARF that declined from 21% in 1981 to 1987 to 9% in 1987 to 1991 (p=0.009). Despite this, overall PCP-related mortality remained stable at 12% in 1981 to 1987 and 9% in 1987 to 1991 (p=0.26). The proportion of patients with PCP-related ARF who received mechanical ventilation decreased from 89% in 1981 to 1987 to 64% in 1987 to 1991 (p<0.001). Despite this, the case fatality rate among mechanically ventilated patients increased from 50% in 1981 to 1987 to 89% in 1987 to 1991 (p=0.003). These changes were associated with a significant change in the pattern of use of corticosteroids as adjunctive therapy for AIDS-related PCP. In 1985 to 1986, nearly 100% of patients admitted to the ICU received corticosteroids only after admission to the ICU, following the development of ARF. In contrast, in 1989 to 1990, 50% of patients were admitted to the ICU already receiving systemic corticosteroids. The rise in the proportion of patients receiving corticosteroids prior to ICU admission between these two intervals was statistically significant (p= 0.017).

Conclusion: Our data show a decreasing frequency but a worsening mortality of ARF secondary to AIDS-related PCP. We conclude that ARF secondary to AIDS-related PCP developing despite maximal therapy, including adjunctive corticosteroids, carries a dismal prognosis.

Chest. 1994;106(5):1460-1462. doi:10.1378/chest.106.5.1460
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Inhaled pentamidine is used to treat Pneumocystis carinii pneumonia. Its potential effects on DNA have raised concerns about its safety for pregnant healthcare workers. We used a pharmacokinetic approach to estimate the fetal risks, based on the published data of pentamidine renal clearance and of urinary pentamidine concentrations in healthcare workers exposed to aerosolized pentamidine. The maximum pentamidine doses (intravenous equivalent) that healthcare workers were exposed to were calculated to be 9.8 µg/kg/d and 1.7 µg/kg/d at the two different institutions reported. In parallel, based on animal data, we derived the intravenous-equivalent reference doses for embryolethality and for teratogenicity, the doses that can be viewed as tentative safe exposure levels. These analyses reveal that the exposure levels of a healthcare worker to aerosolized pentamidine are estimated to be in the vicinity of the teratogenic reference dose (4µg/kg/d) and greater than the embryolethal reference dose (0.08µg/kg/d). Further improvement of the pentamidine administration technique and of environmental management in hospitals is warranted.

Chest. 1994;106(5):1463-1465. doi:10.1378/chest.106.5.1463
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Study objective: To determine the influence of needle gauge in Mantoux skin testing for tuberculosis.

Design: Randomized selection of either a 27- or 30-gauge needle for Mantoux skin test placement; observer-blinded.

Setting: Annual hospital employee screening.

Participants: Six hundred twenty-five employees working in clinical and laboratory research environments.

Results: Blinded observers found that the use of 27-gauge needles caused increased bleeding and bruising compared with 30-gauge needles (p≤0.007 for each). However, the 27-gauge needle produced larger blebs and less leakage of tuberculin solution (p≤0.0003).

Conclusion: Smaller gauge needles could potentially cause false-negative screening results because of decreased antigen delivery. Use of needle gauges smaller than 27 gauge should be avoided until their reliability is validated.

Chest. 1994;106(5):1466-1470. doi:10.1378/chest.106.5.1466
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Although recent studies have reported otherwise, previous conventional wisdom has held that one-half to two-thirds of pregnant women with tuberculosis are asymptomatic. If true, this has important implications for screening programs. Charts of all patients with culture-proven Mycobacterium tuberculosis in Rhode Island between 1987 and 1991 were reviewed. One-third of women aged 21 to 32 years with culture-proven tuberculosis were pregnant at time of diagnosis (7 pregnant; 15 nonpregnant). Pregnant patients with pulmonary conditions were more likely to be found through routine screening (p=0.008) and to be asymptomatic (p=0.008). In addition, pregnant women with pulmonary conditions were more likely to present with unilateral non-cavitary, smear-negative disease (p=0.02). If routine screening is not performed prenatally with radiographic follow-up of all infected individuals, most pregnant women will not have their conditions diagnosed and, therefore, will not be treated in time to prevent risk to the fetus, the newborn, and the obstetric ward.

