Postoperative Blood Use Following Elective Total Hip and Total Knee Arthroplasty
Bibliographic record
Abstract
Abstract Abstract 1181 Use of allogeneic blood in elective procedures should be minimized due to risks of transfusion, potential adverse impact on outcomes, inconvenience to the patient, high cost and limited supply of blood. The purpose of this study was to examine the rate of transfusion following elective total hip (THA) and total knee arthroplasties (TKA) within a preoperative and perioperative blood management program and to examine the relationship between clinical and surgical parameters and blood transfusion. Methods: This was a secondary analysis of prospectively collected data of all consented patients who had undergone joint arthroplasty surgery between January and December, 2011. All patients attended a preoperative clinic 7–14 days prior to their surgery. The preoperative hemoglobin (Hgb) was measured. Transfusion rate was calculated for type of surgery (primary vs. revision and unilateral vs. bilateral). Impact of preoperative Hgb, age, sex, Body Mass Index (BMI), estimated blood loss, type of anaesthetic, type of anticoagulant (rivaroxaban vs. no rivaroxaban), surgeon and drop in hemoglobin (preoperative hemoglobin minus lowest post-operative hemoglobin documented on postoperative day 1, 2 or 3) were examined. Descriptive statistics examined the rate of transfusion in different procedures. Univariate analysis examined the relationship between each factor and having a transfusion. Stepwise logistic regression examined the impact of all factors together. Statistical significance was set at p<0.05. Results: 1605 patients [989 females (62%), mean age 66 (SD:11)] had surgery during 2011. Primary TKA: Unilateral 821 (51%), Bilateral TKA: 41 (3%), Revision TKA: 91 (6%), Primary THA: 588 (37%), Bilateral THA: 4 (0.02%), Revision THA: 60 (4%). Four percent (4%) of females had an Hgb <120 mg/L and 3% of males had an Hgb <130 mg/L at the preoperative visit. There were 1555 cases done under regional anaesthesia (spinal or epidural) and 129 cases received a general anaesthetic. Sixty-seven patients (4%) had a blood transfusion while in hospital. Thirty percent (30%) of the transfused women and 9% of the men had a low pre-operative Hgb. THA procedures required more transfusions than TKA (p=0.0012). Transfusion was associated with the following individual factors: age ≥ 80 years, female sex, low BMI (<18.5), increased estimated blood loss, larger drop in hemoglobin, type of anticoagulant (4% in rivaroxaban vs. 8% in non-rivaroxaban), revision surgery (vs. primary), simultaneous bilateral arthroplasty, general anesthesia (vs. spinal), and surgeon. Stepwise logistic regression analysis maintained the intra-operative blood loss, drop in Hgb, female sex, and age as significant independent factors in explaining the variation in blood transfusion. Discussion: This study was carried out in an independent orthopaedic facility for elective joint surgery. All patients are assessed medically prior to surgery and advised to take supplemental iron for 2 months prior to surgery. Four percent of females and 3% of males were found to be anemic preoperatively. Patients are admitted the morning of their surgery. Approximately 97% of the consented patients had a regional anesthetic (spinal and/or epidural) with sedation. Patients are transferred into the operating room after the anaesthetic was administered. Surgery is carried out without the routine use of cell saver, tranexamic acid or drains. Approximately 50% of the surgeons deflate the tourniquet in a total knee arthroplasty prior to closure of the capsule. Thromboprophylaxis is initiated with rivaroxaban 10 mg on postoperative day 1. The general transfusion trigger for symptomatic patients is a hemoglobin of 80 g/L. Transfusions can be ordered by staff surgeon, hospitalist, medical consultant or Orthopaedic fellow. The blood bank does not group and screen patients scheduled for routine primary total hip or total knee arthroplasty. Following these practices, we observed a transfusion rate for primary THA of 5% and primary TKA of 3% while using rivaroxaban for thromboprophylaxis starting on postoperative day 1. Conclusion: The present study confirmed that intra-operative blood loss, drop in the hemoglobin, being a female, and older than 80 years of age as risk factors in relation to need for blood transfusion following elective total joint arthroplasty. Transfusion rates were not higher when rivaroxaban was used for thromboprophylaxis. Disclosures: Murnaghan: Bayer Healthcare: Honoraria, Research Funding. Off Label Use: Rivaroxaban was used perioperatively for thromboprophylaxis. Our protocol gave the intial dose on postoperative day 1 rather than the 6–10 hours post-operatively recommended by the manufacturer in product monograph. Gollish:Bayer Healthcare: Honoraria, Research Funding.
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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 | 0.003 |
| 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 | 0.000 |
| 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".