R Kushwaha, N Singh
dialysate, dialysis, renal failure
R Kushwaha, N Singh. Peritoneal dialysis in animals- A review. The Internet Journal of Veterinary Medicine. 2008 Volume 7 Number 1.
Peritoneal dialysis has become a commonly practiced technique for the treatment of both acute and chronic kidney failure and for removal of dialyzable exogenous and endogenous poisons in animals. With the increased availability of veterinary services today and with the further advancement expected in the future, peritoneal dialysis likely will find ever widening use, particularly for old and geriatric patients.
Uremia, renal failure and acute intoxication are few medical problems often encountered in animals. In such cases, there is a rise in the waste toxic product in the plasma/blood of the animals. This is frequently reported disease in ruminants seen mainly as a consequence to urolithiasis and ruptures of urinary bladder and following repair of bladder (Reddy
Dialysis has been introduced along with the medical management to cope up with chronic nature of this disease. Dialysis is the diffusion of solutes from one solution (plasma/ blood/interstitial fluid) to another (dialysate in peritoneum cavity) across a semipermeable membrane (Grauer and Brown, 1997). Dialysis particularly removes the waste or toxic substances rapidly by the process of diffusion, ultrafiltration and solute drainage (Parker, 1980; Thornhill, 1981; Carter
Principle of dialysis
Dialysis is transfer of solutes across a semi-permeable membrane by the process of diffusion and the membranes are parietal and visceral peritoneum. Solutes that are in high concentration region pass through the pores in the membrane and the process finally helps in the movement of intoxicants from the blood out of the system.
Mode of dialysis
Peritoneal and haemodialysis are the two ways washing away the toxicants from the system that are in practice for animals, however, hemodialysis in animals appears expensive (Abe et al., 1913) and studies have further indicated that this methods is relatively difficult to perform for animals with higher body weight (>13.6 kgs) (Di Bartola
Need for peritoneal dialysis
Animals with acute intrinsic renal failure (AIRF), acutely decompensated CRF, and post renal azotemia that can not undergo immediate surgical correction are candidates for peritoneal dialysis. Brief indications and contraindications of peritoneal dialysis are:
A. Acute renal failure (AIRF)
Failure of fluid, diuretic and vasodilator therapy to induce a diuresis in oliguric/ anuric patients.
Failure of fluid, diuretic and vasodilator therapy to control the biochemical and clinical manifestations of uremia.
Life threatening fluid overload/ pulmonary edema.
Life threatening electrolyte and / or acid-base disturbance.
B. Chronic renal failure
Uremia that is unresponsive to conventional dietary /medical management.
Long term peritoneal dialysis for irreversible, end stage renal disease rarely practical in animals.
C. Miscellaneous conditions
Severe pulmonary edema that is refractory to conventional medical therapy.
Acute intoxication/drug overdose when the toxicant is dialyzable (eg. Ethylene glycol, barbiturate).
Severe intra-abdominal adhesions
Recent abdominal surgery ( a relative contraindication)
Volume and flow of dialysate solution may contribute to breakdown of suture lines in stomach, intestine, or urinary bladder.
Distention of the abdomen with dialysate solution may result in leakage through a ventral midline incision and increase the possibility of peritonitis.
Selection and preparation of dialysate for peritoneal dialysis
Dialysate is generally chosen to approximate normal plasma composition (with the exception of protein) (Rudnick
Commercial dialysate solution
The composition of commercially available solutions and a home made dialysis solution which approximates 1.5% dextrose containing dialysate that is made by adding 30 ml 50 % dextrose to one liter bag of lactated ringer’s solution is listed below. The dextrose should be added immediately prior to use and all injection ports should be scrubbed with a betadine solution. The transfer should be made as sterile as possible to minimize the chances of contaminating the dialysis solution.
As most patients with renal failure have metabolic acidosis, the lactate in dialysis solution helps to correct the acid/base imbalance. Glucose solution assists to draw water which contains waste products into the abdominal cavity. 1.5% glucose containing solution is slightly hyper-osmolar compared to plasma, and will cause water to be removed from the patient. 4.25% glucose containing dialysate has an osmolality of 486 milli osmol/liter and can quickly volume deplete the patient if care is not exercised in its use in most cases. 1.5% dextrose containing solutions are appropriate. 500 to 1000 units of heparin can be added to each liter of dialysate to reduce clotting in the catheter.
