Written by: Alex Chu, MD. Edited by: Jeff Greco, MD

Case

57 yo F w/ hx HTN, hyperlipidemia, MI, CHF presents with chest pain. This started 12 hours ago and is described as a substernal pain w/o radiation. Associated sx include productive cough, subjective fever, SOB, and increased bilateral LE swelling. No other concerns at this time. She endorses compliance with all medications.

Vitals

T 38.2 C

HR 110

BP 100/70

RR 20 w/ O2 saturation 95% on RA

Physical Examination

Cardiac: Tachycardia. No murmurs, rubs, or gallops.

Pulmonary: Crackles in bilateral lung bases.

MSK: Pitting edema 2+ to tibia in bilateral LE.

Considerations

The differential diagnosis for this patient is broad and includes pneumonia w/ associated sepsis, acute MI, and CHF exacerbation. While the guidelines for sepsis recommend 30 cc/kg fluid bolus, this may worsen a patient with an ongoing CHF exacerbation. For this patient, assessment of their volume status should be performed to help guide clinical management of fluid supplementation.

While there are a number of ways to assess volume status of patients indirectly, ultrasound remains a powerful tool to answer this clinical question. Ablordeppey et al describe in their paper “Volume Status Assessment by Ventricular Filling Pressure Measurement Using Point-of-Care Ultrasound” a method to perform POC echocardiography to assess LV filling pressures. They look at mitral inflow velocity E and average E/e’ to determine volume status.

Their observational study looked at 32 ESRD patients that had two or more liters of fluid removed during their hemodialysis session. Prior to the session and immediately afterwards, two blinded POCUS trained physicians measured the mitral inflow velocity E and the average annual e’. They found no systematic difference between the two providers. They found that overall, there was no statistically significant change in average E/e’ after removal of three liters of fluid from ESRD patients.

Measuring E using POCUS

The image above uses echocardiography to measure the velocity of flow at the mitral valve during two periods, E (left ventricular relaxation in early diastole) and A (peak velocity flow in late diastole due to atrial contraction). Tissue doppler is then used to measure e’, which corresponds to the velocity of the mitral annular motion during the left ventricular relaxation phase in early diastole. The ratio of these two numbers gives the E/e’ ratio.

A normal E/e’ ratio would be less than 8. Greater than 14 would suggest elevated filling pressures, likely corresponding to a fluid overload state.

In this patient, if the E/e’ ratio were normal, then they would likely benefit from more aggressive fluid resuscitation. Conversely, if the E/e’ ratio is significantly elevated, they would likely benefit from smaller aliquots of fluid resuscitation (250-500 mL) if sepsis was a significant consideration.

Interestingly, there was no significant change in the E/e’ ratio in the study pre and post-dialysis. This may suggest that repeated evaluation of the E/e’ ratio may be less useful in guiding clinical management of a patient and assessing their volume status. Other limitations of this study include that the applicability of the findings, as volume status assessment is important in all patients, not just patients with ESRD or another baseline volume status abnormality.

References

Ablordeppey, E., Gharib, A., Tohme, F., Jaeger, L., Tian, L. and Theodoro, D., 2020. 1447: VOLUME STATUS ASSESSMENT BY VENTRICULAR FILLING PRESSURE MEASUREMENT USING POINT-OF-CARE ULTRASOUND. Critical Care Medicine, 48(1), p.700.