心内直视手术期间不同振荡频率下呼吸力学参数的比较

Comparison of mechanical parameters of respiratory system at different oscillation frequency during open heart surgery

目的 研究强迫振荡法4、8Hz两种频率下心内直视手术围麻醉期病人呼吸系统阻力和相位角的变化规律和相关性.方法 心内直视手术成年病人30例,行常规芬太尼静脉全身麻醉,用CUSTO VITM肺功能仪测定围麻醉期10个时段的4Hz、8Hz气道阻力(Resistance forced oscillation,RFO)和相位角(Phase angle,Phi).结果RFO术前仰卧位时最高,机械通气后明显降低,术中各时段均<3.0cmH_2O/L/s.Phi开胸后最大,4Hz可达20°～30°,8Hz在50°～60°范围,体外循环心肺转流(CPB)后明显下降,关胸后回升.Pearson相关分析,气道阻力和相位角与机械通气时相应值比较,相同频率的RFO和Phi在术中各时段均有中至高度正相关.结论 强迫振荡肺功能测定技术适用于麻醉临床,对评价体外循环乃至心内直视手术期间患者呼吸力学机制紊乱具有显著的参考指导意义.

Objective To dynamically monitor the resistance and phase angle of the respiratory system at 4Hz and 8Hz with the forced oscillation technique (FOT) during the peri-anesthesia of an open heart surgery and to discuss the regularity and correlation of the parameters. Methods The parameters of resistance forced oscillation (RFO) and the phase angle (Phi) at 4Hz and 8Hz were gathered on 10 time-points by CUSTO VTTM lung function apparatus, on 30 patients who were taken open heart surgery and anesthetized intravenously by fentanyl. The time-points are before surgeries, at the supine position on an operating table, immediately after IPPV, after the chest opening, before CPB. during CPB, after CPB, before pericardium closing, before and after chest closing and at the end of operations. Results The values of RFO reached the highest point while patients were on supine positions before the operation and obviously dropped after IPPV. During the operation, the values of RFO were less than 3. 0 cmH2O/ L/s. After the chest was opened, the value of Phi was the highest and it would reach up to 20°-30° at 4Hz and 50° -60° at 8Hz. After CPB, the value of Phi came down significantly and would rise after chest closing. Pearson correlation analysis shows that both RFO and Phi at all time-points during the operation have medium or high positive correlation with the corresponding variable at IPPV time-point of the same frequency. Conclusion Lung Function Determination with Forced Oscillation Technique can be applied to clinical anesthesia and has evident importance for evaluating the mechanical disorder of respiratory system during CBP and open heart surgery.