Home made dialysate solutions as first aid in peritoneal dialysis
Home made dialysate should have lacted Ringer’s, 0.45% sodium chloride or 0.9% sodium chloride as base solution can be individually tailored to the patient as an alternative to commercial fluids. Rapid infusion og dialysate at 200 to 300ml /min by gravity is well maintained in animals (Parker et al., 1972; Thornhill, 1981) as and when home made dialysate are used as first aid for peritoneal dialysis. Commercial dialysate fluids are generally preferred, since alternations of the dialysate (additive) increases the risk for bacterial contamination during preparation. All home made-prepared solutions require the addition of glucose. Thirty milliliters of 50% dextrose is added to each liter to achieve a 1.5% dextrose solution, or 50 ml of 50% dextrose to achieve a 2.5% dextrose solution (Chew and Crisp, 1992). In the home made dialysate solutions, magnesium (72 mg/liter of fluid to achieve 1.5 meq/l), sodium bicarbonate (30 -45 meq/liter as a source of alkali), heparin (just prior to infusion, 1000 units/l), antibiotics (if peritonitis is suspected) and potassium (in hypokalemia, 4 meq/l) should be added. In case of hypercalcemia or hyperphosphatemia it may be advisable initially to choose a home made preparation that is lacking in calcium (0.9 % sodium chloride with glucose added). In general, it is advised that rapid drainage of dialysate should not be performed with compressed as it could be painful in dogs (Parker, 1981).
Type of peritoneal dialysis
Technique of peritoneal dialysis
Aseptic technique is imperative with any type of peritoneal dialysis (Thornhill, 1981; Copley, 1987). This includes the use of surgical scrub and sterile surgical technique during catheter placement, as well as the use of sterile gloves, disinfectants, and the careful handling of dialysate fluids, catheters, and catheter line during dialysis.
A. Peritoneal dialysis catheter
An indwelling catheter is recommended because of the repeated dialysate exchanges.
B. Ideal catheters have the following characteristics-
Efficient fluid inflow and outflow
Resistance to infection of the subcutaneous tunnel and peritoneal cavity
Little fluid leakage at the peritoneal interface
C. Type of Catheter
Can usually be inserted with local anesthesia
Catheter holes easily plugged with fibrin and omentum, causing fluid outflow obstruction
Greater potential for dialysate leakage at catheter placement site
Less prone to outflow obstruction
Less prone to leakage at catheter site
Expensive but can be re-sterilized and reused
Usually requires general anesthesia and surgery to insert
Fluted- T peritoneal dialysis catheter (figure 4) (Ash and Janle, 1993)
Method to access into peritoneal cavity
Peritoneal lavage (continuous peritoneal dialysis) is an alternative technique to treat the uremia in bovines (Singh and Sahu, 1995; Cowgill, 1995) and in canines (Rukmani and Tiwari, 2004). A 14 French tube is percutaneously placed in the flank for infusion of dialysate. One or more outflow drains is placed inside a fenestrated penrose drain and then inserted along with ventral abdomen. Infection with this technique can be a problem because this is an open drainage system (Parker, 1972).
Two catheters designed for long term peritoneal dialysis in dogs are commercially available that are parkers and column disk peritoneal dialysis. Parker peritoneal dialysis canula consist of a trocar, guide tube, a stainless steel needle, and a silicone rubber dialysis canula- This catheter can be placed with local anesthetic if the animal is severely depressed and is transfixed across the flank in a bowed manner ventral to the bladder . Leakage of dialysate is minimal because of the dorsal flank exit site for the catheter. A Dacron cuff is present at the level of the body wall to decrease in dogs has been shown to be highly successful in the reduction of uremic solutes and in its ability to freely drain dialysate (Parker et al., 1972). Unfortunately this catheter has not achieved widespread use due to limited commercial availability initially.
