About this trial
Filter clotting is a major complication of continuous renal replacement therapy (CRRT), resulting in blood loss, reduced treatment efficacy, and increased cost. One modifiable factor associated with filter clotting is filtration fraction (FF), or the proportion of plasma water being removed from the blood over the course of the filter. In convention, a cutoff of FF\<20-30% has been used to prevent hemofilter clotting, but no evidence correlating FF with hemofilter clotting has been documented. Some experts have proposed that post-filter hematocrit (Hct) could be a more direct marker for determining hemofilter clotting risk, but evidence supporting clinical utility of this marker is lacking.
HCTpost=HCTpre/(FF(HCTpre-1)+1)
In our proposed validation study, we hope to determine whether our formula for post-filter Hct provides accurate results when compared to measured values. The information obtained from this study will potentially justify the use of utilizing the formula in future studies.
The procedure of this study is collecting blood samples from the post-filter lines of patients on CRRT at different time points and different flow rates. This will be considered the "measured post-filter hematocrit" which will then be compared to the calculated formula above, using the other values obtained from daily labs (for pre-filter hematocrit) and CRRT machine settings.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
patients initiated on CRRT age equal than or greater to 18 years of age
Disqualifiers
patients on ECMO
Trial design
Single group
Treatments tested in this trial
Calculated Post-Filter Hematocrit
Other interventionusing the formula: HCTpost=HCTpre/(FF(HCTpre-1)+1)
Measured Post-Filter Hematocrit
Other interventionMeasured from blood sample taken from CRRT machine
Treatment groups
Trial outcomes
Primary outcomes
Agreement between measured and calculated post-filter hematocrit values.
Use Bland-Altman analysis to assess agreement and quantify bias and limits of agreement. Calculate correlation coefficients (Pearson or Spearman) to evaluate the strength of association.
Secondary outcomes
Analyze the impact of CRRT settings on discrepancies between measured and calculated Filtration Fraction
How do different settings (e.g., Q\_B, Q\_UF, Q\_prefilter, Q\_postfilter) on the machine affect the discrepancies (if there are any) between calculated and measured filtration fraction. Will be using change in post-filter hematocrit values as the measured filtration fraction and comparing to calculated filtration fraction using standard flow-rate derived formula used in practice.
Subgroup analysis based on patient-specific factors
Post-filter hematocrit values will be stratified and compared across subgroups defined by baseline pre-filter hematocrit category, anticoagulation strategy (e.g., citrate vs. heparin vs. none), and blood-flow rate category. The metric reported will be the mean post-filter hematocrit within each subgroup and the between-group differences.
Sponsors and contacts
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Gwyndolyn M. Radford
Lead sponsor
University of Iowa
Sponsor institution