胸椎旁神经阻滞用于微创冠状动脉旁路移植术患者超前镇痛的效果

Efficacy of thoracic paravertebral block for preemptive analgesia in patients undergoing minimally invasive direct coronary artery bypass grafting

目的评价胸椎旁神经阻滞用于微创冠状动脉旁路移植术患者超前镇痛的效果。方法择期拟行微创冠状动脉旁路移植术患者60例，年龄54～75岁，体重55～82kg，性别不限，ASA分级Ⅱ或Ⅲ级，NYHA心功能分级Ⅰ-Ⅲ级，采用随机数字表法分为2组：对照组（C组）和胸椎旁神经阻滞组（P组），每组各30例。P组在神经刺激仪引导下经T4,5，间隙行胸椎旁神经阻滞，注射试验剂量0．5％罗哌卡因5ml，5min后注射0．5％罗哌卡因15ml。麻醉诱导：静脉注射依托咪酯、咪哒唑仑、芬太尼和维库溴铵，双腔气管导管插管后行机械通气，维持PET，CO230～40mmHg。麻醉维持：静脉注射芬太尼和维库溴铵，静脉输注异丙酚，吸入七氟醚，维持BIS值40～60。SBP〉160mmHg时静脉注射芬太尼0．1mg。拔除气管导管后行PCIA至术后48h。镇痛药为吗啡100mg，用生理盐水稀释至100ml，背景输注速率0．5mg／h，PCA剂量2mg，锁定时间10min，维持VAS评分≤4分。VAS评分〉4分时静脉注射吗啡4mg进行镇痛补救。记录术中芬太尼用量；记录术后24和48h内吗啡用量和镇痛补救情况；记录术后48h内嗜睡、恶心呕吐、呼吸抑制、瘙痒和肺不张等不良反应发生情况；记录气管拔管时间、ICU滞留时间及术后恢复时间。分别于术后24和48h时测定肺功能，记录用力肺活量占预计值百分比（FVC％）、第1秒用力呼气量占预计值百分比（FEV1％），计算FEV。／FVC，同时行动脉血气分析，记录PaO2和PaCO2。结果与C组比较，P组术中芬太尼用量、术后24和48h内吗啡用量均减少，气管拔管时间和ICU滞留时间缩短，术后24和48h时FVC％和FEV，％升高，PaCO2降低，嗜睡发生率降低（P〈0．05），FEV。／FVC、PaCO2、镇痛补救率和术后恢复时间差异无统计学意义（P〉0．05）。结论胸椎旁神经阻滞对微创冠状动脉旁路移植术患者具有良好的超前镇痛效应。

Objective To evaluate the efficacy of thoracic paravertebral block for preemptive anal- gesia in the patients undergoing minimally invasive direct coronary artery bypass grafting （MIDCAB）. Methods Sixty patients of both sexes, aged 54-75 yr, weighing 55-82 kg, of American Society of Anesthesiologists physical II or 111 , with New York Heart Association I -llI, scheduled for elective MIDCAB, were randomly divided into 2 groups （n = 30 each） by using a random number table： control group （group C） and thoracic paravertebral block group （group P）. Thoracic paravertebral block was performed under the guidance of a nerve stimulator in group P. A paravertebral catheter was placed at T4.5 interspace, a test dose of 0. 5% ropivacacine 5 ml was injected through the catheter, and 5 min later a bolus dose of 0.5% ropivacacine 15 ml was injected. Anesthesia was induced with intravenous etomidate, midazolam, fentanyl and vecuronium. All the patients were intubated with a double-lumen endobronchial tube and mechanically ventilated, and end-tidal pressure of carbon dioxide was maintained at 30-40 mmHg. Anesthesia was maintained with intravenous injection of fentanyl and vecuronium, intravenous infusion of propofol, and inhalation of sevoflurane. Bispeetral index value was maintained at 40-60. When systolic blood pressure 〉 160 mmHg, fentanyl 0.1 mg was injected intravenously. Both groups started to receive patient-controlled intravenous analgesia （PCIA） after extubation until 48 h after operation. PCIA solution contained morphine in 100 ml of normal saline. The PCIA pump was set up with a 2 mg bolus dose, a 10 min lockout interval and background infusion at a rate of 0.5 mg/h. Visual analogue scale was maintained ≤ 4. When visual analogue scale〉4, morphine 4 mg was injected intravenously as rescue analgesic. The consumption of intraoperative fentanyl was recorded. The consumption of morphine and requirement for rescue analgesics were recorded within 24 and 48 h after operation. The adverse reactions such as somnolence, nausea and vomiting, respiratory depression, pruritus, and atelectasis were recorded within 48 h after operation. The extubation time after operation, length of time in intensive care unit, and recovery time after operation were recorded. At 24 and 48 h after operation, pulmonary function was detected, the forced vital capacity （FVC） expressed as a percentage of the predicted value （ FVC% ） , and forced expiratory volume in 1 second （FEV1 ） expressed as a percentage of the predicted value （FEV1%） were recorded, and the ratio of FEV1/FVC was calculated. Blood gas analysis was performed, and arterial oxygen partial pressure and partial pressure of arterial carbon dioxide were recorded at 24 and 48 h after operation. Results Compared with group C, the intraoperative consumption of fentanyl and consumption of morphine within 24 and 48 h after operation were significantly reduced, the extubation time and length of time in intensive care unit were shortened, FVC% and FEV1% were increased at 24 and 48 h after operation, the partial pressure of arterial carbon dioxide and incidence of somnolence were decreased （P〈0.05） , and no significant change was found in the FEV1/ FVC, arterial oxygen partial pressure, requirement for rescue analgesics and recovery time after operation in group P （P〉 0.05）. Conclusion Thoracic paravertebral block analgesia can provide good preempive analgesia in the patients undergoing MIDCAB.