Pediatrics · Pulmonology ·
Flow-to-compliance ratio associated with strain rate in pediatric ARDS
A secondary analysis of observational data from 31 mechanically ventilated children with early pediatric acute respiratory distress syndrome (PARDS) assessed whether peak inspiratory flow divided by respiratory system compliance reflects lung strain rate. The ratio was moderately correlated with measured strain rate, but agreement was insufficient for the measures to be used interchangeably.
- Flow/CRS moderately correlated with measured strain rate.
- Agreement analysis found systematic bias between the measures.
- Single-center analysis included 31 children with early PARDS.
- Prospective validation is needed before broader clinical use.
Researchers analyzed 2022 data from a single tertiary pediatric intensive care unit in Chile, including 31 mechanically ventilated patients aged 15 years or younger with early PARDS. During volume-controlled ventilation, they measured respiratory mechanics and end-expiratory lung volume, then calculated lung strain, strain rate, and the ratio of peak inspiratory flow to respiratory system compliance (Flow/CRS).
Median strain rate was 0.56 s−1, and median Flow/CRS was 0.94. Across the full dataset, Flow/CRS showed a moderate positive correlation with strain rate (Spearman ρ=0.42; 95% CI, 0.08–0.67). However, Bland–Altman analysis found systematic bias, with limits of agreement from −0.99 to 0.14 s−1, indicating the measures should not be treated as interchangeable. After excluding three outliers, the association was stronger (ρ=0.63; n=28).
The findings suggest Flow/CRS may provide a pragmatic bedside marker related to lung deformation velocity, but they do not establish it as a substitute for measured strain rate. The study was small and single-center; the authors call for prospective validation in larger, more diverse cohorts.
In practice
In mechanically ventilated children with early PARDS, Flow/CRS was associated with measured lung strain rate, but agreement analysis showed systematic bias and limits of agreement that preclude using the ratio as an interchangeable measurement. The result supports further evaluation of Flow/CRS as a pragmatic bedside marker, not a change in monitoring or ventilator management. Evidence is limited by the small, single-center cohort and requires prospective validation in larger, more heterogeneous populations.
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Pediatric Critical Care Medicine: Flow-to-Compliance Ratio as a Bedside Marker of Strain Rate in Pediatric Acute Respiratory Distress Syndrome: Analysis of Observational Cohort Data From 2022 ↗This is an automated AI-condensed summary that has not yet been reviewed by an editor. Always consult the full item at the original source.