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Kidney Week

Abstract: FR-PO891

Effects of Hemodialysis, Isolated Ultrafiltration, and Isolated Diffusion on Oxygen Extraction Ratio (OER)

Session Information

Category: Dialysis

  • 607 Dialysis: Epidemiology, Outcomes, Clinical Trials - Non-Cardiovascular


  • Rotondi, Silverio, Sapienza University of Rome, Latina, Italy
  • Tartaglione, Lida, sapienza university of rome, Rome, Italy
  • Carbone, Luciano, ICOT, Latina, Italy
  • Muci, Maria luisa, Policlinico Umberto I Roma, Roma, Italy
  • Pasquali, Marzia, Policlinico Umberto I, Rome, Rome, Italy
  • Mazzaferro, Sandro, Sapienza University of Rome, Rome, Italy

Hemodialysis sessions cause tissue hypoxia whis is not routinely measured.
OER (n.v. 25-30%), obtained as the ratio between SaO2 and Central Venous Oxygen Saturation (SvcO2), is employed in ICU to quantify tissue hypoxic stress.
We aimed to evaluate if the OER : a. Increases during dialysis session; b. is different after long (HDlong) or short (HDshort) dialysis intervals ; c. is differently affected by isolated ultrafiltration (iUf) or isolated diffusion (iD).


We enrolled 20 clinically stable patients on HD since >6 months, with Central Venous Catheter.
We measured SaO2 (by capillary oxymeter) and ScvO2 (by blood gas analysis) to calculate the OER basally, 15’, 30’, 60’, 120’ and end of HDLong. In 10 of them, OER was re-measured in the following two HDShort sessions. Further in all patients, OER was re-measured during the first hour of the first and second HDShort performed by applying, alternatively, iUF or iD.
During each HD, UF rate was kept at<10 ml/kg/h and symptoms were recorded.


In the HDLong session, OER increased within 30’ (post hoc test p<.05) and then progressively up to the end of HD, by 38%. Mean basal OER of HDLong (34,4±7), HDShort1 (33,8±7) and HDShort2 (36,2±6) were not different (Tab.1). In the two HDShort sessions, OER changes overlapped with those in HDLong. During the first hour of the HDShort session with iUF, the increment of OER was not significant, at variance with the significant increase recorded during the HDShort with iD (Tab. 1). All HD sessions were asymptomatic with no change in blood pressure (systolic or diastolic) or heart rate. During sessions, no significant change was evident for capillary SaO2 (98±1 %), while ScvO2 progressively decreased.


a. OER increases significantly during HD sessions; b. HD intervals do not modify the adaptive process to hypoxia; c. iD affects this adaptive response possibly more than iUF. OER might be a marker of HD stress, potentially useful in fragile patients.

Tab. 1


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