Effect of hypotensive anesthesia on cerebral perfusion and bloodantioxidant levels and HIF 1a

Backround and Aim: Controlled hypotension is the voluntary reversible reduction of arterial blood pressure. Hypotensive anstehesia is a method of anesthesia in which blood pressure is reduced in a controlled manner, especially in certain surgeries. İt reduces intraoperative bleeding and need for blood transfusion and provides a clean surgical vision in narrow-field surgeries or with high bleeding potential. Hypotensive anesthesia can be performed according to mean blood pressure (MBP) or systolic blood pressure (SBP). Near İnfrared Spectroscopy (NIRS) allows continuous and non-invasive monitoring of cerebral oxygenation. HIF 1a, TAS and TOS are laboratory markers that predict tissue oxygenation and perfusion. The aim of this study to evaluate the patients who underwent controlled hypotensive anesthesia under standardized depth of anesthesia; preoperative and postoperative blood HIF 1a, TAS, TOS measurement and serebral perfusion evaluation with NIRS and to investigate tissue hypoxia secondary to hypotensive anesthesia and the cahanges of the mediators at the tissue level and which blood pressure parameters are related. Materials and Methods: A total of 60 ASA 1-2 patients aged between 18-75 who underwent elective rhinoplasty and ortognatic surgery were included the study. Standard anesthesia induction and propofol and remifentanil infusion were applied to all patients with TIVA technique. The patients were divided into two groups. One group received hypotensive anesthesia according to MBP an done group received SBP. Continuous regionel cerebral oxygen saturation was monitored by NIRS in both groups. Blood samples were taken from all patients before anesthesia induction and at the and of the operation and stored for TAS, TOS, HIF 1a. At the and of the operation patients were fallowed in the post anesthesia care unit for 30 minutes and pain and nause vomiting scores were evaluated. İn addition, surgical satisfaction and bleeding scores and anesthetic consumption of both groups were recorded. Results: In our study, no statistically significant difference was found between the RsO2 values of the two groups. However, the number of patients with cerebral desaturation was higher in SBP group. There was no statistically significant difference between input and output TAS, TOS, HIF 1a values in MBP and SBP group. Output TOS of SBP group; output HIF 1a levels of MBP group werw significantly lower than those of input levels. The surgical satisfaction score of the MBP group was significantly higher and the bleeding score was significantly lower. Conclusion: Hypotensive anesthesia can be performed according to both MBP and SBP. However, in our study that follow-up MBP is more adventageous/protective, although it is not supported by very strong data. We recommend hypotensive anesthesia compared to MBP; but further studies are needed.