Purpose: To determine whether or not intravenous nitroglycerin (IV NTG) can prevent a decrease in near-infrared spectroscopy (NIRS) values during cardiopulmonary bypass (CPB).
Methods: We conducted a randomized double-blinded study in a tertiary academic center including 30 patients with a Parsonnet score>or=15 scheduled for a high-risk cardiac surgery. The patients were randomized to receive either IV NTG (initial dose of 0.05 microg.kg(-1).min(-1), followed by 0.1 microg.kg(-1).min(-1)) or placebo after anesthetic induction until the end of CPB. The primary outcome was a decrease of 10% in NIRS values during CPB.
Results: Despite the absence of between-group difference in the mean cerebral oxygen saturation during CPB, there was a significant decrease in NIRS values during CPB in the placebo group, whereas mean NIRS values were maintained in the IV NTG group (-16.7% vs 2.3% in the NTG, P=0.019). Major hemodynamic variables were similar at corresponding time periods in both groups, while patients in the IV NTG group had higher CK-MB values and experienced greater blood loss during the first 24 hr postoperatively.
Conclusion: Intravenous nitroglycerin administration before and during CPB may prevent a decrease in NIRS values associated with CPB in high-risk cardiac surgery. Further studies are warranted to determine the efficacy and the risks associated with IV NTG infusion for this indication during CPB in high-risk patients.