Effect of dexamethasone on cerebrovascular hemodynamics in lowlanders with COPD travelling to 3100m.
Bibliographic record
Abstract
Introduction: Dexamethasone (DEX) is used to treat cerebral edema at altitude. However, effects of DEX at altitude on cerebrovascular regulation are unknown. Methods: 82 patients with COPD, GOLD 1-2, (mean±SD; 56±9yrs, FEV1 90±19%pred) were randomized to placebo (PLC) or DEX (2x4mg/day) one-day prior to and during an altitude sojourn. Middle cerebral artery blood flow velocity (MCAv; transcranial Doppler ultrasound) and mean blood pressure (MBP) were monitored at rest and during isometric handgrip exercise to fatigue at 760m (Bishkek, Kyrgyzstan) and 3100m (Tuja Ashu) Results: In 44 patients receiving DEX there was no altitude-induced increase in MCAv (48.6±8.8 vs. 49.4±10.5cm·s-1) or MBP (93±9 vs. 94±9mmHg) with ascent to 3100m. In 38 patients receiving PLC, ascent increased MCAv and MBP from 47.7±10.0 to 52.2±10.4cm·s-1 and 91±12 to 97±12mmHg, respectively; both P<0.01. Treatment effect, mean difference[95%CI] was -3.8cm·s-1[-7.3;-0.2] and -5mmHg[-9;-1] for MCAv and MBP; both P<0.05. During handgrip at 3100m, DEX blunted MCAv increase (28±14 vs. 21±13%; P≤0.01), despite a similar increase in MBP as at 760m (46±22 vs. 48±26%; P>0.05). With placebo, the MCAv and MBP during handgrip were similar between altitudes (MCAv: 30±14 vs. 28±11%; MBP: 47±27 vs. 45±20%; both P>0.05). The treatment effect was -6%[-11;0] P<0.05 and 4%[-7;15]) for MCAv and MBP, respectively. Conclusion: In mild-moderate COPD DEX attenuated the altitude-related increase in MCAv and MBP, suggesting that DEX may have a protective role preventing an excessive rise in cerebral blood flow and pressure at altitude. Funding: Swiss Lung Foundation, Lung Zurich, NSERC, Brenda Strafford Foundation Chair for Alzheimer Research
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| 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".