| BACKGROUND:Weaning post-cardiac surgery patients from mechanical ventilation(MV)poses a big challenge to these patients.Optimized left ventricular-arterial coupling(VAC)may be crucial for reducing the MV duration of these patients.However,there is no research exploring the relationship between VAC and the duration of MV.We performed this study to investigate the relationship between left ventricular-arterial coupling(VAC)and prolonged mechanical ventilation(MV)in severe post-cardiac surgery patients.PATIENTS AND METHODS:This was a single-center retrospective study of 56 severe post-cardiac surgery patients from January 2015 to December 2017 at the Department of Critical Care Medicine of Peking Union Medical College Hospital.Patients were divided into two groups according to the duration of MV(PMV group:prolonged mechanical ventilation group,MV>6 days;Non-PMV group:non-prolonged mechanical ventilation group,MV ≤6 days).Hemodynamic indicators and tissue perfusion data were collected or calculated at admission(TO),24h,48 h and 72h after admission(T1)to the ICU.Difference analyses were performed between the two groups to find significant indicators that might influence the outcome of prolonged MV.In order to select the risk factors of prolonged MV,we used univariate logistic regression to pick out the significant risk factors,and then built multivariate regression models at T1,T2,T3 to find out the independent factors of prolonged MV respectively.RESULTS:56 patients were included eventually,and 26 in PMV group and 30 in non-PMV group.There were no differences in basic demographic characteristics and baseline data.Compared with the non-prolonged MV group,the prolonged MV group had significantly higher values for heart rate(T1,T2,T3),lactate(T1,T3),and lower in SBP(T2,T3),CI(T1:2.75±0.60 vs 2.33±0.72 L/min/m2,P=0.035;T3:2.97±0.52 vs 2.22±0.62 L/min/m2,P=0.004),SVI(T1:26.26±6.87vs21.56±8.54ml/m2,P=0.043;T2:29.52±10.84 vs 23.58±6.75 ml/m2,P=0.049;T3:30.20±6.48 vs 22.72±7.87 ml/m2,P=0.020).As for VAC associated variables,PMV group had higher Ea/Ees(T2:5.93±1.81 vs.4.05±1.20,P<0.001;T3:4.02±0.71 vs 5.70±1.22,P=0.001)and Ea(T1:3.15±1.20 vs 2.55±0.74 mmHg/ml,P=0.041;T3:2.89±0.88 vs 2.26±0.40 mmHg/ml,P=0.041),while lower in Ees(T2:0.511±0.149 vs 0.642±0.198 mmHg/ml,P=0.021)In our multivariate logistic regression models,the Ea/Ees(OR=3.038;95%CI 1.316-7.013;P=0.009)in T2 model was the only independent risk factor of PMV.The area under the receiver operating characteristic(AUC)of the left VAC for predicting PMV was 0.801,and the cutoff value for Ea/Ees was 5.12,with 65.0%sensitivity and 90.0%specificity.CONCLUSIONS:Worse ventricular-arterial coupling,and lower cardiac output and stroke volume were associated with prolonged mechanical ventilation in severe post-cardiac surgery patients.Compared to CO and SV,VAC after 48h in ICU was an independent risk factor for PMV.Optimizing VAC might be helpful in reducing duration of MV in these patients. |
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