Kidney Week

Abstract: FR-PO0478

First-Hour Arterial Oxygen Saturation Decline During Hemodialysis in a Large US Cohort: Associations with Patient and Treatment Factors

Session Information

• Dialysis: Hemodiafiltration, Ultrafiltration, Profiling, and Interdialytic Symptoms
  November 07, 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

Intradialytic hypoxemia is associated with hospitalization and mortality (Meyring-Wösten, CJASN 2016), yet its etiology remains unclear. Continuous arterial oxygen saturation (SaO₂) monitoring (Crit-Line monitor) captures SaO₂ dynamics during hemodialysis (HD). The steepest SaO₂ decline (Campos, Blood Purif 2016) was observed within the first treatment hour. We here examined patient and treatment factors associated with first-hour SaO₂ decline.

Methods

Patients with ≥10 HD sessions (≥90 min), fistula access, and weight-normalized UFR (nUFR) ≤15 mL/kg/hr were included. First-hour SaO₂ change (%/hr) were calculated from linear fits, and the median used as patient-level measure. Patients were split into groups according to SaO₂ decline: No decline (>0%), minimal (0 to -1%), mild (-1 to –2%), moderate (-2 to -3%) and marked (< -3%). Characteristics and associations were compared across groups.

Results

In 2022, 1,358,478 HD sessions from 25,168 patients met inclusion criteria. SaO₂ declined in 83% of patients (Table 1). A greater decline was progressively associated with higher nUFR, higher pre- and post-HD blood pressure, and greater weight (Fig. 1). Greater declines occurred in younger patients and those with lower Kt/V.

Conclusion

First-hour SaO₂ decline is highly prevalent and its magnitude associated with several clinical parameters. These observations provide a compelling basis for further investigation.

Table 1. Parameters by magnitude of first-hour SaO₂ decline. All values are presented as mean ± SD.

Figure 1. Associations Between Clinical Parameters and SaO₂ Change. Linear fits revealed statistically significant relationships (p-value < 0.001 for all).

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.2025e7gaym4s