不同通气模式对Trendelenburg体位腹腔镜手术患者PaO_2和PaCO_2的影响

Effect of different modes of ventilation on PaO_2 and PaCO_2 in laparoscopic surgery in the Trendelenburg position

目的探讨压力控制通气（PCV）联合呼气末正压（PEEP）在Trendelenburg体位腹腔镜手术中对PaO_2和PaCO_2的影响。方法腹腔镜直肠癌根治术患者40例,年龄35~55岁,随机分为两组,每组20例。A组采用容量控制通气模式（VCV）通气[VT=体重（kg）×10ml]20min后,改用PCV模式通气20min,返回VCV模式继续通气20min后,采用PCV＋低PEEP（5cm H_2O）模式通气20min。B组则将PCV与PCV＋PEEP的顺序调换。在切换通气模式时行动脉血气分析。结果两组VCV模式时PaO_2均明显低于PCV模式及PCV＋PEEP模式（P〈0.05）。PCV模式时PaO_2明显低于PCV＋PEEP模式（P〈0.05）;VCV模式时PaCO_2明显高于PCV模式和PCV＋PEEP模式（P〈0.05）,而PCV模式和PCV＋PEEP模式时PaCO_2差异无统计学意义。VCV模式时动脉血pH值明显低于PCV和PCV＋PEEP模式（P〈0.05）,PCV和PCV＋PEEP模式时动脉血pH值差异无统计学意义。结论 Trendelenburg体位腹腔镜手术时采用PCV＋PEEP通气模式,与单纯VCV或单纯PCV模式比较,在提高PaO_2以及降低PaCO_2方面更具优势。

Objective To investigate the effects of different ventilation modes on PaCO_2 and PaO_2 during laparoscopic surgery in the Trendelenburg position.Methods Forty cases of laparoscopic resection of rectal cancer were randomly divided into group A（n=20）and group B（n=20）.Under general anesthesia,all the cases were in volume-controlled ventilation mode（VCV,tidal volume=10ml/kg）before pneumoperitoneum.After ventilating in VCV mode for 20 minutes with a lower tidal volume（8ml/kg）,group A was converted to PCV mode for 20 minutes and then back to the VCV mode for 20 minutes again.Next we switched to PCV combined with PEEP（5cm H_2O）mode（PCV＋PEEP）for 20 minutes.In group B,we only alternated PCV with PCV combined with PEEP.Arterial blood-gas analysis was obtained at each time when ventilating mode changed.Results In both group A and B,PaO_2 in VCV mode was less than that in PCV mode and PCV＋PEEP mode（P〈0.05）,PaO_2 in PCV mode was also less than that in mode PCV＋PEEP mode（P〈0.05）.PaCO_2 in PCV and PCV combined with PEEP mode was less than that in VCV mode（P〈0.05）,and there was no difference of PaCO_2 in PCV mode and PCV＋PEEP mode.The pH value in VCV mode was less than that in PCV mode and PCV＋PEEP mode（P〈0.05）.There was no difference in pH value between PCV mode and PCV＋PEEP mode.Conclusion PCV combined PEEP mode is beneficial either in increasing or decreasing of PaCO_2 during laparoscopic surgery in the Trendelenburg position comparing with single VCV mode or PCV mode.