Prehospital Analgesia With Intranasal Ketamine (PAIN-K): A Randomized Double-Blind Trial in Adults
Bibliographic record
Abstract
STUDY OBJECTIVE: We compare intranasal ketamine with intranasal placebo in providing pain reduction at 30 minutes when added to usual paramedic care with nitrous oxide. METHODS: This was a randomized double-blind study of out-of-hospital patients with acute pain who reported a verbal numeric rating scale (VNRS) pain score greater than or equal to 5. Exclusion criteria were younger than 18 years, known ketamine intolerance, nontraumatic chest pain, altered mental status, pregnancy, and nasal occlusion. Patients received usual paramedic care and were randomized to receive either intranasal ketamine or intranasal saline solution at 0.75 mg/kg. The primary outcome was the proportion of patients with VNRS score reduction greater than or equal to 2 at 30 minutes. Secondary outcomes were pain reduction at 15 minutes, patient-reported comfort, satisfaction scores, nitrous oxide consumption, and incidence of adverse events. RESULTS: One hundred twenty subjects were enrolled. Seventy-six percent of intranasal ketamine patients versus 41% of placebo patients reported a greater than or equal to 2-point VNRS reduction at 30 minutes (difference 35%; 95% confidence interval 17% to 51%). Median VNRS reduction at 15 minutes was 2.0 and 1.0 and at 30 minutes was 3.0 and 1.0 for ketamine and placebo, respectively. Improved comfort at 15 and 30 minutes was reported for 75% versus 57% and 61% versus 46% of ketamine and placebo patients, respectively. Sixty-two percent of patients (95% confidence interval 49% to 73%) versus 20% (95% confidence interval 12% to 32%) reported adverse events with ketamine and placebo, respectively. Adverse events were minor, with no patients requiring physical or medical intervention. CONCLUSION: Added to nitrous oxide, intranasal ketamine provides clinically significant pain reduction and improved comfort compared with intranasal placebo, with more minor adverse events.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.006 | 0.003 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.004 |
| Insufficient payload (model declined to judge) | 0.009 | 0.001 |
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".