Hemodynamic parameters of venous return and their role in assessment of fluid responsiveness in cardiac surgery

Objective. To evaluate diagnostic value of mean systemic filling pressure (Pmsa) and its derivatives, including cardiac power (CPvol), the driving pressure of venous return (Pmsa–central venous pressure), cardiac efficiency (Eh) and volemic efficiency (Evol) determined by passive leg raise (PLR test) and infusion bolus (IB) tests, in predicting fluid responsiveness after off-pump coronary artery bypass grafting (CABG) under sevoflurane anesthesia. Material and methods. Post hoc analysis included 49 patients after off-pump CABG, who sequentially underwent PLR test and IB test within an hour after surgery. In responders, cardiac index measured by thermodilution increased by ≥15% after reference test with IB and by ≥10% after PLR test. Results. Responders to IB test comprised 55.1%, to PLR test — 75.5% (k=0.31; 95% CI 0.06—0.56). No difference in Pmsa and central venous pressure was revealed. Central venous pressure increment was higher in responders when using both tests (p<0.05). Dynamics of CPvol were similar in both groups. Eh increased from 0.32±0.05 to 0.35±0.07 (p=0.002) in PLR test and to 0.39±0.12 in IB test (p<0.001). AUROC for Evol in PLR test was 0.517 (95% CI 0.349—0.684), in IB test — 0.493 (95% CI 0.326—0.661). Conclusion. Dynamics of mean systemic filling pressure and its derivatives in assessing early postoperative fluid responsiveness after off-pump CABG is nonspecific. Monitoring of these parameters does not improve consistency of PLR and IB tests.