Apnea Associated With the Intrathecal Administration of Morphine in Obstetrics A Case Report

A 21-year old female in active labor was given 1 mg of preservative-free morphine in 10% dextrose solution intrathecally when pain relief was requested. Pain relief was evaluated on a visual analog scale and note made of cardiorespiratory variables including ventilatory rate, degree of alertness and arterial oxygen saturation. Partial analgesia started 30 minutes after drug injection but the pain never showed marked relief, prompting the administration of 8 ml of 0.5% bupivacaine extradurally with complete pain relief. An infant was delivered vaginally without problems nearly 7 hours after intrathecal morphine. 8 1/2 hours after intrathecal injection she required 3 doses of 0.1 mg of naloxone IV for control of vomiting despite which she remained sleepy, had episodes of unconsciousness, and demonstrated decreased SaO2 (92%). Over the next 6 hours she received a total of 3.2 mg of naloxone by bolus and drip to produce improvement of ventilation and consciousness as well as normalization of SaO2.