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Sudden Hypotension in a Medical PatientSudden Hypotension in a Medical Patient FREE TO VIEW

Scott J. Millington, MD; Robert T. Arntfield, MD, FCCP
Author and Funding Information

From the Department of Critical Care Medicine (Dr Millington), The Ottawa Hospital/University of Ottawa, Ottawa; and Division of Critical Care Medicine (Dr Arntfield), University of Western Ontario, London, ON, Canada.

CORRESPONDENCE TO: Scott J. Millington, MD, Department of Critical Care Medicine, The Ottawa Hospital, 501 Smyth Rd, Ottawa, ON, K1H 8L6, Canada; e-mail: smillington@toh.on.ca


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


Chest. 2014;146(3):e78-e80. doi:10.1378/chest.13-2977
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Published online

A woman in her 80s with hypertension and dyslipidemia was seen in the ED complaining of progressive dyspnea for 3 days. She was found to be tachypneic and hypoxemic and was admitted to the internal medicine service with a provisional diagnosis of heart failure. A thoracic CT scan revealed small bilateral pleural effusions, a small pericardial effusion, and no evidence of pulmonary embolism (PE). She was treated with diuretics and afterload reduction.

On hospital day 5, the patient complained of suddenly feeling generally unwell and was found to be hypotensive (systolic BP, 70 mm Hg). Her heart rate, respiratory rate, temperature, and oxygen saturation levels were normal. On further history taking, she admitted to a sensation of chest heaviness with no other features of typical angina. Her ECG revealed ST elevations, which were diffuse but most prominent in the lateral leads (V3-V6). Her physical examination was noncontributory. The hospital’s Rapid Assessment of Critical Events (RACE) team was called, and the patient was treated with acetylsalicylic acid po and a bolus of IV normal saline. Upon arrival, the RACE team performed a point-of-care ultrasound examination using a portable device (Videos 1-4).

Videos 1-4

Point-of-care ultrasound using portable device.

Based on the interpretation of these videos and the patient’s clinical history, what is the likely explanation for the patient’s hypotension?
Answer: Pericardial tamponade

Discussion Video

Discussion Video

Given her subacute presentation, the accumulation of pericardial fluid was likely slow, with diuretic therapy aggravating tamponade physiology by reducing cardiac preload and, thus, permitting the elevated pericardial pressure to exceed right-sided filling pressures. The ECG changes are consistent with pericardial inflammation. Therapy with IV crystalloids resulted in a significant improvement in the patient’s hemodynamic state. The dilated ascending aorta raised the potential of an aortic dissection, and, thus, a thoracic CT scan was performed followed by a transesophageal examination in the operating room. A type A aortic dissection was diagnosed and repaired. The Discussion Video presents further explanation.

Video 1-7

Ultrasound used to diagnose a type A aortic dissection

Video 1 is a parasternal long-axis view demonstrating a moderate-sized circumferential pericardial effusion. The maximum diameter in diastole was 18 mm adjacent to the right ventricle. The root of the ascending aorta (AA) appears dilated, although it is not well seen. Subtle diastolic collapse of the right ventricular (RV) free wall is present.

Video 2 shows a parasternal short-axis view that again demonstrates the pericardial effusion. The right ventricle appears dilated, but the dilation is not severe and the interventricular septum is normal in shape. Left ventricular function is normal, with no segmental wall motion abnormalities.

Video 3 is a subcostal view of the inferior vena cava (IVC), which is dilated (maximum diameter, 25 mm). Upon spontaneous inspiration, the IVC marginally decreases in size, suggesting elevated right-sided filling pressures (consistent with tamponade physiology).

Video 4 shows a second parasternal long-axis view, this time from a follow-up echocardiogram done urgently in the coronary care unit. The view has been shifted to focus on the AA, which is now clearly seen to be markedly dilated. A linear hyperechoic structure is noted within the lumen of the AA, which is suspicious for a dissection flap.

Video 5 shows a parasternal long-axis view from a different patient with similar pathology, where the RV free wall collapse in diastole is more prominent. The examination was performed prior to fluid resuscitation.

Video 6 is a midesophageal view of the AA taken during a transesophageal examination in the cardiac operating room. The previously noted linear hyperechoic structure is again seen in the lumen of the proximal AA. Color Doppler echocardiography of the area demonstrates that blood entering the AA is coming into contact with the suspected dissection flap but not passing through it. This is a helpful finding to ensure that the flap is not a mimicking reverberation artifact, which is a common finding in transesophageal echocardiographic assessment of the aorta.

Video 7 is a midesophageal view at the same level as Video 6 but rotated 90°. The wedge-shaped aortic dissection flap is clearly seen.

There are many potential explanations for hypotension in a hospitalized patient, including myocardial dysfunction, PE, hypovolemia, and sepsis. Point-of-care ultrasonography has been shown to be an extremely powerful tool in rapidly navigating among these possibilities.1 In the present patient case, the diagnostic possibilities were immediately narrowed precisely to a single, unexpected explanation: pericardial tamponade due to aortic dissection.

Other potential explanations for the patient’s hypotension are either excluded or rendered much less probable based on the results of the point-of-care study:

  • • Left ventricular systolic dysfunction in the context of suspected acute coronary syndrome is ruled out by the normal parasternal short-axis view seen in Video 2.

  • • Although PE cannot be completely excluded, an embolus large enough to cause profound hypotension would be expected to cause severe RV dilation, RV dysfunction, and displacement of the interventricular septum to the left. Because none of these features is seen in Video 2, the likelihood of a massive acute PE is decreased. A screening examination for DVT was also performed; the absence of DVT in this case further reduces the probability of an acute PE.

