Comparison of Echocardiographic Indices Used to Predict Fluid Responsiveness in Ventilated Patients

Rationale: Assessment of fluid responsiveness relies on dynamic echocardiographic parameters that have not yet been compared in large cohorts. Objectives: To determine the diagnostic accuracy of dynamic parameters used to predict fluid responsiveness in ventilated patients with a circulatory failure of any cause. Methods: In this multicenter prospective study, respiratory variations of superior vena cava diameter (Delta SVC) measured using transesophageal echocardiography, of inferior vena cava diameter (Delta IVC) measured using transthoracic echocardiography, of the maximal Doppler velocity in left ventricular outflow tract (Delta VmaxAo) measured using either approach, and pulse pressure variations (Delta PP) were recorded with the patient in the semirecumbent position. In each patient, a passive leg raise was performed and an increase of aortic velocity time integral greater than or equal to 10% defined fluid responsiveness. Measurements and Main Results: Among 540 patients (379 men; age, 65 +/- 13 yr; Simplified Acute Physiological Score II, 59 +/- 18; Sequential Organ Failure Assessment, 10 +/- 3), 229 exhibited fluid responsiveness (42%). Delta PP, Delta VmaxAo, Delta SVC, and Delta IVC could be measured in 78.5%, 78.0%, 99.6%, and 78.1% of cases, respectively. Delta SVC greater than or equal to 21%, Delta VmaxAo greater than or equal to 10%, and Delta IVC greater than or equal to 8% had a sensitivity of 61% (95% confidence interval, 57-66%), 79% (75-83%), and 55% (50-59%), respectively, and a specificity of 84% (81-87%), 64% (59-69%), and 70% (66-75%), respectively. The area under the receiver operating characteristic curve of Delta SVC was significantly greater than that of Delta IVC (P = 0.02) and Delta PP (P = 0.01). Conclusions: Delta VmaxAo had the best sensitivity and Delta SVC the best specificity in predicting fluid responsiveness. Delta SVC had a greater diagnostic accuracy than Delta IVC and Delta PP, but its measurement requires transesophageal echocardiography.