日本小児循環器学会雑誌 Pediatric Cardiology and Cardiac Surgery

Malignant hyperthermia has been described as a rare genetic hypermetabolic disorder of skeletal muscle that is triggered by exposure to certain inhalation anesthetics and depolarizing muscle relaxants. The incidence of malignant hyperthermia has declined with improvements in anesthesia in recent years, but it is still a lethal complication of cardiac surgery. We experienced a case of postoperative fulminant malignant hyperthermia after pediatric cardiac surgery. The patient was an 11-month-old boy with a ventricular septal defect (VSD) and Down syndrome. He previously had undergone pulmonary artery banding and ligation of the persistent ductus arteriosus on day 21 after birth due to respiratory distress. In the present treatment, he underwent closure of VSD and de-banding. The operation was performed uneventfully, but soon after surgery, his body temperature rose to as high as 40°C. Two days after surgery, desaturation and cardiac failure occurred with hypermetabolic disorders. We re-opened the sternum, and his condition recovered after this procedure. We diagnosed this condition as a fulminant type of postoperative malignant hyperthermia. Dantrolene sodium hydrate was infused, and strong cooling via a mat was applied. He recovered with no significant neurological damage. We should be aware of this lethal complication after cardiac surgery. This case reminded us that early diagnosis and quick treatment are most important.