Chest. 1994;106(5):1471-1475. doi:10.1378/chest.106.5.1471
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In a prospective study, we investigated whether human immunodeficiency virus (HIV) infection alters the clinical presentation in patients with tuberculous pleuritis. One hundred twelve of 118 patients who presented with pleural effusion suffered from tuberculosis (TB); 65 patients (58%) were HIV seropositive. Evidence of disseminated TB was found more often in HIV-positive than in HIV-negative patients (30.8% vs 10.6%, p<0.02). Dyspnea, fever, night sweat, fatigue, and diarrhea, severe tachypnea, hepatomegaly, splenomegaly, and lymphadenopathy were significantly more common in HIV-infected than in HIV-negative patients with TB. The same applied to a negative Mantoux reaction, lower hemoglobin, higher β2-microglobulin values, and in pleural fluid, lower albumin and higher γ-globulin levels. Among HIV-infected patients, PPD skin test anergy was significantly associated with relative low albumin and γ-globulin levels of pleural fluid. However, the radiographic features did not differ with respect to HIV status; they were predominantly those of primary pleuritis (78% in each group). We conclude that coexisting HIV infection affects clinical and laboratory features, but not the radiographic presentation of patients with TB pleuritis in Tanzania.

Chest. 1994;106(5):1476-1480. doi:10.1378/chest.106.5.1476
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To evaluate the accuracy of noninvasive estimates of VD/VT in clinical exercise testing, we compared measurements of standard VD/VT with estimates based either on end-tidal CO2 (VD/VTET) or a published estimate of arterial Pco2 (VD/VTest) at peak exercise in 68 patients. Using regression analysis, we identified highly significant differences (p<0.001) between each method and VD/VTstand across a broad range of observed VD/VT. Assuming a normal exercise VD/VT≤0.30, estimate methods were specific but were insensitive (50 percent for VD/VTET and 57 percent for VD/VTest) for identifying patients with abnormal gas exchange during exercise. Separate analysis of subgroups based on resting pulmonary function did not identify any group for which either method was acceptable. Our analysis showed that errors in estimating PaCO2, which are amplified by the Bohr equation when calculating VD/VT, are responsible for the inaccuracies of each noninvasive method. We conclude that noninvasive estimates of PaCO2 cannot replace measured arterial Pco2 for calculation of VD/VT during exercise.

Chest. 1994;106(5):1481-1486. doi:10.1378/chest.106.5.1481
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We measured eosinophilic cationic protein (ECP) concentrations in the circulation and bronchoalveolar lavage (BAL) fluids from patients with chronic eosinophilic pneumonia, patients with eosinophilic granuloma, and normal control subjects. Significantly increased ECP concentrations were found in the circulation of patients with chronic eosinophilic pneumonia and with eosinophilic granuloma compared with those found in control subjects. The ECP concentrations were well correlated to eosinophil counts in the circulation of patients with chronic eosinophilic pneumonia, while they were not in patients with eosinophilic granuloma. Chronic eosinophilic pneumonia patients had prominently increased ECP concentrations in BAL fluids compared with those found in control subjects, while eosinophilic granuloma patients did not. Those concentrations in chronic eosinophilic pneumonia patients were well correlated to eosinophil counts in the BAL fluid. Corticosteroid therapy remarkably decreased circulating ECP concentrations in three patients with chronic eosinophilic pneumonia, but it had no significant effects in two patients with eosinophilic granuloma. Measurement of ECP concentrations seems to be useful to evaluate the disease activity of chronic eosinophilic pneumonia.

Chest. 1994;106(5):1487-1492. doi:10.1378/chest.106.5.1487
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Study objective: Local nasal hyperthermia or inhalation of heated water vapor is often recommended as a home remedy for various rhinitis disorders such as the common cold and allergic rhinitis. Inhaled heated vapor treatments and simple saline solution nasal irrigation were investigated for their effect on inflammatory mediator production in nasal secretions.

Design: Three treatments were given for nasal irrigation: heated water particles (large particle water vapor) at 43°C, heated molecular water vapor (molecular water vapor) at 41°C, and simple saline solution nasal irrigation. Nasal washes were done before each treatment (baseline), immediately after treatments, and at 30 min, 2, 4, and 6 h. Histamine, prostaglandin D2, and leukotriene C4 (LTC4) concentrations were measured in nasal secretions and compared with baseline values.

Patients and participants: Thirty symptomatic patients with active perennial allergic rhinitis underwent three treatments at weekly intervals.

Measurements and results: Nasal histamine concentrations fell substantially with the nasal irrigation (p<0.0l immediately posttreatment and at 30 min; p<0.05 at 2, 4, and 6 h). Large particle vapor also reduced histamine concentrations for up to 4 h posttreatment compared with baseline values (p<0.05). Alternatively, molecular water vapor did not alter nasal histamine concentrations. Surprisingly, the three treatments did not alter prostaglandin D2 concentrations over the 6 h. Leukotriene C4 concentrations fell briefly after the large particle treatment but did not with the molecular water vapor. With saline solution irrigation, LTC4 concentrations in nasal secretions were lower than baseline at 30 min to 4 h after a treatment (p<0.05).

