Diagnostic accuracy of superior vena cava variability by transthoracic echocardiography as a fluid responsiveness predictor in critically ill patients.

BACKGROUND

Fluid administration is frequent in critically ill patients and its used should be tailored. A recent window to evaluate the superior vena cava variability (SVC) obtained with transthoracic echocardiography might allow fluid responsiveness prediction. Our objective is to evaluate its diagnostic accuracy as such.

METHODS

We conducted a prospective study in a single intensive care unit in an academic center, including consecutive sedated, ventilated adults with elevated lactate or abnormal clinical perfusion or norepinephrine infusion of 0,1 μg/kg/min or more with <7 days of stay, excluding patients with inadequate acoustic window or special contact precautions. We performed a transthoracic critical care echocardiography adding the SVC respiratory variability and then a mini-fluid challenge as a reference test to evaluate its diagnostic accuracy and obtaining the area under receiver operating characteristic curve (AUROC).

RESULTS

From 100 patients, 55 were excluded, mainly because of insufficient acoustic window. In 45 analysed patients, 16 were fluid responders and 29 non-responders. SVC had an AUROC of 0,88. A cutoff value of 10,14 % had 93.75 % sensitivity and 75.86 % specificity with Youden's index of 0,69,912 while 19,42 % was a high specificity cutoff and 16,03 % a balanced one.

CONCLUSION

Transthoracic SVC variation is hard to obtain and has a good diagnostic accuracy for detecting fluid responsiveness and it could be used in some ventilated patients with hemodynamic instability.

REGISTRATION: ClinicalTrials.gov: NCT05211765.