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Pregnant Patient With Progressive Hypoxemic Respiratory FailurePregnancy and Hypoxemic Respiratory Failure FREE TO VIEW

Dena M. Daglian, MD; Paru Patrawalla, MD
Author and Funding Information

From New York University School of Medicine, New York, NY.

CORRESPONDENCE TO: Dena M. Daglian, MD, Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, Bellevue Hospital Center, 462 First Ave, NBV 7N24, New York, NY 10016; e-mail: Dena.Daglian@nyumc.org


Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2015;147(6):e205-e207. doi:10.1378/chest.14-0967
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Published online

A 39-year-old woman, gravida 4, para 0, at 10 weeks’ gestation was admitted to the obstetrics ward for fever, dysuria, back pain, and a dry cough that she had for 3 weeks. Medical history was significant for pituitary microadenoma, nephrolithiasis status after lithotripsy, and three prior spontaneous abortions. She worked in a daycare center, was married, and denied a history of excessive alcohol use, cigarette smoking, or illicit drugs. Because of her history of nephrolithiasis, the patient was started on ceftriaxone for presumed urinary tract infection. At the time of admission, she was noted to have a temperature of 38.2°C, BP of 112/61 mm Hg, heart rate of 111 beats/min, and an oxygen saturation breathing ambient air of 100%. Admission chest radiograph was not done to prevent radiation exposure to the fetus. Laboratory results were notable for a WBC count of 8 and an unremarkable urinalysis.

Approximately 24 h after admission, the obstetrics resident was called to reevaluate the patient for worsening cough and abdominal pain. On examination, the patient had a temperature of 39.5°C, BP of 102/62 mm Hg, heart rate of 116 beats/min, and an oxygen saturation of 86% on room air. The patient was found lying in bed in mild respiratory distress. She had faint crackles over her right lower chest, and her abdomen was soft and nontender. A chest radiograph was performed, which was interpreted as normal by the resident. Given the unremarkable chest radiograph and risk factors for VTE, including pregnancy and a history of multiple spontaneous abortions, she was empirically started on a heparin drip for presumed pulmonary embolism. The patient had progressive hypoxic respiratory failure and was transferred to the medical ICU for further workup and management. In the medical ICU, the patient was noted to be tachypneic and in significant respiratory distress, with an oxygen saturation of 96% on a 100% non-rebreather. She was placed on noninvasive ventilation to aid in her work of breathing and after a brief history and physical examination, goal-directed ultrasonography was performed. See case patient Videos 1 to 6.

Case Presentation

Running Time: 01:23

What is the likely cause of this patient’s hypoxemic respiratory failure?
Answer: Diffuse alveolar infiltrates likely due to a bacterial pneumonia complicated by ARDS (Videos 7-12)

Discussion

Running Time: 07:39

Ultrasound examination of this patient’s lungs (Video 7 is representative of left and right anterior chest) showed a bilateral predominant B-line pattern with lung sliding anteriorly. Lung sliding represents the visceral and parietal pleura sliding against one another and appears as the shimmering white line at the top of the ultrasound image. Lung sliding indicates that there is no pneumothorax in the area being examined. B lines are comet-tail projections originating from the pleural surface and extending to the edge of the screen. They indicate increased fluid or density in the interstitium or alveolar spaces and can be seen diffusely in cardiogenic and intermittently in noncardiogenic pulmonary edema. Also notable is the absence of A lines. A lines are equidistant and parallel to the pleural surface. A lines, along with sliding lung, represent a normal aeration pattern.1 Further examination of the left lateral lung field seen in Video 8 revealed diffuse hyperechoic areas, known as air bronchograms, through a portion of consolidated lung.2 This pattern of alveolar consolidation is also known as “hepatization of lung” because its appearance is similar to the liver. The air bronchograms are noted to be dynamic and moving with respiration; this pattern is commonly seen with pneumonia. This is in contrast to air bronchograms, which are static and can represent atelectasis.3,4 Examination of the right lower lobe revealed a similar ultrasound appearance with the addition of sub-B lines originating from areas of consolidation or compressed lung.5,6 Identification of a hypoechoic space surrounded by the chest wall, hemidiaphragm, and atelectatic or consolidated lung indicates the presence of pleural effusions bilaterally. In this case, both effusions were small, and thoracentesis was not indicated.

