Canadian Anaesthetists’ Society Journal

, Volume 22, Issue 5, pp 553–560 | Cite as

Sodium nitroprusside in children: Observations on metabolism during normal and abnormal responses

  • D. W. Davies
  • Leila Greiss
  • D. Kadar
  • D. J. Steward


Three different responses to sodium nitroprusside as a hypotensive agent during anaesthesia in children are described. A constant high dose (> 3 mg/Kg) response to, abnormal resistance to and tachyphylaxis to the drug are recognised and are dangerous and potentially lethal. They are probably related to abnormalities of cyanide-thiocyanate metabolism resulting in cyanide accumulation. The abnormal responses produce metabolic acidosis, an increase in mixed venous oxygen tension and a decrease in arterial-mixed venous oxygen content difference. Tachyphylaxis may be due to depletion of endogenous thiosulphate and was reversible by sodium thiosulphate therapy (150 mgm/Kg) in two cases in which it was used.


Sodium Nitroprusside Thiosulphate Pro2 Hypotensive Agent Control Hypotension 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Notre expérience avec le Nitroprussiate de Na, chez les enfants, nous a permis de classifier les patients selon leur réponse à cet agent.

Un groupe de patients a une réponse adéquate avec une dose totale plus petite que 3 mg/kg.

D’autres requièrent une dose élevée constante conduisant à une dose totale plus grande que 3 mg/kg. Chez d’autres patients il y a résistance anormale au Nitro-prussiate. Enfin, l’apparition d’une tachyphylaxie est observée dans un dernier groupe de patients.

Les réponses observées chez ces trois derniers groupes de patients sont probablement liées à un métabolisme anormal de l’agent avec accumulation de cyanure. Il y a alors production d’acidose métabolique, le Po2 du sang veineux mixte s’élève, et la différence artério-veineuse en oxygène diminue.

Une déplétion du thiocyanate endogène peut conduire à une tachyphylaxie. De fait on a pu renverser une tachyphylaxie chez deux enfants en administrant du thiocyanate de sodium à la dose de 150 mg/kg.


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Copyright information

© Canadian Anesthesiologists 1975

Authors and Affiliations

  • D. W. Davies
    • 2
  • Leila Greiss
    • 1
  • D. Kadar
    • 1
  • D. J. Steward
    • 1
  1. 1.Departments of Anaesthesia and PharmacologyUniversity of TorontoTorontoCanada
  2. 2.Department of AnaesthesiaThe Hospital for Sick ChildrenTorontoCanada

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