A Clinical Study On The Predictive Value Of Diaphragm Ultrasonography In Patients With Mechanical Ventilation During The Weaning

Objective To compare the value of the two new indexes that are the diaphragmatic di-splacement-RSBI(respiratory rate/diaphragmatic displacement,DD-RSBI),the diaphragm thickening-RSBI(respiratory rate/diaphragmatic thickness fraction,DT-RSBI)and traditi-onal RSBI to predict weaning outcomes in ICU patients with mechanical ventilation.Methods This study continuously included 192 Patients admitted to intensive care department of 6 hospitals in Zhejiang province received mechanical ventilation more than48 hours who were ready to perform a SBT from December 2016 to June 2017.Accor-ding to the weaning outcome,the patient-s were classified into a success group(147 cases)or a failure group(45 cases).Duringthe spontaneous breathing test,the diaphragmatic displacement and the diaphragm thick-ening fraction were measured with bedside ultrasound.The traditional RSBI could be implemented by substituting VT with diaphr-agmatic displacement(DD)or the diaphrag-m thickening fraction(DTF).Then,the two new indexes,such as the DD-RSBIand the DT-RSBI,were calculated.At the same time,other related parameters that could affect weaning were also recorded including: p-atient general information,vital signs,mechanical ventilation etiology,ventilator param-eters,intra-abdominal pressure,ventilation time,biochemical and blood gas indicators.The difference of each index between the two groups were analyzed and the receiver operator characteristic(ROC)curves were used to evaluate the value of each indicator to predict weaning failure in ICU patients with mechanical ventilation.Results1.Analysis of general clinical data of two groups of patients:Except that the incidence of sepsis,the number of ICU days and total length of stay in the failure group were higher than those in the successful group and the difference was statistically significant(P < 0.05),but there was no statistical difference in the remaining data.2.According to the weaning outcome,the patients were classified into a success group(147 cases)or a failure group(45 cases).The respiratory rate(RR),rapid shallow breathing index (RSBI),DD-RSBI and DT-RSBI in the failure groups were higher than those in success groups,but the diaphragmatic displacement(DD),diaphragmatic thickening fraction(DTF)was lower than those in success groups and the differences were statistically significant(P<0.05).There was no significant difference between two groups of patients with oxygenation index.3.The areas under the ROC curve of the DD-RSBI,DT-RSBI,RSBI,DD,DTF for predicting the failure of weaning are respectively 0.897(95%CI 0.860-0.952),0.905(95%CI 0.877-0.960),0.758(95%CI 0.670-0.846),0.814(95%CI 0.753-0.876)and 0.839(95%CI 0.772-0.906).Using the 1.65 beats /(ml·min),77.5beats/min,68 beats /(ml·min),14.5mm,27.2% as the threshold value,the sensitivity of predicting the weaning failure are 91.1%,86.7%,64.4%,86.7%,82.2% respectively and the specificity are respectively 68%,80.2%,87.8%,62.9%,71.4%.4.Single factor logistic analysis showed that sepsis,RSBI,DD-RSBI,DT-RSBI were the risk factor of weaning failure.Multivariate logistic regression analysis showed that only DD-RSBI(OR=10.88;95%CI 3.04~38.93)and DT-RSBI(OR=1.08;95%CI 1.04~1.11)were independent predictors of weaning failure.Conclusion1.DD in the DD-RSBI and DTF in the DT-RSBI can specifically reflect diaphragm function and are good alternatives to tidal volume.2.DD-RSBI and DT-RSBI are more accurate than RSBI,DD and DTF in predicting the outcome of weaning.3.DT-RSBI is more valuable than DD-RSBI in predicting the success of weaning.