The column disk peritoneal dialysis catheter represents the device used most commonly for long term placement and rapid drainage of dialysate in dogs. The catheter is made of silicone and consists of a single tube opening two parallel disks separated by numerous pillars. Advantage from this catheter includes excellent effluent drainage and minimal leakage of dialysate. The pillars help prevent catheter out follow occlusion by omentum, fibrin, and abdominal organs. The disks are secured into a non-movable position along the body wall. Two Dacron cuffs are placed on the catheter to allow fibrous tissue growth and prevent ascending bacterial migration.
Factors influencing the peritoneal dialysis
The surface active agents’ trisaminomethane and dioctyl sodium sulfosuccinate increase urea clearance in dog through poorly understood mechanisms (Brown
Problems and Complications
1. Penetration of bowel or urinary bladder
2. Laceration of a major vessel
1. The most common problem
2. Characterized by an inability to retrieve all the infused fluid
3. Corrective measures
Flush the catheter rapidly with 20 ml heparinized saline in an attempt to dislodge blood and /or fibrin clots and omentum.
Reposition the animal
Try to reposition the catheter within the abdomen by external manipulation
Placement of a new catheter may be necessary.
Systemic signs (e.g. fever, abdominal pain, vomiting) may or may not be present.
Retrieved dialysate has a cloudy appearance.
Analysis of retrieved dialysate shows large numbers of neutrophils; bacteria may also be observed.
Bacterial culture and sensitivity are performed on the retrieved dialysate.
Flush abdomen with 1 liter o fnorma saline once daily.
Instill a saline –iodine solution (0.2 ml of 2% iodine USP in 1 L of saline) for 4 minutes and then drain (Thornhill, 1983).
Dialysis can usually be continued.
Systemic and intraperitoneal antibiotic treatment is based on bacterial culture and sensitivity of the retrieved dialystae.
Cephalothin is given as a loading dose of 1 g/L of dialysate, followed by a maintenance dose of 250 mg/L of dialysate.
Aminoglycoside is given as a loading dose of 4 mg/kg IM, followed by a maintenance dose of 6 mg/L of dialysate (Thornhill, 1983).
Heparin (500 U/L) is added to the dialysate to prevent fibrin occlusion of the catheter.
Treatment should be continued for 10 – 14 days.
If after 96 hours of aggressive treatment no clinical improvement occurs, the peritoneal access catheter should be removed.
This occurs as a result of the relative permeability of albumin to peritoneal membrane.
The rate of albumin loss is accelerated with peritonitis.
May develop associated with the combination of overhydration and hypoalbuminemia.
May necessitate occasional thoracocentesis.
This is when there is too much fluid in the body and it may be due to (I) increase fluid input and (II) decreased fluid out put from either dialysis fluid or urine. The signs are weight gain, high blood pressure, puffy hands or eyes and breathing difficulties.
This is when there is too little fluid in the body and it may be due to diarrhea, vomiting, increased output from dialysate fluid or urine, decreased fluid intake or sweating. The signs are weight loss, low blood pressure, sunken eyes, dry mouth or coated tongue or inelastic skin.
Future prospects of dialysis in animals
In the animals, cost of treatment and post operative management is a common huddle for popularization of any new technique. This is a one of the reason that haemodialysis is not used in animals clinically. Therefore, it has less future in animals until and unless a artificial kidney is designed for animals with less cost. However, peritoneal dialysis is can be utilized effectively in animals owing to its easiness and simple process. Although in veterinary, uremic cases in spite of high BUN and creatinine oftenly recovered by surgical intervention and intravenous fluid administration, however its use helps in early and faster recovery from the uremia. However, further investigation is needed to develop a type of dialysate that remove the solute effectively and quickly with its reutilization.
Dialysis is an alternative modality to treat the cases of acute renal failure or uremia especially when dietary and a medical remedy is failed. The use of peritoneal dialysis is common in veterinary practice owing to its easy application, whereas haemodialysis, frequently used in medical science, is limited only to some referral Veterinary clinic. A judicious use of peritoneal dialysis, as a sole or in adjunction to medicinal therapy, can restore the patient life towards normalcy.