The parasternal long-axis view of the heart in Video 10 revealed normal size and function of the left ventricle. There was no obvious mitral valve pathology, and there was a suboptimal view of the aortic valve. A limitation of goal-directed echocardiography is often the unstable nature of the patient, which limits the views that can be obtained, in this case a suboptimal view of the aortic valve. In Video 11, the subcostal four-chamber view, the right ventricle was not dilated or hypodynamic. It confirmed good left ventricular and right ventricular function, making obstructive shock caused by a pulmonary embolism very unlikely. There are hypoechoic areas: one above the right ventricle that may represent pericardial fluid and another anteriorly representative of ascites. The apical four-chamber and parasternal short-axis views were not obtained because of the patient’s body habitus and quickly deteriorating clinical status.

Examination of the inferior vena cava in Video 12 showed respiratory variation, which is difficult to interpret in a spontaneously breathing patient. This observation makes an obstructive process such as cardiac tamponade or massive pulmonary embolism unlikely, because the inferior vena cava would be distended and not variable in either case. In addition, ultrasound of the lower extremities was negative for a DVT. Kory et al7 showed that critical care physicians, after only a short period of hands-on training, are capable of performing bedside compression ultrasound DVT studies with an accuracy similar to that of ultrasound technicians. A major advantage of the critical care physician possessing this skill is that a time delay in the diagnosis and treatment of life-threatening DVTs can be avoided.

This patient developed fever and severe hypoxemia with bilateral alveolar consolidations which most likely represented pneumonia/ARDS. Pulmonary embolism was unlikely as a diagnosis given the findings on examination of the lung, the heart, and the deep veins of the lower extremities.8 The anterior B-line pattern with dependent areas of alveolar consolidation, pleural effusions, and irregular pleural surface is more commonly seen in noncardiogenic pulmonary edema such as multifocal pneumonia/ARDS, as described by Copetti et al.9 Cardiogenic pulmonary edema was felt to be unlikely given her normal left ventricular function and the nonhomogeneous distribution of B lines with lung consolidation pattern throughout both lungs. Therefore, she was ultimately diagnosed and treated for pneumonia complicated by ARDS.

The heparin drip was stopped and broad-spectrum antibiotics were administered. Because of worsening hypoxic respiratory failure and an increased work of breathing, the patient was intubated and started on lung protective ventilation. Four days later, she was extubated successfully. She was discharged to home on hospital day 10 with a viable fetus and has since been following up as an outpatient with her obstetrician.

Lichtenstein et al2 have shown that lung ultrasound is better than standard chest radiographs at detecting abnormalities such as pleural effusions and alveolar consolidation. Indeed, in this patient, the relatively normal initial chest radiograph led to an incorrect diagnosis. The focused ultrasound examination of the patient indicated to the team that the reason for her hypoxemic respiratory failure was pneumonia and ARDS rather than a pulmonary embolism. A repeat chest radiograph confirmed these ultrasound findings.

Lichtenstein and Mezière8 have also reported on the bedside lung ultrasound in emergency protocol for the rapid ultrasound diagnosis of respiratory failure and have developed a standardized approach to examine a patient in respiratory distress that can be completed within 3 min. Using this protocol in their assessment of 260 patients, they were able to identify with upward of 95% specificity and 81% sensitivity the cause of respiratory distress. This protocol highlights how ultrasound can aid the critical care physician in making quick and accurate diagnoses. Additional advantages are that the patient does not need to be moved from the ICU for tests such as CT scans.

In addition, because ultrasonography is used at the bedside, it has the advantage of being available to continually monitor and reassess a patient’s progress throughout an ICU admission. In this patient, the presence of a bilateral B-line pattern with posterolateral alveolar and/or pleural syndrome, as described by Lichtenstein and Mezière,8 was highly indicative of a pneumonia and/or ARDS causing respiratory failure. In addition, Koenig et al10 showed that point-of-care ultrasound has the potential to reduce unnecessary CT pulmonary angiograms by suggesting an alternate diagnosis to pulmonary embolism. More importantly in this patient, the timely administration of broad-spectrum antibiotics was dependent on an early diagnosis.

Lastly, for this pregnant patient, avoidance of unnecessary radiation exposure to the fetus was an important concern. Ultrasound examinations allow for an early diagnosis of respiratory failure and can be used for continued monitoring without the need for radiation exposure.

  • 1. ARDS develops rapidly and may be seen on lung ultrasound prior to chest radiograph abnormalities.

  • 2. Point-of-care ultrasound may prevent an unnecessary CT pulmonary angiogram by suggesting an alternate diagnosis in hypoxemic respiratory failure.

  • 3. Lung ultrasound may replace a chest radiograph in the diagnosis and management of pregnant patients with acute respiratory failure and thus reduce radiation exposure to the fetus.

Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Other contributions: CHEST worked with the authors to ensure that the Journal policies on patient consent to report information were met.

Additional information: To analyze this case with the videos, see the online version of this article.

