The effects of time and temperature on umbilical cord gas analysis
Bibliographic record
Abstract
Objective Our objective was to evaluate the effects of time and temperature on umbilical-cord blood analysis.Methods This prospective study included the term spontaneous vaginal deliveries. One venous and seven arterial samples were drawn from each umbilical cord within 5 min from delivery. Three samples were immediately refrigerated (3 °C), while all other samples were stored at room temperature (23–26 °C). Samples were analyzed in pairs (refrigerated and room-temperature samples) at 0, 20, 40, and 60 min after delivery for pH and lactate levels. Repeated-measures analysis using a generalized linear model was used to compare the change in pH and lactate values over time.Results 518 samples from 74 women were analyzed. The mean gestational age was 39.1 ± 1.1 weeks. All neonates had an Apgar score of ≥9 in the 1st and 5th minutes. Mean arterial pH and lactate levels at delivery (time 0) were 7.32 ± 0.07 and 4.00 ± 1.36 mmol/L, respectively. Over time, a statistically significant decrease in pH and a reciprocal increase in lactate levels were observed. The mean change in arterial pH following 60 min was 0.021 ± 0.028 (room-temperature) and 0.016 ± 0.023 (refrigerated); p < 0.001. Compared to pH, a greater change was demonstrated in lactate levels over time; the mean change in lactate following 60 min was −0.896 ± 0.535 (room temperature) and −0.512 ± 0.450 mmol/L (refrigerated). Temperature significantly altered both pH and lactate levels, but lactate levels were altered at earlier time points.Conclusion Both time and temperature have significant effects on cord blood analysis. Yet, these changes are minor and may not have any clinical significance unless in extreme cases in which medicolegal aspects emerge.
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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 | 0.003 | 0.011 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 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".