Additive effects of non‐invasive ventilation to hyperoxia on cerebral oxygenation in <scp>COPD</scp> patients with exercise‐related O<sub>2</sub> desaturation
Bibliographic record
Abstract
BACKGROUND: It is currently unknown whether potential haemodynamic improvements induced by non-invasive ventilation (NIV) would positively impact upon cerebral oxygenation (COx) in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD). OBJECTIVE: To investigate the effects of NIV on exercise COx in COPD patients presenting with exercise-related O(2) desaturation. METHODS: On a double-blind trial, 13 males (FEV1 = 48·8 ± 15·1% predicted) were randomly assigned to NIV (16 cmH(2)O IPS and 5 cmH(2)O PEEP) plus HOx (FiO(2) = 0·4) or sham NIV (7 cmH(2)O IPS and 5 cmH(2)O PEEP to overcome breathing circuit resistance) plus HOx during ramp-incremental exercise performed on different days. Near-infrared spectroscopy and impedance cardiography assessed changes (Δ) in COx and cardiac output (Q(T)), respectively. RESULTS: There were no significant between-intervention differences in peak work rate, ventilation and reported symptoms (P>0·05). Peripheral oxyhaemoglobin saturation remained above 98% throughout the tests. NIV + HOx was associated with larger increases in Δ COx, Δ Q(T) and Δ stroke volume at maximal and submaximal exercise (P<0·05). Increases in the area under the curve (to an iso-work rate) of Δ COx under NIV + HOx were significantly (P<0·01) correlated with improvements in Δ Q(T) (r = 0·82) and Δ stroke volume (r = 0·87). There was, however, no significant correlation between enhancement in these physiological responses with changes in peak work rate with NIV + HOx (P>0·05). CONCLUSIONS: NIV added benefit to HOx in improving central haemodynamics and COx in O(2) 'desaturators' with COPD. The clinical relevance of such beneficial effects on exercise tolerance, however, remains to be demonstrated.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".