Limited value of end-expiratory inferior vena cava diameter to predict fluid responsiveness impact of intra-abdominal pressure.

Purpose: We sought to determine the diagnostic ability of the end-expiratory inferior vena cava diameter (IVC) to predict fluid responsiveness (FR) and the potential confounding effect of intra-abdominal pressure (IAP).

Methods: In this multicenter study, 540 consecutive ventilated patients with shock of various origins underwent an echocardiographic assessment by experts. The IVC, velocity time integral (VTI) of the left ventricular outflow tract (LVOT) and intra-abdominal pressure (IAP) were measured. Passive leg raising (PLR) was then systematically used to perform a reversible central blood volume expansion. FR was defined by an increase in LVOT VTI ≥ 10% after 1 min of PLR.

Results: Since IVC was not obtained in 117 patients (22%), 423 were studied (septic shock: 56%), 129 of them (30%) having elevated IAP (≥ 12 mmHg) and 172 of them (41%) exhibiting FR. IVC ≤ 13 mm predicted FR with a specificity of at least 80% in 62 patients (15%), while IVC ≥ 25 mm predicted the absence of FR with a specificity of at least 80% in 61 patients (14%). In the remaining 300 patients (71%), the intermediate value of IVC did not allow predicting FR. An adjusted relationship between IVC and FR was observed while this relationship was less pronounced in patients with IAP ≥ 12 mmHg.

Conclusions: Measurement of IVC in ventilated patients is moderately feasible and poorly predicts FR, with IAP acting as a confounding factor. IVC might add some value to guide fluid therapy but should not be used alone for fluid prediction purposes.