Conclusions: This study demonstrated the usefulness of large particle vapor treatment and saline solution irrigation in reducing inflammatory mediators in nasal secretions and indirectly supports the clinical efficacy of these treatments for chronic rhinitis.

Chest. 1994;106(5):1493-1498. doi:10.1378/chest.106.5.1493
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Objective: To evaluate the safety and effectiveness of antibiotics in reducing the infectious complications following closed tube thoracostomy for isolated chest trauma.

Design: Double-blind, randomized clinical trial.

Setting: Medical school affiliated large urban teaching hospital and trauma center.

Patients: One hundred nineteen of 159 patients over 18 years old presenting to the emergency department requiring closed tube thoracostomy for isolated chest injuries (113 penetrating, 6 blunt).

Intervention: Patients received either placebo or 1 g cefonicid daily intravenously started at chest tube insertion and stopped within 24 h of removal.

Measurements and results: The development of wound infections, pneumonia (CDC criteria), or empyema; the incidence of adverse events; length of hospitalization. One nonspecific infection was seen in the cefonicid group (1.6 percent) and six respiratory tract infections (10.7 percent) in the placebo group (three empyema, one empyema with pneumonia, two pneumonia) (p=0.0505; p=0.0094 [excluding nonspecific infection]). No significant differences with antibiotic use were seen in the duration of chest tube use (p=0.766), peak WBC counts (p=0.108), lower peak temperatures (p=0.063), or length of hospitalization (p=0.165). Patients who developed infectious complications averaged approximately 8 days longer hospitalization than those without (p<0.0001).

Conclusion: This study showed that patients receiving antibiotics had a significantly reduced rate of infection than did patients administered placebo. No significant adverse events were seen in either group.

Chest. 1994;106(5):1499-1507. doi:10.1378/chest.106.5.1499
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Background: Studies evaluating the dose of epinephrine required to optimize return of spontaneous circulation and survival after CPR have shown that doses greater than recommended by advanced cardiac life support (ACLS) improve coronary perfusion pressure and short-term resuscitation rates. Since survival has not improved, it is possible that higher doses of epinephrine may be physiologically detrimental in the postresuscitation period.

Objective: The object of this study is to measure the effect of the total cumulative dose of epinephrine given during ACLS on the hemodynamic, oxygen transport, and utilization variables in the postresuscitation period.

Design: A prospective nonrandomized control trial of inception cohorts.

Setting: A large urban emergency department and intensive care unit.

Patients: Forty-nine successfully resuscitated witnessed, normothermic, nontraumatic, out-of-hospital patients, who had suffered cardiac arrests.

Interventions: All patients were treated according to ACLS guidelines; however, the epinephrine dose (0.01 to 0.2 mg/kg or 1 to 14 mg) was selected at the clinician's discretion and given through central venous access every 3 to 5 min. Hemodynamic, oxygen transport, and utilization variables were measured on a return of spontaneous circulation, and at least every 30 min thereafter under a standardized postresuscitation protocol.

Main outcome measures: Hemodynamic, oxygen transport/utilization variables, and mortality in patients resuscitated from cardiac arrest. The total cumulative dose of epinephrine given during ACLS until a return of spontaneous circulation was recorded.

Results: A total cumulative epinephrine dose of 15 mg was found to best predict 24-h mortality. Of the 49 patients, 20 received less than 15 mg (group 1) and 29 received greater than 15 mg (group 2). Age, premorbid health status, sex, presenting rhythm, and duration of cardiac arrest were similar in both groups. The 24-h survival was 17 of 20 (85%) and 12 of 29 (41%) in group 1 and 2, respectively (p<0.002). Over the first 6 h of the postresuscitation period, both groups had similar mean arterial pressure (MAP), mixed venous oxygen saturation, and systemic oxygen extraction ratio (all p>0.1). Group 2, however, had a significantly lower cardiac index (CI), systemic oxygen consumption (VO2), and systemic oxygen delivery (Do2) (all p<0.01). Systemic vascular resistance index (SVRI), initial and 6-h lactic acid levels were significantly higher in group 2 (all p<0.03).

Conclusions: The administration of all doses of epinephrine during the resuscitation of out-of-hospital cardiac arrest is associated with impairment of Do2 and VO2 in the postresuscitation period. Both duration and severity of these impairments correlate with the total cumulative epinephrine dose given during the resuscitation. Thus, inadvertent catecholamine toxicity represents a further complicating factor in the production of postresuscitation disease. Diagnostic and therapeutic interventions addressed toward mitigating these potentially reversible adverse effects may impact morbidity and mortality in out-of-hospital cardiac arrests.

