The effect of sodium citrate 4% locking solution for central venous dialysis catheter on the international normalized ratio (INR) value
Bibliographic record
Abstract
Sir, We read with great interest the article by Grudzinski et al . [ 1 ], demonstrating the benefits of sodium citrate 4% locking solution for central venous catheters. The authors concluded that citrate locking improves reliability of international normalized ratio (INR) measurement compared to standard heparin locking. Unfortunately, the study was not designed specifically to assess this question. In addition, the authors reported a surprisingly low incidence (0.8%) of falsely elevated INR due to heparin contamination following heparin locking. They also reported an absence of falsely elevated INR following citrate locking. Such findings are unexpected, given that INR may be clearly overestimated when the blood is contaminated with either heparin [ 2 ] or citrate [ 3–5 ]. We performed a pilot study with 19 haemodialysis (HD) patients at our centre to assess the reliability of INR measurement when blood samples are drawn directly from central catheters locked with either sodium citrate 4% or standard heparin. INRs were measured simultaneously prior to dialysis from both a peripheral vein and the HD catheter after discarding 5 cc of blood from the arterial port. The INR values obtained following citrate or heparin locking were compared using ANOVA. We found that INR values were falsely elevated in all patients with heparin lock. The mean INR was falsely elevated by 56% ± 28% (INR catheter: 1.7 ± 0.3; INR peripheral vein: 1.1 ± 0.04) in patients without warfarin ( n = 7), whereas the mean INR was overestimated by 114% ± 51% (INR catheter: 4.8 ± 1.4; INR peripheral vein: 2.1 ± 0.15) in patients with warfarin ( n = 12). In contrast, INRs drawn from citrate-locked catheters were not or were only minimally elevated compared to samples drawn from peripheral venipuncture. In patients without warfarin, the mean INR was increased by 0.04% ± 0.7% (INR catheter: 1.06 ± 0.02; INR peripheral vein: 1.06 ± 0.03) whereas in patients with warfarin, the mean INR was increased by 1.9% ± 0.6% (INR catheter: 2.20 ± 0.16; INR peripheral vein: 2.19 ± 0.16). These results clearly demonstrate that sodium citrate catheter locking minimally interferes with INR measurements when blood is drawn directly from the catheter prior to dialysis treatment. They also demonstrate that the overestimation of INR with heparin locking is more frequent than reported by Grudzinski et al. [ 1 ]. Hence, the use of citrate catheter locking improves INR measurement reliability and thus facilitates the management of anticoagulation in HD patients. Conflict of interest statement. None declared.
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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 | 0.013 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.010 | 0.006 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".