Elevated Hematocrit Concentration and the Risk of Mortality and Vascular Events in Patients Undergoing Major Surgery.
Bibliographic record
Abstract
Abstract Abstract 2088 Background: Preoperative anemia is associated with adverse outcomes after major surgery. This study evaluates the effect of elevated hematocrit concentration on 30-day postoperative mortality and vascular events in patients undergoing major surgery. Methods: We conducted a cohort study using the American College of Surgeons National Surgical Quality Improvement Program database. Thirty-day mortality and vascular events, demographic, and perioperative risk factors were obtained for 197,469 adult patients undergoing major surgery in nonveteran's administration hospitals across the US, Canada, Lebanon, and the UAE during 2008 and 2009. We assessed the adjusted effect of elevated (>0.50) compared to normal preoperative hematocrit concentration (≥0.41–0.50, American Medical Association reference-range) on postoperative outcomes. Separate sex-specific analysis using hematocrit concentration thresholds commonly used in the diagnosis and management of patients with apparent or absolute erythrocytosis was also done. Results: A total of 3,961 patients (2.0%) had elevated hematocrit concentration preoperatively. After adjustment, postoperative mortality at 30 days was higher in patients with elevated hematocrit concentration than in those without (odds ratio [OR]: 2.23, 95% CI: 1.77–2.80). 30-day deep vein thrombosis (OR: 1.95, 95% CI: 1.44–2.64) and pulmonary embolism (OR: 1.79, 95% CI: 1.17–2.73), but not myocardial infarction or cerebrovascular events, were also higher in patients with elevated hematocrit concentration than in those without. Similar evaluation of various clinically relevant hematocrit concentrations revealed the following: an effect on mortality was noted beyond the thresholds of 0.48 in women and 0.52 in men, with the effect estimates becoming considerably high for values >0.54. Values between 0.41–0.45 were not associated with increased odds mortality. Similar observations were noted for deep vein thrombosis, although with higher variation and uncertainty especially in women; while the effects on pulmonary embolism were restricted to men. Conclusion: Elevated hematocrit concentration is associated with an increased risk of 30-day mortality and venous thrombosis following major surgery. Further investigation of the impact of elevated hematocrit concentration and its reduction on surgical outcomes is warranted. Disclosures: No relevant conflicts of interest to declare.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.001 | 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".