Canadian Journal of Anesthesia, Vol 26, 375-380, Copyright © 1979 by Canadian Anesthesiologists' Society

Etude Des Concentrations Sanguine et Urinaire en Cyanure au Cours de Perfusion de Nitroprussiate de Sodium de Longue Duree

¹ Département d'Anesthésie-Réanimation (Pr. J. du Caillar), Hôpital Saint-Eloi 34059 Montpellier CEDEX (France)

Five deeply comatose neurological patients were administered a continuous perfusion of sodium nitroprusside (SNP) at the rate of 3 µg·kg^-1·min^-1. The levels of blood cyanide (CN^-) were measured two hours after the start, then every 12 hours during, and 12 and 24 hours after the end of perfusion. The urinary output of CN^- was also studied. The results show that total blood CN^- stabilized after 36 hours to a mean value of 0.11 mg/l. When perfusion was stopped, CN^- blood levels dropped but did not reach pre-perfusion values at the 24th hour. Urinary excretion of CN^- which reached a maximum value of 0.050 mg/24 h represents a negligible amount and does not explain the fall of blood CN^- and the occurrence of a concentration plateau. The results showing lower values obtained on non-anesthetized patients during the first hours of perfusion compared to those of a previous study done under neuroleptanaesthesia are discussed. These results suggest that prolonged perfusions at SNP at the rate of 0.177 mg·kg^-1·h^-1 do not produce toxic blood level of CN^-.