右美托咪啶对成人胸腔镜手术单肺通气氧合度的影响

目的本研究评估右美托咪啶对成人胸腔镜手术单肺通气时缺氧性肺血管收缩和氧合作用的影响。方法将38名进行胸腔镜手术的患者随机分为右美托咪啶组(D组)和生理盐水安慰剂对照组(C组)。两组患者麻醉诱导后均应用七氟醚吸入麻醉,使BIS指标在40～60之间,并使用舒芬太尼和去氧肾上腺素稳定血压升降在10%。D组给予右美托咪啶,首次剂量0.3μg/kg,维持剂量0.3μg/kg/h。C组给予生理盐水进行对照。记录两组血流动力学指标(心率和平均动脉压),呼气末七氟醚浓度。进行动脉血气分析评价右美托咪啶对氧合的影响。结果右美托咪啶能改善单肺通气病人的氧合,PaO2/FiO2的比率在右美托咪啶组是(185±57),安慰剂组是(136±70),P<0.05。两组间的血流动力学指标和麻醉深度没有统计学差异。与对照组相比,BIS维持在40～60之间右美托咪啶组所需要的呼气末七氟醚浓度较低(4.5±0.8)%:(5.1±0.8)%,P<0.05,所需要的舒芬太尼用量也较低(2.1±0.6)μg/kg:(2.6±0.4)μg/kg,P<0.05。为维持血流动力学稳定,右美托咪啶组去氧肾上腺素的用量比安慰剂组大(9.4±2.6)μg/kg:(1.6±3.5)μg/kg,P<0.05。结论右美托咪啶在成人胸腔镜手术单肺通气时能改善患者的氧合,可能与其减少吸入麻醉药的用量从而减少缺氧性肺血管收缩的抑制有关。

Objective To evaluate the effects of dexmedetomidine on hypoxic pulmonary vasoconstriction （HPV） and oxygenation during onelung ventilation （OLV） in adults undergoing video-assisted thoracic surgery（VATS）. Methods During inhalational anesthesia with sevflurane, 38 patients during VATS were randomized to receive either dexmedetomidine （bolus dose of 0.3μg/kg followed by an infusion of 0.3μg/kg/h） or saline placebo.Arterial blood gas samples （ABG） were obtained to evaluate the effects of dexmedetomidine on oxygenation. Secondary outcomes included differences in hemodynamic parameters （heart rate and mean arterial pressure）, end-tidal sevflurane concentration required to maintain the bispectral index （BIS） at 40-60, supplemental sufentanyl to maintain hemodynamic stability, and phenylephrine to keep the mean arterial pressure （MAP） within 10% of baseline values. Results Oxygenation during OLV change following the administration of dexmedetomidine （PaO2/FiO2 ratio of 185 ± 57 in dexmedetomidine patients versus （136 ± 70） in placebo patients, P〈0.05）. There were no differences in hemodynamic variables or depth of anaesthesia between the two groups. With the administration of dexmedetomidine, there was a decrease in the expired concentration of sevflurane required to maintain the BIS at 40-60 when compared with the control group （4.5±0.8% versus 5.1±0.8%, P〈0.05）. In patients receiving dexmedetomidine, sufentanyl requirements were decreased when compared to placebo （2. 1±0.6μg/kg versus 2.6±0.4μg/kg, P〈0.05）. However, more patients receiving dexmedetomidine required phenylephrine to maintain hemodynamic stability and the total dose of phenylephrine was greater in patients receiving dexmedetomidine when compared with placebo （9.4±2.6μg/kg versus 1.6±3.5μg/kg, P〈0.05 ）.Conclusion Dexmedetomidine improve oxygenation during OLV in adults undergoing video-assisted thoracic surgical procedures. The improvement in oxygenation in the dexmedetomidine patients may be related to a decrease in the requirements for inhalational anaesthetic agents thereby limiting its effects on HPV.