CEC-Hemolise e NPS

Cardiopulmonary Bypass, Hemolysis, and
Nitroprusside-Induced Cyanide Production
Albert T. Cheung, MD
Gonzalo E. Cruz-Shiavone, BA
Qing C. Meng, PhD
Alberto Pochettino, MD
John A. Augoustides, MD
Joseph E. Bavaria, MD
E. Andrew Ochroch, MD, MSCE
BACKGROUND: Cyanide toxicity is a complication of sodium nitroprusside administration.
Cardiac surgery may increase the risk of cyanide toxicity, because
hemolysis during cardiopulmonary bypass (CPB) may catalyze the release of free
cyanide from sodium nitroprusside.
METHODS: We obtained serial blood specimens from 25 cardiac surgical patients
during CPB. Plasma specimens were analyzed for free hemoglobin concentration
and ability to generate free cyanide anion upon exposure to sodium nitroprusside.
RESULTS: Hemolysis based on plasma-free hemoglobin concentration increased over
time during CPB at an average rate of 0.27 mg
dL
1
min
1 (P 0.001). The
concentration of free cyanide generated by the addition of sodium nitroprusside to
the plasma samples was directly related to the plasma-free hemoglobin concentration
(P 0.001).
CONCLUSION: CPB-associated hemolysis and free hemoglobin release accelerated the
immediate release of free cyanide from sodium nitroprusside. These in vitro
findings suggest that cardiac surgical patients may be at increased risk of cyanide
toxicity in response to the perioperative administration of sodium nitroprusside.
(Anesth Analg 2007;105:29 –33)