CO2气胸对剑突下入路胸腔镜胸腺切除术MG患者血气及相关指标的影响

Effects of CO2 pneumothorax on blood gas and related indexes in MG patients undergoing thoracoscopic thymectomy via subxiphoid approach

目的分析CO2气胸对剑突下入路胸腔镜胸腺切除术患者血气、肺内分流率、气道压及肺动态顺应性的影响。方法选择行剑突下入路胸腔镜胸腺切除术的重症肌无力(MG)患者40例,术中均行单腔气管导管通气和CO2气胸。分别于CO2气胸前(T1),CO2气胸30 min(T2),CO2气胸60 min(T3),关胸结束即刻(T4),抽取动脉血进行血气分析,根据肺泡-动脉氧分压差P(A-a)O2值,计算肺内分流率(Qs/Qt),同时监测记录气道峰压(Pmax)并根据公式计算肺动态顺应性(Cdyn)。结果CO2气胸期间(T2~T3)与T1比较PaCO2、肺泡-动脉氧分压差P(A-a)O2、肺内分流率(Qs/Qt)、Pmax均明显升高(P<0.05),PaO2、BE(B)、Cdyn均明显降低(P<0.05)。CO2人工气胸期间HCO3-、pH值虽然都在正常范围内,但是HCO3-有升高趋势,pH值有下降趋势。T1与T4比较,各项指标差异无统计学意义(P>0.05)。结论CO2人工气胸对剑突下入路胸腔镜胸腺切除术患者的血气、肺内分流率、气道峰压及肺动态顺应性,有明显影响。术中需加强监测与管理,减小对患者的不利影响。

Objective To investigate the effects of CO2 pneumothorax on blood gas,airway pressure,intrapulmonary shunt rate and pulmonary dynamic compliance in patients undergoing thoracoscopic thymectomy via subxiphoid approach.Methods Forty patients with myasthenia gravis(MG)who underwent thoracoscopic thymectomy via subxiphoid approach,and intraoperative single-lumen tracheal tube ventilation and CO2 pneumothorax were performed during operation.The blood samples were taken before CO2 pneumothorax(T1),at 30 min after CO2 pneumothorax(T2),at 60 minafter CO2 pneumothorax(T3)and at the end moment of CO2 pneumothorax(T4)respectively to analyze blood gas.Pulmonary shunt rate(Qs/Qt)was calculated according to P(A-a)O2 value of alveolar-arterial partial pressure difference,meanwhile,the peak airway pressure(Pmax)was monitored and recorded.And pulmonary dynamic compliance was calculated according to the formula.Sex(Cdyn).Results As compared with those at T1,the PaCO2,alveolar arterial oxygen partial pressure difference P(Aa)O2,intrapulmonary shunt rate(Qs/Qt)and Pmax during CO2 pneumothorax(T2~T3)were increased significantly(P<0.05),however,the PaO2,BE(B),Cdyn were decreased significantly(P<0.05).HCO3 and PH values were within the normal range,but HCO3 showed an increasing trend and PH values showed a decreasing trend.In addition,there were no significant differences in the indexes mentioned above between T1 and T4.Conclusion The CO2 artificial pneumothorax has significant effects on blood gas,intrapulmonary shunt rate,peak airway pressure and pulmonary dynamic compliance in patients undergoing thoracoscopic thymectomy via subxiphoid approach.And monitoring and management during operation should be strengthened to reduce adverse effects.