Correlation between left ventricular outflow tract-velocity time integral (LVOT-VTI) and transthoracic echocardiographic pulmonary to left atrial ratio (e-PLAR) in critically ill patients as a predictor of fluid responsiveness

Abstract

Background
Assessing fluid responsiveness in critically ill patients remains a significant clinical challenge. This study was designed to evaluate whether the echocardiographic pulmonary-to-left atrial ratio (e-PLAR), calculated as TR Vmax/ mitral (E/E`), can predict fluid responsiveness in critically ill patients, and to compare its predictive value with that of left ventricular outflow tract velocity time integral (LVOT-VTI) variability.


Methods
A prospective cohort study was conducted involving 63 critically ill patients requiring fluid resuscitation. Both the TR Vmax/mitral (E/E`) and LVOT-VTI variability were measured before and after administering a mini-fluid challenge (100 ml). Patients were classified as fluid responders if their mean LVOT-VTI variability exceeded 15%.


Results

Of the 63 patients enrolled, 46 (73%) were identified as fluid responders, while 17 (27%) were non-responders. LVOT-VTI variability predicted fluid responsiveness with a cutoff value of less than 20 cm, demonstrating a sensitivity of 84% and a specificity of 88.6% (
P
 < 0.005). The TR Vmax/Mitral (E/E`) did not reliably predict fluid responsiveness, with an area under the ROC curve of 0.4 and a
P
value of 0.8. Notably, patients with a TRV max/(E:E`) ratio greater than 0.3 m/s showed a more significant change following the fluid challenge (
P
 = 0.02).



Conclusion
The findings indicate that the TRVmax/(E:E’) ratio is not a reliable predictor of fluid responsiveness in critically ill patients and does not correlate with mortality or ICU length of stay. In contrast, LVOT-VTI variability remains a more effective tool for assessing fluid responsiveness in this patient population.