Effects of Subarachnoid Block vs General Anaesthesia on Intraoperative Blood Glucose Levels in Non Diabetic Patients undergoing Elective Surgeries: A Prospective Interventional Study

Introduction: The inhibition of the pituitary gland, an increase in the production of catabolic hormones, and the stimulation of the sympathetic nervous system culminate in surgical stress. These factors result in elevated hepatic glycogenesis and gluconeogenesis, decreased skeletal muscle glucose uptake and glycogen synthesis, and hyperglycaemia. Aim: To examine the effects of Subarachnoid Block (SAB) and General Anaesthesia (GA) on perioperative Capillary Blood Glucose (CBG) levels in individuals undergoing surgery lasting 1-3 hours. Materials and Methods: This prospective interventional study included 100 non diabetic patients undergoing surgery of 1-3 hours duration with 50 patients in each group (GA and SAB). CBG was checked 30 minutes before the administration of anaesthesia, 30 and 60 minutes after the induction of anaesthesia, and 30 minutes after shifting to the Post Anaesthesia Care Unit (PACU) in both the GA and SAB groups. Differences in participant characteristics, such as age and CBG levels in the two groups (SAB and GA), were examined using the two-tailed Independent samples t-test and the Chi-square/Fisher’s exact test Results: The mean CBG levels measured 30 minutes before anaesthesia in the GA group were 105.50±21.13 mg/dL, while in the SAB group they were 99.67±19.04 mg/dL, with a p-value of 0.330. However, CBG levels measured 30 minutes after anaesthesia in the GA group were 125.69±22.95 mg/dL, compared to 104.67±20.94 mg/dL in the SAB group, with a p-value of 0.001. At 60 minutes after anaesthesia, CBG levels in the GA group were 152.41±28.97 mg/dL, while in the SAB group they were 99.65±22.69 mg/dL, with a p-value of 0.003. Finally, 30 minutes after shifting to PACU, CBG levels in the GA group were 147.49±27.20 mg/dL, compared to 92.86±24.35 mg/dL in the SAB group, with a p-value of 0.002. Conclusion: CBG levels significantly increased in individuals receiving GA for surgery. This indicates that the hormonal stress response is greater during GA compared to SAB.