Canadian Journal of Anesthesia, Vol 44, 662-665, Copyright © 1997 by Canadian Anesthesiologists' Society

ARTICLES

Hyperthermia after cardiac surgery

K Abe, Y Miyamoto and K Ohnishi
Department of Anaesthesiology, Osaka University Medical School, Japan. abe@anes.med.osaka-u.ac.jp

PURPOSE: To describe two cases of hyperthermia occurring after cardiac surgery. CLINICAL FEATURES: At the end of cardiopulmonary bypass, protamine was injected to reverse heparin. Following protamine, hypotension, pulmonary hypertension and hypoxia developed, but protamine induced hypotension recovered after administration of methyl predonisolone and catecholamines. Rectal temperature increased to 41 degrees C in the first case and 40 degrees C in the second after recovery from protamine induced hypotension. Arterial blood gas analysis, breathing 100% oxygen, showed severe acidosis and hypercapnia (pH 6.96, PaCO2 73 mmHg, PaO2 45 mmHg. BE -18 in the first case, and pH 7.13, PaCO2 59.9, PaO2 52.8, BE -11 in the second). At the same time, creatine phosphokinase levels showed 8400 u.L-1 in the first case and 4369 u.L-1 in the second. Serum and urine myoglobin concentrations were 334.2 ng.ml-1 and 1085 ng.ml-1, and 468 ng.ml-1 and 885 ng.ml-1, respectively. Efforts to cool the patients using alcohol were made. Following dantrolene (400 mg and 200 mg), the hyperthermia, acidosis, hypoxaemia and hypercarbia subsided (temperature 37.5 and 37.5 degrees C, PaO2 220 mmHg and 180 mmHg with 100% oxygen, PaCO2 35 mmHg and 41 mmHg respectively). Postoperatively, 20 mg.hr-1 dantrolene infusion were administered for 24 hr. In the first case, an anaphylactoid reaction was confirmed by increased plasma tryptase. CONCLUSION: We report two cases of hyperthermia after cardiac surgery in whom dantrolene was very effective in reducing the high rectal temperature.