Hemodialysis is a procedure which enables the removal metabolic solute and fluid waste from the blood. The dialysis machine pumps blood through an extracorporeal circuit where it passes through a semi-permeable membrane called a dialyzer. Dissolved solutes like urea and other toxins, diffuse through the dialyzer membrane and out of the blood. The purified blood is then returned back to the patient. The duration of the dialysis treatment and amount of toxin removed is tailored to each patient and the severity of the patient's disease process.
Applications of Hemodialysis
Hemodialysis provides a new standard of care for a variety of diseases and clinical conditions for which there are no effective medical alternatives, including:
• Severe acute or chronic renal failure
• Acute poisoning
• Severe overhydration
• Severe electrolyte derangements
• Severe acid-base disturbances
• Conditioning for kidney transplantation
Acute uremia is the most common indication for hemodialysis in dogs and cats. Hemodialyis should be considered when the clinical consequences of acute uremia cannot be effectively managed with medical therapy alone. Common reasons for dialysis referral include leptospirosis, pyelonephritis, pre-operative stabilization of ureteral obstruction, ischemic injury, acute renal failure from systemic disease and acute uremia of unknown cause. Clear indications to start dialysis include diuretic unresponsive oliguria/anuria, and/or life-threatening hyperkalemia or volume overload. Relative indications include no response to fluid therapy for 24 hours or severe azotemia (BUN >100 mg/dl; creatinine >10mg/dl).
Hemodialysis is also used in the management of some acute toxin exposures if the toxic compound is readily dialyzable. Dialysis can hasten the elimination of the toxin or its metabolites. Hemodialysis has been used in the management of a number of common poisonings including: ethylene glycol, methanol, salicylate, phenobarbital, acetaminophen, theophylline, aminoglycosides and tricyclic antidepressants. We encourage referral for ethylene glycol within the first 12 hours of ingestion. Hemoperfusion enables removal of large protein-bound molecules by passing the patients blood through a charcoal filter. This process is particularly useful for the removal of NSAIDS and other toxins that cannot be cleared with a conventional dialyzer.
Chronic dialysis is also effective for animals with chronic, end stage renal disease that is no longer responsive to fluid diuresis, but is less commonly performed in veterinary patients.
Referral for dialysis
Spare the jugular veins. The blood flow rates required to perform hemodialysis require placement of a large-gauge jugular catheters. Dogs and cats have limited options for vascular access and the jugular veins should be protected at all cost. Jugular venipuncture and jugular catheters should be avoided in all patients for which hemodialyisis remains an option.
Hemodialysis is an emotionally and financially intensive therapy with no guarantee of a successful outcome. While hemodialysis is an outstanding bridging mechanism to maintain the patient during the healing phase of acute renal injury, the clients must understand that dialysis does not 'fix'� damaged kidneys. It is difficult to determine at the onset how long therapy must continue to allow a patient's tubular function to resume. In general, with severe acute tubular necrosis, clients should financially and emotionally be prepared to undertake 2-4 weeks of dialytic therapy. The client can anticipate spending $10,000-$15,000 for 3 weeks of therapy. Many patients, who were initially critically ill, will become dialysis outpatients after several days of therapy. Not only does this eliminate hospitalization costs, but also significantly improves the patients quality of life.
In the event of acute toxin ingestion, one or two treatments are required to remove the toxin from the bloodstream. Clients should expect $2000 to $3000 for the removal of the toxin.
Please call us early in the course of patient management
DVM Dialysis Referral Summary Sheet - please fill out this sheet and return to VSC via fax
We encourage consultation as soon as you suspect a patient might benefit from dialysis; delay in instituting therapy for a pet with acute renal failure can jeopardize a successful outcome. If you suspect a patient might be a candidate for dialysis or have any questions, please contact Dr. Linda Barton, Amanda Adams, or Adriane Evans at (425) 697-6106.