Zbinden A M, Maggiorini M, Petersen-Felix S, Lauber R, Thomson D A, Minder C E
Institute for Anesthesiology and Intensive Care, University Hospital, Bern, Switzerland.
Anesthesiology. 1994 Feb;80(2):253-60. doi: 10.1097/00000542-199402000-00004.
Potency of inhaled anesthetics usually is defined by determining the minimal alveolar concentration (MAC) that prevents movement in 50% of patients in response to skin incision. Skin incision, however, is usually only a single event and, thus, determination of potency cannot be repeated in one patient. Traditional MACskin incision cannot be used to predict response to other noxious stimuli. The aim of this study was to investigate the effects of other noxious stimulation patterns and then compare these to MACskin incision measuring the end-tidal isoflurane concentrations with the corresponding arterial concentrations.
In 26 patients, the end-tidal and corresponding arterial isoflurane concentrations needed to suppress eye opening to verbal command and motor response after trapezius squeeze, 50 Hz electric tetanic stimulation, laryngoscopy, skin incision, and tracheal intubation in 50% of all patients were determined.
The end-tidal (equivalent arterial) isoflurane concentrations (mean +/- SE, adjusted to sea level) expressed in vol% (to allow comparison) increased in the following order (mean +/- SE): vocal command 0.37 +/- 0.09 (0.36 +/- 0.09); trapezius squeeze 0.84 +/- 0.07 (0.65 +/- 0.07); laryngoscopy 1.00 +/- 0.12 (0.78 +/- 0.09); tetanic stimulation 1.03 +/- 0.09 (0.80 +/- 0.06); skin incision 1.16 +/- 0.10 (0.97 +/- 0.17); and intubation 1.76 +/- 0.13 (1.32 +/- 0.11).
Different stimuli require different isoflurane concentrations to suppress motor responses. Tetanic stimulation and, to some extent, trapezius squeeze are reproducible and noninvasive stimulation patterns that can be used as an alternative to skin incision when evaluating potency of an anesthetic agent. In contrast to skin incision, they can be repeated.
吸入麻醉药的效能通常通过确定能防止50%的患者对皮肤切开产生动作反应的最低肺泡浓度（MAC）来定义。然而，皮肤切开通常只是单个事件，因此，在一名患者身上无法重复测定效能。传统的皮肤切开MAC不能用于预测对其他有害刺激的反应。本研究的目的是调查其他有害刺激模式的影响，然后将这些影响与测量呼气末异氟烷浓度及相应动脉浓度的皮肤切开MAC进行比较。
在26例患者中，测定了在所有患者的50%中抑制对言语指令睁眼及斜方肌挤压、50Hz电强直刺激、喉镜检查、皮肤切开和气管插管后运动反应所需的呼气末及相应动脉异氟烷浓度。
以体积百分比表示（以便比较）的呼气末（等效动脉）异氟烷浓度（平均值±标准误，已校正至海平面）按以下顺序增加（平均值±标准误）：言语指令0.37±0.09（0.36±0.09）；斜方肌挤压0.84±0.07（0.65±0.07）；喉镜检查1.00±0.12（0.78±0.09）；强直刺激1.03±0.09（0.80±0.06）；皮肤切开1.16±0.10（0.97±0.17）；插管1.76±0.13（1.32±0.11）。
不同的刺激需要不同的异氟烷浓度来抑制运动反应。强直刺激以及在一定程度上斜方肌挤压是可重复且无创的刺激模式，在评估麻醉药效能时可作为皮肤切开的替代方法。与皮肤切开不同，它们可以重复进行。
