Bibliographic record
Abstract
Biphasic anaphylaxis is a poorly understood allergic phenomenon with significant variation in causative agent, time to onset, outcome and overall frequency. The aim of this review is to better determine the clinical characteristics of this type of allergic reaction. A systematic review was performed identifying case reports and retrospective and prospective studies reporting biphasic allergic reactions. “Biphasic anaphylaxis” (BA) was defined as an anaphylactic reaction consisting of 2 distinct phases separated by at least 1 hour, with both phases meeting internationally recognized diagnostic criteria for anaphylaxis. Pediatric and adult cases were evaluated. Biphasic and uniphasic data was compared using the Chi test. 28 articles included descriptions of patients having biphasic reactions with sufficient information for evaluation of clinical characteristics. In total, 150 patients were identified as having biphasic reactions. 84 of these patients met clinical criteria for true BA. Of these, 28 were pediatric cases and 56 were adult. Overall frequency of biphasic reactions was 7.36% of anaphylactic reactions with prospective studies reporting a frequency of 9.07%. Mean time to the second phase of BA was 8.13 hours (95% CI, 6.13-10.14) with similar times between both pediatric and adult populations. The range of reported times to onset of the second phase of biphasic reactions was 1 – 72 hours. 8 articles allowed comparison of medication use and likelihood of biphasic reactions suggesting that the use of epinephrine in the initial treatment may predict the presence of the biphasic reaction (p=0.19). Fatal biphasic reactions were described in 5 patients. Significant limitations were encountered because of inconsistent definition of BA and inadequate reporting of individual patient data. Biphasic reactions are common presentations of anaphylaxis with both pediatric and adult patients being affected. Mean and median times to onset of the second phase are variable, but are longer than most emergency department observation time recommendations. Carefully designed prospective studies with clear definitions of BA are necessary to accurately determine the characteristics of these life-threatening reactions.
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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 | 0.005 | 0.022 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.007 | 0.005 |
| Bibliometrics | 0.020 | 0.014 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".