摘要目的 研究右美托咪定和咪达唑仑用于外科重症监护病房(SICU)术后机械通气(MV)患者的镇静效果及安全性。方法 选择术后带气管导管人SICU行呼吸机辅助通气患者200例，按随机数字表法分为两组，分别给予咪达唑仑（98例）和右美托咪定(102例)镇静治疗，两组均常规给予芬太尼持续静脉泵入镇痛，根据Prince-Henry镇痛评分调整芬太尼剂量，使疼痛评分维持在1～2分；根据Riker镇静和躁动评分(SAS)调整镇静药剂量，使镇静深度评分控制在2～4分；连续监测记录呼吸机参数、心电图、心率、血压、呼吸、脉搏血氧饱和度，并进行血气分析。观察记录两组药物用量，MV时间，以及低血压、心动过缓、谵妄、恶心等副作用发生率。结果 右美托咪定与咪达唑仑均能使患者达到镇静及镇痛目标评分，右美托咪定组更易唤醒并保持安静。与咪达唑仑组比较，右美托咪定组芬太尼用量(μg．kg-1· h-1)明显减少（0.23±0.13比0.41±0.12，P＜0.01），MV时间(h)明显缩短(7.20±6.29比12.44±8.96，P＜0.01)，低血压发生率(27.45％比11.22％)和心动过缓发生率(24.51％比10.20％)明显升高(均P＜0.05)，谵妄发生率明显降低（3.92％比31.63％，P＜0.01），恶心发生率降低(9.80％比11.22％，P＞0.05)。将右美托咪啶组按是否发生低血压再分为两个亚组分析：低血压与非低血压组间术中失血量(ml/kg)、术中输液量(ml．kg-1．h-1)、术后当日及术后1d血乳酸含量(mmol/L)比较差异无统计学意义（术中失血量：12.79±12.13比13.52±11.62；术中输液量：11.91±4.59比13.09±7.05;术后当日乳酸含量：1.88±1.07比1.71±0.87，术后1d乳酸含量：1.43±0.98比1.37±0.79，均P＞0.05）。结论 右美托咪定用于外科术后MV患者镇静效果满意，易唤醒，谵妄发生率低，可缩短MV时间，减少芬太尼用量约50％，是一种较为理想的SICU镇静剂。但要加强用药期间的监测，防治低血压和心动过缓。

abstractsObjective To study sedative effect and safety of dexmedetomidine and midazolam for post-operative patients undergoing mechanical ventilation (MV) in surgical intensive care unit (SICU).Methods Two hundred cases of post-operative patients undergoing MV with tracheal intubation in SICU were enrolled and divided into two groups by random numerical table method. They were treated either with midazolam (98 cases) or dexmedetomidine (102 cases). In both groups fentanyl was given intravenously continually for analgesia. The amount of fentanyl was adjusted according to Prince-Henry analgesic score to keep on 1 - 2 analgesic score; the dose of sedation was regulated by Riker sedative and restless score (SAS) maintain 2 - 4 sedative score. During the course, parameters of the ventilator, electrocardiogram, heart rate (HR), blood pressure, respiratory rate, pulse oxygen saturation (SpO2), blood gas analysis were observed and registered continuously. The amount of the drug, duration of MV, and incidence of side-effects such as hypotension, bradycardia, delirium, nausea, etc. were recorded in two groups. Results In all the patients in two groups taking dexmedetomidine or midazolam expected sedative and analgesia scores were obtained. In the group with dexmedetomidine, the patients were aroused easier with adequate sedation, and when compared with the group with midazolam, dose of fentanyl (μg · kg-1 · h-1) was significantly smaller (0. 23± 0. 13 vs. 0. 41 ± 0. 12, P ＜ 0. 01 ), duration of MV (hours) was clearly shorter (7.20 ± 6.29 vs.12. 44±8. 96, P＜0. 01), the rates of hypotension (27. 45％ vs. 11.22％) and bradycardia (24.51％ vs.10. 20％) were significantly higher (both P＜0. 05), the rate of delirium was clearly lower (3. 92％ vs.31.63％, P＜0. 01), the rate of nausea showed a slight decrease (9.80％ vs. 11.22％, P＞0. 05). Thepatients in the group with dexmedetomidine were divided into two subgroups of hypotension and non-hypotension. The quantity of blood loss during operation (ml/kg), amount of fluid infusion during operation (ml · kg-1 · h-1), blood lactic acid concentration (mmol/L) on the day of surgical operation and the 1st day post-operative showed no significant difference between these subgroups (quantity of blood loss on the day of surgical operation: 12.79± 12. 13 vs. 13. 52± 11.62; amount of fluid infusion during surgical operation: 11.91 ± 4.59 vs. 13. 09 ± 7.05 ;blood lactic acid concentration on the day of operation: 1.88 ± 1.07vs. 1.71± 0. 87, blood lactic acid concentration on the 1st day post-operative : 1.43± 0. 98 vs. 1.37± 0. 79,all P＞0. 05). Conclusion Sedative effect of dexmedetomidine is satisfactory for patients undergoing MV after operation, with the property of easier arousal, lower delirium rate, and it helps to shorten the duration of MV with reduction the dosage of fentanyl by 50％. However, it is necessary to enhance observation in order to prevent and control hypotension and bradycardia.