van Zundert T, Brebels A, Hendrickx J, Carette R, De Cooman S, Gatt S, De Wolf A
Department of Anaesthesiology, Intensive Care and Pain Therapy, University of Maastricht, Maastricht, The Netherlands.
Anaesth Intensive Care. 2009 Nov;37(6):911-7. doi: 10.1177/0310057X0903700608.
Simple vaporiser setting (F(D)) and fresh gas flow (FGF) sequences make the practice of low-flow anaesthesia not only possible but also easy to achieve. We sought to derive a sevoflurane F(D) sequence that maintains the end-expired sevoflurane concentration (F(A)sevo) at 1.3% using the fewest possible number of F(D) adjustments with a previously described O2-N2O FGF sequence that allows early FGF reduction to 0.7 l min(-1). In 18 ASA physical status I to IH patients, F(D) was determined to maintain F(A)sevo at 1.3% with 2 l min(-1) O2 and 4 l min(-1) N2O FGF for three minutes, and with 0.3 and 0.4 l min(-1) thereafter. Using the same FGF sequence, the F(D) schedule that approached the 1.3% F(A)sevo pattern with the fewest possible adjustments was prospectively tested in another 18 patients. The following F(D) sequence approximated the F(D) course well: 2% from zero to three minutes, 2.6% from three to 15 minutes and 2.0% after 15 minutes. When prospectively tested, median (25th; 75th percentile) performance error was 0.8 (-2.9; 5.9)%, absolute performance error 6.7 (3.3; 10.6)%, divergence 18.2 (-5.6; 27.4)%.h(-1) and wobble 4.4 (1.7; 8.1) %. In one patient, FGF had to be temporarily increased for four minutes. One O2/N2O rotameter FGF setting change from 6 to 0.7 l min(-1) at three minutes and two sevoflurane F(D) changes at three and 15 minutes maintained predictable anaesthetic gas concentrations during the first 45 minutes in all but one patient in our study.
简单的蒸发器设置（F(D)）和新鲜气体流量（FGF）序列使得低流量麻醉不仅可行，而且易于实现。我们试图推导一种七氟醚F(D)序列，该序列使用尽可能少的F(D)调整次数，并结合先前描述的氧气-氧化亚氮FGF序列（该序列允许早期将FGF降至0.7升/分钟），将呼气末七氟醚浓度（F(A)sevo）维持在1.3%。在18例美国麻醉医师协会（ASA）身体状况I至III级的患者中，确定F(D)，在2升/分钟氧气和4升/分钟氧化亚氮FGF条件下维持F(A)sevo为1.3%三分钟，之后分别为0.3升/分钟和0.4升/分钟。使用相同的FGF序列，在另外18例患者中前瞻性测试了以最少调整次数接近1.3% F(A)sevo模式的F(D)方案。以下F(D)序列与F(D)过程拟合良好：0至3分钟为2%，3至15分钟为2.6%，15分钟后为2.0%。前瞻性测试时，中位（第25百分位数；第75百分位数）性能误差为0.8（-2.9；5.9）%，绝对性能误差为6.7（3.3；10.6）%，离散度为18.2（-5.6；27.4）%·小时-1，摆动为4.4（1.7；8.1）%。在1例患者中，FGF不得不临时增加4分钟。在我们的研究中，除1例患者外，所有患者在最初45分钟内，3分钟时将一个氧气/氧化亚氮转子流量计FGF设置从6升/分钟改为0.7升/分钟，以及在3分钟和15分钟时进行两次七氟醚F(D)改变，维持了可预测的麻醉气体浓度。
