FLUID THERAPY IN RENAL INSUFFICIENCY
THE CORNERSTONE OF TREATMENT
Assuring optimal hydration is the single most important aspect in the treatment of insufficient kidneys. The kidneys are made up of millions of small filtration units called “nephrons.” Blood is filtered by these nephrons such that waste chemicals and toxins are separated from desirable materials (such as proteins, sugars, electrolytes, etc.). The chemicals which the body needs are returned to the circulation and the excesses and toxins are channeled into the urinary tract. The excesses and toxins must be kept dissolved in water for this process to work but the kidney, one of whose jobs is to conserve water for the body, must be able to use the smallest amount of water possible to keep the toxins dissolved. This solution of waste toxins dissolved in water is urine. It is produced continuously by the kidneys, stored in the urinary bladder, and periodically dumped into the environment.
Over the time of one’s life, nephrons are damaged and are no longer able to participate in the filtration process. They die from poor circulation or they become clogged by toxin sludge or they may simply wear out. Fortunately, we have many extra nephrons so losing some is not a big problem; that is, not a big problem until have lost about 2/3 of them. At this point the remaining nephrons will have trouble keeping up with the waste removal demands of the body. Extra water is needed to remove the same amount of metabolic toxin. Since water cannot be conserved, the patient begins to drink excessively. Eventually, toxins build up and the patient feels sick.
This means that if the kidney disease is not detected until the patient is already feeling sick, less than 1/3 of the original number of nephrons are left. We need to maximize the efficiency of these remaining nephrons, and hopefully slow down their loss. We also need to get rid of enough toxin for the patient to feel good again. The build up of toxins is called "azotemia." Actually feeling sick from the toxins is called "uremia."
Diuresis is the medical term for increased urine production. The patient may have already doing this somewhat by drinking excessively but there comes a point when it is not possible to drink enough and toxins build up as mentioned. When the patient first begins to feel sick, he tends to eat less and drink less. Dehydration results which is disastrous for the patient that already had an increased need for fluids to start with. To solve these problems, we will need to correct the dehydration and maximize the circulation through the remaining nephrons. This is accomplished by giving the patient more fluid, either intravenously in the hospital or under the skin in either the hospital or the home setting.
INTRAVENOUS FLUID THERAPY
Intravenous fluid therapy involves placement of an intravenous catheter in the leg or neck and a continuous drip of fluids is given directly into the bloodstream. The procedure is not painful nor stressful as after the catheter is placed, the patient simply relaxes in a hospital cage, periodically receiving adjunctive oral or injectable medications. After 2 or 3 days, lab tests are repeated to see what parameters have changed. Therapy is revised at that point to either continue IV fluids or discharge the patient with a new plan for home treatment.
Intravenous fluid therapy offers many benefits to the kidney patient:
The disadvantages of Intravenous fluid therapy include:
SUBCUTANEOUS FLUID THERAPY
The word “subcutaneous” means “under the skin.” Here, fluids are given all at once in a “pocket” under the skin and the patient absorbs them gradually. Initially, intravenous fluid therapy is generally considered superior to subcutaneous fluid therapy but this depends on the blood test results of the patient; some are able to skip straight to subcutaneous fluids or are forced to by the expense of intravenous therapy. Fluids are typically given every couple of days with the frequency increasing if the pet gets worse or decreasing as the pet gets better.
Advantages of subcutaneous fluids include:
Disadvantages of subcutaneous fluids include:
For more details on how to give subcutaneous fluids, click here.
FLUID ADMINSTRATION BY ESOPHAGOSTOMY
Other Pages in the Chronic Renal Failure Center: