THE RATIONAL CLINICIAN’S CORNER CLINICAL EXAMINATION Does This Patient With a Pericardial Effusion Have Cardiac Tamponade? Christopher L. Roy, MD Context Cardiac tamponade is a state of hemodynamic compromise resulting from Melissa A. Minor, MD cardiac compression by fluid trapped in the pericardial space. The clinical examination M. Alan Brookhart, PhD may assist in the decision to perform pericardiocentesis in patients with cardiac tam- ponade diagnosed by echocardiography. Niteesh K. Choudhry, MD, PhD Objective To systematically review the accuracy of the history, physical examina- tion, and basic diagnostic tests for the diagnosis of cardiac tamponade. CLINICAL SCENARIOS Data Sources MEDLINE search of English-language articles published between 1966 Case 1 and 2006, reference lists of these articles, and reference lists of relevant textbooks. A 55-year-old woman with chronic ob- Study Selection We included articles that compared aspects of the clinical exami- structive pulmonary disease presents to nation to a reference standard for the diagnosis of cardiac tamponade. We excluded your office with 2 weeks of progressive studies with fewer than 15 patients. Of 787 studies identified by our search strategy, dyspnea. She had breast cancer diagnosed 8 were included in our final analysis. and treated more than 10 years ago and Data Extraction Two authors independently reviewed articles for study results and has had no evidence of recurrence. She quality. A third reviewer resolved disagreements. was seen in the emergency department 1 Data Synthesis All studies evaluated patients with known tamponade or those re- week ago, where her evaluation included ferred for pericardiocentesis with known effusion. Five features occur in the majority an echocardiogram that demonstrated a of patients with tamponade: dyspnea (sensitivity range, 87%-89%), tachycardia (pooled moderate-sized (15 mm in maximum sensitivity, 77%; 95% confidence interval [CI], 69%-85%), pulsus paradoxus (pooled width), circumferential pericardial effu- sensitivity, 82%; 95% CI, 72%-92%), elevated jugular venous pressure (pooled sen- sion without echocardiographic evidence sitivity, 76%; 95% CI, 62%-90%), and cardiomegaly on chest radiograph (pooled ofcardiactamponade.Duringyourexami- sensitivity, 89%; 95% CI, 73%-100%). Based on 1 study, the presence of pulsus para- nation, you note tachycardia and faint doxus greater than 10 mm Hg in a patient with a pericardial effusion increases the heart sounds. A pulsus paradoxus is 6 likelihood of tamponade (likelihood ratio, 3.3; 95% CI, 1.8-6.3), while a pulsus para- mm Hg with a blood pressure of 100/60 doxus of 10 mm Hg or less greatly lowers the likelihood (likelihood ratio, 0.03; 95% CI, 0.01-0.24). mmHg,thejugularvenouspressureisnot elevated, and auscultation of her lungs re- Conclusions Among patients with cardiac tamponade, a minority will not have dys- veals diminished breath sounds. You ob- pnea, tachycardia, elevated jugular venous pressure, or cardiomegaly on chest radio- graph. A pulsus paradoxus greater than 10 mm Hg among patients with a pericardial tain a chest radiograph that is unchanged effusion helps distinguish those with cardiac tamponade from those without. Diag- from previous films and that shows hy- nostic certainty of the presence of tamponade requires additional testing. perinflated, clear lung fields and no en- JAMA. 2007;297:1810-1818 www.jama.com largement of the cardiac silhouette. You suspect that the patient’s symptoms are attributabletoherlungdisease,butshould He is found to have a pulsus para- Author Affiliations: Divisions of General Medicine and Primary Care (Dr Roy) and Pharmacoepidemiology and you evaluate further for tamponade? doxus of 18 mm Hg with a blood pres- Pharmacoeconomics (Drs Brookhart and Choudhry), sure of 130/70 mm Hg and a heart rate Brigham and Women’s Hospital, Harvard Medical Case 2 School, Boston, Mass; Hospitalist Service, Brigham and of 90/min. The remainder of the physi- Women’s Hospital, Boston (Drs Roy and Choudhry); A previously healthy 34-year-old man cal examination is unremarkable. The and Harvard Vanguard Medical Associates, Boston (Dr chest radiograph shows an enlarged car- Minor). presents to the emergency depart- Corresponding Author: Christopher L. Roy, MD, Di- ment with dyspnea for the past 3 days. diac silhouette. You order an echocar- vision of General Medicine and Primary Care, Hospi- diogram that shows a moderate-sized, talist Service, Brigham and Women’s Hospital, 75 Fran- cis St, Boston, MA 02115 ([email protected]). See also Patient Page. circumferential pericardial effusion with The Rational Clinical Examination Section Editors: a left ventricular ejection fraction of David L. Simel, MD, MHS, Durham Veterans Affairs CME available