Bennarosh L, Peuch C, Cohen J, Dauzac C, Guigui P, Mantz J, Dahmani S
Department of anaesthesia, Beaujon university hospital, assistance publique des hôpitaux de Paris and Paris-7 university, 100, boulevard du Général-Leclerc, 92110 Clichy, France.
Ann Fr Anesth Reanim. 2008 Feb;27(2):158.e1-5. doi: 10.1016/j.annfar.2007.10.037. Epub 2008 Jan 8.
The knee-chest (KC) position is often used for spine surgery. It is considered to promote significant changes in venous return and cardiac output. However, the magnitude of these changes and their consequences on intraoperative haemodynamics and anaesthetic requirements remain to be determined. The goal of the present study was to determine the changes in cardiac index and propofol requirements of patients undergoing spine surgery in the KC position.
Twenty ASA 1-3 patients scheduled for elective spine surgery were included in the study. A radial artery catheter and an oesophageal Doppler probe were properly positioned after induction of anaesthesia. Anaesthesia consisted of bispectral index (BIS)-guided, plasma target-controlled, propofol-remifentanil anaesthesia. After positioning the patient KC, remifentanil target concentration was maintained throughout the case as in the supine position whilst propofol target concentration was adjusted to maintain BIS values between 40 and 50. Cardiac index, stroke volume, heart rate, end-tidal CO(2) (ETCO(2)), mean arterial pressure, peak and plateau airway pressures, BIS values and plasma target concentrations of propofol and remifentanil were compared 15 min after induction of anaesthesia (in the supine position) and 15 min after placing the patients KC. Data are expressed as mean+/-S.D. except for DeltaPP expressed as a number of patients with DeltaPP greater than 13%.
Cardiac index, stroke volume, mean arterial pressure and propofol target concentration were significantly decreased from supine to KC position: 2.6+/-0.03 to 1.7+/-0.04 l/min/m(2), p<0.0001; 68+/-1.2 to 45+/-1 ml, p<0.0001; 83+/-1.2 to 76+/-1.4 mmHg, p<0.0001 and 3+/-0.06 to 2+/-0.05 microg/ml, p<0.0001, respectively. The number of patients with DeltaPP greater than 13% was zero in the supine position and 18 (90%) in the KC position (p<0.0001).
Placing surgical patients in the KC position during BIS guided anaesthesia was associated with marked decrease in cardiac index and propofol requirements. These results suggest that monitoring intraoperative cardiac index via an oesophageal Doppler and depth of anaesthesia with the BIS may be useful in patients undergoing spine surgery in the KC position.
膝胸位（KC）常用于脊柱手术。人们认为该体位会促使静脉回流和心输出量发生显著变化。然而，这些变化的程度及其对术中血流动力学和麻醉需求的影响仍有待确定。本研究的目的是确定处于KC体位的脊柱手术患者的心脏指数和丙泊酚需求量的变化。
本研究纳入了20例计划接受择期脊柱手术的美国麻醉医师协会（ASA）1-3级患者。麻醉诱导后正确放置桡动脉导管和食管多普勒探头。麻醉采用脑电双频指数（BIS）引导、血浆靶控丙泊酚-瑞芬太尼麻醉。患者置于KC体位后，瑞芬太尼靶浓度在整个手术过程中保持与仰卧位时相同，同时调整丙泊酚靶浓度以维持BIS值在40至50之间。比较麻醉诱导后15分钟（仰卧位）和患者置于KC体位后15分钟时的心脏指数、每搏量、心率、呼气末二氧化碳分压（ETCO₂）、平均动脉压、气道峰压和平台压、BIS值以及丙泊酚和瑞芬太尼的血浆靶浓度。数据以平均值±标准差表示，除ΔPP以ΔPP大于13%的患者数量表示。
从仰卧位到KC体位，心脏指数、每搏量、平均动脉压和丙泊酚靶浓度均显著降低：分别从2.6±0.03降至1.7±0.04升/分钟/平方米，p<0.0001；从68±1.2降至45±1毫升，p<0.0001；从83±1.2降至76±1.4毫米汞柱，p<0.0001；从3±0.06降至2±0.05微克/毫升，p<0.0001。仰卧位时ΔPP大于13%的患者数量为零，KC体位时为18例（90%）（p<0.0001）。
在BIS引导麻醉期间将手术患者置于KC体位与心脏指数和丙泊酚需求量显著降低相关。这些结果表明，通过食管多普勒监测术中心脏指数以及用BIS监测麻醉深度可能对处于KC体位的脊柱手术患者有用。
