A Pilot Study Of Diaphragm Excursion Measured With Ultrasound As A Weaning Predictor In Mechanical Ventilation Patients

Object To explore the value of diaphragm excursion measured with ultrasound in the process of spontaneous breathing trial(SBT) as a weaning predictor in mechanical ventilation patients in Intensive Care Unit. Make a contribution to the optimization of weaning time.Methods Twenty four patients,age 18~80 years old,treated by invasive ventilation more than 24 h were enrolled from Dec 2014 to Aug 2015 in the department of Intensive Care Unit. patients who met the clinical weaning criteria were extubated after 120 min SBT. 44 patients were divided into the success and failure groups according to the result.Each group had 22 cases. Before SBT, PH value, partial pressure of oxygen(Pa O2), arterial partial pressure of carbon dioxide(Pa CO2), oxygenation index(Pa O2/Fi O2), respiratory rate(f), heart rate(HR) and mean artery pressure(MAP) were recorded. During SBT,patients in supine position, DE was measured with bedside ultrasound, the right DE, left DE, rapid shallow breathing index(RSBI) were recorded or calculated at the first, 10thand30 thminute of SBT. Oxygenation index(Pa O2/Fi O2) was recorded at 30 thminute of SBT. Observed change of various indices closely during SBT, instead of original mechanical ventilation mode when the SBT failure criteria was met.Results1. Diaphragm Excursion(1)There was statistics difference in DE of both sides about success group patients among the first, 10 thand 30thminute of SBT(P<0.05).(2)There was statistics difference in DE of both sides about failure group patients among the first, 10 thand 30thminute of SBT(P<0.05).(3)The left side DE at 10 thand 30thminute of SBT were lower than the right side in success group(P<0.05),While there was no difference in DE at the first, 10 thand 30th minute of SBT between the left and right side about failure group patients(P>0.05).(4)There was no difference in DE of both sides about patients between the success group and the failure group at the first, 10 thand 30thminute of SBT(P>0.05).(5)There were no difference of ΔDE010-and ΔDE030-between the success group patients and the failure group patients(P>0.05).(6)ΔDE1030-showed higher values in the failure group patients. There was significant difference of ΔDE1030-in patients between success and failure group(P<0.05).(7)The area under the ROC curves(AUC) of the right ΔDE1030-was 0.940, Using0.175 cm as the threshold value for prospectively predicting failed weaning, the sensitivity,specificity were 95.5%, 86.4% respectively.(8)The area under the ROC curves(AUC) of the left ΔDE1030-was 0.907, Using0.270 cm as the threshold value for prospectively predicting failed weaning, the sensitivity,specificity were 81.8%, 90.9% respectively.2. Rapid-shallow breathing index(f/Vt)(1)The f/Vt in successful weaning patients were lower than that in failed weaning patients at 10 thand 30thminute of SBT(P<0.05).(2)The area under the ROC curves(AUC) of the f/Vt at 30 thminute of SBT was 0.744,Using 44bpm/L as the threshold value for prospectively predicting weaning, the sensitivity, specificity were 81.8%, 72.7% respectively.3. Oxygen index(Pa O2/Fi O2)(1)There was no difference of Pa O2/Fi O2 in patients between the success groupand the failure group before SBT(P>0.05).(2)There was significant difference of Pa O2/Fi O2 in patients between success and failure group at 30 thminute of SBT(P<0.05).(3)The area under the ROC curves(AUC) of the Pa O2/Fi O2 at 30thminute of SBT was 0.837, Using 203 mm Hg as the threshold value for prospectively predicting weaning,the sensitivity, specificity were 86.4%, 72.7% respectively.ConclusionCompare with the rapid shallow breathing index(f/Vt) and oxygen index(Pa O2/Fi O2), the right side ΔDE1030-measured with ultrasound in the process of 30 minutes SBT was a more valuable predictor for the patients to wean from mechanical ventilation in ICU.1. The Δ DE measured with ultrasound during 30 minutes SBT, particularly ΔDE1030-was a useful reference index for predicting weaning in ICU.2. As a result, the sensitivity of the right side Δ DE1030-(95.5%)measured with ultrasound as a weaning predictor was higher than the left side ΔDE1030-(81.8%). The specificity of the left side Δ DE1030-(90.9%)was higher than right side(86.4%). Both sensitivity and specificity of the two sides were higher than f/Vt(sensitivity81.8%,specificity 72.7%).