[Hyperventilation syndrome before induction of and after awakening from general anesthesia].

Hyperventilation syndrome has often occurred as a reaction to anxiety and stress. We experienced hyperventilation syndrome before induction of and after awakening from general anesthesia. A 53-year-old woman with no central nervous and psychiatric disease was scheduled for left total hip arthroplasty under general and epidural anesthesia. After entering the operating room, she was breathing faster and deeper than necessary. She complained of dyspnea, and the numbness and sweating of her lower extremities. We found that she had the same experience on her dental treatment. We diagnosed her as preoperative hyperventilation syndrome. Twenty minutes after she had become relaxed, we could insert the lumbar epidural catheter, and tracheally intubate following anesthesia induction with fentanyl, thiopental, and vecuronium. Anesthesia was maintained using inhalation of sevoflurane and epidural anesthesia with ropivacaine. As end-tidal carbon dioxide (EtCO2) value was 18 mmHg after anesthesia induction, we controlled the ventilator to regulate EtCO2. The operation was finished in 54 minutes successfully without a special event. She was extubated because there was no clinical problems. The total anesthesia time was 2 hours and 4 minutes. Postoperatively in the recovery room, she breathed fast and complained of dyspnea and the numbness of her extremities again. The arterial blood gas analysis showed reduced arterial partial pressure of carbon dioxide tension with resulting respiratory alkalosis. We diagnosed her as postoperative hyperventilation syndrome. We let her breathe in and out of a vinyl bag continuously and injected antipsychotic medication haloperidol intravenously. After injection of haloperidol 3 mg for 30 minutes, she recovered from hyperventilation. Hyperventilation syndrome before general anesthesia could occur postoperatively again. We supposed that her hyperventilation syndrome is induced by anxiety and stress of operation before induction and again after awakening from general anesthesia. Haloperidol could be effective for repeated hyperventilation syndrome induced by psychogenic factors during perioperative period.