Lower Respiratory Tract Infection and Short-Term Outcome in Patients With Acute Respiratory Distress Syndrome.

Fernando G Zampieri,Ignacio Martin-Loeches,Lorenzo Socias,Sandrine Valade,Anahita Rouzé,Alejandro Rodriguez,Nicolas Boussekey,Jean Reignier,Jordi Almirall,Paula Ramirez,Elena Molinos,Pedro Póvoa,William N Viana,Jorge I Salluh,Saad Nseir,José Andrade Gomes

doi:10.1177/0885066618772498

Abstract

Objective:To assess whether ventilator-associated lower respiratory tract infections (VA-LRTIs) are associated with mortality in critically ill patients with acute respiratory distress syndrome (ARDS).Materials and Methods:Post hoc analysis of prospective cohort study including mechanically ventilated patients from a multicenter prospective observational study (TAVeM study); VA-LRTI was defined as either ventilator-associated tracheobronchitis (VAT) or ventilator-associated pneumonia (VAP) based on clinical criteria and microbiological confirmation. Association between intensive care unit (ICU) mortality in patients having ARDS with and without VA-LRTI was assessed through logistic regression controlling for relevant confounders. Association between VA-LRTI and duration of mechanical ventilation and ICU stay was assessed through competing risk analysis. Contribution of VA-LRTI to a mortality model over time was assessed through sequential random forest models.Results:The cohort included 2960 patients of which 524 fulfilled criteria for ARDS; 21% had VA-LRTI (VAT = 10.3% and VAP = 10.7%). After controlling for illness severity and baseline health status, we could not find an association between VA-LRTI and ICU mortality (odds ratio: 1.07; 95% confidence interval: 0.62-1.83; P = .796); VA-LRTI was also not associated with prolonged ICU length of stay or duration of mechanical ventilation. The relative contribution of VA-LRTI to the random forest mortality model remained constant during time. The attributable VA-LRTI mortality for ARDS was higher than the attributable mortality for VA-LRTI alone.Conclusion:After controlling for relevant confounders, we could not find an association between occurrence of VA-LRTI and ICU mortality in patients with ARDS.

Highlights

Acute respiratory distress syndrome (ARDS) is a common and severe condition occurring in the most severely ill patients admitted to the intensive care unit (ICU).[1]
Ventilator-associated lower respiratory tract infection was stratified into ventilator-associated tracheobronchitis (VAT) or ventilator-associated pneumonia (VAP) according to the presence or absence of new abnormal imaging on chest radiography; patients without new infiltrates were categorized as having VAT, while patients with new infiltrates were considered to have VAP.[3]
The time course of patients in the TAVeM database is shown in Figure 1, with sequential 100% stacked barplots representing the proportion of patients on a given status at a given day; panels B and C show the information for patients with and without ARDS

Summary

Introduction

Acute respiratory distress syndrome (ARDS) is a common and severe condition occurring in the most severely ill patients admitted to the intensive care unit (ICU).[1]. Lower respiratory tract infections (LRTIs) are a major issue in critically ill patients, being associated with prolonged hospitalization, higher costs, and possibly, an increase in mortality.[3,4,5,6] In mechanically ventilated patients, ventilator-associated LRTIs (VA-LRTIs) are stratified into ventilator-associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP) according to the presence of new abnormal chest imaging findings, which are a prerequisite for the diagnosis of VAP.[3] Since VAP may impair oxygenation, there is, an important interplay between ARDS and VAP, which challenges both diagnoses in clinical practice. The impact of the occurrence of VA-LRTI in patients with ARDS on mortality is debatable, with most reports focusing on VAP only.[4,6,7,8]

Methods

Results

Discussion

Conclusion