This commentary evaluates a prospective study by Lopes et al. examining diaphragmatic atrophy—detected by serial ultrasound—in children (median age 1.3 months, median weight 3.5 kg) requiring mechanical ventilation after cardiac surgery, and discusses methodological strengths, limitations, and clinical interpretation of findings.
The authors note that Lopes et al. found diaphragmatic atrophy in 56% of the cohort and that diaphragmatic thickening fraction (dTF) was independently associated with extubation success; however, they caution that dTF may reflect increased respiratory effort rather than preserved reserve, especially in smaller infants where raw dTF was paradoxically higher in the extubation failure group.
- No early-extubated comparison group limits the ability to separate ventilation-induced atrophy from surgery/perioperative effects. - Small final cohort and limited extubation failures constrain multivariable adjustment and definitive conclusions. - The clinical significance of a ≥10% reduction in diaphragm thickness in neonates and young infants after cardiac surgery remains uncertain.
Diaphragmatic thickening fraction should not be used as a stand-alone extubation predictor; integrate it with respiratory effort, ventilator settings, sedation level, and body size. Serial diaphragmatic ultrasound from the preoperative period onward may help identify early structural changes in this high-risk infant population.
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