七氟醚对室间隔缺损患儿脑血管CO2反应性的影响

Effects of sevoflurane on cerebrovascular carbon dioxide reactivity in ventricular septal defect children

目的使用经颅多普勒超声监测脑血流,比较静脉麻醉药与七氟醚对室间隔缺损患儿脑血管二氧化碳反应性(cerebrovascular carbon dioxide reactivity,CO2R)的影响。方法纳入3~12月龄患儿32例,随机分为两组。静脉组静注哌库溴铵0.2 mg/kg、咪达唑仑0.2 mg/kg及舒芬太尼1 μg/kg,肌松满意后行气管插管,全凭静脉维持麻醉。吸入组持续吸入七氟醚1.5 MAC,静注哌库溴铵0.2 mg/kg,自主呼吸消失后行气管插管,七氟醚1.0 MAC维持麻醉。调整机械通气条件,使PETCO2依次维持在30 mmHg(T1)、35 mmHg(T2)、40 mmHg(T3)、45 mmHg(T4),使用经颅多普勒超声测量右侧大脑中动脉血流平均速度(VMCA),同时记录HR、心脏指数(CI)及BIS,计算CO2R。结果T1—T4时两组VMCA明显增加,HR明显减慢(P<0.01);吸入组BIS值和CO2R明显下降(P<0.01或P<0.05)。与静脉组比较,吸入组T3和T4时VMCA,T1—T4时HR、T1—T2时段CO2R明显增高(P<0.01或P<0.05)。结论1.0 MAC七氟醚麻醉下,在低PETCO2范围内CO2R更高,且高于使用静脉麻醉药物。

Objective To compare the effects of sevoflurane on cerebrovascular carbon dioxide reactivity(CO2R) and intravenous anesthetics in children with ventricular septal defect by monitoring cerebral blood flow with transcranial Doppler. Methods Thirty-two patients aged 3-12 months were enrolled and randomly divided into intravenous group and inhalational group. After admission, sevoflurane was administered via facemask and peripheral intravenous access was established after disappearance of body movement. In intravenous group, sevoflurane was ceased, pipecuronium(0.2 mg/kg), midazolam(0.2 mg/kg), and sufentanil(1 μg/kg) were administered intravenously, tracheal intubation was performed when muscle relaxation was satisfied. In inhalational group, sevoflurane at 1.5 MAC was administered continuously, pipecuronium(0.2 mg/kg) was administered intravenously, tracheal intubation was performed after spontaneous respiration disappeared, and anesthesia was maintained with 1.0 MAC sevoflurane. By manipulating mechanical ventilation, PETCO2 was maintained at 30 mmHg(T1), 35 mmHg(T2), 40 mmHg(T3), and 45 mmHg(T4) in sequence. Transcranial Doppler was used to measure right middle cerebral artery blood flow velocity(VMCA), meanwhile, heart rate, cardiac index, and bispectral index were recorded, and CO2R was calculated. Results During T1-T4 in both groups, VMCA significantly increased and heart rate obviously decreased(P<0.01), in inhalational group, BIS and CO2R decreased markedly(P<0.01 or P<0.05). Compared with intravenous group, VMCA at T3 and T4 (P<0.05), heart rate at T1-T4 phase(P<0.05), and CO2R during T1-T2 phase(P<0.01) were significantly higher in inhalational group. Conclusion Under 1.0 MAC sevoflurane anesthesia, CO2R is higher in hypocapnic range and higher than CO2R under intravenous anesthesia.