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NCT Number: NCT06886191

PuO2 in RenalGuard Pilot Study

The PuO2 in RenalGuard (PURE) study is planned as a single center, randomized controlled pilot study comparing renal oxygenation during cardiac surgery with cardiopulmonary bypass (CPB) with or without balanced forced diuresis using the RenalGuard (RG) system.

Renal oxygenation will be assessed by urine oxygen tension, continuously measured by optodes placed through the urine catheter. Measurements will start after induction of anesthesia and continue for 24 hours.

In total, 30 patients will be randomized 1:1 to RG or standard of care (SOC) during cardiac surgery with CPB. In the RG group, the forced diuresis with neutral fluid balance will be maintained from before the start of surgery until 3 hours after weaning from CPB.

The primary endpoint is the group difference (RG vs SOC) in delta PuO2, defined as the change in mean PuO2 from baseline to the last 5-minute period at 45 minutes after start of CPB.

The secondary endpoints include

1. Group difference in mean PuO2 before, during and after CPB 2. Group difference in time weighted area under the curve for PuO2 3. Group differences in renal near infrared spectroscopy (NIRS) before, during and after CPB 4. Group difference in urine and blood biochemistry including renal biomarkers 5. Group difference in urine output and fluid balance during surgery and first postoperative day 6. Group differences in postoperative AKI according to the KDIGO criteria 7. Time (minutes) with puO2 ≤ 15 and ≤ 10 mmHg during and after CPB 8. Dynamics of PuO2 during the early postoperative phase

Patients ≥18 years scheduled for cardiac surgery with CPB with estimated glomerular filtration rate ≥50 ml/min are eligible for inclusion. Exclusion criteria include patients on higher doses of furosemide, patients with AKI or under renal replacement therapy.

Patients will be analyzed according to study group. In patients where hemofiltration has been used during CPB, control group patients who has received furosemide and patients in the RG group who do not reach target urine flow will be excluded from the main analysis but will be included in a separate analysis.

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Key information

Conditions

Cardiac Surgery Subjects

Age range

18 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients ≥18 years of age
  • scheduled for cardiac surgery with normothermic CPB
  • Estimated glomerular filtration rate ≥50 ml/min as assessed by the CKD-EPI formula

Exclusion criteria

  • Patient receiving furosemide at a dose>100 mg/day orally (or the equivalent dose of an alternative loop diuretic) in the last week
  • Patient who cannot be urethrally catheterized for any reason
  • Patient already dialysis dependent
  • Known or suspected AKI (KDIGO criteria) at the time of screening
  • Any condition which, in the judgement of the investigator, might increase the risk to the patient

Treatment and study plan

RenalGuard Therapy

Device

Fluid management system, which weighs urine and controls intravenous administration of crystalloid solution.

Primary outcomes

  1. Delta PuO2

    Time frame: Baseline (before start of surgery) to 45 minutes after start of CPB

    The primary endpoint is the group difference (RG vs controls) in delta PuO2, defined as the change in mean PuO2 from baseline to the last 5-minute period at 45 minutes after start of cardiopulmonary bypass (CPB) (or the last 5 minutes if cross clamp release is done before)

Secondary outcomes

  1. Repeated PuO2

    Time frame: baseline, 30, 45 minutes on CPB and at 30, 60 and 240 minutes after CPB

    Group difference in mean PuO2 at specified times

  2. PuO2 AUC

    Time frame: From baseline before start of surgery until 4 hours after CPB

    Group difference in time weighted area under the curve (AUC) for PuO2 during CPB and until removal of the PuO2 measurement

  3. PuO2 sub threshold

    Time frame: From baseline before surgery until 4 hours after CPB

    Time (minutes) with puO2 ≤ 15 and ≤ 10 mmHg during and after CPB

  4. Diuresis and fluid balance

    Time frame: 24 hours

    Diuresis and net fluid balance (incorporating fluids given and lost) during surgery and during the first 24 hours.

Other outcomes

  1. Dynamics of PuO2 during the early postoperative phase

    Time frame: 24 hours

    Repeated measurements of PuO2 during the first postoperative 24 hours.

  2. Urine Nephrocheck

    Time frame: 4 hours after CPB

    Urine IGFBP2*TIMP2 at 4 hours after Cardiac surgery

  3. Renal near-infrared spectroscopy (NIRS)

    Time frame: From baseline before surgery until 4 hours after CPB

    Group differences in renal NIRS at baseline, 30 minutes on CPB and at 30, 60 and 240 minutes after CPB

  4. Creatinine

    Time frame: 7 days

    Development of serum creatinine from baseline and daily for up to seven postoperative days

Study contacts

Contact information is provided by the study sponsor or research team.

Lukas Lannemyr Lannemyr, MD, PhD

CONTACT

[email protected]

0046 708350971

Sponsors and collaborators

Lead sponsor

Sahlgrenska University Hospital

Other

Registry information

Official study title

Effects on Urine Oxygenation of Forced Diuresis with Neutral Fluid Balance During Cardiac Surgery, a Randomized Controlled Trial

Acronym: PURE

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Mar 20, 2025
Registry last updated
Mar 20, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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