Efficacy of Glyceryl trinitrate (GTN) to facilitate the rewarming process during cardiopulmonary bypass

Abstract

Background: Does Glyceryl trinitrate (GTN) administered during rewarming on cardiopulmonary bypass (CPB) impact: time to completion of rewarming prior to separation from CPB circuit, early post-op patient peripheral - core temperature gradient, time to maintenance of normothermia (core temperature > 36.5 °C) for minimum of 2 h in the initial post-op period, and plasma lactate concentrations initially post-CPB.

Methods: Single centre prospective randomized trial conducted in the Mater Misericordiae University teaching hospital in Dublin Ireland.

Trial registration: ISRCTN registry, ISRCTN10480871 , registered 16th of August 2017. 82 patients enrolled. Patients randomised to low dose GTN infusion (0.01 mcg/kg/min) or higher dose GTN infusion (0.5 mcg/kg/min) during rewarming on CPB.

Measurements and main results: There was no significant difference between the treatment arms for the total time to being rewarmed, U = 759.0, p = 0.84. There were also no differences between the treatment arms for the time to achieve core temperature greater than 36.5 after two hours, U = 714.0, p = 0.52, the time to achieve plateau core skin temperature, U = 688.0, p = 0.37, and the post-intervention protamine lactate, U = 721.0, p = 0.56.

Conclusions: Higher dose GTN infusion during rewarming on CPB does not improve peripheral-core temperature gradient post operatively and has no effect on post-operative lactate concentrations.

Keywords: Cardiopulmonary bypass; Glyceryl trinitrate; Lactate; Rewarming; Temperature gradient.

Fig. 1

Box-plot for Total Time to Re-warm

Fig. 2

Box-plot for Time to Achieve Core Temperature Greater Than 36.5 × 2 Hours

Fig. 3

Box-plot for Time to Achieve Plateau Core Skin Temperature

Fig. 4

Box-plot for Post-Protamine Lactate

Fig. 5

CONSORT flow diagram reflecting recruitment of patients [23]