QA of the Month: December 2013

Chest Pain and Cough

Congratulations Dr. Kate Shea!

Case

47 Y Tongan female with no known PMH who presents with 3 weeks of atypical pleuritic chest pain, shortness of breath, and dry cough. Had a witnessed syncopal episode lasting a few seconds the previous evening while watching TV without trauma. No smoking, fevers, or chills. 

Vitals

HR 95 RR 20 BP 141/94 SpO2 96% RA T 36.8 116 Kg

Physical Exam

Obese, regular tachycardia, slight end expiratory wheeze 

EKG

Sinus rhythm 96, non-­-specific T-­-wave flattening

Because of the long­-lasting and unexplained symptoms, a bedside cardiac echo was performed by Dr. Shea. 

Subxiphoid View

IVC Ultrasound

That’s right! Seen here is a large pericardial effusion and RV free wall near -­-collapse during diastole, consistent with early cardiac tamponade! Confirming the diagnosis is a plethoric IVC measuring just over 3cm (see small hashmarks on side of US screen). In real time, there was no respiratory variation of the IVC. 

Cardiology was emergently consulted who confirmed echo-­- and doppler evidence of tamponade. The patient was then taken to the cath lab for urgent/emergent pericardiocentesis. She improved markedly with draining 1.2L of sanguineous fluid. 

She remained hospitalized for 10 days with a pericardial drain in place. She was found to have a mediastinal mass, with an inconclusive inpatient workup suggestive of malignancy versus sarcoid versus post-­-infectious. The patient gradually improved and was discharged with outpatient mediastinoscopy and biopsy arranged. 

Who's at risk for pericardial effusion?

Echo when evaluating for pericardial effusion

A black, anechoic area surrounding the heart within the pericardial sac characterizes pericardial effusion. The amount of fluid is not as important as looking for right ventricular collapse during diastole, which would be consistent with tamponade physiology. 

The rate of fluid accumulation is a key factor as quicker results in smaller pericardial fluid causing tamponade, while fluid accumulating over a longer time period may be larger with or without tamponade physiology 

But, grading of pericardial effusion size can help in discussing findings with consultants. 

  • Small: less than 1cm depth, non-­-circumferential
  • Moderate: less than 1cm depth, circumferential
  • Large: more than 1cm depth, circumferential

Echo when evaluating for Cardiac Tamponade

Occurs when pericardial pressure exceeds right ventricular end diastolic pressure. Best recognized sonographically as an inability of the right heart to fully expand in diastole. 

  • RV collapse in diastole (more specific)
  • RA ‘furiously contracting’ in systole (more sensitive)
  • Plethoric IVC dilation with minimal respiratory variation

Differentiate Pericardial Effusion from Pleural Effusion by viewing the fluid in parasternal long view

  • Critical landmark is the transverse descending aorta
  • Black fluid anterior to descending aorta is pericardial effusion
  • Black fluid posterior to descending aorta is pleural effusion

Pitfalls

  • Epicardial fat pad can be mistaken for pericardial effusion
  • Ascites can mimic pericardial effusion in subxiphoid view

Physical exam and diagnostic testing is insensitive for tamponade

Pooled Sensitivities (95% CI): 

  • Hypotension 26% (16-­-36%)
  • Tachycardia 77% (69-­-85%)
  • Low voltage on EKG: 42% (32-­-53%)
  • Cardiomegaly on CXR: 89% (73-­-100%)

Pulsus Paradoxus: an exaggeration of the drop in BP seen with inspiration

Roy CL et al. Does this patient with a Pericardial Effusion have Cardiac Tamponade? JAMA (2007)297;16 

Strategies for sonographically documenting tamponade

Determining phases of cardiac cycle is often the most difficult part, but tips to help include:

  • Attaching EKG monitoring leads to the ultrasound machine
  • M-mode in parasternal long view. Place M-mode cursor simultaneously through RV free wall and anterior leaflet of the mitral valve (MV). Diastole is recognized by MV opening; Look at the RV free wall for paradoxical collapse during this time.

Congrats again to Dr. Shea for a job well done! 

- Josh Ennis, Mansour Jammal, and Laleh Gharahbagian