online at 65%. The study is limited by body habi- Medical Center and Duke University Medical Center, www.jama.com Durham, NC; Drummond Rennie, MD, Deputy Edi- tus and rapid respirations, and the right tor, JAMA. 1810 JAMA, April 25, 2007—Vol 297, No. 16 (Reprinted) ©2007 American Medical Association. All rights reserved. Downloaded from www.jama.com on April 24, 2007 DOES THIS PATIENT WITH A PERICARDIAL EFFUSION HAVE CARDIAC TAMPONADE? atrium and right ventricle are poorly vi- too sensitive and overdiagnose cardiac The Pathophysiology sualized. Do the physical examination tamponade in patients with only subtle of Cardiac Tamponade findings alter your assessment of this evidence of hemodynamic compro- The pericardial sac consists of 2 layers: patient’s pericardial effusion? mise.4,6,7 Nonetheless, because echocar- an outermost parietal pericardium and diography is a noninvasive modality that the inner visceral pericardium (epicar- WHY IS THE CLINICAL is highly accurate, it is an essential com- dium) that reflects directly over the sur- EXAMINATION FOR CARDIAC ponent of the evaluation.8-11 face of the heart. Normally, no more than TAMPONADE IMPORTANT? There are several scenarios in which 15 to 30 mL of fluid exists between the Cardiac tamponade occurs when fluid the clinical examination for cardiac tam- 2 layers, held at pressures approximat- trapped in the pericardial space com- ponade could be useful. If the clinical ex- ing the pleural pressure or approxi- presses the heart and compromises car- amination could rule out tamponade mately 5 mm Hg lower than central ve- diac output. The consequences of car- with a high degree of certainty, it could nous pressure.13,14 diac tamponade range from barely preclude the need for echocardiogra- When pericardial fluid accumulates detectable effects to overt hemody- phy in some patients and allow the cli- slowly, parietal pericardium compli- namic collapse.1-3 When a pericardial ef- nician to pursue other potential diag- ance increases. Increasing amounts of fusion becomes large enough or accu- noses. On the other hand, the clinician fluid causes intrapericardial pressure to mulates rapidly enough to cause is sometimes faced with echocardio- increase, while the central venous pres- hemodynamic consequences, readily ob- graphic findings suggestive of cardiac sure responds by increasing to main- served symptoms and signs herald im- tamponade, and clinical correlation is tain a gradient that allows cardiac fill- pending circulatory collapse that neces- necessary to guide the decision for ur- ing. When pericardial compliance can sitates urgent therapeutic intervention. gent pericardiocentesis.6,12 increase no more, the intrapericardial The invasive reference standard for the diagnosis of cardiac tamponade re- Figure 1. Relationship Between Intracardiac Filling Pressures and Intrapericardial Pressure and quires simultaneous measurement of in- Cardiac Output in Cardiac Tamponade trapericardial and intracardiac pres- sures. The intrapericardial, right atrial, Normal Cardiac Tamponade pulmonary artery diastolic, and pul- monary capillary wedge pressures are all elevated and equalized in cardiac tamponade (FIGURE 1). In the ab- sence of other pathology (eg, effusive- constrictive disease), pericardiocente- sis will normalize pressures and improve the cardiac output, confirm- Pressure ing the diagnosis.4 Echocardiographyisthediagnostictest Left Heart Filling Pressure used most frequently to evaluate cardiac tamponade when it is clinically suspected Intrapericardial Pressure (FIGURE 2). While echocardiography is the noninvasive reference standard for Increasing Pericardial Effusion Volume the diagnosis of pericardial effusion,5 the mere presence of an effusion does not define cardiac tamponade. Rather, sev- Cardiac Output eral echocardiographic findings, includ- Normal ingrightatrialsystoliccollapse,rightven- tricular diastolic collapse, inferior vena caval plethora, and exaggeration of res- pirophasic changes in flow velocities across the tricuspid and mitral valves, are indicative of tamponade physiology and make the diagnosis with near cer- Increasing Pericardial Effusion Volume tainty when the pretest probability is As pericardial fluid volume increases to the limit of pericardial compliance, intrapericardial pressure rises. Car- high. Because cardiac tamponade occurs diac output begins to fall as intrapericardial pressure equalizes with central venous, right atrial, and right ven- on a continuum of hemodynamic effects, tricular end-diastolic pressures (right heart filling pressures), then rapidly falls as it equalizes with left atrial and left ventricular end-diastolic pressures (left heart filling pressures). the findings on echocardiogram may be ©2007 American Medical Association.