Chest. 1994;106(5):1508-1510. doi:10.1378/chest.106.5.1508
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Attempts to correctly reposition endotracheal tubes (ETTs) are not always successful in pediatric patients, even when chest radiographs (CXRs) are measured to determine the distance that the ETT deviates from the correct position. We determined the frequency of continued ETT malposition after repositioning in a pediatric intensive care unit (PICU). Forty children with malpositioned ETTs were identified during a 4-month period. After repositioning, ten (25 percent) continued to be malpositioned on the next CXR. Of 47 children with correctly positioned ETTs, only one ETT (2 percent) was found to be incorrectly positioned on the next routine CXR obtained 24 h later. The difference in frequency of ETT malposition between these two groups of children is significant (p<0.000l). The children were similar in weight and age. Despite repositioning based on measurements taken from a CXR, a large percentage of pediatric patients had continued ETT malposition. However, after radiographic documentation of correct position, we demonstrated that significant movement was uncommon. Routine confirmation of ETT position by CXRs should be considered after repositioning ETTs in pediatric patients.

Chest. 1994;106(5):1511-1516. doi:10.1378/chest.106.5.1511
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In 12 patients with severe adult respiratory distress syndrome (ARDS), pulmonary gas exchange and hemodynamics were evaluated before, during, and after a 2-h period of pressure-controlled mechanical ventilation with the patient in the prone position. Ventilation-perfusion relationships (VA/Q) were assessed by a multiple inert gas elimination technique. Pressure-controlled mechanical ventilation in the prone position resulted in an overall increase (p≤0.05) of arterial oxygenation after 120 min (98.4±50.3 to 146.2±94.9 mm Hg). Whereas eight patients revealed an improvement of PaO2 of more than 10 mm Hg after 30 min in the prone position (responders), four patients reacted to positional changes with a deterioration of arterial oxygenation (nonresponders). Data about the continuous distribution of ventilation-perfusion ratios revealed that in the responder group positioning caused a decrease of shunt perfusion of 11±5% and a concomitant increase of normal VA/Q by 12±4% after 30 min. There was no change demonstrable within low VA/Q areas. Returning the patient to the supine position reversed the improvement in gas exchange. The nonresponder group did not show any significant alteration in the distribution of VA/Q during the study. We concluded that improvement of oxygenation during pressure-controlled mechanical ventilation in the prone position is due to a shift of blood flow away from shunt regions, thus increasing areas with normal VA/Q. This redistribution of blood flow is most likely caused by a recruitment of previously ateletatic but nondiseased areas induced by altered gravitational forces.

Chest. 1994;106(5):1517-1523. doi:10.1378/chest.106.5.1517
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The acute respiratory distress syndrome (ARDS) is a disorder of diffuse lung injury secondary to a wide variety of clinical insults (eg, sepsis) and is manifested by impaired oxygenation, pulmonary edema, and decreased static and dynamic compliance. More recently, airflow resistance has been shown to be increased in humans with ARDS. We designed a prospective, randomized, placebo-controlled, crossover trial to determine the presence and reversibility of increased airflow resistance in ARDS. We studied eight mechanically ventilated patients with ARDS (criteria: PaO2 ≤70 mm Hg with FIO2 ≤0.4; diffuse bilateral infiltrates; and pulmonary artery wedge pressure ≤18 mm Hg). Each was intubated with a No. 8.0 orotracheal tube. We measured dynamic compliance (Cdyn), static compliance (Cstat), airflow resistance across the lungs (RL), shunt fraction (Qs/Qt on FIO2=1.0), minute ventilation (VE), PaO2/PAO2, and dead space to tidal volume ratio (VD/VT). Patients were blindly assigned to receive either metaproterenol (1 mL 0.5% in 3 mL saline solution) or saline solution (4 mL) aerosolized over 15 min 6 h apart and in random order so that patients served as their own controls. Metaproterenol significantly reduced RL, peak and plateau airway pressure, and increased Cdyn. Metaproterenol tended to increase PaO2/PAO2, but had no effect on pulmonary shunt or dead space ventilation. We conclude that the increase in airflow resistance of ARDS is substantially reversed by aerosolized metaproterenol without affecting dead space. These data suggest that abnormalities of RL are at least partially due to bronchospasm.

Chest. 1994;106(5):1524-1531. doi:10.1378/chest.106.5.1524
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Background: During severe sepsis, the existence of a pathologic oxygen supply dependency remains controversial.

Study objective: To evaluate the relationship between oxygen delivery (DO2) and oxygen consumption (VO2) during severe sepsis and to compare, in this respect, survivors and nonsurvivors and patients with normal or increased concentration of plasma lactate.

Study design: Cohort analytic study.

Setting: Three European ICUs in university hospitals.

