Kidney Week

Abstract: TH-PO0469

Association Between Arterial Oxygen Saturation Changes and Ultrafiltration Rate During the First Hour of Hemodialysis

Session Information

• Hemodialysis: Novel Markers and Case Reports
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Dialysis

• 801 Dialysis: Hemodialysis and Frequent Dialysis

Authors

• Yueh, Sheng-Han, Renal Research Institute, New York, New York, United States

Sheng-Han Yueh, MS, MSc

• Bergling, Karin, Renal Research Institute, New York, New York, United States

Karin Bergling, MD, PhD

• Nandorine Ban, Andrea, Renal Research Institute, New York, New York, United States

Andrea Nandorine Ban, MS, MSc

• Desai, Priya, Renal Research Institute, New York, New York, United States

Priya Desai, MPH

• Usvyat, Len A., Renal Research Institute, New York, New York, United States

Len A. Usvyat, PhD

• Kotanko, Peter, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Peter Kotanko, MD, FASN

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

Hanjie Zhang, PhD

Background

In patients with arterio-venous vascular access, Crit-Line (Fresenius Medical Care, Waltham, MA) enables real-time tracking of arterial oxygen (SaO₂) during hemodialysis (HD). Using Crit-Line, we observed that SaO₂ declined during the first hour of treatment in most patients (Campos, Blood Purif, 2016). To explore this early desaturation, we examined the relationship between weight-normalized ultrafiltration rate (nUFR) and first-hour SaO₂ change.

Methods

We studied HD patients treated in 2022 in Fresenius Kidney Care clinics in the U.S. Only patients with ≥10 treatments lasting ≥90 minutes were included; SaO₂ change (%/hr) was calculated by linear regression fit to first-hour SaO₂ data per dialysis session. To assess the nUFR–SaO₂ change relationship, we fitted a linear model for each patient (Fig. 1).

Results

We analyzed 1,286,319 HD sessions from 24,688 patients; nUFR was 3.46 to 15.09 mL/kg/hr. 47.3% of patients showed a negative relationship between nUFR and SaO₂ change, reflecting a greater SaO₂ decline at higher nUFR, while 52.7% showed a positive relationship. The overall distribution of relationship was centered near zero (Fig. 2).

Conclusion

We found no clinically meaningful associations between nUFR and SaO₂ changes during the first hour of dialysis. Other clinical or treatment-related factors should be further explored.

Figure 1. Examples showing changes of SaO₂ over nUFR in two patients, (A) with a negative and (B) with a positive trend. Each dot represents one treatment of the patient.

Figure 2. Patient-Level Distribution of SaO₂ Change in Relation to nUFR. The mean -0.002 is indicated by a red vertical line.

Funding

• Commercial Support – Renal Research Institute LLC, a wholly owned subsidiary of Fresenius Medical Care Holdings Inc.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025hspfzktr