The Effects Of Single Lung Ventilation Combined With Artificial Pneumothorax On The Arterial-End Tidal Carbon Dioxide Gradient

Objective To observe the effects of single lung ventilation combined with artificial pneumothorax on the arterial-end tidal carbon dioxide gradient( Pa-ETCO2) during thoraco laparoscopic oesophagectomy.Methods Forty-three patients undergoing thoraco laparoscopic oesophagectomy were selected in our study, aged 40-60 yr,males or females,BMI 22-28 kg/m2, ASA I or II. Respectively in intubation after double lung ventilation immediately(T0), single lung ventilation for 15min(T1), single lung ventilation combined with artificial pneumothorax after 30 min(T2), 60 min(T3), restore double lung ventilation after 15 min(T4), collecting radial arterial and central venous blood specimens of blood gas analysis, PETCO2, airway peak pressure(Ppeak) and dynamic lung compliance(Cdyn) was recorded at the same time point. According to the results of blood gas analysis, PaETCO2,Pa-ETCO2/Pa CO2,Oxygenation index(Pa O2 / Fi O2), pulmonary shunt fraction(QS / QT) were calculated.Then, investigate correlation and clinical significance between arterial partial pressure carbon dioxide(Pa CO2) and end expiratory partial pressure of carbon dioxide(Pet CO2).Results Compared with lung ventilation, Pa CO2, Pa-ETCO2, Pa-ETCO2 / Pa CO2 in OLV tended to increase after 15min( P<0.05),When combined with artificial pneumothorax was significantly higher than that of single-lung ventilation after 30min(P<0.05),After 1h, the trend is more obvious(P<0.05), Pa CO2 and Pa-ETCO2 were recovered to the level of double lung ventilation after the termination of the artificial pneumothorax. The statistical analysis show that OLV with artificial pneumothorax affect the correlation between the Pa CO2 and Pa-ETCO2 significantly.Conclusion Arterial-end tidal carbon dioxide gradient(Pa-ETCO2) increased significantly during single lung ventilation combined with artificial pneumothorax, Pa CO2 could not be accurately reflected by Pet CO2. Pa CO2 is needed to monitor intermittent to correct Pet CO2 during OLV with artificial pneumothorax for a long time.