Abstract
This paper describes a very rare case that suffered hyperventilation syndrome in sadated or sleeping state under spinal anesthesia. Acute hyperventilation occured in a 15-year-old female patient during orthopedic surgery of hip joint under spinal anesthesia <sensory level of Th-7>. Although no such symptom as pain, metabolic acidosis, hypercapnia, drug intoxication, an no past history of central nervous disorder or psychosomatic disorder, were evidenced to trigger hyperventilation, the patient suffered 13 episodes of hyperventilation which produced profound hypocapnia <PaCO2 19.7mmHg> during two and half hours. At the first hyperventilation attack the subject was under intravenous diazepam sedation. To supress each hyperventilation syndrome, diazepam fentanyl and/or thiamylal were injected. The patient showed normal neurologic or psychosomatic function in the post operative period. The cause of hyperventilation attack in this patient was unknown.
