Liu E H C, Wong H K, Chia C P, Lim H J, Chen Z Y, Lee T L
Department of Anaesthesia, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074.
Br J Anaesth. 2005 Feb;94(2):193-7. doi: 10.1093/bja/aei003. Epub 2004 Oct 29.
The aim of this study was to determine if propofol caused less suppression of cortical somatosensory evoked potentials (SSEPs) during spine surgery compared with isoflurane during comparable depth of anaesthesia as guided by bispectral index (BIS) measurements.
This was a randomized controlled trial of propofol and isoflurane involving 60 patients undergoing elective spine surgery. BIS monitoring was used to guide a consistent and comparable depth of anaesthesia, the index was maintained at between 40 and 50 during anaesthesia. The cortical SSEP P40-N50 peak-to-peak amplitude and latency time to the P40 peak were measured before induction of anaesthesia, after induction of anaesthesia, at the start of skin incision, at the start of pedicle screw insertion and at the start of rod insertion, by a neurophysiologist blinded to drug allocation.
Both propofol and isoflurane decreased SSEP amplitude and increased latency during the course of anaesthesia. After achieving a comparable depth of anaesthesia, the SSEP amplitude was significantly lower with isoflurane, 1.5 (1.0) vs 2.4 (1.4) muV (P=0.005). Latency was significantly longer with isoflurane, 39.5 (3.9) vs 37.3 (3.1) ms (P=0.024). Isoflurane was associated with greater variability of SSEP amplitude during the course of anaesthesia and surgery, coefficient of variation 35.4 (18.0) vs 21.2 (10.2)% (P=0.008).
Propofol anaesthesia caused less suppression of the cortical SSEP, with better preservation of SSEP amplitude, and less variability at an equivalent depth of anaesthesia.
本研究的目的是确定在脊柱手术中，在脑电双频指数（BIS）测量引导下的可比麻醉深度时，丙泊酚与异氟烷相比是否对皮质体感诱发电位（SSEP）的抑制作用更小。
这是一项关于丙泊酚和异氟烷的随机对照试验，涉及60例接受择期脊柱手术的患者。使用BIS监测来引导达到一致且可比的麻醉深度，麻醉期间该指数维持在40至50之间。由对药物分配不知情的神经生理学家在麻醉诱导前、麻醉诱导后、皮肤切口开始时、椎弓根螺钉插入开始时以及棒插入开始时，测量皮质SSEP的P40 - N50峰峰值幅度和P40峰的潜伏期。
在麻醉过程中，丙泊酚和异氟烷均降低了SSEP幅度并延长了潜伏期。在达到可比的麻醉深度后，异氟烷组的SSEP幅度显著更低，分别为1.5（1.0）μV和2.4（1.4）μV（P = 0.005）。异氟烷组的潜伏期显著更长，分别为39.5（3.9）ms和37.3（3.1）ms（P = 0.024）。异氟烷在麻醉和手术过程中与SSEP幅度的更大变异性相关，变异系数分别为35.4（18.0）%和21.2（10.2）%（P = 0.008）。
在等效麻醉深度下，丙泊酚麻醉对皮质SSEP的抑制作用更小，能更好地保留SSEP幅度，且变异性更小。
