The value of changes in end-tidal carbon dioxide pressure induced by passive leg raising test in predicting fluid responsiveness in mechanically ventilated patients with septic shock / 中华内科杂志

ABSTRACT

Objective To test whether the changes of partial end-tidal carbon dioxide pressure (PETCO2) during passive leg raising (PLR) predict fluid responsiveness in mechanically ventilated patients with septic shock.Methods Forty-two mechanically ventilated patients with septic shock admitted from January 2012 to November 2012 were prospectively recruited.Hemodynamic parameters monitored by a pulse indicator continuous cardiac output(PiCCO) device and PETCO2 monitored by an expiratory-CO2 device were studied at baseline,after PLR,and after volume expansion.Fluid responsiveness was defined as an increase in cardiac index (CI) of 15％ or greater after volume expansion.The correlation between PLR-induced CI change (△CIPLR) and PETCO2 (△PETCO2-PLR) was analyzed.The value of △PETCO2-PLR to predict fluid responsiveness was evaluated by receiver operating characteristic (ROC) curves.Results A total of 42 patients were enrolled in this study,of whom,24 had a CI increase of ≥ 15％ after volume expansion (responders).After PLR,CI and PETCO2 were both significantly increased in the response group compared with baseline [(21.4 ± 12.9) ％ of CI and (9.6 ± 4.7) ％ of PETCO2,P ＜ 0.05],while no significant changes were observed (P ＞ 0.05) in the non-response group.Both △CIPLR and △PETCO2-PLR were significantly higher in responder group than in the non-responder group (both P ＜ 0.05).△CI and △PETCO2 after PLR were strongly correlated (r =0.64,P ＜ 0.05).In responders after PLR,the area under ROC curve of △PETCO2-PLR was 0.900 ± 0.056 (95％ CI 0.775-1.000,P ＜ 0.05).An increase of ≥ 5％ in △PETCO2-PLR predicted fluid responsiveness with a sensitivity of 88.0％ and specificity of 88.2％.Conclusions The change of PETCO2 induced by passive leg raising is a non-invasive and easy way to predict fluid responsiveness in mechanically ventilated patients with septic shock.