Effects of Sodium Nitroprusside on the Time of Rewarming and Cardioversion during Heart Operations in Children up to Three Years of Age

Objective To study the effects of sodium nitroprusside on the time of rewarming and cardioversion during heart operations in children up to three years of age. Methods 56 children suffering from congenital heart diseases and scheduled for corrective therapy of the deformities were randomly divided into 2 groups: the sodium nitropruside group(n=36) and the control group(n=20).These children up to 3 years of age had a cardiac function of Grade Ⅱ to Grade Ⅲ.Systemic rewarming was begun at the time when 2/3 of the work of operation had been completed and the nasopharyngeal temperature and rectal temperature gradually rose to 36.5-37 ℃ and 35-36 ℃,respectively.Beginning from the starting of rewarming,patients of the sodium nitroprasside group was given each sodium nitroprusside(0.2-6.5 μg·kg~(-1)·min~(-1)) administered continuously via the central vain with a Grasly micropump.The mean arterial blood pressure in all patients were maintained within the range of 40-50 mmHg.All of the patients were subjected to extracorporeal circulation while endotracheal intubation was used to control respiration.The patients were given each IV injections of midazolam(0.15 mg·kg~(-1)),fentanyl(20(μg·kg~(-1))) and pancuronium bromide(0.1 mg·kg~(-1)) for anesthesia induction and disconnected IV injections of fentanyl(10(μg·kg~(-1))) and pancuronium bromide(0.1 mg·kg~(-1)) for maintenance anesthesia.Electric cardioversion was carried out of no spontaneous heartbeat took place or cardiac arrhythmias could not be converted to sinus rhythm 5 min after the declamping of the aorta.The time from the beginning to the termination of rewarming(t_(1)) and that from declamping the aorta to the restoration of sinus rhythm(t_(2)),as well as quantity of sodium nitroprusside used from the beginning of rewarming to the reappearance of sinus rhythm(Q) were noted down. Results The value of t_(1) and t_(2) in patients of the sodium nutroprusside group were significantly smaller than those in patients of the control group(P0.01).The value of Q in patients of the sodium nitroprusside group was negatively correlated with t_(1) and t_(2)(P0.01) while the value of t_(1) was positively correlated with t_(2) in these patients(P0.01). Conclusion Proper use of sodium nitroprusside during heart operations in young children was shown to shorten the time of rewarming and promote restoration of sinus rhythm.