Show Notes
REBEL Rundown
Key Points
POCUS diastology answers one ED question: Is left atrial pressure (LAP) elevated right now? (not “diagnose diastolic dysfunction”) E/e’ estimates LAP using mitral inflow E (PW Doppler) and annular e’ (TDI) from an apical 4-chamber view Interpretation: E/e’ ≥ 14 → likely elevated LAP (supports cardiogenic pulmonary edema); ≤ 8 → LAP likely normal; 8–14 → indeterminate Fast + actionable: With a decent apical view, E and e’ can be captured in ~60 seconds to guide diuresis/afterload reduction vs non-cardiac pathways Use context: E/e’ performs best in reduced EF and can be confounded by MR/MS, tachycardia, and BiPAP/PEEP
Introduction
A formal echocardiographic diagnosis of diastolic dysfunction is multivariable, nuanced, and not an ED priority in most acute dyspnea cases. In the emergency setting, the bedside question that changes management is simpler: Is left atrial pressure (LAP) elevated right now? Elevated LAP is the physiologic substrate for cardiogenic pulmonary edema and the target for therapies like diuresis and afterload reduction. “POCUS diastology” is a focused ultrasound approach that helps you answer that question quickly—often faster than CXR, BNP, or a “CHF vs pneumonia” radiology impression.
POCUS diastology ≠ chronic diagnosis. It’s a real-time estimate of filling pressure to guide acute resuscitation.
Case: Acute dyspnea with an unclear story
A 72-year-old obese woman presents with severe dyspnea. EMS placed her on BiPAP for hypoxia. She’s uncomfortable, with bibasilar crackles and faint wheezing. Vitals: BP 166/98, HR 110, RR 22, SpO₂ 86%. Your differential is broad: Pneumonia? COPD exacerbation? Flash pulmonary edema? CXR: “Atypical pneumonia vs pulmonary edema” (not helpful) Labs: WBC 14.1, pBNP 320 (still not helpful) Your bedside ultrasound: The IVC is dilated → tempting to anchor on CHF But you pause: COPD on BiPAP can also dilate the IVC via increased intrathoracic pressure and RV loading.
You obtain a cardiac view: EF looks normal → but that doesn’t rule out elevated filling pressures (hello HFpEF physiology)
Does this settle it? Can we give this patient bronchodilators, steroids and antibiotics?
The goal of POCUS diastology
You’re not trying to label the patient with “diastolic dysfunction.” You’re asking one resuscitation question: Is LAP elevated in this moment? If yes → cardiogenic pulmonary edema becomes much more likely and diuresis/afterload reduction moves up the priority list. If no → search hard for non-cardiogenic causes (COPD, pneumonia, PE, ARDS, etc.).
Pathophysiology Refresher
Diastolic filling depends on: Intrinsic: LV relaxation, LV compliance, atrial contraction Extrinsic: pericardial pressure, RV function, intrathoracic pressure (BiPAP), volume status When the LV is stiff/noncompliant, blood backs up into the LA → LAP rises → pressure transmits to the pulmonary vasculature → pulmonary edema. This can happen even with normal EF.
The POCUS method: E/e’ to estimate LAP
To estimate LAP, you measure: E wave: early diastolic mitral inflow velocity (PW Doppler) e’ wave: early diastolic mitral annular tissue velocity (TDI) Then calculate: E/e’ = Mitral inflow (E) ÷ Mitral annular velocity (e’) This ratio is used as a noninvasive estimate of LV filling pressures and correlates with formal echocardiography-derived estimates. Example formula cited in echo literature: LAP ≈ (1.24 × E/e’) + 1.9 Important nuance (keep your wording tight): E/e’ can be used in both preserved and reduced EF, but performance is generally stronger in reduced EF. In normal EF, treat E/e’ as a high-value clue rather than a standalone verdict—especially in the intermediate zone.
Spectral Doppler feels intimidating (so let’s make it practical)
A lot of POCUS users avoid Doppler because it feels “advanced.” Here’s the reality: If you can obtain a decent apical 4-chamber, you can obtain E and e’. Once the view is good, capturing waveforms is straightforward.
Step-