Correlation of Symphysiofundal Height and Abdominal Girth with the Incidence of Hypotension in Cesarean Section Under Spinal Anesthesia using Bupivacaine with Fentanyl as Adjuvant: A Clinical Study

BACKGROUND AND AIMS: A decreased lumbosacral subarachnoid space volume is a major factor in cephalad intrathecal spread of local anesthetic in term parturients due to compressive effect of the gravid uterus. The aim of this study was to assess the relationship of symphysiofundal height (SFH) and abdominal girth (AG) with the incidence of hypotension and the highest level of sensory blockade. SETTINGS AND DESIGN: This study was a prospective observational study. MATERIALS AND METHODS: Ninety parturients under the American Society of Anesthesiologists physical status class II within the age range of 20–30 years, weighing between 60 and 65 kg, and height between 150 and 155 cm were studied, and the SFH and AG of all parturients had been measured just before spinal anesthesia. Hyperbaric bupivacaine 9 mg with 12.5 μg intrathecal fentanyl was administered for subarachnoid block. The incidence of hypotension and the highest level of sensory block were assessed. STATISTICAL ANALYSIS: Correlation analysis (Spearman's rank test) was applied to analyze the data, and P < 0.05 was considered to be statistically significant. RESULTS: The incidence of hypotension was higher with increasing SFH (16.9% with SFH of 30–35 cm, 78.37% with SFH of 36–40 cm; correlation coefficient ρ =0.338) and with increasing AG (5.3% with AG between 85 and 89 cm, 35.7% with AG 90–94 cm, 62.8% with AG 95–99 cm; ρ =0.341), and both were statistically significant (P < 0.001). There was a statistically significant correlation between increasing SFH and maximum sensory block achieved (ρ =0.157, P < 0.001). There was increased level of sensory blockade with increased AG but was not statistically significant (ρ =0.011, P = 0.32). CONCLUSION: In term parturients undergoing cesarean section under spinal anesthesia, the SFH has a significant positive correlation with the incidence of hypotension and ascent of spinal anesthesia. AG also has a positive correlation with the incidence of hypotension but is not significant with the ascent of spinal anesthesia.