Patients: Seventeen mechanically ventilated patients with severe sepsis (six with high blood lactate levels) studied within the first day of diagnosis.

Interventions and measurements: Pulmonary elimination of carbon dioxide, or carbon dioxide production (VCO2) and VO2 were measured by indirect calorimetry before and after two interventions designed to increase DO2 (calculated from the Fick equation): inflation of a military antishock trouser (MAST) and infusion of dobutamine.

Results: During MAST inflation, DO2 increased by 19% in patients with a normal concentration of plasma lactate (p <0.01), but remained unchanged in patients with high lactate levels. During dobutamine infusion, DO2 increased in both groups by 16% (p <0.01) and 20% (p <0.05), respectively. In both groups, we found that the VO2 and VCO2 were not affected by either the MAST or the dobutamine-induced increase in DO2. There was no difference between survivors and nonsurvivors.

Conclusion: There was no evidence of a pathologic oxygen supply dependency in patients with severe sepsis, even in those who had an elevated concentration of plasma lactate and in those who ultimately died. These results do not favor the conclusion that maximizing DO2 is a primary therapeutic objective in such patients.

Chest. 1994;106(5):1558-1562. doi:10.1378/chest.106.5.1558
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We utilized low-dose intraembolic urokinase (UK) infusions in a canine model of experimental pulmonary embolism (PE) and compared the arteriographic extent of thrombolysis with three other treatment regimens. Group 1 animals (n=16) received the intraembolic UK infused directly into the PE offering the mechanical effect of the infusion combined with pharmacologic thrombolysis. In the group 2 animals (n=5), UK was delivered via a guide catheter placed proximal to the clot. Group 3 animals (n=6) were treated with a direct intraembolic saline solution infusion. Group 4 (n=7) received only intravenous heparin. The arteriographic extent of thrombolysis was graded 1+ to 3+. The extent of thrombolysis was 2.88+ in the group 1 animals and was significantly greater than in groups 2, 3, or 4 (p=0.003, 0.0005, and 0.0001, respectively). Fibrinogen levels did not significantly decrease with intraembolic treatment (p=0.07). Delivery of UK directly into emboli in an experimental canine PE model appears to elicit a combined mechanical and pharmacologic effect resulting in extensive thrombolysis.

Chest. 1994;106(5):1563-1569. doi:10.1378/chest.106.5.1563
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Objectives: The present study was designed to evaluate if continuous positive airway pressure (CPAP) augments the effect of nitric oxide (NO) inhalation on matching between ventilation and perfusion (VA/Q) during acute lung injury.

Design: Prospective, randomized study.

Setting: A research laboratory at a university medical center.

Subjects: Ten anesthetized mongrel dogs with oleic acid-induced lung injury.

Interventions: Zero or 40 parts per million of NO in the inspiratory gas, with and without 10 cm H2O CPAP in random order.

Measurements and main results: Gas exchange was assessed by estimating the VA/Q distributions using the multiple inert gas elimination technique. Application of CPAP decreased blood flow to shunt units by 26±2 percent (mean±SD) and increased the fraction of cardiac output to normal VA/Q units (VA/Q ratio of 0.1 to 10) by 26±2 percent (p<0.05). Inhalation of NO during CPAP accounted for a further 10±2 percent decrease in the blood flow to shunt units and an 8±2 percent increase in the fraction of the cardiac output to normal VA/Q units (p<0.05). Inhalation of NO alone had no significant effect on the VA/Q distributions. Inhalation of NO decreased mean transmural pulmonary artery pressure (Ppatm) both without (Ppatm from 30±2 to 23 ±2 mm Hg; PVR from 323±44 to 228±43 dynes·s ·cm−5; p<0.05) and with CPAP (Ppatm from 25±2 to 20±2 mm Hg; PVR from 255±30 to 173±31 dynes·s·cm−5; p<0.05).

Conclusions: Although pulmonary vascular resistance can be lowered with NO inhalation alone, recruitment of gas exchange units with CPAP is necessary to produce a beneficial effect of NO inhalation on VA/Q matching and oxygenation. When recruitment of gas exchange units with CPAP brings gaseous NO in contact with enough pulmonary blood vessels, NO-induced vasodilation will augment VA/Q matching by a steal mechanism.

