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Mechanical Power Is Associated With Mortality in Pediatric Acute Respiratory Distress Syndrome
Andrew G Percy1, Mark V Mai2, Anoopindar K Bhalla3
1Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA.
Insights
Higher mechanical power (MP) during ventilation is linked to increased mortality in pediatric acute respiratory distress syndrome (ARDS). Positive end-expiratory pressure (PEEP) is a key driver, suggesting potential therapeutic targets.
Area of Science:
- Pediatric Critical Care Medicine
- Respiratory Physiology
- Mechanical Ventilation
Background:
- Mechanical power (MP) is a proposed metric for ventilator-lung interactions.
- Previous studies have not established a link between MP and mortality in pediatric acute respiratory distress syndrome (ARDS).
Purpose of the Study:
- To investigate the association between mechanical power and mortality in intubated children with ARDS.
- To identify which components of mechanical power contribute to mortality in this population.
Main Methods:
- Secondary analysis of a prospective observational study involving 546 intubated children with ARDS.
- Children received pressure-controlled ventilation.
- Mechanical power and its components were analyzed for association with mortality and ventilator-free days.
Main Results:
- Higher mechanical power was significantly associated with increased mortality (aHR 1.34).
- Positive end-expiratory pressure (PEEP) was the primary component of MP associated with mortality (HR 1.32).
- Modified MP calculations (e.g., from static strain, dynamic strain, mechanical energy) also correlated with mortality.
Conclusions:
- Increased mechanical power is associated with higher mortality in pediatric ARDS.
- PEEP appears to be the main driver of this association, though it may reflect illness severity.
- Findings support further research into optimizing PEEP levels in pediatric ARDS management.
Objectives:
Mechanical power (MP) transferred from the ventilator to the lungs has been proposed as a summary variable that may impact mortality in children with acute respiratory distress syndrome (ARDS). To date, no study has shown an association between higher MP and mortality in children with ARDS.
Design:
Secondary analysis of a prospective observational study.
Setting:
Single-center, tertiary, academic PICU.
Patients:
Five hundred forty-six intubated children with ARDS enrolled between January 2013 and December 2019 receiving pressure-controlled ventilation.
Interventions:
None.
Measurements And Main Results:
Higher MP was associated with increased mortality (adjusted hazard ratio [HR] 1.34 per 1 sd increase, 95% CI 1.08-1.65; p = 0.007). When assessing the contribution of individual components of MP, only positive end-expiratory pressure (PEEP) was associated with mortality (HR 1.32; p = 0.007), whereas tidal volume, respiratory rate, and driving pressure (ΔP = [peak inspiratory pressure (PIP)-PEEP]) were not. Finally, we tested whether there remained an association when specific terms were removed from the MP equation by calculating MP from static strain (remove ΔP), MP from dynamic strain (remove PEEP), and mechanical energy (remove respiratory rate). MP from static strain (HR 1.44; p < 0.001), MP from dynamic strain (HR 1.25; p = 0.042), and mechanical energy (HR 1.29; p = 0.009) were all associated with mortality. MP was associated with ventilator-free days only when using MP normalized to predicted body weight, but not when using measured weight.
Conclusions:
Higher MP was associated with mortality in pediatric ARDS, and PEEP appears to be the component most consistently driving this association. As higher PEEP is used in sicker patients, the association between MP and mortality may reflect a marker of illness severity rather than MP itself being causal for mortality. However, our results support future trials testing different levels of PEEP in children with ARDS as a potential means to improve outcome.
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