Case: 49 year-old woman with past medical history of HTN presented to the ED with approximately four days of malaise, myalgias, a feeling of “coming down with something” accompanied by mild shortness of breath.  She developed dyspnea while climbing stairs today, which is new for her, prompting her ED visit.  She denies fever, cough, chest pain, leg swelling or pain, estrogen use or smoking.  ROS was otherwise unremarkable.  Rare EtOH use, never smoker, no drugs.

VS: 99.9F  HR 116   BP 110/80  RR 20   SpO2 97% on RA

Physical exam
GEN: well appearing, NAD
HEENT: no conjunctival pallor, no lymphadenopathy
CV: tachycardic but regular rhythm no MRG
PULM: Tachypneic but CTAB
ABD: SNT
EXT: no LE edema, redness or tenderness
SKIN: WWP

EKG shown below

EKG

Prior to obtaining lab results or portable CXR, point-of-care ECHO was performed.

RV free wall M-mode

Effusion Measurement

Portable CXR was also obtained

pCXR

Diagnosis: Pericardial tamponade

Case resolution: Patient was given 3L crystalloid bolus, Cardiology was consulted and she remained tachycardia but hemodynamically stable in the ED until she was taken to IR and underwent pericardiocentesis, yielding 300cc of pericardial fluid.  At discharge, the etiology was attributed to viral pericarditis.

Learning Points:

  1. DDx for emergent causes of SOB/DOE with normal heart and lung exam:
    • Anemia
    • PE
    • Pulmonary hypertension
    • Metabolic Acidosis
    • Pericardial tamponade
  2. POCUS exam of the patient with SOB may include:
    • ECHO + IVC (i.e. tamponade, low EF, HOCM, valvular dz, dissection, right heart strain)
    • Thoracic/PULM (i.e. PNX, pleural effusion, PNA, interstitial lung dz, pulmonary edema)
    • FAST (i.e. ruptured spleen or etopic, etc)
    • Aorta (AAA)
    • Lower extremity compression/doppler (DVT ~> ?PE)
  3. Pericardial effusion ECHO
    • Subxyphoid is most sensitive view for effusion
    • Measure largest distance from myocardium to pericardium during end diastole
      • Small: <0.5cm (<100cc)
      • Moderate: 0.5-2.0cm (~100-500cc)
      • Large: >2.0cm (>500cc)
    • Effusion or fake out?
      • Effusions can have clots and fibrin which appear more hyperechoic than simple fluid
      • Effusions can be loculated – not always circumferential
      • Epicardial fat can mimic small effusions
        • usually hyperchoic (vs hypoechoic fluid)
        • usually on RV free wall (vs circumferential)
    • Tamponade
      • Early diastolic RV collapse (see Subxyphoid view  and M-mode across RV free wall above)
      • Late diastolic atrial collapse (see Subzyphoid Right Atrium view above)
      • Distended IVC with minimal respiratory variation
  4. Other signs of tamponade/pericardial effusion
    • Beck’s triad: low BP, distended neck veins, muffled heart sounds
    • EKG with electrical alternans (not present in this patient)
    • Globus/enlarged cardiac silhouette on chest x-ray (present in this patient)
    • Pulses paradoxus: respiratory variability in SBP
      • Measure highest SBP at which Korotkoff can be heard DURING INSPIRATION
      • Measure the lowest SBP at which Korotkoff can be heard at all
      • The difference between these two measurement = pulses paradoxus
      • Normal: <10mmHg
  5. Acute management of pericardial tamponade
    • IV Fluid -> increase cardiac preload
    • Pericardiocentesis
      • Emergent if unstable or pulseless

Sources:
#Life in the Fast Lane. Pericardial Effusion/Tamponade Echocardiography.
#Sonospot — SonoTip&Trick: “I can’t tell if it’s a pleural or pericardial effusion.” Really? well here’s a tip…
#ICU Sonography. Tutorial 8 Assessment of Pericardial Disease
#Stanford Medicine 25. Pulsus Paradoxus and Blood Pressure.

 

Resident Author: Joe Benedict MD, MPH

Ultrasound Faculty Review: Meera Muruganandan, MD

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