Moon P F, Scarlett J M, Ludders J W, Conway T A, Lamb S V
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14850, USA.
Anesthesiology. 1995 Sep;83(3):535-42. doi: 10.1097/00000542-199509000-00012.
Fentanyl is used in anesthetic protocols for swine, but there are no reports on its potency in this species. This study measured the extent to which fentanyl reduces the minimum alveolar concentration of isoflurane (MACISO) in swine.
Sixteen swine were randomly assigned to four groups. For each group, baseline MACISO was determined, and three groups received two of three fentanyl infusions as follows: 50 micrograms.kg-1.h-1 intravenously followed by 100 micrograms.kg-1.h-1, 50 micrograms.kg-1.h-1 followed by 200 micrograms.kg-1.h-1, or 100 micrograms.kg-1.h-1 followed by 200 micrograms.kg-1.h-1 (n = 8 for each dosage). A loading dose of fentanyl preceded each infusion. Each infusion was maintained for 60 min before initiating minimum alveolar concentration determination. The infusions were maintained throughout the period of minimum alveolar concentration determination. Plasma fentanyl samples were obtained after 30 min of each infusion, and plasma fentanyl and hemodynamic parameters were obtained immediately before stimulating swine for the final isoflurane concentration used in determining minimum alveolar concentration. A fourth group, control animals, received saline infusions. After each infusion, the MACISO was redetermined. Minimum alveolar concentration was determined using incremental changes in isoflurane concentrations until gross purposeful movement resulted when using a hemostat stimulus applied for 1 min to a rear dewclaw.
MACISO for controls was 2.19 +/- 0.17% (mean +/- SEM) and changed minimally over time (-0.13 +/- 4.77%). MACISO decreased significantly (P < or = 0.01) 24.5 +/- 3.2%, 29.9 +/- 4.8%, and 45.9 +/- 5.5% with fentanyl dosages of 50, 100, and 200 micrograms.kg-1.h-1, respectively. Corresponding plasma fentanyl concentrations were 14 +/- 1 ng/ml, 26 +/- 3 ng/ml, and 59 +/- 5 ng/ml, respectively. A ceiling effect on reduction of MACISO was not observed. Changes over time or between groups were not observed for arterial blood gas tensions, blood pressure, heart and respiratory rate, or body temperature.
These fentanyl dosages are larger than those commonly used in humans and other species. Anesthetic protocols using fentanyl for swine should be designed with the knowledge that a fentanyl infusion of 200 micrograms.kg-1.h-1 contributes approximately a 50% MACISO equivalent.
芬太尼用于猪的麻醉方案，但尚无关于其在该物种中效能的报道。本研究测定了芬太尼降低猪异氟烷最低肺泡浓度（MACISO）的程度。
16头猪随机分为四组。对每组测定基线MACISO，其中三组接受三种芬太尼输注中的两种，具体如下：静脉输注50微克·千克⁻¹·小时⁻¹，随后为100微克·千克⁻¹·小时⁻¹；50微克·千克⁻¹·小时⁻¹，随后为200微克·千克⁻¹·小时⁻¹；或100微克·千克⁻¹·小时⁻¹，随后为200微克·千克⁻¹·小时⁻¹（每种剂量n = 8）。每次输注前给予芬太尼负荷剂量。每次输注维持60分钟后开始测定最低肺泡浓度。在整个最低肺泡浓度测定期间维持输注。每次输注30分钟后采集血浆芬太尼样本，在刺激猪以确定用于测定最低肺泡浓度的最终异氟烷浓度之前，立即采集血浆芬太尼和血流动力学参数。第四组为对照动物，接受生理盐水输注。每次输注后重新测定MACISO。使用异氟烷浓度的增量变化来确定最低肺泡浓度，直到使用止血钳刺激后肢悬蹄1分钟出现明显的有目的运动。
对照组的MACISO为2.19±0.17%（平均值±标准误），随时间变化极小（-0.13±4.77%）。芬太尼剂量为50、100和200微克·千克⁻¹·小时⁻¹时，MACISO分别显著降低（P≤0.01）24.5±3.2%、29.9±4.8%和45.9±5.5%。相应的血浆芬太尼浓度分别为14±1纳克/毫升、26±3纳克/毫升和59±5纳克/毫升。未观察到对MACISO降低的封顶效应。未观察到动脉血气张力、血压、心率和呼吸频率或体温随时间或组间的变化。
这些芬太尼剂量大于人类和其他物种常用的剂量。在设计用于猪的芬太尼麻醉方案时，应了解输注200微克·千克⁻¹·小时⁻¹的芬太尼约相当于50%的MACISO。
Zotero 插件