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The following is a summary of “Diaphragmatic ultrasound and its relationship to breathing effort and load: a prospective observational study,” published in the May 2025 issue of Critical Care by Menis et al. 

Failure to wean from mechanical ventilation involves multiple factors, with diaphragmatic dysfunction playing a key role, and ultrasound offers a noninvasive way to assess diaphragm function, though its response to varying breathing effort is not well understood.  

Researchers conducted a retrospective study to assess how diaphragmatic ultrasound measurements changed with varying breathing efforts during weaning from mechanical ventilation.  

They evaluated diaphragmatic ultrasound measurements [diaphragmatic excursion (Dex), diaphragmatic thickening fraction (Tfdi)] alongside manometric breathing effort indices [esophageal pressure swings (ΔPes), transdiaphragmatic pressure swings (ΔPdi), pressure–time product of esophageal pressure (PTPes)] in patients weaning from mechanical ventilation. Assessments occurred during an unassisted spontaneous breathing trial (phase SBT) and with inspiratory resistive loading of 30 cmH₂ O/L/s (phase IRL) applied during the same trial. The primary goal was to examine the correlation between ultrasound measurements and breathing effort using repeated measures correlation.  

The results showed that in 49 enrolled patients, Dex correlated with ΔPes (r = 0.5, P< 0.001), ΔPdi (r = 0.55, P< 0.001), and PTPes (r = 0.32, P= 0.031), Tfdi showed no significant correlation with ΔPes (r = 0.27, P = 0.052), ΔPdi (r = 0.2, P = 0.235), or PTPes (r = 0.24, P = 0.110). Both Dex and Tfdi increased during an IRL compared to SBT [1.44 (0.89–1.96) vs 1.05 (0.7–1.59), P= 0.002] and [0.55 (± 0.32) vs 0.46 (± 0.2), P=0.019]. Similarly, ΔPes, ΔPdi, and PTPes rose during IRL vs SBT [(11.87 (7.86, 18.32) vs 6.8 (4.6–10.23), P< 0.001), (10.89 (± 6.42) vs 7.94 (± 3.81), P< 0.001), and (181.10 (108.34, 311.7) vs 97.52 (55.96–179.87), P< 0.001), respectively].  

Investigators concluded that patients breathing spontaneously under resistive load in critical care, Dex showed a weak to moderate correlation with breathing effort and varied between weaning success and failure. 

Source: ccforum.biomedcentral.com/articles/10.1186/s13054-025-05436-1