Chest. 1994;106(5):1570-1574. doi:10.1378/chest.106.5.1570
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Peripheral undefined pulmonary nodules have become a favorable indication for the videoendoscopic approach in thoracic surgery. In our latest experience, we also successfully applied this technique in centrally located lesions of the lung. In reviewing our first 29 cases, we looked for preoperative features of videoendoscopic resectability. From March 1992 to September 1993, 29 patients underwent videothoracoscopy for undefined pulmonary nodules at our hospital. This group consisted of 17 men and 12 women (aged 25 to 77 years). Pulmonary nodules of this group of patients were defined as centrally located when close attachement to the segmental or subsegmental bronchiopulmonary unit was observed and/or the distance to the visceral pleura exceeded 10 mm. Nodules that did not meet any of these criteria were hence interpreted as peripheral lesions. In the course of 21 excisions of peripheral lesions, we had to convert to open thoracotomy only once for anatomic reasons. When using the video-assisted thoracic surgery (VATS) approach for centrally located lesions, we succeeded in removing four of six. We failed only if the lesions were located in the upper lobe but could easily apply the technique for centrally located lesions in the lower lobes. In conclusion, undefined peripheral pulmonary nodules are a favorite indication for VATS. Centrally located pulmonary nodules of the lower lobes can often be managed easily by VATS, especially if the interlobar fissure extends to the stem of the pulmonary artery. Centrally located pulmonary nodules in the upper lobes may not be suitable for the VATS approach due to the special anatomic arrangement of the upper lobe segmental arteries and bronchioles.

Chest. 1994;106(5):1575-1576. doi:10.1378/chest.106.5.1575
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Chest. 1994;106(5):1577-1579. doi:10.1378/chest.106.5.1577
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Chest. 1994;106(5):1580-1582. doi:10.1378/chest.106.5.1580
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Severe tracheomalacia secondary to extrinsic vascular compression following a switch operation for transposition is reported. Two attempts at surgical correction failed but successful treatment has been achieved by implantation of two endobronchial Gianturco Z stents. Nonabsorbable stenting in children should be used only in severe obstruction as a last resource, but this technique proved to be feasible in a child weighing 6.2 kg.

Chest. 1994;106(5):1582-1586. doi:10.1378/chest.106.5.1582
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Six patients with the acquired immunodeficiency syndrome (AIDS) who suffered eight spontaneous pneumothoraces between January 1990 and January 1993 underwent videothoracoscopy. The predominant macroscopic findings, found in four patients on five occasions, were white-yellow nodules dispersed throughout the lung surface. In addition, in one patient, these lesions were associated with multiple small apical bullae and, in another, a large reddish nodule with several smaller white satellite nodules was noted on the parietal pleura. Methenamine silver stain of biopsy samples of both the visceral and parietal nodules in these patients showed the presence of Pneumocystis carinii. May-Grunwald-Giemsa stain of brushing samples of visceral lesions revealed P-carinii in two patients. In one of these patients, previously performed bronchoalveolar lavage (BAL) had not yielded P-carinii. On two occasions, the thoracoscopic findings were unremarkable, although in one of these patients, computed tomography (CT) had shown a large thick-walled cyst near the left hilum and BAL revealed P-carinii. Talc poudrage through the thoracoscopic cannula followed by chest tube drainage was performed in all patients and was successful in treating three of five with proved P-carinii pneumonia-related pneumothorax. The etiology of pneumothorax in AIDS and the diagnostic and therapeutic utility of videothoracoscopy in these patients are discussed.

Chest. 1994;106(5):1586-1589. doi:10.1378/chest.106.5.1586
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Two adult patients with cor triatriatum, which was shown by echocardiography and magnetic resonance imaging (MRI) using both spin-echo and cine-MR techniques, are presented. Spin-echo MRI clearly demonstrated an anatomical relationship between the membrance and pulmonary veins or left atrial appendage, which was not clear on transthoracic echocardiography. In addition, cine-MRI depicted abnormal flow through the fenestration of the anomalous membrane (case 1 and 2) and shunted flow through the associated atrial septal defect (case 2).

Chest. 1994;106(5):1589-1590. doi:10.1378/chest.106.5.1589
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We report two cases of tracheobronchomegaly with differing presentations. The radiologic, fiberoptic bronchoscopic, and clinical findings as well as management of this rare condition are reviewed.

Chest. 1994;106(5):1590-1594. doi:10.1378/chest.106.5.1590
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We describe a 56-year-old man with the new onset of hemoptysis, increasing in frequency and magnitude, initially diagnosed and treated as pulmonary embolism. Bronchoscopy, computed tomography, and thoracic aortography were performed twice before the diagnosis was made. Thirteen years previously, the patient underwent thoracic aortic interposition graft placement for aortic laceration as a result of a motor vehicle accident. The second aortogram demonstrated a small pseudoaneurysm at the expected proximal graft suture line. Aortobronchial fistula, a rare cause of hemoptysis, was diagnosed. The patient underwent successful resection of the graft and placement of a new dacron interposition graft. All cultures, including blood, sputum, and operative specimen cultures, were negative. The patient is alive and well 1 year following surgery.

