Dynamic Tests to Predict Fluid Responsiveness After Off-Pump Coronary Artery Bypass Grafting

To test the hypothesis that a positive end-expiratory pressure test and the mini-fluid challenge predict fluid responsiveness in patients after off-pump coronary artery bypass grafting.

Single-center pilot prospective observational study.

City Hospital #1 of Arkhangelsk, Russian Federation.

Thirty-two adult patients after off-pump coronary artery surgery.

To assess fluid responsiveness, after arrival to the intensive care unit, all patients received a test with increase in positive end-expiratory pressure from 5 to 20 cmH₂O for 2 minutes, a mini-fluid challenge test with administration of crystalloids at 1.5 mL/kg during 2 minutes, and standard fluid challenge test using 7 mL/kg during 10 minutes.

The patients with an increase in cardiac index by ≥15% after a standard fluid challenge test were defined as fluid responders. According to receiver operating characteristic analysis, a decrease in mean arterial pressure exceeding 5 mmHg in 120 seconds of the positive end-expiratory pressure test identified fluid responsiveness with an area under the curve of 0.73 (p = 0.03). The reduction in pulse pressure and stroke volume variations by more than 2% during mini-fluid challenge test predicted positive response to fluid load with an area under the curve of 0.77 and 0.75, respectively (p < 0.05).

Both the positive end-expiratory pressure test and the mini-fluid challenge test are feasible after off-pump coronary artery bypass grafting and can be used to predict fluid responsiveness in these patients.