A Clinical Study On The Ability Of Weaning Index To Predict Weaning From Mechanical Ventilation

Objective: To determine the effection of two different mechanicalventilation modes for the ability of Weaning Index to predict weaning frommechanical ventilation.Methods: The study was conducted from August2013to February2014in intensive care unit at hospital,No.4,Hebei Medical University.Forty patientsmechanically-ventilated for more than48hours randomly divided into2groups as two different mechanical ventilation modes, AC group and PSVgroup， then divided into Sucsess group and Faliure group as successfulweaning or not.Ventilator support condition was gradually reduced then SBTwas taken when the criteria of weaning was meated.Before the SBT,some datewas measured.The Age,Sex,weight,the cause Faliure of weaning, APACHEII,the sign of life,the days of mechanical ventilation, the rate of successfulweaning,Rapid shallow breathing index (RSBI), weaning index,MinuteVentilation,Maximum inspiratory pressure(MIP),Peak pressure,the days inICU,the days in hospital,Rapid shallow breathing index (RSBI) in the first、three and30minutes of SBT was measured.WI=RSBI*peak pressure/MIP*MV/10.Statistical analysis was performed with SPSS16.0softwarepackage. We compared the date between the patients who successful weaningwith who was failure of all patients、AC group and PSV patients，also withother paraments.The ROC of all paraments was calculated with Medcalc11.4software.The area under the ROC curves (AUC)of WI was compared withother paraments. We compared the ability of Weaning Index to Predictweaning from mechanical ventilation with the area under the ROC curves.Astatistical significant was P-value＜0.05.Results:1There is40patients in the two groups.After the first SBT,25pa tients(62.5%)were successfully liberated from mechanical ventilation while15patients failured.12patients(63%)were successfully liberated frommechanical ventilation while7patients failured in AC group.13patients(62%)were successfully liberated from mechanical ventilation while8patients failured in PSV group.After24h,31patients(77.5%)were successfully liberated from mechanical ventilation while9patients failured.16patients(84%)were successfully liberated from mechanical ventilation while3patients failured in ACgroup.15patients(71.42%)were successfully liberated from mechanical ventilation while6patients failured in PSV group.After48h,34patients(85%)were successfully liberated from mechanical ventilation while6patients failured.16patients(84%)were successfullyliberated from mechanical ventilation while3patients failured in AC group.20patients(95%)were successfully liberated from mechanical ventilation while1patients failured in PSV group.After72h,36patients(90%)were successfully liberated from mechanical ventilation while4patients failured.16patients(84%)were successfullyliberated from mechanical ventilation while3patients failured in AC group.15patients(71.42%)were successfully liberated from mechanical ventilation while6patients failured in PSV group.2When WI<61.45for patients in AC group,As a threshold for predicting successfully weaning,Sensitivity=98%，Specificity=72%.The AUCof WI was0.917±0.068. There was no significantly different compare the AUC of WI with the AUC of RSBI(P>0.05).Comparing with RSBI,WIhas not higher accuracy.Comparing the AUC of WI with MIP、Peak pressure/MIP、MV，there was significantly different and WI has higher accuracy. The average of WI，RSBI of patients who successful weaningwas significantly smaller than the failure group（P＜0.05）.while the average of MIP、Peak pressure/MIP、MV are not（P＞0.05).3When WI<51.45for patients in PSV group,As a threshold for predicting successfully weaning,Sensitivity=74.6%，Specificity=100%.The A UC of WI was0.933±0.046. There was no significantly different compare the AUC of WI with the AUC of RSBI(P>0.05).Comparing with RSBI,WI has not higher accuracy.Comparing the AUC of WI with MIP、Peak pressure/MIP、MV，there was significantly different and WI has higher accuracy. The average of WI，RSBI of patients who successful weaning was significantly smaller than the failure group（P＜0.05）.while the average of MIP、Peak pressure/MIP、MV are not（P＞0.05).4When WI<50.4for all patients,As a threshold for predicting successfully weaning,Sensitivity=84.6%，Specificity=100%.The AUC of WIwas0.933±0.05. There was no significantly different compare the AUCof WI with the AUC of RSBI(P>0.05).Comparing with RSBI,WI has not higher accuracy.Comparing the AUC of WI with MIP、Peak pressure/MIP、MV，there was significantly different and WI has higher accuracy. The average of WI，RSBI of patients who successful weaning was significantly smaller than the failure group（P＜0.05）.while the averageof MIP、Peak pressure/MIP、MV are not（P＞0.05).5There was no significant different between the two groups of theage,sex,weight,APACHE II,ratio of weaning success,duration of ventilation,the time in ICU and hospital,（P>0.05).、RSBI、MIP、Peak presure/MIP、MV、WI were not significant different between the two groups（P>0.05)。There was no significant different of the age,sex,weight,APACHEII,ratio of weaning success,the time in ICU and hospital between patients who successful weaning and failure of tall patients（P>0.05).While the duration of ventilation in the group of weaning failure is longer thanthe weaning success.There was significant different between the two groups（P<0.05)。Conclusions:1In A/C group,WI has good ability of predict weaning from mechanical ventilation.Except RSBI,Compared with MIP、PP/MIP、MV,WI has higher accuracy.2In PSV group,WI has good ability of Predict weaning from mec hanical ventilation.Except RSBI,compared with MIP、PP/MIP、MV,WI has higher accuracy.3There was no significant different of MIP、PP/MIP、MV、WI between the two groups.Both A/C and PSV are good mechanical ventilation mode for weaning.