甲氧明持续泵注预防开胸手术中低血压的效果观察

The preventive effects of methoxamine pretreatment on hypotension in thoracotomy

目的探讨全麻复合硬膜外麻醉开胸手术中持续泵注甲氧明预防低血压的临床效果。方法选择在全身麻醉复合硬膜外麻醉下行开胸手术患者151例,年龄40~65岁,ASAⅠ~Ⅱ级,将其随机分为3组。A组(n=52)当基础血压降低超过20%或收缩压<80 mm Hg时则推注甲氧明2 mg,必要时再推注甲氧明1 mg,直至血压恢复基础值水平的±20%之内。B1组(n=51)和B2组(n=48)在硬膜外穿刺成功后推入1%利多卡因3 mL试验量后即刻推注甲氧明1 mg,并以3μg/(kg·min)和4μg/(kg·min)泵注,5 min后间断推注0.375%罗哌卡因6~10 mL,若血压低于基础血压的20%或收缩压<80 mm Hg时追加甲氧明1 mg,直到血压恢复基础值水平的±20%。记录患者硬膜外操作前(T0)、推注罗哌卡因5 min后(T1)、推注罗哌卡因15min后(T2)、全麻诱导后(T3)、开胸探查时(T4)血流动力学参数:收缩压(SBP)、舒张压(DBP)、心率(HR)。并记录手术时间、术中输液量、尿量、失血量以及纠正低血压时推注甲氧明的次数等。结果与A组(59.61%)比较,B1组、B2组低血压发生率分别为23.53%和8.33%,差异均有统计学意义(P<0.05),B1组与B2组比较差异有统计学意义(P<0.05)。与A组比较,B1组、B2组甲氧明纠正低血压时需要单次给药次数明显减少(P<0.05)。SBP、DBP、HR的变化:与T0相比3组患者SBP、DBP、HR在T2、T3均显著降低(P<0.05);与A组相比,B1组、B2组SBP、DBP在T2、T3显著升高(P<0.05),B2组SBP、DBP在T3比B1组升高更明显,差异有统计学意义(P<0.05)。结论全麻复合硬膜外麻醉在开胸手术中应用甲氧明可有效防治麻醉期间低血压,相对于补救性单次给药,预防性持续给药可明显降低低血压的发生率、有效的维持血压稳定,甲氧明持续泵入速度4μg/(kg·min),其血流动力学更稳定。

Objective To observe the preventive effects of methoxamine infused with micro-pump on hypotension induced by combined extradural and general anesthesia（ CEGA） in thoracotomy. Methods Under CEGA,151 patients（ aged 40-65 years old,ASA Ⅰ-Ⅱ） undergoing thoracotomy were randomly divided into 3 groups,Group A（ n = 52,received single dose methoxamine）,Group B1（ n = 51,received methoxamine 3 μg/（ kg·min） infused with micro-pump）,Group B2（ n = 48,received methoxamine 4 μg/（ kg· min） infused with micro-pump）. Patients in Group A received a bolus methoxamine of 2 mg whenever systolic blood pressure（ SBP） decreased to 80 mmHg or lower than 80% of baseline. If necessary,additional bolus of methoxamine of 1 mg was administered until the SBP recovered to（ 100 ± 20） % of the baseline. After epidural puncture,patients in Group B1 and Group B2 received 3 ml of 1% Lidocaine via spinal needle and 1 mg bolus of methoxamine intravenous injection. Subsequently,patients in Group B1 received methoxamine 3 μg/（ kg·min） infused with micro-pump,as patients in Group B2 received methoxamine 4 μg/（ kg·min） infused with micro-pump followed by intermittent 0. 375% Ropivacame via spinal needle. Whenever SBP decreased to 80 mmHg or lower than 80% of the baseline,additional a bolus of methoxamine of 1 mg was administered until the SBP recovered to（ 100 ± 20） % of the baseline. Systolic blood pressure（ SBP）,diastolic blood pressure（ DBP） and heart rate（ HR） were recorded before anesthesia（ T0）,5 min after ropivacaine administration（ T1）,15 min after ropivacaine administration（ T2）,during general anesthesia induction（ T3） and at beginning of thoracotomy（ T4）. The time of operation,infusion quantity during operation,urine volume,bleeding volume and frequency of methoxamine required were also recorded. Results Compared with Group A,the incidence of hypotension in Group B1 and B2 were 23. 53% and8. 33%,respectively,which was significantly lower（ P 〈 0. 05）. There were significant differences in the frequencies of methoxamine required between Group B1 and B2（ P 〈 0. 05）. At T2 and T3,the SBP,DBP,HR in Groups A,B1 and B2 were significantly lower than those at T0. The SBP and DBP in Group B1 and B2 were significantly higher than those in Group A（ P 〈 0. 05）. At T3,the SBP and DBP in Group B2 was significantly higher than group B1（ P 〈 0. 05）. Conclusion The usage of methoxamine has preventive effects on hypotension induced by CEGA in thoracotomy. In comparison with irregular administration,prophylactically sustained administration provides lower incidence of hypotension and more stable blood pressure. The infusion speed of 4 μg/（ kg·min） is more beneficial for hemodynamic stability.