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The effect of mechanical ventilation on respiratory muscle echogenicity in critically ill children: an observational
Marloes M Ijland1, Jeroen L M van Doorn2, Axel Beukman3
1Department of Intensive Care Medicine, Radboud University Medical Center, Postbox 9000, Nijmegen, 6500 HB, The Netherlands. Marloes.ijland@radboudumc.nl.
Insights
Mechanical ventilation in critically ill children did not increase respiratory muscle echogenicity. Short-term ventilation with low settings appears not to cause significant structural changes in respiratory muscles.
Area of Science:
- Pediatric Critical Care Medicine
- Respiratory Physiology
- Medical Ultrasound Imaging
Background:
- Respiratory muscle weakness is prevalent in critically ill children, often linked to structural muscle changes.
- Muscle echogenicity, assessed via ultrasound, serves as a non-invasive indicator of skeletal muscle structural alterations.
- Understanding these changes is crucial for managing respiratory compromise in pediatric intensive care.
Purpose of the Study:
- To evaluate respiratory muscle echogenicity in mechanically ventilated children admitted to the pediatric intensive care unit (PICU) compared to a control group.
- To assess changes in respiratory muscle echogenicity over time during mechanical ventilation.
- To explore the association between respiratory muscle echogenicity and clinical parameters or outcomes.
Main Methods:
- A prospective longitudinal observational study of mechanically ventilated children (n=32) and a control group (n=13).
- Ultrasound analysis of diaphragm and expiratory muscles for echogenicity, thickness, and thickening fraction.
- Collection of clinical data including inflammation markers, fluid balance, protein intake, and outcomes like ventilation-free days and mortality.
Main Results:
- No significant difference in respiratory muscle echogenicity between ventilated children at PICU admission and controls.
- No increase in respiratory muscle echogenicity observed after four days of mechanical ventilation, despite interindividual variability.
- No correlation found between echogenicity changes and muscle thickness, thickening fraction, or clinical outcomes. Excellent intra-observer repeatability for echogenicity measurements.
Conclusions:
- Four days of mechanical ventilation in critically ill children does not lead to increased respiratory muscle echogenicity.
- Findings suggest that short-term mechanical ventilation, particularly with lower settings in moderately ill children, does not induce substantial structural changes in respiratory muscles.
Background:
Respiratory muscle weakness is common in critically ill children. Changes in respiratory muscle structure play pivotal role in the development of weakness. Echogenicity is a non-invasive marker to detect structural changes in skeletal muscles. In this study, we evaluated respiratory muscle echogenicity in critically ill ventilated children at PICU admission compared to a control group and its change over time. Secondary, we explored its association with clinical parameters and outcome.
Methods:
Two cohorts were studied: a secondary analysis of a prospective longitudinal observational cohort study in mechanically ventilated children (n = 32) and a prospective control group (n = 13) for obtaining reference values. Ultrasound images of the diaphragm and expiratory muscles were analysed. Muscle echogenicity, muscle thickness, muscle thickening fraction, clinical parameters (inflammation, fluid balance and protein intake) and clinical outcome measurements (ventilation free days, extubation failure and 28-day mortality) were collected.
Results:
The analysis included 174 diaphragm ultrasounds and 144 expiratory respiratory muscles ultrasounds. Echogenicity at PICU admission was not different from controls; for the diaphragm: 27.3 [20.0-32.0] vs 26.3 [19.3-29.3] (P = 0.488), m. obliquus externus: 32.2 [25.5-37.9] vs 34.0 [28.0-51.3] (P = 0.166), m. obliquus interna: 29.8 [25.8-38.8] vs 33.0 [27.8-39.3] (P = 0.390), m. transversus: 30.0 [20.8-38.8] vs 32.3 [24.7-37.0] (P = 0.762), respectively. There was no increase in respiratory muscle echogenicity after four days of mechanical ventilation, though a substantial interindividual variation existed. No correlation was found between changes in echogenicity and changes in muscle thickness, thickening fraction and echogenicity on day four of mechanical ventilation, or clinical outcome. The intra-observer repeatability of the echogenicity for all the respiratory muscles was excellent (all ≥ 0.97).
Conclusion:
In critically ill children, four days of mechanical ventilation does not result in an increase in respiratory muscle echogenicity. Our findings suggest that short periods of mechanical ventilation with relatively low ventilator setting in moderate critically ill children do not lead to large structural changes in the respiratory muscles.
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