Correlation On PetCO₂ And The Elderly Patients Reaction Capacity Under General Anaesthesia

Objective:To study the dynamic change of end-tidal carbon dioxide partial pressure in elderly patients under general anesthesia during volume expansiontest and its relevance with CO changes,and to evaluate its predictive value on the fluid responsiveness.Methods: 60 elderly patients of elective abdominal surgery were chosen from Jan 2015 to Jan 2016 in The First Affiliated Hospital of Hebei North University,with ASA grade I^Ⅲ,aged 65 to 75 years old,weighing 50 80 kg were included in this study.All cases were given general anesthesia,midazolam 0.04mg/kg,etomidate 0.3mg/kg,sufentanil 0.4ug/kg,rocuronium 0.6mg/kg were given for induction of anesthesia,the patients were intubated and received mechanical ventilation.After the patient was stable,the volume expansion test was undertaken: the patients received the rapid infusion of Ringer 250 ml for 15 min,with measurement and recording of the parameters:Invasive blood pressure monitoring（SBP、DBP、MAP）,electrocardiogram（ECG）,pulse oxygen saturation（SpO₂）,Partial pressure of end-tidal carbon dioxide,（PetCO₂）,stroke volume variation（SVV）,stroke volume index（SVI）and cardiac index（CI）in the operation of monitoring.Considering the change of CI before and after the volume expansion test（△CI）≥15% as capacity-positive,patients with △CI≥15% as reactive group andthose[1,2],△CI<15% as non-responders.Calculate changes in hemodynamic parameters and PetCO₂ before and after volumeexpansion test,and the correlation between cardiac output and PetCO₂.Result:1 Total 60 patients were included in this study,of which volume expansion test responders are 51 cases,non-responders are 5 cases and 4 cases of other condition.respectively.Cardiac index and PetCO₂ in responders group increased significantly after the volume expansion test,while in the non-responders group cardiac index and PetCO₂ did not change.2 Correlation analysis: After the volume expansion changes in ΔCI and ΔPetCO₂ positively correlated（r = 0.79,P <0.05）,After the volume expansion changes in ΔCI and ΔPP positively correlated（r = 0.96,P<0.05）,fter the volume expansion changes in ΔPetCO₂ and ΔPP positively correlated（r = 0.70,P <0.05）.Conclusion:Change of PetCO₂ can effectively and non-invasively predict the volume responsiveness of elderly patients under general anesthesia.