Diagnostic Accuracy of the Inferior Vena Cava Collapsibility to Predict Fluid Responsiveness in Spontaneously Breathing Patients With Sepsis and Acute Circulatory Failure.

OBJECTIVE

To investigate whether the collapsibility index of the inferior vena cava recorded during a deep standardized inspiration predicts fluid responsiveness in nonintubated patients.

DESIGN

Prospective, nonrandomized study.

SETTING

ICUs at a general and a university hospital.

PATIENTS: Nonintubated patients without mechanical ventilation (n = 90) presenting with sepsis-induced acute circulatory failure and considered for volume expansion.

INTERVENTIONS: We assessed hemodynamic status at baseline and after a volume expansion induced by a 30-minute infusion of 500-mL gelatin 4%.

MEASUREMENTS AND MAIN

RESULTS

We measured stroke volume index and collapsibility index of the inferior vena cava under a deep standardized inspiration using transthoracic echocardiography. Vena cava pertinent diameters were measured 15-20 mm caudal to the hepatic vein junction and recorded by bidimensional imaging on a subcostal long-axis view. Standardized respiratory cycles consisted of a deep standardized inspiration followed by passive exhalation. The collapsibility index expressed in percentage equaled the ratio of the difference between end-expiratory and minimum-inspiratory diameter over the end-expiratory diameter. After volume expansion, a relevant (≥ 10%) stroke volume index increase was recorded in 56% patients. In receiver operating characteristic analysis, the area under curve for that collapsibility index was 0.89 (95% CI, 0.82-0.97). When such index is superior or equal to 48%, fluid responsiveness is predicted with a sensitivity of 84% and a specificity of 90%.

CONCLUSIONS

The collapsibility index of the inferior vena cava during a deep standardized inspiration is a simple, noninvasive bedside predictor of fluid responsiveness in nonintubated patients with sepsis-related acute circulatory failure.