Predictive value of ultrasonographic assessment of inferior vena cava variability in the weaning of patients with mechanical ventilation / 中华超声影像学杂志

ABSTRACT

Objective To investigate the predictive value of bedside echocardiographic assessment of the inferior vena cava variability ( ΔIVC ) in the weaning of patients with mechanical ventilation before spontaneous breathing test ( SBT ) . Methods Eighty-two mechanical ventilation patients admitted to the department of critical care medicine in our hospital from June to December 2017 and ready to wean from the mechanical ventilation were successively included . SBT was performed by T-tube mode after screening and the success of weaning is defined that the spontaneous breathing time exceeds 48 h after extubated . According to the outcomes of weaning ,the patients were divided into the weaning success group( 61 cases) and the weaning failure group(21 cases) ,the successful rate of weaning was 76 .1％ . The basic clinical characteristics of the patients ,including age ,sex ,acute physiology and chronic health score II ,heart rate , respiratory rate ,mean arterial pressure ,central venous pressure ( CVP) and the level of lactic acid were recorded ,and the inferior vena cava variability ( ΔIVC ) were measured before SBT with bedside echocardiography . The ΔIVC differences between the patients in the weaning success group and the weaning failure group were compared ,and the predicted value of ΔIVC for the weaning results was evaluated by ROC curve ,expressed as the area under the curve ( AUC) . Results The CVP of the weaning failure group was higherthanthatintheweaningsuccessgroup[(10.0±3.2)mmHgvs(7.2±2.8)mmHg(1mmHg =0 .133 kPa) , P =0 .01] . There was no significant difference in other basic clinical characteristics( all P >0 .05) . The ΔIVC of the weaning success group was significantly higher than that of the weaning failure group[(67.1±25.8)％ vs(33.8±23.2)％ ,P =0.001].TheAUCofthe ΔIVC predicted the weaning result before SBT was 0 .76 . The sensitivity of ΔIVC>50％ predicting successful weaning was 81 .8％ and the specificity was 79 .2％ . Conclusions Echocardiographic assessment of the inferior vena cava variability in patients with mechanical ventilation before SBT can predict the weaning outcome and guide fluid management clinically .