Rapid sequence induction of general anesthesia and paralysis, with intubation of the trachea, is the standard of care for patients who require emergency cesarean section because of severe fetal distress in the absence of preexisting regional anesthesia. As a result of the impaired gastric emptying associated with pregnancy and labor, these patients are treated as if their stomachs are full; there is a serious risk of maternal morbidity or mortality if aspiration occurs. [1] Rapid sequence induction requires an intravenous route for drug administration. In rare instances, intravenous access may not be available, and the severity of the fetal distress may mandate delivery before access can be obtained. The authors describe a case wherein inhalation induction of anesthesia with a volatile anesthetic that does not irritate the airways proved to be a suitable alternative.

Our anesthesia call team was emergently summoned to the labor and delivery floor to care for a uniparous, 29-yr-old woman, gravida 2, at 38 weeks gestation, who presented a few minutes earlier complaining of labor pain. During the initial vaginal examination, her membranes ruptured to reveal a double footling breach fetus with 15–20 cm of prolapsed umbilical cord. The obstetrician had applied a heel electrode and was manually attempting to keep the fetus in the uterus as the patient was wheeled into the delivery room. When we arrived, the patient was on her hands and knees on the operating table. The fetal heart rate was 50 beats/min, and an obstetrician was performing a bimanual manipulation of the fetus. Nurses and technicians were preparing for emergency cesarean section, and the obstetrician stated, “The baby has to come out now.” There was no intravenous access, and no monitors had been applied to the mother.

Within 1 min of our arrival, the patient was rolled onto her back with left uterine displacement, and the abdomen was hastily painted with Betadine(R). During this time, both arms and the neck were inspected for a vein that could be used for intravenous catheter insertion or direct injection of induction drugs; unfortunately, no veins were apparent. The necessity for immediate delivery because of worsening fetal distress was repeatedly emphasized by the obstetricians and the neonatologists. Although the mother was slightly agitated, she remained cooperative and followed our instructions without hesitation. We applied the anesthesia mask and administered 10 l/min of oxygen with sevoflurane, 8%. The patient was gently but deliberately instructed to take several slow, deep breaths, as the sevoflurane filled the circuit and her lungs. Within about 30 s, the patient no longer responded to verbal commands, and her eyelash reflex was absent, but spontaneous ventilation continued. To minimize the risk of inducing coughing or retching, neither cricoid pressure nor positive pressure ventilation was used. During this time, a pulse oximeter was applied to the patient and revealed that the SpO2was 100%. At this point, we allowed the surgeon to begin. The patient showed no movement, change in respiratory pattern or increase in heart rate after incision. The baby was delivered less than 5 min after the patient's arrival in the operating room, less than 3 min after the start of anesthesia, and within 1 min of surgical incision.

After delivery, we applied routine intraoperative monitors. The vasodilation associated with anesthesia revealed an antecubital vein, where an intravenous infusion was initiated. After cis-atracurium, 10 mg given intravenously, we applied cricoid pressure and intubated the trachea without complication; we then progressively reduced the sevoflurane concentration to 1%. For the remainder of the procedure, anesthesia was maintained with N2O in O2, sevoflurane, and small amounts of midazolam and fentanyl. At the end of surgery, the muscle relaxant was reversed, the patient awakened, and the trachea was extubated without complication.

The 1-, 5-, and 10-min Apgar scores were 2, 6, and 8, respectively. The neonate was intubated to assist oxygenation and ventilation. His umbilical arterial blood had a pH of 7.18, PCO2of 60.2 mmHg, and a base excess of -6.9 mEq/l, suggestive of a mixed metabolic and respiratory acidosis. [2] Within 2 h, he had been extubated and spent time with his mother in her room. After an uneventful night of observation in the neonatal intensive care unit, he was transferred to the newborn nursery and was discharged to home with his mother 2 days later.

For the anesthesiologist, the first concern in an emergency cesarean section is to ensure the safety of the mother; concerns about fetal compromise do not justify placing the mother at undue risk of anesthesia-related complications. However, as in all medical decisions, the risk-to-benefit ratio should be considered when choosing the best anesthetic technique in a given circumstance. The primary concern in these situations is that parturients are at high risk for aspiration of gastric contents, with its attendant morbidity and potential mortality. For this reason, rapid sequence induction of general anesthesia is indicated where there is a nonreassuring fetal heart rate tracing or prolonged fetal bradycardia and time constraints prevent the initiation of regional blockade. [1] However, with a fetus in extremis, where any delay in delivery may lead to fetal demise, there may not be time to obtain the intravenous access necessary for rapid sequence induction. In such patients, the options are limited: infiltration with local anesthetics or induction of anesthesia by a nonintravenous route. Adequate local infiltration may take several minutes to accomplish, and the technique is no longer taught in most obstetric residencies; induction of anesthesia and paralysis by intramuscular injection of an induction agent (e.g., ketamine) and succinylcholine may not produce paralysis rapidly enough to avoid coughing, straining, or vomiting.

Because of its nonpungent odor, sevoflurane is well tolerated during gradual and single-breath vital capacity induction of anesthesia. [3] Sevoflurane's low blood-gas solubility coefficient allows for a rapid increase of its partial pressure in the vessel-rich group, with the speed of induction approaching that of intravenous anesthetics. [4] During pregnancy, the increase in VE and decreased FRC and MAC would be expected to further hasten induction. The low incidence of airway irritability with this agent minimizes the risk of coughing, gasping, retching, or breath holding, thus reducing the likelihood of vomiting during induction, despite the presumed full stomach of the parturient. Sevoflurane does not sensitize the myocardium to catecholamines or cause serious tachycardia during induction (in contrast to desflurane).

Although it does not provide the same degree of safety afforded by rapid sequence endotracheal intubation, general anesthesia for obstetrical procedures can be managed without endotracheal intubation in certain critical situations. When cyclopropane was the anesthetic of choice for cesarean section, inhalation induction and maintenance of anesthesia with spontaneous or assisted ventilation via a facemask was routine, [5] although not without risk. In addition, administration of a nonirritating inhalation anesthetic with spontaneous or positive pressure ventilation via a facemask is presently recommended in patients in whom endotracheal intubation proves impossible and fetal distress requires immediate delivery. [1]

We have presented a case of inhalation induction with sevoflurane for emergency cesarean section in a patient with a prolapsed umbilical cord and no intravenous access, with a good outcome for the mother and the infant. The availability of a rapidly acting nonpungent anesthetic like sevoflurane provides another option in the treatment of patients requiring emergency cesarean section during these circumstances.

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