Araújo Marcelo A, Deschk Maurício, Wagatsuma Juliana T, Floriano Beatriz P, Siqueira Carlos E, Oliva Valéria Nls, Santos Paulo Sp
Faculty of Veterinary Medicine and Animal Science, Federal University of Mato Grosso do Sul (UFMS), Campo Grande-MS, Brazil.
Department of Animal Clinic, Surgery and Reproduction, Faculty of Veterinary Medicine, (UNESP) - São Paulo State University, Araçatuba-SP, Brazil.
Vet Anaesth Analg. 2017 Jul;44(4):854-864. doi: 10.1016/j.vaa.2017.03.006. Epub 2017 Apr 26.
To assess the cardiopulmonary effects caused by reverse Trendelenburg position (RTP) at 5° and 10° in sevoflurane-anesthetized yearling steers.
Prospective, experimental study.
Eight Holstein steers aged (mean ± standard deviation) 12 ± 2 months and weighing 145 ± 26 kg.
In the first phase of the study, the individual minimum alveolar concentration (MAC) of sevoflurane was determined using electrical stimulation. In the second phase, the effects of RTP were assessed. The animals were anesthetized on three separate events separated by ≥7 days in an incomplete crossover design: control treatment using a table without tilt (RTP0); treatment with the table at 5° RTP (RTP5) and table tilted 10° RTP (RTP10). Subjects were physically restrained in dorsal recumbency on the table, which was already tilted according to each treatment. Anesthesia was induced with sevoflurane at 8% in 5 L minute oxygen via face mask followed by maintenance with sevoflurane at 1.3 MAC and spontaneous breathing. Cardiopulmonary variables were obtained immediately after instrumentation (T) and then after 30, 60, 120 and 180 minutes (T, T, T and T, respectively).
The mean sevoflurane MAC for the eight steers was 2.12 ± 0.31%. Cardiac output was lower at all time points and the systemic vascular resistance index was higher at T and T in RTP10 compared with RTP0. Oxygen consumption was lower at T and at T in RTP10 compared with RTP0 and at all time points except T compared with RTP5. Oxygen extraction was lower at T in RTP10 compared with RTP0 and RTP5, and at T and T compared with RTP5.
RTP 5° and 10° did not improve ventilatory and oxygenation variables in sevoflurane-anesthetized steers when compared with no tilt, however the cardiovascular variables were adversely affected in RTP10.
评估七氟醚麻醉的一岁育肥牛处于5°和10°头高脚底位（RTP）时的心肺效应。
前瞻性实验研究。
八头荷斯坦育肥牛，年龄（平均±标准差）为12±2个月，体重145±26千克。
在研究的第一阶段，使用电刺激确定七氟醚的个体最低肺泡浓度（MAC）。在第二阶段，评估RTP的效应。动物在三个单独的事件中接受麻醉，事件间隔≥7天，采用不完全交叉设计：使用无倾斜的手术台进行对照处理（RTP0）；手术台处于5°RTP（RTP5）和手术台倾斜10°RTP（RTP10）的处理。将动物仰卧固定在已根据每种处理倾斜的手术台上。通过面罩以8%的七氟醚在5升/分钟的氧气中诱导麻醉，随后以1.3 MAC的七氟醚维持麻醉并自主呼吸。在仪器安装后立即（T）以及之后30、60、120和180分钟（分别为T、T、T和T）获取心肺变量。
八头育肥牛的七氟醚平均MAC为2.12±0.31%。与RTP0相比，RTP10在所有时间点的心输出量均较低，且在T和T时全身血管阻力指数较高。与RTP0相比，RTP10在T和T时的耗氧量较低，与RTP5相比，除T外的所有时间点耗氧量均较低。与RTP0和RTP5相比，RTP10在T时的氧摄取较低，与RTP5相比，在T和T时氧摄取较低。
与无倾斜相比，5°和10°的RTP在七氟醚麻醉的育肥牛中并未改善通气和氧合变量，然而RTP10对心血管变量有不利影响。
