Sarcopenia is an effective predictor of difficult-to-wean and mortality among critically ill surgical patients

Abstract

Background: Critically-ill surgical patients are at higher risk for sarcopenia, which is associated with worse survival. Sarcopenia may impair the respiratory musculature, which can subsequently influence the outcome of ventilator weaning. Although there are a variety of weaning parameters predictive of weaning outcomes, none have tried to incorporate "muscle strength" or "sarcopenia". The aim of the current study was to explore the association between sarcopenia and difficult-to-wean (DtW) in critically-ill surgical patients. The influence of sarcopenia on ICU mortality was also analyzed.

Methods: Ninety-six patients undergoing mechanical ventilation in the surgical intensive care unit (ICU) were enrolled. Demographic data and weaning parameters were recorded from the prospectively collected database, and the total psoas muscle area (TPA) was determined at the level of the 3rd lumbar vertebra by computed tomography. Sarcopenia was defined by previously established cut-off points and its influence on clinical outcomes was examined. Receiver operating characteristic (ROC) curve analysis was conducted to investigate the predictive capability of TPA and weaning parameters for predicting weaning outcomes.

Results: The median age of the studied patients was 73 years. Thirty patients (31.3%) were sarcopenic and 30 (31.3%) were defined as DtW. Eighteen patients (18.8%) had ICU mortality. Multivariate logistic regression analyses revealed that sarcopenia was an independent risk factor for DtW and ICU mortality. The area under the ROC curve (AUC) of TPA for predicting successful weaning was 0.727 and 0.720 in female and male patients, respectively. After combining TPA and conventional weaning parameters, the AUC for DtW increased from 0.836 to 0.911 and from 0.835 to 0.922 in female and male patients, respectively.

Conclusion: Sarcopenia is an independent risk factor for DtW and ICU mortality. TPA has predictive value when assessing weaning outcomes and can be used as an effective adjunct predictor along with conventional weaning parameters.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. Representative computed tomography image at the level of the L3 vertebral body.

The red lines represent the greatest anterior/posterior and transverse diameters of psoas muscle obtained by using a picture archiving and communications system.

Fig 2. Receiver operating characteristic (ROC) curves for various predictors of weaning outcomes in the study patients.

TPA represents the total psoas muscle area. Panels A and B show ROC curves predicting successful weaning when TPA alone was used for analysis of female and male patients, respectively. A logit model of the logistic regression incorporating 5 conventional weaning parameters (WS-5P; with respiratory rate, tidal volume, rapid-shallow breathing index, maximum inspiratory pressure, and PaO2/FiO2 ratio as the included weaning parameters) or that model in combination with TPA (WS-5P+TPA) was employed to yield a single weaning score. Panels C and D show ROC curves predicting difficult-to-wean (DtW) when WS-5P and WS-5P+TPA were used for analysis of female and male patients, respectively. The purple line is the reference line.