[A case of bronchospasm under isoflurane anesthesia]

Isoflurane is generally considered to have little effect on bronchomotor tone. The following case report shows that isoflurane anesthesia can be associated with severe bronchospasm. A 9-year-old girl (35 kg, 140 cm) with no history of asthma or drug sensitivity was scheduled for emergency appendectomy. Anesthesia was induced with fentanyl, methohexital, and vecuronium. Breath sounds were normal prior to induction and after endotracheal intubation. Isoflurane was added to the gas mixture 5 min after the last injection. Almost immediately after isoflurane was added the mean inspiratory pressure increased from 15 to ca. 35 cm H2O, expiration was prolonged, and wheezing was heard on auscultation. End-expiratory CO2 increased from 5.1% to more than 8% (pCO2 ca. 60 mmHg). Halothane was substituted for isoflurane and theophylline was injected, i.v. shortly after which the inspiratory pressure decreased, the wheezing improved, and the end-expiratory CO2 returned to normal. The remaining course and postoperative period were uneventful. Isoflurane is considered to be the causative agent in this case. Other possible mechanisms are discussed and pertinent literature is reviewed.