Oral sodium citrate increases nausea amongst elective Cesarean delivery patients

Historically, aspiration of gastric contents with subsequent pneumonia was a major cause of anesthesia-related maternal mortality. Before elective Cesarean delivery, gastric fluid can be neutralized with histamine-2 blockers or with oral sodium citrate. Although sodium citrate is commonly used, many patients dislike its taste. We designed this study to determine whether or not patients are more likely to experience nausea during Cesarean delivery when sodium citrate is administered preoperatively.

One hundred and twenty-three healthy women carrying a singleton fetus and scheduled for elective Cesarean delivery under spinal anesthesia were randomized to receive either sodium citrate 30 mL p.o. and saline 2 mL i.v. (sodium citrate group), or water 30 mL p.o. and famotidine 20 mg i.v. (famotidine group). Spinal anesthesia consisted of 1.6 mL of 0.75% bupivacaine (12 mg), fentanyl 20 microg, and preservative-free morphine 200 microg. Patients were asked to rate the degree of nausea present at one and five minutes after spinal placement, at the time of uterine exteriorization, and upon arrival to the recovery room. At each time point, the patient's systolic blood pressure and heart rate were recorded.

At all recorded intervals, the average degree of nausea was greater in the sodium citrate group compared to the famotidine group. The frequency of nausea was also greater in the sodium citrate group compared with the famotidine group (37% vs 14% respectively, P < 0.05) five minutes after establishment of spinal anesthesia. The frequencies of nausea were not significantly different between groups at other time periods.

Nausea is more common during Cesarean delivery in women who receive oral sodium citrate rather than i.v. famotidine for aspiration prophylaxis.