预注甲氧明预防老年患者腰硬联合麻醉后低血压的临床观察

Clinical observation of pre-injection of methoxamine on the prevention of hypotension in elderly patients after combined spinal-epidural anesthesia

目的 探讨预注甲氧明防治老年人椎管内麻醉低血压的临床效果。方法 将67例拟行腰硬联合麻醉下肢骨折切开复位内固定术或人工股骨头置换术患者随机分成甲氧明组（M组）和麻黄碱组（E组）。入室静脉输注复方乳酸钠山梨醇注射液200-300 ml,穿刺成功后蛛网膜下腔注入布比卡因8-12 mg,腰麻给药同时M组静脉给予甲氧明2 mg,E组给予麻黄碱5 mg。出现低血压时,给予静注麻黄碱5-10 mg;当心率〈60次/min时,给予阿托品0.25-0.50 mg。记录麻醉前,麻醉5 min、15 min及30 min时两组患者收缩压（SBP）、舒张压（DBP）及心率（HR）,以及恶心呕吐、心动过缓等不良反应发生情况。结果 M组麻醉后5 min、15 min及30 min时点SBP及DBP均高于E组,心率在15 min及30 min低于E组,差异有统计学意义（P〈0.05）。术中M组低血压、心动过缓、心悸等不良反应发生率明显低于E组,差异有统计学意义（P〈0.05）。结论 静脉预注甲氧明能有效降低腰硬联合麻醉后老年下肢骨科手术中的低血压发生率,且不良反应少。

Objective To investigate the effects of pre-injection of methoxamine on prevention of elderly hypoten-sion after spinal-epidural anesthesia. Methods Sixty-seven patients who were going to have open reduction and internal fixation for lower extremity fracture under combined spinal-epidural anesthesia or those undergoing hemi-arthroplasty were randomly divided into two groups： the methoxamine group（group M） and the ephedrine group（group E）. Patients were firstly given sodium lactate sorbitol compound 200-300 ml intravenously in the operation room. Then bupivacaine 8-12 mg were given after successful anesthesia puncture. Besides drugs in spinal anesthesia, patients of group M were also giv-en methoxamine 2 mg, group E were given ephedrine 5 mg. Once hypotension occurred, patients were given ephedrine in-travenously injection 5-10 mg. If heart rate were lower than 60 beats per minute, patients were given intravenous injection of 0.25-0.50 mg atropine. SBP, DBP and HR were recorded before anesthesia, 5 min, 15 min and 30 min post-anesthetic respectively in the two groups. We also observed adverse effects such as drop of blood pressure, nausea, vomiting and bradycardia. Results SBP and DBP in group M were significantly higher than those in group E when given 5 min, 15 min and 30 min post-anesthetic. HR were significantly lower than group E in 15 min and 30 min. The differences between two groups were statistical（P〈0.05）. During operation, the rates of adverse reactions such as nausea and vomiting, hypotention in group M were significantly lower than those in group E（P〈0.05）. Conclusion Pre-injection of methoxamine can effec-tively reduce the incidence of hypotension in lower limb orthopedic surgery in elderly after combined spinal-epidural anes-thesia and cause fewer adverse reactions.