A healthy 35-year-old man who was scheduled for closed reduction of nasal bone fracture developed atrial fibrillation during induction of general anesthesia after intravenous glycopyrrolate injection. During emergence of general anesthesia, atrial fibrillation was suddenly changed to paroxysmal supraventricular tachycardia with 200 beat per minute and lasted for about 10 seconds. Because blood pressure was stable, esmolol was used to reduce ventricular response. At recovery room, ventricular response reduction about 55 beat per minute was observed after intravenous injection of verapamil 5 mg. Thereafter, the rhythm was returned to normal sinus rhythm with bradycardia.
Maternal hypotension is a common problem during cesarean section under spinal anesthesia. We evaluated the influence of injection speed of local anesthetic to subarachnoid space on maternal hypotension and level of sensory block.
Methods
Bupivacaine (0.5%) 9 mg with fentanyl 10 µg was injected to subarachnoid space either quickly (during 20 seconds, 0.1 mL/sec, n=20) or slowly (during 100 seconds, 0.02 mL/sec, n=20) in parturients scheduled for elective cesarean section. The onset and level of sensory block was checked and heart rate and blood pressure was checked by 2.5 minutes during 20 minutes. Hypotension (systolic blood pressure <100 mmHg or <70% of baseline) was treated with ephedrine.
Results
Hypotension occurred 70% of parturients with spinal anesthesia. Slow injection didn't influence on the onset and level of sensory block and didn't reduce the incidence of hypotension. But onset of hypotension was delayed.
Conclusion
Slow injection (during 100 seconds, 0.02 mL/sec) of local anesthetic delayed onset of hypotension and required less amount of ephedrine. Slow injection of local anesthetic was one of the effective methods for the cardiovascular stability during cesarean section under spinal anesthesia.