Continuous Renal Replacement Therapy for Acute Kidney Injury by Cooling Blood

Improving Outcomes in Patients Receiving Continuous Renal Replacement Therapy for Acute Kidney Injury by Cooling Blood in the Dialysis Circuit (CRRiTiCool): a Randomized Controlled Trial

Acute kidney injury (AKI) is common in intensive care unit (ICU) patients and is associated with longer hospital stays and worse survival. The mortality rate of critically ill patients in the ICU who receive renal replacement therapy for AKI ranges between 50-80%, cardiovascular disease being the second largest cause of death. A previous pilot study from the investigator's group showed that myocardial stunning occurs in AKI patients during continuous renal replacement therapy (CRRT) and may explain the high cardiovascular mortality in this population. In the chronic intermittent dialysis setting, mild dialysate cooling was shown to improve intradialytic hemodynamic stability and prevent myocardial stunning. The aim of this study is to find out whether cooling the blood in the CRRT circuit is an effective intervention to prevent myocardial stunning in AKI patients undergoing CRRT and improve patient outcomes.

This is a single center, prospective, randomized, open label, controlled trial comparing standard-of-care temperature management with blood cooling CRRT. We will recruit approximately 140 patients (70 in each group) from the Medical Surgical Intensive Care Unit at University Hospital and The Critical Care Trauma Center at Victoria Hospital in London, Ontario.

The study team will randomize patients with acute kidney injury requiring continuous dialysis therapy into one of two groups; either to standard of care continuous dialysis therapy or to cool blood continuous dialysis therapy. All therapy will be delivered using the Baxter PrisMaxTM CRRT machine with TherMaxTM blood warmer.

All participants will undergo a series of echocardiograms (ultrasound of your heart) prior to continuous dialysis therapy initiation, 4-12 hours into therapy, for up to 7 days after therapy initiation, and at discharge from the intensive care unit. Blood work will be collected at 4 time points, prior to continuous dialysis therapy initiation, 4-12 hours into therapy, 24 hours into therapy, and at ICU discharge.

Hourly nasopharyngeal and skin temperatures will be collected. Oral temperature will be collected every four hours.

Inclusion Criteria:

• AKI as defined by 2012 AKI KDIGO guidelines requiring CRRT.
• Patient's core temperature between 35°C and 40°C at the time of recruitment.
• Age 18 years old and older.

Exclusion Criteria:

• Hypothermia (patient core temperature <35°C) at the time of recruitment
• Extreme hyperthermia or hyperpyrexia (patient core temperature >40°C) at the time of recruitment.
• Contraindication to cooling (e.g., hemorrhagic shock or severe coagulopathy)
• Patients undergoing targeted temperature management for cardiac arrest.
• Chronic kidney disease stage 5 as defined by CKD KDIGO guidelines [19] requiring renal replacement therapy prior to recruitment.
• Receiving palliative care or immediate plans for withdrawal of life sustaining therapy at the time of recruitment.