Corrigendum to High-efficiency, high-flux in-line hemofiltration using a high blood flow extracorporeal circuit, by Alison Grazioli, Sanjeev R Shah, Joseph Rabin, Rashmikant Shah, Ronson J Madathil, Joshua D King, Laura DiChiacchio, Raymond P Rector, Kristopher B Deatrick, Zhongjun J Wu and Daniel L Herr, DOI: 10.1177/0267659119871232. First published online 16 Sep 2019 and Perfusion 2020; 35(4): 351–355.
The authors wish to share the following changes to Table 1 in their article with the readers. The changes have been highted in the following table. The changes have been made to the article.
Table 1.
Comparison of theoretical and achieved Cr clearance using one and two Sorin-14 hemofilter in-line with a high blood flow extracorporeal circuit. Theoretical comparison is made between CVVH, conventional hemodialysis, and extracorporeal circuit hemofiltration looking at small-molecule clearance at various blood flows and different filtration fractions.
| Comparison of creatinine clearance achieved with one versus two Sorin-14 hemofilters | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Time of treatment | Hemofiltration amount (L) | Theoretical Cr clearance (K) L/houra | Filtration fraction* | Serum Cr before treatment (mg/dL) | Serum Cr after treatment (mg/dL) | Average serum Cr over treatment time (mg/dL) | Effluent Cr (mg/dL) | Calculated clearance (K′) L/hourb | |
| Treatment 1—one hemoconcentrator | 50 minutes | 5 L | 6 L/hour | 13% | 3.62 | 3.07 | 3.3 | 4.6 | 8.3 L/hour |
| Treatment 2—two hemoconcentrators | 25 minutes | 5 L | 12 L/hour | 13% | 4.26 | 3.86 | 4.06 | 3.8 | 11.2 L/hour |
| Comparison of clearance capabilities between renal replacement modalities | |||||||||
| Modality | CVVH | Standard hemodialysis using one filter with K0A of 800c | Extracorporeal circuit hemofiltration with two in-line Sorin-14 hemoconcentrators | Extracorporeal circuit hemofiltration using multiple hemoconcentrators (>2) to accommodate total circuit blood flow | Extracorporeal circuit hemofiltration using multiple hemofilters to accommodate total circuit blood flow | ||||
| Average blood flow rate | 250 cc/minute | 400 cc/minute | 2 L/minute | 5 L/minute | 5-7 L/minute | ||||
| Filtration fraction* | 26% | Not applicable | 26% | 26% | 28-39%d | ||||
| Replacement rate | 50 cc/minute | Not applicable | 400 cc/minute | 1 L/minute | 1.5 L/minute | ||||
| Theoretical clearance | 3 L/hour | 14.4 L/hour | 24 L/hour | 60 L/hour | 90 L/hour | ||||
| Kt/V in 1 hour in 70 kg male assuming 60% volume of distributione | 0.07 | 0.34 | 0.57 | 1.42f | 2.1 | ||||
CVVH: continuous veno-venous hemofiltration; RRT: renal replacement therapy; ECMO: extracorporeal membrane oxygenation.
High-efficiency hemofiltration is easily able to rival hemodialysis with two filters in parallel and clearance markedly increases at maximal blood flows. If systemic anticoagulation is used to prevent filter clotting, traditional filtration fraction limits of 20% can be exceeded and clearance enhanced even further (right most column).
Theoretical clearance (K) = (hemofiltration amount/treatment time) × S, where S is the sieving coefficient of the membrane. For small molecules, this is assumed to be 1. That is, all of the compounds are able to be filtered at the membrane. Post-filter administration of replacement fluid is assumed.
Calculated clearance is K′ = (hemofiltration amount/treatment time) × effluent Cr/average serum Cr4.
K′ may be different from K due to higher effluent Cr in relation to average serum Cr. This may relate to inherent variability of Cr measurements at very low effluent concentrations. In addition, this may reflect other compounds hemofiltered along with Cr (e.g. antibiotics) that can affect the values in the Cr assay5.
K0A refers to the efficiency of a given dialyzer at infinite blood flow and dialysate flow, with higher values suggesting a bigger surface area. Clearance K is calculated from nomograms based on actual blood flow provided in standard tables.
Filtration fraction of higher than 20% is rarely applied with conventional RRT given risk of filter clotting. However, filtration fraction can be increased when using systemic anticoagulation (as is routinely used in high blood flow extracorporeal circuits like ECMO).
KT/V is a unitless number that compares the amount of clearance in a given time period in comparison to the total volume of distribution of a substance in the body.
Even with convention filtration fraction value limitations, 1.42 times the value of the volume of distribution of a small molecular substance can be eliminated from the body with high blood flow ECMO-based therapy. It would take 20× as long to achieve equivalent clearance with CVVH (Column 2 vs Column 5).
Based on patient hemoglobin of 8 g/dL (hematocrit 24%).