Blood Pump Speed, Recirculation, and Urea Clearance in Hemodialysis Patients with Dysfunctional Catheters
Bibliographic record
Abstract
Urea clearance varies with dialysis blood pump speed (Qb) for well-functioning hemodialysis (HD) catheters. Patients with dysfunctional HD catheters often have reduced Qb due to catheter thrombosis, fibrin sheath, or central venous stenosis. One method of achieving higher Qb is to reverse the position of the HD lines (i.e., connect the arterial line to the venous port and vice versa). However, line reversal is associated with greater catheter access recirculation (AR) and resultant decreased urea clearance. Objective : To determine the effect of line reversal with varying Qb on % AR, and urea clearance in HD patients with dysfunctional. Methods : 7 patients with dysfunctional internal jugular catheters in our HD unit were identified. During a regularly scheduled HD session, we measured each patient's on-line urea clearance using dialysance (Diascan) at the maximum achievable Qb with the lines in the normal position, and at varying Qb with the lines in reversed position. With lines in the reversed position at Qb of 200, 300 and 400 ml/min, dialysance was 123, 159, and 195 ml/min respectively (figure).Conclusions: Line reversal is associated with significant AR in patients with dysfunctional catheters. However, in patients with dysfunctional HD catheters in whom the maximum achievable Qb is ≤ 200 ml/min in the normal position, greater urea clearance can be achieved by line reversal and increasing Qb to ≥ 300 ml/min. Dialysance was used as a surrogate measurement of urea clearance. AR was also measured using ultrasound dilution technique. (Transonic machine) Linear regression was used to model the relationships between Qb, dialysance and AR. Results: AR in dysfunctional IJ catheters with lines in the normal position was 0% for all Qb in the range 150–400 ml/min. According to the regression model, AR with lines in the reverse position was 19% at Qb 300 ml/min. Maximum achievable dialysance with lines in the normal position for Qb ≤ 200 ml/min was 144 ml/min.
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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 | 0.001 | 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".