Chest. 1994;106(5):1595-1596. doi:10.1378/chest.106.5.1595
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We describe the clinical and pathologic findings of a patient with mixed blastoma-germ cell malignancy primary in the lung. Serum alpha-fetoprotein levels were elevated at presentation, and normalized with anti-germ cell chemotherapy. The resection specimen contained massively necrotic germ cell tumor with viable mature neural tissue, plus viable biphasic blastoma with stromal bone and skeletal muscle differentiation. It is not clear whether the germ cell component represents unusual differentiation of a somatic cell line or whether the blastoma component represents an unusual pattern of teratomatous differentiation.

Topics: lung , germ cell tumor
Chest. 1994;106(5):1597-1599. doi:10.1378/chest.106.5.1597
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We report the first case of recurrent sarcoidosis manifested by clinical symptoms, radiographic abnormalities, and pathologic changes in a patient following sequential double allogeneic lung transplantation. A 40-year-old male patient underwent bilateral allogeneic lung transplantation for end-stage pulmonary sarcoidosis. Thirteen months posttransplantation, he developed fatigue, shortness of breath, and bilateral upper lobe pulmonary infiltrates. Transbronchial biopsy specimens revealed noncaseating granulomata. The patient's symptoms and radiographic abnormalities resolved with an increased dose of oral prednisone.

Chest. 1994;106(5):1599-1601. doi:10.1378/chest.106.5.1599
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A young woman presented with cough, dyspnea on exertion, and weight loss. A chest roentgenogram revealed collapse of the left lung. On doing fiberoptic Bronchoscopy, a growth was found in the left main bronchus. Cytologic examination and sections from cell block revealed that it was a metastatic growth from a giant cell tumor (GCT) of the bone. To the best of our knowledge, this is the first report of endobronchial metastasis from a GCT of the bone.

Chest. 1994;106(5):1601-1603. doi:10.1378/chest.106.5.1601
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A 35-year-old man had a history of recurrent syncope for more than a decade. During a witnessed episode, an ambulatory electrocardiographic recording showed ventricular flutter/fibrillation that lasted for 2½ minutes and terminated spontaneously without adverse neurologic sequelae. No structural heart disease and no possible etiologic factor for the ventricular tachyarrhythmia was found. The patient received an automatic implantable cardioverter defibrillator. Review of the literature suggests that the automatic implantable cardioverter defibrillator is a valid option in idiopathic ventricular fibrillation in young individuals to avoid the potential risk of recurrent cardiac arrest.

Chest. 1994;106(5):1603-1607. doi:10.1378/chest.106.5.1603
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A patient with cardiac sarcoidosis proved by biopsy specimen and no history of sudden death or clinical sustained ventricular tachycardia prophylactically received an implantable cardioverter defibrillator (ICD) that later reversed an episode of near syncope. The patient was supported with the ICD until heart transplantation. The physiology and treatment of arrhythmias associated with cardiac sarcoidosis is described. Consideration for use of the ICD in asymptomatic patients and as bridge therapy until heart transplantation is discussed.

Chest. 1994;106(5):1607-1609. doi:10.1378/chest.106.5.1607
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Inferior vena cava thrombosis is a major complication after filter placement. The thrombus can propagate through the filter leading to a high risk of pulmonary embolism. We report such a case in a patient with a Günther filter, successfully treated with urokinase, and we discuss the efficacy and the safety of thrombolytic therapy in such situations.

Chest. 1994;106(5):1609-1611. doi:10.1378/chest.106.5.1609
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Platypnea, or dyspnea in the upright position relieved by recumbency, is most commonly associated with cardiac or pulmonary disease. We describe a patient who presented to the emergency department with platypnea due to a laryngeal carcinoma. A tumor of the upper airway should be considered in any patient presenting with platypnea.

Chest. 1994;106(5):1611-1615. doi:10.1378/chest.106.5.1611
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Localized pleural mesotheliomas are rare tumors that have a variety of clinical presentations, from an asymptomatic solitary nodule to a massive, highly symptomatic neoplasm filling most of the pleural cavity. Two cases are reported which show the clinical spectrum of the more common benign variant. The clinical differentiation between the benign tumor as well as the less frequent malignant neoplasms of localized mesotheliomas has been disappointing. Complete surgical resection is the preferred treatment for both types and is usually curative with the benign mesothelioma.

Topics: mesothelioma , pleura
Chest. 1994;106(5):1615-1617. doi:10.1378/chest.106.5.1615
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Pleural effusion represents an unusual but significant manifestation of actinomycosis, as illustrated in this case presentation. The diagnosis was made after bronchoscopy and examination of bronchoalveolar fluid and culture. No parenchymal abnormality was noted on the chest film.

