Etiology and incidence of endotracheal intubation following spinal anesthesia for cesarean section

Background: The incidence of spinal failure necessitating general anesthesia and endotracheal intubation following spinal anesthesia for cesarean section is extremely low. Aspiration prophylaxis prior to spinal anesthesia is often recommended in case of spinal failure or excessive spinal block requiring the emergency administration of general anesthesia. Objectives: To determine the incidence of endotracheal intubation following spinal anesthesia for cesarean section. Methods: We retrospectively reviewed the peri-operative course of parturients undergoing cesarean section under spinal anesthesia at our institution from February 1991 to December 1993. If spinal failure occurred, 10 ml of sodium bicarbonate was administered by mouth prior to induction of general anesthesia. Results: Among the 743 cases that we reviewed, spinal failure occurred in 15 patients (2%) because of inadequate analgesia in 14 patients (1.9%) and unexpected prolonged surgery for hysterectomy in one patient (0.1%). No patient required intubation due to excessive spinal block. In none of the patients was a record of pulmonary aspiration identified. Conclusions: The extremely low incidence of spinal failure or excessive block necessitating endotracheal intubation suggests that routine aspiration prophylaxis may not be necessary prior to spinal anesthesia. However, these results should be confirmed by a prospective, controlled study on larger populations. An antacid should be readily available and administered whenever general anesthesia is required.