What are the recommendations for using extracorporeal (EC) oxygenation and ozonation in patients with chronic kidney disease (CKD)?

Extracorporeal Oxygenation and Ozonation in Chronic Kidney Disease

There is no established role for extracorporeal ozonation in CKD management, and extracorporeal membrane oxygenation (ECMO) is indicated only for acute cardiorespiratory failure, not as a treatment for CKD itself.

Extracorporeal Ozonation: Not Recommended

• No guideline or evidence supports the use of extracorporeal ozonation therapy for CKD patients. The provided evidence contains no references to ozonation as a therapeutic modality for kidney disease.
• The K/DOQI guidelines discuss oxidative stress in CKD but focus on antioxidant supplementation (vitamin E, acetylcysteine) rather than ozonation therapy 1.
• While vitamin E-modified dialysis membranes have been studied to reduce oxidative stress during hemodialysis, no study has demonstrated cardiovascular morbidity or mortality benefit from these expensive modifications 1.

Extracorporeal Membrane Oxygenation (ECMO) in CKD Patients

ECMO Is Not Contraindicated by CKD

• Pre-existing CKD, including end-stage renal disease (ESRD) requiring dialysis, should not be considered an absolute contraindication to ECMO when indicated for cardiorespiratory failure 2.
• ESRD patients receiving VA-ECMO do not have independently higher mortality when adjusted for other factors, particularly in the extracorporeal cardiopulmonary resuscitation (ECPR) subgroup where survival is equivalent 2.

ECMO Indications Remain Standard

• ECMO is indicated for reversible cardiac and/or respiratory failure requiring cardiorespiratory support, not for treating kidney disease itself 3, 4.
• The decision to initiate ECMO should be based on cardiopulmonary criteria (bridge-to-recovery, bridge-to-transplant, bridge-to-decision), with CKD status informing risk stratification rather than serving as an exclusion criterion 4.

Acute Kidney Injury Risk with ECMO

• AKI occurs in 30-78% of patients on ECMO, with 47-60% requiring renal replacement therapy (RRT) 5.
• ECMO-associated AKI increases mortality approximately 4-fold and frequently progresses to chronic kidney damage 3.
• The pathophysiology is multifactorial: reduced renal oxygen delivery, hemodynamic alterations, inflammatory damage from the circuit, RBC breakdown, nephrotoxic drug coadministration, and hormonal pathway impairment 3, 5.

Renal Replacement Therapy During ECMO

Modality Selection

• Continuous renal replacement therapy (CRRT) is the most appropriate RRT modality for ECMO patients due to hemodynamic instability and fluid overload sensitivity 6.
• Deliver an effluent volume of 20-25 mL/kg/h, though higher prescription may be needed to achieve target delivery 6.

Circuit Configuration

• RRT can be integrated into the ECMO circuit or run as a parallel system; the choice depends on institutional expertise and available technology 6.
• For parallel configuration, use right internal jugular or femoral vein access with an uncuffed non-tunneled dialysis catheter 6.

Anticoagulation Management

• Anticoagulation protocols for RRT during ECMO are not standardized 6.
• Citrate anticoagulation is possible but comparative effectiveness data are lacking 6.
• Base anticoagulation choice on bleeding risk, circuit setup, and institutional protocols 6.

Management Considerations for CKD Patients on ECMO

Pre-ECMO Assessment

• Recognize that CKD patients have baseline increased cardiovascular risk, anemia, mineral-bone disease, and volume management challenges 7.
• Account for altered drug pharmacokinetics due to both CKD and extracorporeal circuits when dosing medications 1.

During ECMO Support

• Earlier RRT initiation may be required specifically for fluid overload prevention compared to non-ECMO patients 6.
• Monitor for ECMO-specific complications that worsen kidney function: hemolysis, inflammatory mediator release, and inadequate renal perfusion 3, 5.
• Adjust nephrotoxic medication exposure and ensure adequate dosing adjustments for both kidney function and extracorporeal clearance 1.

Post-ECMO Transition

• Consider transitioning from CRRT to intermittent hemodialysis when vasopressor support is discontinued and hemodynamic stability is achieved 6.
• Kidney recovery is defined as sustained RRT independence for minimum 14 days 8.
• Patients who receive RRT during ECMO have improved renal function and reduced mortality compared to those who develop AKI without RRT 5.

Critical Pitfalls to Avoid

• Do not withhold ECMO solely based on pre-existing ESRD or advanced CKD when cardiorespiratory indications are present 2.
• Do not pursue extracorporeal ozonation therapy as there is no evidence base for this intervention in CKD 1.
• Do not delay RRT initiation in ECMO patients with fluid overload, as earlier intervention improves outcomes 6, 5.
• Do not assume standard dialysis adequacy measures apply during ECMO; higher CRRT prescriptions may be needed to achieve target delivery 6.