  • • The ultrasound features of hypovolemia and sepsis are similar: a small, collapsible IVC and a hyperdynamic, underfilled left ventricle. Absence of either finding in Videos 2 and 3 makes these diagnoses less likely, especially in the presence of a pericardial effusion large enough to justify the state of shock.

Pericardial tamponade is a clinical diagnosis, and the echocardiographic signs of tamponade physiology are complex and easy to misinterpret. Faced with a patient who is unstable and who has a nontrivial pericardial effusion, presumption of tamponade until proven otherwise is a reasonable approach, and the role of the point-of-care ultrasonographer is to take appropriate measures to stabilize the patient while urgent referral is made.

Where time and expertise permit, additional echocardiographic features of tamponade can be sought. Of highest sensitivity is assessment of the IVC for distension; its absence all but rules out tamponade.2 The ease of acquiring and interpreting IVC images makes it a particularly helpful tool for the sonographer without advanced experience. Because IVC distension is nonspecific (as in this case, see Video 3), its presence alone cannot rule in cardiac tamponade, and other echocardiographic signs of tamponade must be sought.

The primary echocardiographic sign of tamponade is diastolic collapse of the right-sided cardiac chambers. The phenomenon occurs as intrapericardial pressure rises and eventually exceeds intracardiac pressure; this occurs first in the right atrium followed by the right ventricle because these are lower-pressure chambers compared with the left-sided chambers. In this particular case, it is likely that diuretic therapy aggravated this phenomenon by reducing preload and, thus, right-sided intracardiac pressure. The mainstay of noninvasive therapy in the case of suspected tamponade is fluid therapy because most patients will show at least transient hemodynamic improvement that will allow time for advanced echocardiographic assessment, pericardial drainage by an experienced provider, or both.

Subtle diastolic RV collapse can be seen in Video 1. By the time of the point-of-care ultrasound examination, the patient had already received a significant amount of IV fluid and had shown marked hemodynamic improvement, explaining the relatively subtle degree of RV collapse. Video 5 shows a different patient with similar pathology wherein diastolic collapse of the RV free wall is readily appreciated in the parasternal long-axis view.

Once the patient has been stabilized, attention must be turned to explaining the cause of the pericardial effusion. Upon detecting a significant effusion while performing a goal-directed study, it is crucial to review the patient’s history and continue the ultrasound examination to look for potential sources. In this case, the suspected dilation of the AA raised the possibility of a type A aortic dissection, and further examination of the aorta is an essential next step. The patient was quickly moved to a monitored environment where a second transthoracic study was performed, this time more clearly demonstrating the marked aortic dilation and a likely dissection flap as seen in Video 4. An urgent thoracic CT scan confirmed the diagnosis, and the patient was taken to the cardiac operating room for a transesophageal study (Videos 6, 7) prior to repair of the aorta. The surgery was completed without major complication, and although she had a lengthy postoperative stay of 6 weeks, the patient was successfully discharged home.

  • 1. Point-of-care ultrasonography performed by the treating physician or rapid response team can quickly and accurately determine the etiology of hypotension in most critically ill patients.

  • 2. Pericardial tamponade, a clinical diagnosis, is ironically very difficult to make using the traditional clinical tools of history and physical examination.3Bedside ultrasonography can reliably detect the presence of a pericardial effusion4and can sometimes determine its etiology.

  • 3. For complex diagnoses, it is essential that initial abnormalities seen on point-of-care testing prompt timely interdisciplinary discussions to expedite further testing and therapeutic interventions.

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.

Jones AE, Tayal VS, Sullivan DM, Kline JA. Randomized, controlled trial of immediate versus delayed goal-directed ultrasound to identify the cause of nontraumatic hypotension in emergency department patients. Crit Care Med. 2004;32(8):1703-1708. [CrossRef] [PubMed]
 
Himelman RB, Kircher B, Rockey DC, Schiller NB. Inferior vena cava plethora with blunted respiratory response: a sensitive echocardiographic sign of cardiac tamponade. J Am Coll Cardiol. 1988;12(6):1470-1477. [CrossRef] [PubMed]
 
Cooper JP, Oliver RM, Currie P, Walker JM, Swanton RH. How do the clinical findings in patients with pericardial effusions influence the success of aspiration? Br Heart J. 1995;73(4):351-354. [CrossRef] [PubMed]
 
Mandavia DP, Hoffner RJ, Mahaney K, Henderson SO. Bedside echocardiography by emergency physicians. Ann Emerg Med. 2001;38(4):377-382. [CrossRef] [PubMed]
 

Figures

Tables

Videos 1-4

Point-of-care ultrasound using portable device.

Discussion Video

Discussion Video

Video 1-7

Ultrasound used to diagnose a type A aortic dissection

References

Jones AE, Tayal VS, Sullivan DM, Kline JA. Randomized, controlled trial of immediate versus delayed goal-directed ultrasound to identify the cause of nontraumatic hypotension in emergency department patients. Crit Care Med. 2004;32(8):1703-1708. [CrossRef] [PubMed]
 
Himelman RB, Kircher B, Rockey DC, Schiller NB. Inferior vena cava plethora with blunted respiratory response: a sensitive echocardiographic sign of cardiac tamponade. J Am Coll Cardiol. 1988;12(6):1470-1477. [CrossRef] [PubMed]
 
Cooper JP, Oliver RM, Currie P, Walker JM, Swanton RH. How do the clinical findings in patients with pericardial effusions influence the success of aspiration? Br Heart J. 1995;73(4):351-354. [CrossRef] [PubMed]
 
Mandavia DP, Hoffner RJ, Mahaney K, Henderson SO. Bedside echocardiography by emergency physicians. Ann Emerg Med. 2001;38(4):377-382. [CrossRef] [PubMed]
 
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