Kodaka M, Okamoto Y, Handa F, Kawasaki J, Miyao H
Department of Anesthesiology, Saitama Medical Center, Saitama Medical School, 1981, Tsujido-cho, Kamoda, Kawagoe, Saitama 350-8550, Japan.
Br J Anaesth. 2004 Feb;92(2):238-41. doi: 10.1093/bja/aeh033.
This study sought to determine the effective concentration for 50% of the attempts to secure laryngeal mask insertion (predicted EC(50LMA)) of propofol using a target-controlled infusion (Diprifusor) and investigated whether fentanyl influenced these required concentrations, respiratory rate (RR) and bispectral index (BIS).
Sixty-four elective unpremedicated patients were randomly assigned to four groups (n = 16 for each group) and given saline (control) or fentanyl 0.5, 1 or 2 micro g kg(-1). Propofol target concentration was determined by a modification of Dixon's up-and-down method. Laryngeal mask airway insertion was attempted without neuromuscular blocking drugs after equilibration had been established for >10 min. Movement was defined as presence of bucking or gross purposeful muscular movement within 1 min after insertion. EC(50LMA) values were obtained by calculating the mean of 16 patients in each group.
Predicted EC(50LMA) of the control, fentanyl 0.5, 1 and 2 micro g kg(-1) groups were 3.25 (0.20), 2.06 (0.55), 1.69 (0.38) and 1.50 (0.54) micro g ml(-1) respectively; those of all fentanyl groups were significantly lower than that of control. RR was decreased in relation to the fentanyl dose up to 1 micro g kg(-1). BIS values after fentanyl 1 and 2 micro g kg(-1) were significantly greater than in the control and 0.5 micro g kg(-1) groups.
A fentanyl dose of 0.5 micro g kg(-1) is sufficient to decrease predicted EC(50LMA) with minimum respiratory depression and without a high BIS value.
本研究旨在确定使用靶控输注（得普利麻）时，50%的喉罩置入尝试成功的丙泊酚有效浓度（预测的EC50LMA），并研究芬太尼是否会影响这些所需浓度、呼吸频率（RR）和脑电双频指数（BIS）。
64例择期未使用术前药的患者被随机分为四组（每组n = 16），分别给予生理盐水（对照组）或0.5、1或2μg·kg-1的芬太尼。丙泊酚靶浓度采用改良的Dixon上下法确定。在达到平衡>10分钟后，在不使用神经肌肉阻滞药物的情况下尝试插入喉罩气道。运动定义为插入后1分钟内出现呛咳或明显的有目的肌肉运动。通过计算每组16例患者的平均值获得EC50LMA值。
对照组、0.5、1和2μg·kg-1芬太尼组预测的EC50LMA分别为3.25（0.20）、2.06（0.55）、1.69（0.38）和1.50（0.54）μg·ml-1；所有芬太尼组的该值均显著低于对照组。RR随芬太尼剂量增加至1μg·kg-1而降低。1和2μg·kg-1芬太尼组后的BIS值显著高于对照组和0.5μg·kg-1组。
0.5μg·kg-1的芬太尼剂量足以降低预测的EC50LMA，同时呼吸抑制最小且BIS值不高。
