Predictive Value Of Inferior Vena Cava Variation And Diaphragm Thickening Fraction On Withdrawal Outcome Of Mechanical Ventilation Patients

Objectives At 30 minutes of spontaneous breathing trial（SBT）,patients on mechanical ventilation in an intensive care unit（ICU）need to gather date about the inferior vena cava variability（△DIVC）and Diaphragmatic thickening fraction（DTF）through bedside ultrasonic measurement.To assess the predictive value of inferior vena cava variability,diaphragmatic muscle thickening score,and their combination in the withdrawal of patients with invasive mechanical ventilation.Methods 65 patients admitted to ICU of Affiliated Hospital of North China University of Science and Technology whose mechanical ventilation duration was longer than 48 hours were selected for voluntary breathing test,however,a total of 61 patients met the exclusion criteria and were eventually included in this study.The general data of the patients were recorded before the spontaneous breathing trial:the etiology of respiratory failure,gender,age,and acute physiology and chronic health evaluation（APACHE II）.After 30 minutes of the spontaneous breathing test,the patients’clinical data were recorded:p H,Pa O₂,Pa CO₂,Pa O₂/Fi O₂,tidal volume and the shallow fast breathing index（RSBI）as calculated by the formula.The diameter of the inferior vena cava and the thickness of the right diaphragm were measured by bedside ultrasound at 30 minutes after the spontaneous breathing trial.The variation of the inferior vena cava and the thickening fraction of the right diaphragm were calculated and recorded by formula.According to the results of the withdrawal,the patients were divided into successful withdrawal group and the failed withdrawal group.The data collected were statistically analyzed with SPSS 22.0 software,and the curve of receiver operating characteristic（ROC）was plotted with Med Calc software.To assess the predictive value of inferior vena cava variability,diaphragmatic muscle thickening score,and their combination in the withdrawal of patients with invasive mechanical ventilation.Results 1 A total of 61 patients met the criteria and were included in the study.The major causes of respiratory failure requiring invasive mechanical ventilation through otracheal intubation was severe pneumonia in 12 patients（19.67%）,chronic obstructive pulmonary diseases（COPD）in 10 cases（16.40%）,sepsis and acute respiratory distress syndrome（ARDS）in 7 cases（11.48%）,heart failure in 6 cases（9.84%）and myocardial infarction in 5 cases（8.20%）,gastrointestinal surgery and ketoacidosis occurred in 4 cases（6.56%）,cerebral infarction and cerebral hemorrhage in 3 cases（4.92%）.There was no statistical difference in the etiology of respiratory failure between the successful group and the failure group（x²=1.592,P=0.996）.2 The general data of 45 patients in the successful weaning group and 16 patients in the failed weaning group were compared:there was no statistical differences in gender,age and APACHE II score between the two groups before the spontaneous breathing test（P<0.05）.3 Comparison of clinical data between the successful withdrawal group and the failed withdrawal group at 30 minutes of spontaneous breathing test:there were no statistical differences in p H,Pa CO2,Pa O2/Fi O2,and tidal volume（P>0.05）;The shallow fast index of the successful withdrawal group was lower than that of the failed group（38.05±13.87 vs 52.83±17.18,P=0.022）,and the difference has statistically significant（P<0.05）.4 At 30 minutes of spontaneous breathing test,the variability of inferior vena cava in successful weaning group was higher than that in failure group（0.28±0.04 vs 0.21±0.06,P<0.001）,and the diaphragm thickening score in successful weaning group was higher than that in failure group（42.91±21.58 vs22.44±11.66,P<0.001）.There was significant difference between the two clinical indexes.5 Three indexes with statistical differences（the rapid shallow breathing index,inferior vena cava variability and diaphragm thickening score）were analyzed by ROC curve:the optimal threshold of the rapid shallow breathing index was 47.50,the sensitivity was62.5%,and the specificity was 82.2%,and area under the curve（AUC）was 0.737;the optimal threshold of inferior vena cava variability was 0.22,the sensitivity was 68.7%,and the specificity was 91.1%,and AUC was 0.811;the optimal threshold of diaphragm thickening score was 29%,the sensitivity was 81.2%,and the specificity was 73.3%,and AUC was 0.778.6 The combined prediction index of inferior vena cava variability and diaphragm thickening score was calculated by Logistic regression,and the ROC curve analysis of the combined prediction index showed that the optimal threshold was 0.31,the sensitivity was 87.5%,the specificity was 86.7%,and the AUC was 0.907.7 According to the ROC curve analysis of three indexes with statistical differences（the rapid shallow breathing index,inferior vena cava variability and diaphragm thickening score）and their combined predictive indexes（inferior vena cava variability and diaphragm thickening score）,the predictive value of combined predictive index was higher than that of single index（the rapid shallow breathing index,inferior vena cava variability,diaphragm thickening score）.Conclusions The measurement of the rapid shallow breathing index,inferior vena cava heterogeneity and diaphragm thickening score at 30 minutes of spontaneous breathing test can predict the outcome of weaning in patients with ICU.At the same time,bedside ultrasound measurement of inferior vena cava variability combined with diaphragm thickening fraction can improve the accuracy of prediction.Figure 4;Table 6;Reference 78...