Effects on hypotension incidence: hyperbaric, isobaric, and combinations of bupivacaine for spinal anesthesia in cesarean section

To determine if hypotension frequency changes when hyperbaric or isobaric formulations of bupivacaine, or their sequential administrations, are used for cesarean section. Hypotension after spinal anesthesia for cesarean section is common. Materials and methods: A total of 144 patients who were to undergo cesarean section with spinal anesthesia were allocated into 4 groups. Spinal anesthesia was achieved with 10 mg of hyperbaric bupivacaine in Group H10, sequential 5-mg administrations of hyperbaric and isobaric bupivacaine in Group H5P5, sequential 5-mg administrations of isobaric and hyperbaric bupivacaine in Group P5H5, and 10 mg of isobaric bupivacaine in Group P10. Hemodynamic parameters were determined and the incidence of hypotension, incidence of bradycardia, and amount of ephedrine required to treat hypotension were recorded. Fetal Apgar scores, the pH of the umbilical cord blood, and side effects were also noted. Results: American Society of Anesthesiologists risk group, surgical duration, and demographic values were similar among the groups. The incidence of hypotension was found to be 69.4%, 66.7%, 75.0%, and 83.3% in the H10, H5P5, P10, and P5H5 groups, respectively. The incidences of hypotension were not significantly different. Bradycardia incidence, ephedrine consumption, the pH of cord blood, and side effects were not different among the groups. Conclusion: When the dose of local anesthetic is the same, the incidence of spinal-induced hypotension cannot be lowered using hyperbaric, isobaric, or sequential injections of a half dose of bupivacaine for spinal anesthesia during cesarean section.