Dialysis in Infants

Pediatric Critical Care Columnist · Sep 24, 2007

Is this continuous or intermittent dialysis? Short-term or long-term?

Care plans will have to focus on fluid and electrolyte balance, risk of infection and safety. The nephrologist will determine the type of dialysate and additives, volume and length of cycles, frequency of lab work and so on, but you should know the signs and symptoms of electrolyte imbalances, especially potassium, calcium and phosporus. PD dialysate usually contains a percentage of dextrose, as much potassium as the desired serum level (i.e. if you want the serum K+ to be 4, then you'd have 4 mmol per liter in your fluid) and sodium bicarbonate to maintain acid-base balance. Remember, the kidneys are part of the acid-base control mechanism along with the lungs; the kidneys do the lion's share of retaining bicarbonate, so if they aren't working, they aren't holding on to it. PD works by using the peritoneum as the filter; the abdominal cavity is filled with the desired volume of fluid which is allowed to dwell for the ordered amount of time then drained off. The dextrose pulls fluid into the space by diffusion to create a balance on both sides of the membrane. The higher the concentration of dextrose, the more fluid it pulls off. The fluid will also pull potassium to the point of equilibrium, and because there's no urea or creatinine in the fluid, it gets pulled over too. Protein molecules are generally too large to cross the membrane and are retained in the serum.

The kidneys also play a role in calcium and phosphorus metabolism. Dialysis patients are usually on calcitriol to correct for hypocalcemia; failing kidneys aren't able to process Vitamin D into calcitriol for proper absorption of dietary calcium. They also don't excrete phosphorus (in the form of phosphate) in the usual amounts, so calcium deposition in bone is impaired. Calcium is also significant in muscle contraction and vascular tone, so deficiencies cause muscle cramps, cardiac dysrhythmias and hypotension.

The risk of infection is astronomically high in PD patients. PD dialysate is a perfect culture medium for all sorts of nasty bugs; contaminated fluid leads to peritonitis. Scrupulous asepsis is absolutely non-negotiable while preparing the fluid, changing bags (even the effluent bag), accessing the catheter and any other intervention that might involve potential contamination. Assessment of the effluent is essential to observe for changes in clarity, color, odor and consistency. The catheter site is also a site prone to infection; the catheter passes through the abdominal wall and muscle into the peritoneal space and creates a portal or colonization and infection. Careful, aseptic catheter care is vitally important.

A child this age may be at risk for pulling the catheter out, either on purpose or by accident. The internal portion of the catheter has a 'mushroom' on it that helps keep it in place, but any good yank on it and it's toast. There are a few things that can be done to help prevent that; running the line from the pump to the port up the child's pants leg (outside the diaper, of course) will conceal it from sight and contain it so it doesn't snag on anything. If the child is on intermittent treatment, then the catheter can be held in place with a stockinette vest tied between the legs, and that will serve the same purpose. The caps are usually well-secured, but may become dislodged by an inquisitive kid, and then you've not only got a mess, but you've got that lovely corridor to the peritoneum open for business. Supervision cannot be replaced by tricks and tools!

I'm running out of characters here. I'll address developmental stuff in another post.

OldButCuteBSNStudent · Sep 24, 2007

Thanks for your reply. The peritoneal dialysis is continuous right now while she's in the hospital. She developed acute renal failure 7 weeks ago and was placed on a cycler at home. Her mother made a change in formula and within a few days the 5 month old infant was back in the hospital with hyperkalemia. We are managing that and the nephrologist has told the mother that the infant will be placed on the transplant list eventually. I am very unfamiliar (and haven't worked much on a floor) and being so interested in the pathophysiology I thought you all might give me pointers She has a tenckhoff catheter in place. And I was wondering how well these little one's do at that age; long term. Tx again!

Pediatric Critical Care Columnist · Sep 24, 2007

Her mother made a change in formula and within a few days the 5 month old infant was back in the hospital with hyperkalemia.

Are you talking about formula for feeds, or for dialysis? Only the renal team should be making changes to dialysis components. As for feeds, renal failure means a low potassium and protein diet to decrease the nitrogen load on the body and to allow the PD to work best. This mom should be working with a nephrology team dietician so that her baby has the best outcome. Nobody with renal failure should be making diet changes without consulting nephro.

the nephrologist has told the mother that the infant will be placed on the transplant list eventually. I am very unfamiliar (and haven't worked much on a floor) and being so interested in the pathophysiology I thought you all might give me pointers

Are you talking about renal failure, or renal transplant?

And I was wondering how well these little one's do at that age; long term.

A lot depends on the underlying cause of the renal failure. If it's from a metabolic disorder, there are morbidities that will go along with that. If it's because of a hypercoagulable state for whatever reason causing a clot to the renal artery, the risk of recurrence is fairly high so she may need anticoagulation to preserve her graft, at least in the short term. If it's because of a prolonged hypotensive episode, thens he'll have lots of other issues to deal with besides renal failure. Once she has her transplant there are the issues of immunosuppression and compliance, no contact sports, and the usual surgical healing things. Some kids do really well right off the hop and get two decades from the transplant and some have problems right from the get-go. One big early post-op management issue is compartment syndrome, and monitoring is quite rigorous... can't let the kidney get crushed.

One thing I meant to mention when talking care plans is the fact that the kidney makes erythropoetin, and people with renal failure are always anemic without regular EPO injections. We teach our parents how to place and use Insufflon catheters for subcutaneous injections of EPO and low molecular weight heparins; the oncology team also teaches them G-CSF. Maybe you've already started that. EPO I mean.

Developmentally, she should still be able to do the tasks of growing up but within a circumscribed area... the length of her dialysis tubing. She should still learn how to sit, crawl, walk, talk, play and everything within the limits of her environment. Depending on what type of cycler she uses, she should still be able to go for walks in the stroller (might take some McGyvering, but is possible), play outside (bearing in mind infection risk) and so on. No swimming though. As time passes, she should be able to do only night-time cycles and then she'll be pretty much like everybody else.