Effect of spinal anesthesia on the QT interval in term and post-term pregnancies scheduled for elective cesarean section: a prospective study.

Objectives

In this study, we aimed to investigate the effects of spinal anesthesia on the QT interval in patients with term and post-term pregnancy that were scheduled for elective cesarean section.Materials and methods: Forty pregnant women scheduled for elective cesarean section under spinal anesthesia were assigned into two groups: Post-term group (Group P) (n = 20) and Term group (Group T) (n = 20). After entering the operation room, standard monitoring [electrocardiography (ECG), noninvasive blood pressure, heart rate, respiratory rate, and peripheral oxygen saturation] was performed. The patient was placed in the sitting position and spinal anesthesia was performed with a median approach at the L3-L4a level using a 25G Quincke-type spinal needle. After cerebrospinal fluid was viewed, 12.5 mg (2.5 mL) hyperbaric bupivacaine was administered intrathecally over 1 min. Other ECG records were made at min 1 (T1), 5 (T2), and 10 (T3) after the induction of spinal anesthesia and after skin closure (T4). QT and QT dispersion were measured from ECG. Heart rate-corrected QT (QTc) and QT dispersion (QTcd) values were calculated using the Bazett formula.

Results

Demographic characteristics of the patients were similar in both groups. Postoperative QTc, QTd, and QTcd values were significantly increased in Group P compared to those in Group T (p < .05).

Conclusion

Spinal anesthesia led to increased postoperative QTc, QTd, and QTcd values in the patients with a gestational age of ≥42 weeks who underwent cesarean section. Accordingly, it is advisable to perform postoperative strict cardiac monitoring particularly in post-term pregnant women undergoing spinal anesthesia.