Background: Intraoperative hypotension is associated with increased postoperative morbidity and mortality.
Methods: We randomly assigned patients undergoing major general surgery to early warning system (EWS) and hemodynamic algorithm (intervention group, n = 20) or standard care (n = 20). The primary outcome was the difference in hypotension (defined as mean arterial pressure < 65 mmHg) and as secondary outcome surrogate markers of organ injury and oxidative stress.
Results: The median number of hypotensive episodes was lower in the intervention group (-5.0 (95% CI: -9.0, -0.5); p < 0.001), with lower time spent in hypotension (-12.8 min (95% CI: -38.0, -2.3 min); p = 0.048), correspondent to -4.8% of total surgery time (95% CI: -12.7, 0.01%; p = 0.048).The median time-weighted average of hypotension was 0.12 mmHg (0.35) in the intervention group and 0.37 mmHg (1.11) in the control group, with a median difference of -0.25 mmHg (95% CI: -0.85, -0.01; p = 0.025). Neutrophil Gelatinase-Associated Lipocalin (NGAL) correlated with time-weighted average of hypotension (R = 0.32; p = 0.038) and S100B with number of hypotensive episodes, absolute time of hypotension, relative time of hypotension and time-weighted average of hypotension (p < 0.001 for all). The intervention group showed lower Neuronal Specific Enolase (NSE) and higher reduced glutathione when compared to the control group.
Conclusions: The use of an EWS coupled with a hemodynamic algorithm resulted in reduced intraoperative hypotension, reduced NSE and oxidative stress.
Keywords: biomarkers; hypotension; organ injury; oxidative stress; surgery.