Renal replacement therapy (RRT) should be initiated for acute kidney injury (AKI) patients who have life-threatening complications and are not responding to medical management, said Anitha Vijayan, MD, FASN, including those with volume overload and respiratory failure, hyperkalemia, or metabolic acidosis. But be wary of aggressive fluid resuscitation, said Vijayan, a professor of medicine at Washington University School of Medicine in St. Louis.
She noted there is no data yet to support early initiation of RRT in COVID patients.
Available RRT modalities that may be employed include continuous renal replacement therapy (CRRT), prolonged intermittent renal replacement therapy (PIRRT), or intermittent hemodialysis, she said. CRRT is the preferred modality in hemodynamically unstable patients, and it is recommended that nephrologists use the established CRRT modality at their home institutions. There is no need to buy a different machine than what your hospital has, but more machines may be needed, according to COVID projections for your city and hospital, Vijayan noted.
PIRRT may be performed either with intermittent hemodialysis or CRRT machines. It can last from six to 12 hours, does not need 1:1 hemodialysis nursing, and allows one machine to be used for two to three patients, Vijayan said. To dose PIRRT, use a 20 mL/kg/hour dose for 24 hours, divided by the number of hours you are planning to treat the patient. Treating 10 hours or fewer allows time for cleaning the machine and using it for additional patients, she said.
Anticoagulation during CRRT/PIRRT in COVID patients with AKI is essential, Vijayan added. If there are no contraindications, use heparin, either via machine circuit or systemically. Citrate may also be used, but its use is nursing-intensive and there is a risk for patient safety. If a center does not already use citrate, Vijayan suggested not starting a new protocol at this time. In addition, hemodialysis catheters normally placed by nephrologists and intensivists may need to be placed by other providers, given shifting workforce needs. She noted the importance of the correct length to ensure adequate blood flow and reduce clotting and suggested creating a cheat sheet to be used by others that includes appropriate lengths.
“This is a critical time everywhere—we’re all trying to figure out how to conserve resources,” Vijayan said.
Among the suggestions for conserving resources are the following:
For intermittent hemodialysis, consider the shortest duration that achieves metabolic and volume control and minimize 1:1 nurse time in the room.
Delay RRT if possible in patients whose COVID tests are pending, which can conserve PPE.
Use high-dose diuretics in AKI patients, with binders to lower potassium.
Decrease flow rates in CRRT after metabolic control has been achieved to save fluids.
Cross-train nephrologists and additional nurses if necessary to help set up or monitor patients undergoing dialysis.
If resources or capacity for acute dialysis and continuous venovenous hemodiafiltration has been exceeded, nephrologists can turn to peritoneal dialysis (PD), said Jeffrey Perl, MD, SM FRCP, an associate professor of medicine at the University of Toronto and St. Michael’s Hospital. PD uses less nursing time with direct patient exposure. But there are some concerns to keep in mind, he said: PD has less predictable fluid removal rates, a critical care treatment team may be uncomfortable with the therapy, complications include peritonitis or catheter leaks, and there can be a deleterious impact on respiratory biomechanics in patients on a ventilator.
PD for AKI requires a team approach, buy-in from the care team and nursing expertise, as well as careful, and perhaps more restrictive, consideration of candidates, Perl said.
Vijayan and Perl spoke about their experiences during an ASN webinar about hospital care and treatment options for COVID-19–positive patients.