Edner Anna, Nyman Görel, Essén-Gustavsson Birgitta
Department of Large Animal Clinical Sciences, Veterinary Faculty, Swedish University of Agricultural Sciences, Box 7018, Uppsala, Sweden.
Department of Large Animal Clinical Sciences, Veterinary Faculty, Swedish University of Agricultural Sciences, Box 7018, Uppsala, Sweden.
Vet Anaesth Analg. 2002 Oct;29(4):182-199. doi: 10.1046/j.1467-2995.2002.00101.x. Epub 2016 Nov 15.
To study in horses (1) the relationship between cardiovascular variables and muscle perfusion during propofol-ketamine anaesthesia, (2) the physiological effects of a single intravenous (IV) detomidine injection, (3) the metabolic response of muscle to anaesthesia, and (4) the effects of propofol-ketamine infusion on respiratory function.
Prospective experimental study.
Seven standardbred trotters, 5-12 years old, 416-581 kg.
Anaesthesia was induced with intravenous (IV) guaifenesin and propofol (2 mg kg) and maintained with a continuous IV infusion of propofol (0.15 mg kg minute) and ketamine (0.05 mg kg minute) with horses positioned in left lateral recumbency. After 1 hour, detomidine (0.01 mg kg) was administered IV and 40-50 minutes later anaesthesia was discontinued. Cardiovascular and respiratory variables (heart rate, cardiac output, systemic and pulmonary artery blood pressures, respiratory rate, tidal volume, and inspiratory and expiratory O and CO) and muscle temperature were measured at pre-determined times. Peripheral perfusion was measured continuously in the gluteal muscles and skin using laser Doppler flowmetry (LDF). Muscle biopsy samples from the left and right gluteal muscles were analysed for glycogen, creatine phosphate, creatine, adenine nucleotides, inosine monophosphate and lactate. Arterial blood was analysed for PO, PCO, pH, oxygen saturation and HCO. Mixed venous blood was analysed for PO, PCO, pH, oxygen saturation, HCO, cortisol, lactate, uric acid, hypoxanthine, xanthine, creatine kinase, creatinine, aspartate aminotransferase, electrolytes, total protein, haemoglobin, haematocrit and white blood cell count.
Circulatory function was preserved during propofol-ketamine anaesthesia. Detomidine caused profound hypertension and bradycardia and decreased cardiac output and muscle perfusion. Ten minutes after detomidine injection muscle perfusion had recovered to pre-injection levels, although heart rate and cardiac output had not. No difference in indices of muscle metabolism was found between dependent and independent muscles. Anaerobic muscle metabolism, indicated by decreased muscle and creatine phosphate levels was evident after anaesthesia.
Muscle perfusion was closely related to cardiac output but not arterial blood pressure. Total intravenous anaesthesia with propofol-ketamine deserves further study despite its respiratory depression effects, as the combination preserves cardiovascular function. Decreases in high-energy phosphate stores during recovery show that muscle is vulnerable after anaesthesia. Continued research is required to clarify the course of muscle metabolic events during recovery.
研究马匹中（1）异丙酚 - 氯胺酮麻醉期间心血管变量与肌肉灌注之间的关系；（2）单次静脉注射右美托咪定的生理效应；（3）肌肉对麻醉的代谢反应；（4）异丙酚 - 氯胺酮输注对呼吸功能的影响。
前瞻性实验研究。
7匹标准赛马，年龄5 - 12岁，体重416 - 581千克。
静脉注射愈创甘油醚和异丙酚（2毫克/千克）诱导麻醉，并通过持续静脉输注异丙酚（0.15毫克/千克·分钟）和氯胺酮（0.05毫克/千克·分钟）维持麻醉，马匹处于左侧卧位。1小时后，静脉注射右美托咪定（0.01毫克/千克），40 - 50分钟后停止麻醉。在预定时间测量心血管和呼吸变量（心率、心输出量、体循环和肺动脉血压、呼吸频率、潮气量以及吸气和呼气时的氧和二氧化碳）和肌肉温度。使用激光多普勒血流仪（LDF）连续测量臀肌和皮肤的外周灌注。分析左右臀肌的肌肉活检样本中的糖原、磷酸肌酸、肌酸、腺嘌呤核苷酸、肌苷单磷酸和乳酸。分析动脉血中的氧分压、二氧化碳分压、pH值、氧饱和度和碳酸氢根。分析混合静脉血中的氧分压、二氧化碳分压、pH值、氧饱和度、碳酸氢根、皮质醇、乳酸、尿酸、次黄嘌呤、黄嘌呤、肌酸激酶、肌酐、天冬氨酸转氨酶、电解质、总蛋白、血红蛋白、血细胞比容和白细胞计数。
异丙酚 - 氯胺酮麻醉期间循环功能得以维持。右美托咪定导致严重高血压和心动过缓，并降低心输出量和肌肉灌注。右美托咪定注射后10分钟，肌肉灌注恢复到注射前水平，尽管心率和心输出量尚未恢复。在受压和非受压肌肉之间未发现肌肉代谢指标的差异。麻醉后，肌肉和磷酸肌酸水平降低表明存在无氧肌肉代谢。
肌肉灌注与心输出量密切相关，但与动脉血压无关。尽管异丙酚 - 氯胺酮全静脉麻醉有呼吸抑制作用，但由于其能维持心血管功能，仍值得进一步研究。恢复过程中高能磷酸储备的减少表明麻醉后肌肉很脆弱。需要继续研究以阐明恢复过程中肌肉代谢事件的进程。
