Silva Aura, Venâncio Carlos, Ortiz Ana Liza, Souza Almir P, Amorim Pedro, Ferreira David A
Toxicology, REQUIMTE, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal.
Vet Anaesth Analg. 2014 Mar;41(2):153-62. doi: 10.1111/vaa.12091. Epub 2013 Sep 30.
To study the effects of a high remifentanil bolus dose on pig's electroencephalographic indices and on brain regional and global oxygenation.
Prospective experimental study.
Twelve healthy Large-White male pigs, age 3 months and weight 26.2 ± 3.6 kg.
Anaesthesia was induced with intravenous propofol 4 mg kg⁻¹, then maintained with constant rate infusions of propofol (15 mg kg⁻¹ hour⁻¹) and remifentanil (0.3 μg kg⁻¹ minute⁻¹). Following instrumentation, all pigs received a 5 μg kg⁻¹ remifentanil bolus. The responses of jugular venous oxygen saturation, cardiac output and cerebral oxygen saturation to the remifentanil bolus were studied. The Bispectral index, spectral edge frequency 95%, total power, approximate entropy and permutation entropy were also studied. Repeated measures anova and Pearson correlation were used to analyze the effect of remifentanil bolus on these variables until 5 minutes after the bolus.
Cardiac output and cerebral oxygen saturation decreased significantly after the remifentanil bolus from 4.6 ± 0.9 to 3.8 ± 1.0 L minute⁻¹ and from 65 ± 6 to 62 ± 1% (p < 0.05), respectively. No significant changes were observed in the jugular venous oxygen saturation (p > 0.05) nor in any of the electroencephalogram derived indices (p > 0.05). Correlation analysis revealed strong positive significant correlations between cerebral oxygen saturation and cardiac output (r = 0.82, p < 0.001) and between cerebral oxygen saturation and approximate entropy (r = 0.65, p < 0.001).
The effect caused by the remifentanil bolus on the brain oxygenation seems to be better reflected by the cerebral oxygen saturation than the jugular venous oxygen saturation. The effect of remifentanil on the electroencephalogram may not be reflected in indices derived from the electroencephalogram, but the potential of the approximate entropy in reflecting changes caused by opioids on the electroencephalogram should be further investigated.
研究大剂量瑞芬太尼推注对猪脑电图指标以及脑局部和整体氧合的影响。
前瞻性实验研究。
12只健康的3月龄大白公猪，体重26.2±3.6千克。
静脉注射4毫克/千克丙泊酚诱导麻醉，随后以丙泊酚（15毫克/千克·小时⁻¹）和瑞芬太尼（0.3微克/千克·分钟⁻¹）持续输注维持麻醉。仪器安装完成后，所有猪均接受5微克/千克的瑞芬太尼推注。研究瑞芬太尼推注对颈静脉血氧饱和度、心输出量和脑血氧饱和度的影响。还研究了脑电双频指数、频谱边缘频率95%、总功率、近似熵和排列熵。在推注后5分钟内，采用重复测量方差分析和Pearson相关性分析来分析瑞芬太尼推注对这些变量的影响。
瑞芬太尼推注后，心输出量和脑血氧饱和度显著下降，分别从4.6±0.9降至3.8±1.0升/分钟和从65±6降至62±1%（p<0.05）。颈静脉血氧饱和度（p>0.05）和任何脑电图衍生指标（p>0.05）均未观察到显著变化。相关性分析显示，脑血氧饱和度与心输出量之间（r = 0.82，p<0.001）以及脑血氧饱和度与近似熵之间（r = 0.65，p<0.001）存在强正相关。
瑞芬太尼推注对脑氧合的影响似乎用脑血氧饱和度比颈静脉血氧饱和度能更好地反映。瑞芬太尼对脑电图的影响可能无法在脑电图衍生指标中体现，但近似熵在反映阿片类药物引起的脑电图变化方面的潜力应进一步研究。
