Ultrasound Evaluation of Diaphragm Force Reserve in Patients with Chronic Obstructive Pulmonary Disease
Bibliographic record
Abstract
Abstract Rationale Diaphragm function is a key determinant of dyspnea in chronic obstructive pulmonary disease (COPD); however, it is rarely assessed in clinical practice. Lung hyperinflation can also impair diaphragm function. Ultrasound can assess the activity, function, and force reserve of the diaphragm. Objectives To compare diaphragm activity, function, and force reserve among patients with COPD and healthy control subjects. Methods Patients with stable COPD (n = 80) and healthy control subjects (n = 20) were enrolled (97% of them were men). Ultrasound was used to measure the thickening fraction of the diaphragm during tidal breathing and maximum volitional effort. Outcome measures were as follows: 1) the difference in diaphragm force reserve, activity, and function between patients with COPD and control subjects; 2) the correlation between lung volumes and diaphragm force reserve, activity, and function; and 3) the relationship between diaphragm force reserve and the rate of moderate to severe exacerbation of COPD. Results The tidal thickening fraction of the diaphragm during resting breathing (TFdi-tidal) was higher in patients with COPD than in control subjects (P = 0.002); it was approximately twice as high in patients with severe COPD than in control subjects. Patients with COPD had poorer diaphragm function than control subjects as assessed by the maximal thickening fraction of the diaphragm during Muller maneuver (P < 0.01). Diaphragm force reserve ratio assessed by 1−(tidal thickening fraction of the diagphragm during resting breathing/maximal thickening fraction of the diaphragm) was lower in patients with COPD than in control subjects, and it fell with increasing Global Initiative for Chronic Obstructive Lung Disease stages (P < 0.001); it correlated with inspiratory capacity (r = 0.46) and the body mass index, airflow obstruction, dyspnea, exercise capacity (BODE) index, a multidimensional scoring system (r = −0.49). Patients who developed exacerbation during the following 2 years had less force reserve than patients without exacerbation (P = 0.024). Conclusions Male patients with COPD have increased diaphragm workload, impaired diaphragm function, and reduced force reserve compared with healthy subjects. Ultrasound assessment of the diaphragm in COPD provides important functional information. Clinical trial registered with the Thai Clinical Trials Registry (TCTR20160411001). Registered 31 April 5, 2016.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".