The effects of using preoperative oral carbohydrate solution on perioperative hemodynamic changes in patients under spinal anesthesia

ABSTRACT THE EFFECTS OF USING PREOPERATIVE ORAL CARBOHYDRATE SOLUTION ON PERIOPERATIVE HEMODYNAMIC CHANGES IN PATIENTS UNDER SPINAL ANESTHESIA The aim of the present study was to explore the effects of an oral carbohydrate solution given during preoperative fasting on perioperative hemodynamic changes in a group of patients undergoing surgery with spinal anesthesia. Male or female patients between 20 and 60 years of age with an ASA status of I or II undergoing elective lower abdominal or lower extremity surgery with spinal anesthesia were included in this study. Patients were randomly assigned into one of the three study groups, i.e. the carbohydrate (Group KH), lactater Ringer's (Group RL), or control (Group K) group. Patients in Group KH received a total of 800 ml of oral carbohydrate solution in two equal divided doses one given at 12.00 p.m. the night before surgery and one approximately 2 to 3 hours prior to anesthesia, while patients in Group RL received i.v. RL at an infusion rate of 100 ml/hour from 12.00 am prior to surgery until spinal anesthesia was given. The traditional fasting protocol was given in patients in Group K. Non-invasive systolic and diastolic arterial blood pressure (SBP, DBP), heart rate (HR), peripheral oxygen saturation (SpO2), and electrocardiography monitorization were performed in all patients. Prior to anesthesia, RL 10 ml/kg was administered intravenously in 20 to 30 minutes. Spinal anesthesia was accomplished using a 24 G "Quincke" spinal needle with 0.5% isobaric bupivacaine 2.5 ml (12.5 mg) injected into the subarachnoid space at L3-L4 level. Hemodynamic parameters were recorded prior to anesthesia, with 5 minute intervals in the first 30 minutes following the administration of local anesthetic, followed by 10 minute intervals until the termination of the surgery, and with 15 minute intervals during the postoperative recovery period. Then, patients were monitored for 24 hours in their surgical ward for the occurrence of possible complications, after which the patient satisfaction was assessed. There was no significant difference in demographic features and total fluid intake between the groups. In all three groups, heart rates decreased significantly 10 minutes after spinal anesthesia, compared to the basal values before spinal anesthesia; however, these changes were not clinically significant. In Group RL and Group K, perioperative heart rates were lower compared to the basal values; however, in Group KH, hear rates exceeded the basal values after perioperative 70th minute. In all three groups, systolic and diastolic blood pressures decreased significantly 10-20 minutes after the spinal anesthesia compared to the basal values before spinal anesthesia; however, these changes were not clinically significant. Systolic and diastolic blood pressure decreases in Group K were more significant and long term compared to Group KH and Group RL. We observed certain complications including headache, urinary retention and nausea and/or vomitting. However, there was no significant difference in the incidence of these complications between three groups. Patients expressed similar degree of satisfaction concerning the anesthesia method used in their case. In conclusion, preoperative oral carbohydrate solution given prior to regional anesthesia resulted in similar hemodynamic changes associated with spinal anesthesia as compared to intravenous administration of lactated Ringer's solution, with similar levels of patient satisfaction. Considering other additional beneficial effects of preoperative carbohydrate solutions such as reduced anxiety, hunger, nausea and/or vomiting, and insulin resistance, and improved patient comfort, these solutions seem to represent a viable alternative to lactated Ringer's solution for the prevention of adverse hemodynamic changes associated with spinal anesthesia. Keywords: Spinal anesthesia, oral carbohydrate solution, blood pressure, heart rate.