Avramov M N, White P F
Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas, 75235-9068, USA.
Anesth Analg. 1997 Sep;85(3):566-72. doi: 10.1097/00000539-199709000-00015.
Propofol and alfentanil are both rapid and short-acting drugs that can be used for sedation and analgesia during monitored anesthesia care (MAC). This study was designed to determine the optimal infusion rates of propofol and alfentanil when administered during local anesthesia. In this randomized, double-blind study, we evaluated the effects of different propofol infusion rates on the alfentanil requirement, level of sedation, intraoperative recall, respiratory and cardiovascular variables, and recovery. Seventy-two consenting ASA physical status I or II female outpatients undergoing breast biopsy procedures with local anesthesia were randomly assigned to one of four treatment groups. All patients received midazolam, 2 mg intravenously (I.V.) for premedication. Propofol was infused at 0, 25, 50, or 75 microg x kg(-1) x min(-1) during the operation. Sedation was evaluated using the Observer's Assessment of Alertness/Sedation (OAA/S) scale at 5-min intervals by a blinded observer. Two minutes before the infiltration of the local anesthetic solution, a bolus of alfentanil, 2.5 microg/kg I.V., was administered, followed by a maintenance infusion of 0.5 microg x kg(-1) x min(-1). The alfentanil infusion rate was subsequently varied to maintain patient comfort and stable cardiovascular and respiratory function. Pictures were shown at the start of the propofol infusion, upon initiating the alfentanil infusion, and at 45 min after the skin incision to evaluate recall of intraoperative events. Propofol produced dose-dependent increases in the level of sedation (with median OAA/S scores of 2-4, P < 0.05). Higher infusion rates of propofol (50-75 microg x kg(-1) x min(-1)) produced significant amnesia, opioid-sparing effects (alfentanil 0.3 +/- 0.2 vs 0.6 +/- 0.2 microg x kg(-1) x min(-1)), and less postoperative nausea and vomiting (P < 0.05). However, episodes of transient hemoglobin oxygen desaturation were more common in the deeply sedated patients. Thus, in healthy outpatients premedicated with midazolam, 2 mg I.V., a propofol infusion of 25-50 microg x kg(-1) x min(-1) in combination with an alfentanil infusion of 0.2-0.4 microg x kg(-1) x min(-1) is recommended for sedation and analgesia during MAC in the ambulatory setting.
Sedation is often given during local anesthesia. This study demonstrated that administration of an intravenous anesthetic, propofol, in combination with an opioid infusion (i.e., alfentanil) to provide sedation analgesia and amnesia with a low incidence of side effects, such as nausea and vomiting and respiratory depression in outpatients premedicated with midazolam.
丙泊酚和阿芬太尼都是起效迅速且作用时间短的药物，可用于麻醉监护（MAC）期间的镇静和镇痛。本研究旨在确定局部麻醉期间丙泊酚和阿芬太尼的最佳输注速率。在这项随机、双盲研究中，我们评估了不同丙泊酚输注速率对阿芬太尼需求量、镇静水平、术中知晓、呼吸和心血管变量以及恢复情况的影响。72名接受局部麻醉下乳腺活检手术的美国麻醉医师协会（ASA）身体状况I或II级的女性门诊患者，被随机分配到四个治疗组之一。所有患者均静脉注射2mg咪达唑仑进行术前用药。手术期间丙泊酚以0、25、50或75μg·kg⁻¹·min⁻¹的速率输注。由一名不知情的观察者每隔5分钟使用观察者警觉/镇静评估（OAA/S）量表评估镇静情况。在局部麻醉溶液浸润前两分钟，静脉注射2.5μg/kg的阿芬太尼推注量，随后以0.5μg·kg⁻¹·min⁻¹的速率持续输注。随后调整阿芬太尼输注速率以维持患者舒适度以及稳定的心血管和呼吸功能。在丙泊酚输注开始时、阿芬太尼输注开始时以及皮肤切开后45分钟展示图片，以评估对术中事件的回忆。丙泊酚产生了剂量依赖性的镇静水平增加（OAA/S中位数评分2 - 4，P < 0.05）。较高的丙泊酚输注速率（50 - 75μg·kg⁻¹·min⁻¹）产生了显著的遗忘作用、阿片类药物节省效应（阿芬太尼0.3±0.2 vs 0.6±0.2μg·kg⁻¹·min⁻¹）以及较少的术后恶心和呕吐（P < 0.05）。然而，深度镇静患者中短暂血红蛋白氧饱和度下降的情况更为常见。因此，对于静脉注射2mg咪达唑仑进行术前用药的健康门诊患者，建议在门诊MAC期间，丙泊酚以25 - 50μg·kg⁻¹·min⁻¹的速率输注并联合阿芬太尼以0.2 - 0.4μg·kg⁻¹·min⁻¹的速率输注用于镇静和镇痛。
局部麻醉期间常给予镇静。本研究表明，静脉注射麻醉药丙泊酚联合阿片类药物输注（即阿芬太尼），可为术前用咪达唑仑的门诊患者提供镇静、镇痛和遗忘作用，且副作用如恶心、呕吐和呼吸抑制的发生率较低。
