Effect Of Nicardipine In Preventing Pituitrin-induced Cardiovascular Responses

Objective:To evaluate the efficiency of nicardipine in preventing pituitrin- induced cardiovascular responses in patients undergoing laparoscopic myomectomy. Methods:Using the method of random number table, sixty ASA I or II patients, aged 32~50 years old, body mass index 20 ~ 25, planned to undergo selective laparoscopic myomectomy applied with general anesthesia, were divided into three groups(n=20): control group(group C), urapidil group(group U) and nicardipine group(group N). The diluted substance of pituitrin 6 units and 0.9% sodium chloride 20 ml was injected into the uterine fibroid. And 2 minutes later, the patients were given intravenously 2 ml of 0.9% sodium chloride in group C, 0.5mg/kg urapidil in group U and 5mg/kg nicardipine in group N. Anesthesia was induced with midazolam 0.05 mg/kg, sufentanil 0.3mg/kg, etomidate 0.3mg/kg and vecuronium 0.1mg/kg. Patients were tracheal intubated and mechanically ventilated with the model of IPPV. The tidal volume was changed from 8 to 10 ml/kg, the respiratory rate was maintained between 12 and 14 times per minute, and inspiratory expiratory was keeped 1: 1.5~2. Anesthesia was maintained with TCI of propofol(target effect-site concentration 4 mg/ml) and remifentanil 0.3 mg·kg-1·min-1. The analgesics and muscular relaxants can be injected if needed during the operation. The bispectral index(BIS) was maintained between 45 and 55. The mean arterial pressure(MAP) and heart rate(HR) were recorded in 1 min(T0) before injection of pituitrin, 1 min(T1), 2 min(T2), 3 min(T3), 5 min(T4), 10 min(T5), 20 min(T6) and 30 min(T7) after injection of pituitrin. The occurrence of cardiovascular responses was also recorded at last. Results:1. The Comparison of hemodynamic index at T0By comparison, there was no statistically significant difference in MAP and HR at T0 among the three groups of the patients(P>0.05).2. The Comparison of MAP among the three groupsThe MAP in group C was decreased at T1, but increased at T4~T7 as compared with that at T0(P<0.05). The MAP in group U was reduced at T1 and T4 as compared with that at T0(P<0.05). The MAP in group N was reduced at T1 and T4 as compared with that at T0(P<0.05). The MAP in group U and group N at T4~T7 was significantly lower than that in group C(P<0.05). There was no significant difference in MAP between group U and group N(P>0.05).3. The Comparison of HR among the three groupsThe HR in three groups was increased significantly at T1 as compared with that at T0(P<0.05). In group N, the HR at T3~T7 was higher than that in group C and group U(P<0.05).4. The Comparison of the incidences of cardiovascular responses among the three groupsThe incidences of cardiovascular responses were 100%, 40% and 35% in groups C, U and N respectively. The incidence of cardiovascular responses was significantly lower in groups N and group U than in group C(P<0.0167). There was no significant difference in the incidence of cardiovascular responses between groups N and group U(P>0.0167). Conclusion:Nicardipine can effectively prevent pituitrin- induced cardiovascular responses in patients undergoing laparoscopic myomectomy, and it is superior to urapidil in reversing pituitrin-induced low heart rate.