Objective To evaluate the effectiveness of thoracic epidural anesthesia (TEA) combined with general anesthesia (GA) versus GA alone on intrapulmonary shunting during one-lung ventilation (OLV). Methods We searched the Cochrane Library (Issue 4, 2009), the specialized trials registered in the Cochrane anesthesia group, PubMed (1966 to Dec. 2009), EMbase (1966 to Dec. 2008), CBM (1978 to Dec. 2009), VIP (1989 to Dec. 2009), CNKI (1915 to Dec. 2009), and handsearched Clinical Anesthesia Journal and Chinese Anesthesia Journal. Randomized controlled trials (RCTs) about the effectiveness of TEA combined with GA versus GA alone on intrapulmonary shunting during OLV were included, The methodological quality of included RCTs was evaluated by two reviewers independently, Meta-analysis was conducted using RevMan 5.0 software. Results Ten RCTs involving 506 patients were included. The results of meta-analyses showed that there were no significant differences in intrapulmonary shunting during OLV at different times-points of 5, 15, 20, 30, and 60 minutes after OLV. Conclusion Both TEA combined with GA and GA alone have the same Security during OLV. But owing to the low quality and small sample size of the included studies, further more well-designed, large sample size RCTs are needed.
Objective To investigate whether the new oxygenation index [ PaO2 /( FiO2 ×Paw ) ]which including mean airway pressure ( Paw ) for assessing intrapulmonary shunting of acute respiratory distress syndrome( ARDS) could be more accurate than the conventional oxygenation ratio ( PaO2 /FiO2 ) .Methods Twelve patients with ARDS were recruited. All patients received mechanical ventilation under lung ventilation protective strategy ( VT 6 mL/kg, f 16 bpm, FiO2 60% ) , and had a Swan-Ganz catheter inserted. Then, pressure/ volume curves were determined by low-flow method and the lower inflection point pressure was surveyed. Subsequently, parameters of respiratory mechanics and haemodynamics were recorded while periphery and pulmonary artery blood gas analysis were performed when positive end expiratory pressure ( PEEP) were changed. PaO2 /FiO2 and Qsp/Qt were calculated through special formula respectively. Results The progressive PEEP could not change Cst, PaO2 /FiO2 , and PaO2 / ( FiO2 ×Paw) in patients with ARDS significantly ( P gt; 0. 05) . The progressive PEEP did not change Qsp/Qt significantly ( P gt;0. 05) . The Δz which was used to test the difference between the correlation coefficient of Qsp/Qt and PaO2 / ( FiO2 ×Paw) and the correlation coefficient of Qsp/Qt and PaO2 /FiO2 was 0. 571, and there was no difference between the two correlation coefficients ( P gt; 0. 05) . It was not Paw but Cst which impacted on Qsp/Qt and PaO2 /FiO2 . Conclusion PaO2 / ( FiO2 × Paw ) is equal to PaO2 /FiO2 in assessing intrapulmonary shunting of ARDS.