A Clinical Study On The Changes Of End-tidal Carbon Dioxide Partial Pressure Is Used For Predict Fluid Responsiveness Assessment In Patients With Shock

Background and AimsShock is a common acute and critical diseases in clinic,it’s morbidity and case fatality rate is high,the most important thing of treating on establish the correct fluid resuscitation targets of shock,for the patients who need fluid resuscitation,there is an appreciation of patient’fluid responsiveness is very important.The good fluid responsiveness is the premise of liquid resuscitation,currently,there are many techniques to evaluate fluid responsiveness,that are invasive or rely on the operator subjective experience are difficult to generalize widely.So we are looking for a safe,simple and fast method to judge the fluid responsiveness.In recent years,at home and abroad have many researches point out that the changes of end-tidal carbon dioxide partial pressure（ΔPetCO₂）correlated with the fluid responsiveness,has great value in clinical and characteristics of simple,economic and reliable.So we choose"A clinical study on the changes of end-tidal carbon dioxide partial pressure is used for predict fluid responsiveness assessment in patients with shock"as the research’sdirection,to test whether the changes of end-tidal carbon dioxide partial pressure can provide the basis for fluid replacement therapy of patients with shock.Methods patients with shock in ICU as the research object,who are on mechani cal ventilation and LVT ventilation strategy,applications analgesia and sedative,without spontaneous breathing,maintaining RASS-2 or less.During the test,the parameters of ventilator,vasoactive drugs and the dosage of sedatives remained unchanged.Collec ting Basic information of patients,in the 56 patients,a Passive leg raising test（PLR）was performed:first,raise the head of a bed to 45°for 1 minute,and then patients were transferred from the initial semirecumbent position to the PLR position for 1 mi nute,in which the legs are elevate at 45oand the trunk is in horizontal position.Rec ording the inferior vena cava（IVC）diameter and end-tidal carbon dioxide partial pressu re of patients before and after the PLR,and working out the inferior vena cava variat ion rate of breathing（ΔIVC）and the value of PLR-induced PetCO₂ change,Accordin g toΔIVC,patients were classified as responders（ΔIVC≥18%）and non-responders（ΔIVC<18%）.Using Pearson test,the correlations ofΔIVC andΔPetCO₂ were analyze d.The value ofΔPetCO₂ to predict fluid responsiveness was evaluated by receiver oper ating characteristic curves（ROC）.Results（1）Among the 56 patients enrolled,39 had fluid responsiveness（response group）,and 17 had no-responsiveness（non-response group）.After PLR,theΔPetCO₂ was significantly increased in the response group compared with non-response group[ΔPetCO₂:（3.8±2.9）%vs.（0.5±2.5）%,P<0.05].ΔPetCO₂ was positively correlated withΔIVC（r=0.56,P<0.05）.The area under POC curve ofΔPetCO₂ was 0.813（95%CI 0.739⁰.930,P<0.05）.An increase of 5%inΔPetCO₂ predicted fluid responsiveness with a se nsitivity of 75.7%,and specificity of 89.6%.Conclusion（1）The changes of end-tidal carbon dioxide partial pressure can be us ed as an indicator of the fluid responsiveness of mechanically ventilated patients with shock.（2）The changes of end-tidal carbon dioxide partial pressure was positively corr elated with the inferior vena cava variation rate of breathing.（3）The end-tidal carbon dioxide partial pressure can replace invasive hemodynamic monitoring and ultrasound,as a method of simple,rapid and accurate to provide the basis for the patients with shock to accept the capacity recovery.