Respective contribution of intensive care unit-acquired limb muscle and severe diaphragm weakness on weaning outcome and mortality: a post hoc analysis of two cohorts

Martin Dres,Nicolas Molinari,Bruno-Pierre Dubé,Samir Jaber,Alexandre Demoule,Thomas Similowski,Federico Manna,Boris Jung,Gerald Chanques

doi:10.1186/s13054-019-2650-z

Abstract

BackgroundIntensive care unit (ICU)-acquired weakness (ICU-AW) and ICU-acquired diaphragm dysfunction (ICU-DD) occur frequently in mechanically ventilated (MV) patients. It is unknown whether they have different risk factors and different impacts on outcome. This study was designed to (1) describe the respective risk factors associated with ICU-AW and severe ICU-DD and (2) evaluate the respective impact of ICU-AW and severe ICU-DD on outcome.MethodsPost hoc analysis of two prospective cohort studies conducted in two ICUs. In patients mechanically ventilated for at least 24 h undergoing a first spontaneous breathing trial, severe ICU-DD was defined as diaphragm twitch pressure < 7 cmH2O and ICU-AW was defined as Medical Research Council Score < 48.ResultsOne hundred sixteen patients were assessed. Factors independently associated with severe ICU-DD were age, longer duration of MV, and exposure to sufentanil, and those factors associated with ICU-AW were longer duration of MV and exposure to norepinephrine. Severe ICU-DD (OR 3.56, p = 0.008), but not ICU-AW, was independently associated with weaning failure (59%). ICU-AW (OR 4.30, p = 0.033), but not severe ICU-DD, was associated with ICU mortality. Weaning failure and mortality rate were higher in patients with both severe ICU-DD and ICU-AW (86% and 39%, respectively) than in patients with either severe ICU-DD (64% and 0%) or ICU-AW (63% and 13%).ConclusionSevere ICU-DD and ICU-AW have different risk factors and different impacts on weaning failure and mortality. The impact of the combination of ICU-DD and ICU-AW is more pronounced than their individual impact.

Highlights

Intensive care unit (ICU)-acquired weakness (ICU-AW) and ICU-acquired diaphragm dysfunction (ICU-DD) occur frequently in mechanically ventilated (MV) patients
In study 2, patients were eligible for inclusion if they were diagnosed with Intensive care unit-acquired weakness (ICU-AW), had been mechanically ventilated for at least 48 h, and were undergoing a spontaneous breathing trial
Prevalence and factors associated with ICU-AW and S-ICUDD Figure 1 displays the distribution of patients according to the presence of ICU-AW and S-ICU-DD

Summary

Introduction

Intensive care unit (ICU)-acquired weakness (ICU-AW) and ICU-acquired diaphragm dysfunction (ICU-DD) occur frequently in mechanically ventilated (MV) patients. Several studies have evaluated the interactions between respiratory and limb muscle dysfunction in critically ill patients [5, 8, 9], but few of them have assessed diaphragm strength by twitch tracheal pressure in response to bilateral phrenic nerve stimulation (Ptr,stim), Dres et al Critical Care (2019) 23:370 which is recognized to be the gold standard [5, 8,9,10]. These studies present a number of limitations. This cut-off has been recently disputed since a recent report showed that Ptr, stim < 7 cmH2O would be the most reliable cut-off to predict weaning failure [10,11,12], as Ptr,stim < 7 cmH2O defines “severe” ICU-acquired diaphragm dysfunction (S-ICU-DD), with weaning failure being the most relevant outcome [13]

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Results

Discussion

Conclusion