Background: The hemodynamic variations of cardiac and cerebral blood monitoring during pneumoperitoneum and head-down tilt position in general anesthetized elderly patients remain unresolved.We evaluated the time course of cerebral tissue oxygen saturation (SctO 2 ) and cardiac output (CO) and investigated how the changes in hemodynamic values during the surgery would affect cerebral perfusion in elderly patients. Methods: In this prospective observational study of 47 elderly patients (≥65 years old, American Society of Anesthesiologists Physical status I to III) undergoing laparoscopic colorectal radical resection with headdown position, SctO 2 by near-infrared spectroscopy and arterial pressure-based cardiac output (APCO), Cardiac index (CI), stroke volume (SV), and SV index (SVI) according to FloTrac/Vigileo were measured at 9 time points. Heart rate (HR), mean arterial blood pressure (MAP), end-tidal carbon dioxide (ETCO 2 ), bispectral index (BIS), central venous pressure (CVP), and ventilator settings were recorded. Results are reported as medians [95% confidence interval (CI)]. Results: Heart Rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), MAP, CO, CI, SV, SVI, and SctO 2 before incision decreased significantly compared with the waking state (P<0.05). SBP, CO, CI, SV, and SVI before incision decreased significantly compared with induction and intubation (P<0.05). SBP, DBP, MAP, and CVP increased significantly after pneumoperitoneum and head-down tilt, and then decreased during the following hour. CO and SVI decreased, while CI and SV increased after pneumoperitoneum and head-down tilt. CO, CI, SV and SVI decreased at the following 20, 40, and 60 minutes respectively. SctO 2 increased after pneumoperitoneum and head-down tilt and remained stable during the following hour. CVP decreased while CO, CI, SV, and SVI increased significantly at the end of pneumoperitoneum and head-down tilt (P<0.05). HR and MAP increased significantly at the end of surgery compared to at the end of pneumoperitoneum and head-down tilt (P<0.05). CI was associated with SctO 2 as indicated by a Pearson r of 0.035 (P<0.05).Conclusions: Anesthesia, pneumoperitoneum, and head-down tilt affect cardiac function and cerebral perfusion in elderly patients. cardiac index independently affects elderly patients' cerebral blood flow.
