The relationship between abdominal circumference measurement and sensory block level in pregnant women undergoing cesarean section with spinal anesthesia

Aim: The aim of this study is to investigate the effect of abdominal circumference measurement on the sensory block level after spinal anesthesia in pregnant women undergoing cesarean section and to explore the relationship between abdominal circumference and unwanted conditions such as hypotension, bradycardia, nausea, vomiting, and the need for vasoconstrictor agents and/or colloids during spinal anesthesia. Material and Method: A total of 166 voluntary pregnant women aged 18 and above, undergoing elective cesarean section with spinal anesthesia in the Central Operating Room of Dokuz Eylül University Hospital, were included in the study. Patient data, including height, weight, age, pre-pregnancy body mass index (BMI), current BMI, fetal gestational age, and ASA classification, were recorded. In contrast to routine practice, abdominal circumference was measured with a tape measure from the level of the umbilicus while the patient was in the supine position. Spinal anesthesia was administered with the patient in the sitting position, and hyperbaric bupivacaine with added opioid was used at a dose determined according to body weight. Blood pressure and heart rate were recorded at 1 minute after spinal anesthesia and subsequently every 2 minutes for a total of 20 minutes. The level of cold sensation loss along the mid-clavicular line and the level of sensory loss determined by pin prick testing were recorded at 1, 5, 10, and 15 minutes after spinal anesthesia. Any nausea, vomiting, bradycardia, hypotension, and administered drugs occurring post-spinal anesthesia were documented on a follow-up form. The newborn's APGAR score and body weight were obtained from the pediatric team and recorded. Correlations between umbilical circumference measurements, sensory block levels, and unwanted side effects were statistically analyzed. Results: The participants in the study had abdominal circumferences ranging from 80 to 139 cm. After spinal anesthesia, hypotension was observed in 44.6% of patients, nausea in 19.9%, vomiting in 4.2%, and bradycardia in 7.2%. Correlations were found between abdominal circumference measurements and sensory block levels at 1st, 5th, and 10th minutes. Additionally, a significant association was observed between abdominal circumference measurements and the occurrence of hypotension, bradycardia, and nausea, while no significant association was found with vomiting. We also identified a statistically significant correlation between waist circumference and the dose of ephedrine required after hypotension Conclusion: A relationship has been observed between the umbilical circumference and the hypotension observed after spinal anesthesia in pregnant women, along with associated complications. Consequently, it has been concluded that research should be conducted to calculate the spinal anesthesia dose based on the umbilical circumference.