Koenig SJ, Narasimhan M, Mayo PH. Thoracic ultrasonography for the pulmonary specialist. Chest. 2011;140(5):1332-1341. [CrossRef] [PubMed]
 
Lichtenstein D, Goldstein I, Mourgeon E, Cluzel P, Grenier P, Rouby JJ. Comparative diagnostic performances of auscultation, chest radiography, and lung ultrasonography in acute respiratory distress syndrome. Anesthesiology. 2004;100(1):9-15. [CrossRef] [PubMed]
 
Lichtenstein D, Mezière G, Seitz J. The dynamic air bronchogram. A lung ultrasound sign of alveolar consolidation ruling out atelectasis. Chest. 2009;135(6):1421-1425. [CrossRef] [PubMed]
 
Bolliger CT, Herth FJF, Mayo PH, Miyazawa T, Beamis JF., eds. Clinical Chest Ultrasound: From the ICU to the Bronchoscopy Suite. Prog Respir Res.Vol 37. Basel, Switzerland: Karger; 2009:60-68.
 
Lichtenstein DA. Whole Body Ultrasonography in the Critically Ill. Berlin Heidelberg, Germany: Springer-Verlag; 2010.
 
Corradi F, Brusasco C, Pelosi P. Chest ultrasound in acute respiratory distress syndrome. Curr Opin Crit Care. 2014;20(1):98-103. [CrossRef] [PubMed]
 
Kory PD, Pellecchia CM, Shiloh AL, Mayo PH, DiBello C, Koenig S. Accuracy of ultrasonography performed by critical care physicians for the diagnosis of DVT. Chest. 2011;139(3):538-542. [CrossRef] [PubMed]
 
Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008;134(1):117-125. [CrossRef] [PubMed]
 
Copetti R, Soldati G, Copetti P. Chest sonography: a useful tool to differentiate acute cardiogenic pulmonary edema from acute respiratory distress syndrome. Cardiovasc Ultrasound. 2008;6:16. [CrossRef] [PubMed]
 
Koenig S, Chandra S, Alaverdian A, Dibello C, Mayo PH, Narasimhan M. Ultrasound assessment of pulmonary embolism in patients receiving CT pulmonary angiography. Chest. 2014;145(4):818-823. [CrossRef] [PubMed]
 

Figures

Tables

Case Presentation

Running Time: 01:23

Discussion

Running Time: 07:39

References

Koenig SJ, Narasimhan M, Mayo PH. Thoracic ultrasonography for the pulmonary specialist. Chest. 2011;140(5):1332-1341. [CrossRef] [PubMed]
 
Lichtenstein D, Goldstein I, Mourgeon E, Cluzel P, Grenier P, Rouby JJ. Comparative diagnostic performances of auscultation, chest radiography, and lung ultrasonography in acute respiratory distress syndrome. Anesthesiology. 2004;100(1):9-15. [CrossRef] [PubMed]
 
Lichtenstein D, Mezière G, Seitz J. The dynamic air bronchogram. A lung ultrasound sign of alveolar consolidation ruling out atelectasis. Chest. 2009;135(6):1421-1425. [CrossRef] [PubMed]
 
Bolliger CT, Herth FJF, Mayo PH, Miyazawa T, Beamis JF., eds. Clinical Chest Ultrasound: From the ICU to the Bronchoscopy Suite. Prog Respir Res.Vol 37. Basel, Switzerland: Karger; 2009:60-68.
 
Lichtenstein DA. Whole Body Ultrasonography in the Critically Ill. Berlin Heidelberg, Germany: Springer-Verlag; 2010.
 
Corradi F, Brusasco C, Pelosi P. Chest ultrasound in acute respiratory distress syndrome. Curr Opin Crit Care. 2014;20(1):98-103. [CrossRef] [PubMed]
 
Kory PD, Pellecchia CM, Shiloh AL, Mayo PH, DiBello C, Koenig S. Accuracy of ultrasonography performed by critical care physicians for the diagnosis of DVT. Chest. 2011;139(3):538-542. [CrossRef] [PubMed]
 
Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008;134(1):117-125. [CrossRef] [PubMed]
 
Copetti R, Soldati G, Copetti P. Chest sonography: a useful tool to differentiate acute cardiogenic pulmonary edema from acute respiratory distress syndrome. Cardiovasc Ultrasound. 2008;6:16. [CrossRef] [PubMed]
 
Koenig S, Chandra S, Alaverdian A, Dibello C, Mayo PH, Narasimhan M. Ultrasound assessment of pulmonary embolism in patients receiving CT pulmonary angiography. Chest. 2014;145(4):818-823. [CrossRef] [PubMed]
 
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