CO_2波形用于评价单肺通气时肺泡及氧合功能的临床研究

Evaluation of the clinical significance of CO_2 waveform monitoring on the alveolar function and oxygenation during OLV in thoracic anesthesia

目的评价PETCO2监测中CO2波形在单肺通气麻醉期间对肺泡通气及氧合功能的临床指导作用。方法选择拟在右侧开胸手术患者30例,ASAⅠ或Ⅱ级,年龄43～75岁。丙泊酚1.5～2 mg/kg、芬太尼2μg/kg、和维库溴铵0.2 mg/kg麻醉诱导后37～39 F双腔气管导管插管,左侧体位下听诊法证实双肺通气和隔离良好,待手术开胸实施左侧单肺通气后,依次采用预定通气参数(PP)和校准通气参数(AP)两种单肺通气参数设置进行机械通气。单肺通气参数设置包括潮气量(VT)、通气频率(RR)、吸呼比(I∶E)和呼气末正压(PEEP);当SpO2≤90%时,双肺持续正压通气(CPAP),再次SpO2≤93%时,双肺CPAP,并依据CO2波形设置校准单肺通气参数,参数设置使CO2波形的形态趋近双肺通气时的CO2波形(双肺通气时的CO2波形作为基础波形)。观察并记录单肺通气前、SpO2≤93%时、正压通气后、调整通气参数后的血压(BP)、心率(HR)、脉搏血氧饱和度(SpO2)和通气参数值。结果左侧单肺机械通气期间,PP设置的CO2波形与双肺通气明显不同,尤其以CO2波形的呼气相升支和肺泡平台支变化显著;并在较短时间内(18.5±3.7)min发生SpO2明显下降(SpO2≦90%),CPAP纠正后,继续采用PP设置,仍在短时间内(9.6±2.7)min出现SpO2≤93%;采用AP设置,均能够使CO2波形与双肺通气趋近,波形的呼气相升支与肺泡平台支夹角变小,且保持SpO2在正常水平。两种设置单肺通气各项参数比较,差异均有统计学意义(P<0.05)。结论 CO2波形对调整单肺通气参数和肺泡及氧合功能具有一定的临床指导作用。

Objective To evaluate the clinical application value of expiratory CO2 waveform monitoring on the alveolar and oxygenation function during left-sided one-lung ventilation （OLV） in thoracic surgery. Methods 30 ASA physical status Ⅰ - Ⅱ patients aged 43-75 undergoing thoracic surgery for which a period of left-sided one-lung ventilation were enrolled in this study. Study was undertaken in all patients after standardized induction of anesthesia and muscle relaxation, and two consecutive parameters in OLV were carried out by preset parameters （PP） and adjustable parameters （AP） in a specified order of seniority. Setting parameters of OLV included VT, RR, I：E and PEEP; AP for setting OLV parameters was based on CO2 waveform, which was similar to two lung ventilation （as basic waveform）. The CO2 waveform was analysed in two lung ventilation, with PP setting and AP setting patients during OLV through a SpO2 change. The BP, HR, Sp02 and ventilation parameters value were recorded and observed before and after OLV, when SpO2≤93, after CPAP and after AP setting from both AP setting and PP setting, and statistic analysis was performed. Results CO2 waveform in PP setting showed significant difference after OLV as compared with the basic waveform; there was significant decrease in SpO2 （SpO2≤90%）in PP onset period （18.5±3.7min）. The SpO2 was lowered again （SpO2≤ 93%）in PP setting after ventilated with continuous positive airway pressure （CPAP） to two lungs,where hypoxemia during OLV might be treated causally by correcting the parameters of OLV according to the basic waveform, and SpO2 were kept at normal levels in AP setting. Each parameter value for AP setting during OLV after regulation according to basic waveform was significantly different from that for PP setting （P 〈0.05 ）. Conclusion CO2 waveform monitoring can provide more guidance for the alveolar function and oxygenation during OLV in thoracic anesthesia.