Abstract / Summary
Abstract Background The cephalad spread of intrathecal local anesthetic in term parturients is influenced by pregnancy-related anatomical and physiological changes. This study aimed to evaluate the association between demographic and pregnancy-related variables and sensory block level following single-shot spinal anesthesia with 12.5 mg hyperbaric bupivacaine for cesarean delivery. Methods The study included 183 term parturients who underwent cesarean delivery under spinal anesthesia at a single tertiary center. All received 12.5 mg of 0.5% hyperbaric bupivacaine with 25 mcg of fentanyl. Sensory block height at 5 min of spinal injection and maximum block level were used for analysis. Using multivariate ordinal logistic regression we evaluated the association between block levels and maternal variables including age, height, weight, weight gain, gestational age, gravidity and parity. Additional analyses included height-based subgroup comparisons (≤ 166 cm vs. >166 cm). Results No significant associations were identified between anthropometric variables and maximum sensory block height in the overall cohort. In contrast, several variables were associated with sensory block height at 5 min: greater maternal height (OR 0.95 per cm; p = 0.023) and higher pregnancy weight gain (OR 0.93 per kg; p = 0.009) were associated with lower early block levels, while higher maternal weight predicted higher block levels (OR 1.03 per kg; p = 0.010). Height subgroup analysis revealed no association between anthropometric factors and block height among parturients ≤ 166 cm, whereas in taller parturients weak positive correlations were noted between maximum block level and both gravidity ( r = 0.23; p = 0.023) and parity ( r = 0.25; p = 0.012). Conclusions No association was observed between maternal anthropometric characteristics, including height, weight, BMI, gestational weight gain and the maximum sensory block level when ED95-range dose of hyperbaric bupivacaine was used for cesarean delivery. However, early block dynamics at 5 min may be modestly related to maternal height, weight, and pregnancy weight gain.