Chest. 1994;106(5):1617-1619. doi:10.1378/chest.106.5.1617
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Delayed-onset pericardial effusion following coronary artery bypass grafts can give rise to significant morbidity in its presentation and in its management by traditional surgical techniques. A video-assisted thoracoscopic technique to create a pericardial window, with the advantage of a minimally invasive approach combined with excellent visualization in such a patient is described.

Chest. 1994;106(5):1619-1622. doi:10.1378/chest.106.5.1619
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Takayasu's arteritis is an uncommon condition affecting predominantly young women. Because the disorder affects women in childbearing age, it may be recognized the first time during pregnancy. Various cardiovascular events may occur in the perinatal period. We describe a patient with Takayasu's arteritis who presented with massive hemoptysis. To our knowledge, this manifestation has not been documented previously.

Chest. 1994;106(5):1622-1624. doi:10.1378/chest.106.5.1622
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We report a case of 63-year-old man who developed massive pulmonary hemorrhage following intravenous streptokinase for acute myocardial infarction. Pulmonary hemorrhage was diagnosed by the triad of hemoptysis, a drop in hematocrit, and a new unilateral infiltrate on chest radiograph. This diagnosis was confirmed by autopsy findings. Pulmonary hemorrhage has rarely been reported following thrombolytic therapy. We believe that pulmonary hemorrhage is a rare but a potentially life-threatening complication of thrombolytic therapy and should be considered in the differential diagnosis of pulmonary infiltrates or falling hemoglobin after thrombolytic therapy for acute myocardial infarction with no obvious site of bleeding.

Chest. 1994;106(5):1624-1626. doi:10.1378/chest.106.5.1624
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A 68-year-old man developed fever, cough, and dyspnea after intravesical bacillus Calmette-Guerin (BCG). Chest radiograph revealed diffuse reticulonodular infiltrates with caseating granulomas on transbronchial biopsy specimen. Cultures were negative and the patient's condition improved with corticosteroids. The mechanism for BCG-induced granulomatous inflammation is poorly understood. Optimal therapy includes corticosteroids.

Chest. 1994;106(5):1626-1628. doi:10.1378/chest.106.5.1626
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We describe a case of unsuspected infrahepatic interruption of the inferior vena cava with hemiazygos continuation in a 67-year-old man presenting with chest pain and evidence of mitral regurgitation. He had no persistent superior vena cava, with the hemiazygos draining directly into the right superior vena cava. Polysplenia and severe mitral prolapse were also present: the latter may represent more than an incidental finding in this condition. This malformation may deserve consideration in adults undergoing femoral right heart catheterization. Chest radiographic studies are the basic clue to the diagnosis.

Reviews

Chest. 1994;106(5):1538-1550. doi:10.1378/chest.106.5.1538
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Topics: lung cancer , chest ct
Chest. 1994;106(5):1551-1557. doi:10.1378/chest.106.5.1551
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Communications to the Editor

Chest. 1994;106(5):1629. doi:10.1378/chest.106.5.1629
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Chest. 1994;106(5):1629-1630. doi:10.1378/chest.106.5.1629
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Chest. 1994;106(5):1630-1631. doi:10.1378/chest.106.5.1630
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Chest. 1994;106(5):1631-1632. doi:10.1378/chest.106.5.1631
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Chest. 1994;106(5):1632. doi:10.1378/chest.106.5.1632
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Chest. 1994;106(5):1632-1633. doi:10.1378/chest.106.5.1632
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Chest. 1994;106(5):1633-1634. doi:10.1378/chest.106.5.1633
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Chest. 1994;106(5):1634. doi:10.1378/chest.106.5.1634
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Chest. 1994;106(5):1634-1636. doi:10.1378/chest.106.5.1634
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Chest. 1994;106(5):1636. doi:10.1378/chest.106.5.1636
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Chest. 1994;106(5):1636-1637. doi:10.1378/chest.106.5.1636
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Chest. 1994;106(5):1637. doi:10.1378/chest.106.5.1637
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Chest. 1994;106(5):1637. doi:10.1378/chest.106.5.1637b
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Chest. 1994;106(5):1637-1638. doi:10.1378/chest.106.5.1637
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Chest. 1994;106(5):1638. doi:10.1378/chest.106.5.1638
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Chest. 1994;106(5):1638-1639. doi:10.1378/chest.106.5.1638
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Chest. 1994;106(5):1639. doi:10.1378/chest.106.5.1639
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Chest. 1994;106(5):1639-1640. doi:10.1378/chest.106.5.1639b
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Chest. 1994;106(5):1640. doi:10.1378/chest.106.5.1640
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  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543