Is body mass index a risk factor for low cerebral oxygenation during spinal anesthesia in women undergoing cesarean section? A preliminary study

BACKGROUND/AIM: In this study, it was aimed to investigate the relationship between body mass index (BMI) and cerebral oxygenation during spinal anesthesia in women undergoing cesarean section. This study also aimed to demonstrate whether fetal cord blood oxygenation was affected by maternal BMI and/or delivery time. MATERIALS AND METHODS: The study included parturients with ASA I score undergoing cesarean section under spinal anesthesia in 2015 and 2016. They were divided into two groups according to BMI: Group 1 comprised parturients with BMI of <30 (n = 11) and Group 2 comprised parturients with BMI of ≥30 (n = 17). Right cerebral oxygenation (RSO2) and left cerebral oxygenation (LSO2) monitoring was performed using near-infrared spectroscopy (NIRS). The participants were divided into two groups according to the duration of fetal delivery. Group A included parturients with delivery time of <2 min (n = 7) and Group B those with delivery time of >2 min (n = 18), and fetal cord blood oxygenation was measured using a blood gas analyzer. RESULTS: Evaluation was made of a total of 25 patients. The RSO2 values were​​ measured at the 20th, 30th, and 35th minutes of the cesarean section procedure and the median values of all the time intervals in Group 1 were significantly lower than those of Group 2 (P < 0.05). The LSO2 value ​​was significantly lower in Group 1 at the 35th minute compared to Group 2 (P < 0.05). The PO2 values of fetal cord blood were significantly lower in Group B (P < 0.05). CONCLUSION: The results of this study showed that parturients with BMI of <30 who are undergoing cesarean section under spinal anesthesia might have an increased risk of complications due to decreased cerebral oxygenation related with hypotension. Therefore, it can be suggested that before and during cesarean section these patients should be closely monitored for cerebral oxygenation using NIRS.