[Intraoperative anaphylactic shock induced by methylergometrine and oxytocin]

We report a case of intraoperative anaphylactic shock in a 32-year-old multigravida woman undergoing elective cesarean section for partial placenta previa. Anesthesia was performed using combined spinal and epidural technique. After the baby was born, methylergometrine was administered i.v. simultaneously with oxytocin, the latter injected directly into the uterine muscle by an obstetrician. Several minutes later, she presented with dyspnea and became agitated. Because of the potential risk of pulmonary embolism, the patient was immediately intubated and mechanical ventilation was started. Her systolic blood pressure decreased to 50 mmHg and SpO2 to 87% under 100% oxygen administration. After catecholamine infusion, however, her respiratory condition soon improved. Postoperatively, her conjunctiva and vulva were not edematous. From the clinical course, it was considered that the patient was very likely to have suffered an anaphylactic reaction to oxytocin or methylergometrine. Forty days later, serological examinations as well as skin tests for those two drugs were carried out. While the serological tests were negative, the skin tests indicated the patient was allergic to both drugs. It is concluded that the endogenous peptide oxytocin can induce anaphylactic shock in multiparous women.