Studies of phosphate dynamics during hemodialysis
Bibliographic record
Abstract
Regulation of phosphate (PO4) in hemodialysis patients is very difficult and ideal levels are rarely maintained. A high removal and a normal phosphate level is important, as high and low levels are both associated with morbidity and a very high mortality. We studied phosphate dynamics and its relation to other small “uremic” molecules in 48 patients by measuring pre‐ and postdialysis levels and all removed phosphate, urea and creatinine (creat) in all dialysate during 455 dialyses done at different frequencies (freq): 3.7 ± 1.2, range 3–6 treatments per week and durations of dialysis (t): mean: 196 ± 95, range 80–560 min and with high (HF) and low flux membranes. Kt/V‐PO4, Kt/V‐urea and Kt/V‐creat, volumes (Vr) for all solutes and their relationships to frequency and duration of dialysis, urea clearance and predialysis phosphate were calculated. Factor/solute: PO4 Urea‐N Creatinine Predialysis mg/dl 5.7 ± 1.9 73 ± 24 12 ± 3 Postdialysis mg/dl 3.0 ± 1.0 33 ± 15 6 ± 2 100 × Vr/BW 63 ± 78 58 ± 24 41 ± 15 Kt/V 1.01 ± 0.66 1.04 ± 0.32 0.97 ± 0.26 Weekly stdKt/V 1.75 ± 0.81 2.12 ± 0.68 1.96 ± 0.71 Removed gm/week 3.1 ± 1.3 56 ± 23 6.2 ± 2.5 Vr = removed solute ÷ (predialysis minus postdialysis concentration.); BW = body weight. Uf = ultrafiltration. Results: Vr as a percentage of BW for PO4 was dependent on predialysis PO4 and rose steeply as predialysis PO4 decreased: Vr% BW = 212 − 88 × ln (predialysis PO4), (r = 0.39, p < 0.0001). There was no such relationship for Vr for urea or creatinine and no relation between urea and PO4 Vr, (r = 0.07, p = 0.141). In stepwise multiple regression analysis: Mg PO4 removed per week = t × 6.5 + freq × 387 + Uf × 140 + pre‐PO4 × 273 + PO4 stdKt/V × 343 − HF × 375 − 1824, (r = 0.73, p < 0.0001). Blood flow(QB) and dialysate flow (QD), urea weekly stdKt/V were not significant variables in the model. Pre‐dialysis PO4 = 6.8 − Hrs/week × 0.07 − QB × 0.003 + Uf × 0.26. QD, membrane type or dialyses/week did not enter the model. Only patients dialyzing>28 hrs/week could stop phosphate binders within 3 weeks. Conclusions: Phosphate shows a highly variable dynamic during dialysis. Apparently, the body maintains extracellular PO4 concentration by releasing PO4 from unknown compartments when the blood concentration of PO4 decreases. Vr for phosphate thus varies not only from patient to patient but also in a patient, depending on blood concentration of PO4. Kt/V for urea and creatinine are inaccurate in describing PO4 removal. To remove PO4 efficiently it is most important to use long and daily dialysis. QB, QD and membrane type are relatively unimportant in phosphate removal.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".