Kidney Week

Abstract: SA-PO876

Agreement Between Spectra Hemoglobin and Crit-Line® Monitor Estimated Hemoglobin

Session Information

• Dialysis: Cardiovascular, BP, Volume
  October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Dialysis

• 701 Dialysis: Hemodialysis and Frequent Dialysis

Authors

• Tapia, Mirell, Renal Research Institute, New York City, New York, United States

Mirell Tapia,

• Zhang, Hanjie, Renal Research Institute, New York City, New York, United States

Hanjie Zhang,

• Tao, Xia, Renal Research Institute, New York City, New York, United States

Xia Tao,

• Thijssen, Stephan, Renal Research Institute, New York City, New York, United States

Stephan Thijssen,

• Kotanko, Peter, Renal Research Institute, New York City, New York, United States

Peter Kotanko,

Background

Monitoring hemoglobin (Hgb) in hemodialysis is key in anemia management. Due to hemodilution, Hgb by Crit-Line® monitor (Hgb_CritLine) underestimates the pre-dialysis values measured by Spectra (Hgb_Spectra). An equation that considers blood volume, ultrafiltration rate, and saline dissipations can correct Hgb measured by Crit-Line (Hgb^CritLine_corrected). The aim of this study was to explore the concordance between the Hgb_Spectra and Hgb^CritLine_corrected.

Methods

Pre-dialysis Hgb was measured by Spectra East, Inc. (Rockleigh, NJ, USA). ΔHgb (Hgb_Spectra- Hgb_CritLine) and Hgb^CritLine_corrected were estimated mathematically. The difference between Hgb^CritLine_corrected and Hgb_Spectra was denominated Hgb_offset. Hgb_CritLine was determined by averaging the measurements between 0-2 minutes after the beginning of Crit-Line recording. Pre-dialysis blood volume was derived using anthropometric equations, then back-calculating the start of dialysis absolute blood volume based on the change in relative blood volume over the course of the treatment as measured by the Crit-Line® monitor and subtracting the saline infused (V_saline= 250ml). Saline’s half-life was considered of 20min.

Results

5731 hemodialysis treatments from 952 patients with Hgb_Spectra and estimated Hgb^CritLine_corrected measurements were analyzed. Hgb_offset average was –0.068g/dL, the standard deviation 0.59g/dL, and the bias -0.07g/dL. To asses the comparability between Hgb^CritLine_corrected and Hgb_Spectra measurements, the Hgb_offset was plotted against the mean of the two measurements in a Bland-Altman plot.

Conclusion

With Crit-Line Hgb correction for hemodilution, the Hbg_CritLine values are on average identical to the Hgb_Spectra and they share similar accuracy. This could be an opportunity in the future to replace Hgb laboratory measurements in the management of anemia.

Funding

• Commercial Support – Fresenius Medical Care. Renal Research Institute