Although peritoneal dialysis (PD) is frequently utilized in the management of acute kidney injury (AKI), unlike the adult literature, there are no RCTs comparing the effectiveness or outcomes of different renal replacement modalities for the treatment of AKI in children.
This week we’ll discuss a guideline on the use of PD for the treatment of AKI in children led by Peter Nourse from South Africa. In the absence of an evidence-base, recommendations are largely based on observational studies and expert opinion. Very practically, the guideline differentiates between minimum standards vs optimal care, empowering colleagues in lower and middle-income countries to consider and perform PD even in resource-limited settings. The prodigious experience of the authors provides the reader with several clearly defined and comprehensive practice points from catheter insertion and PD fluid selection to adapting the PD prescription for fluid and solute clearance. Topics for future research are clearly outlined, stressing that we have a long way to go in our understanding of optimal care for these children.
A recent internet survey has shown that in high income countries, HD (72%) and CRRT (24%) were the preferred modalities, while in low- and lower middle-income countries, 68% of infants were dialysed with PD. This seems to be due to geographical region and socioeconomic conditions, as well as the patients’ clinical characteristics.
PD may be the preferred option for low birthweight babies, cardiac surgery in small babies, the presence of bleeding diatheses, and cardiovascular instability in small babies where there is a lack of specialized equipment for handling low extracorporeal blood volumes.
Contraindications to PD
recent abdominal surgery
paralytic ileus
open chest post cardiac surgery
abdominal compartment syndrome
difficulty ventilating the patient
pleuroperitoneal connection allowing dialysate in the chest
diaphragmatic hernia
inguinal hernia
hypercatabolic renal failure where clearance of small solutes may be insufficient
clinical situations where precise removal of large volumes of fluid is required
abdominal wall cellulitis or abdominal wall burn
fungal peritonitis.
The recommendations below propose a minimum standard to be achieved to ensure that the benefits of PD treatment for AKI outweigh the risks.
Peritoneal Access and Fluid Delivery
A Tenckhoff catheter inserted by a surgeon in an operating theatre is the best choice. This has been successful even in small babies.
A PD catheter with an insertion kit and using the Seldinger technique, and interventional radiological placement combining ultrasound and fluoroscopy are acceptable alternatives. Although there is no data for the latter approach in children, this could avoid the need for temporary vascular access catheters.
Rigid catheters placed using a stylet should only be used when soft Seldinger catheters are not available, and only used for < 3 days, since longer use has a high risk of leakage, dislodgement, viscus injury and peritonitis. Improvised catheters should only be used when no standard PD access is available. Some improvised ones have been very effective, but there is no data to back this up.
The best place for the procedure (e.g., bedside or operating theatre) will depend on the clinical situation.
The recommended sites for insertion are in the midline in the mid-rectus abdominis sheath below the umbilicus or midpoint between the umbilicus and the anterior superior iliac spine of the hip. Using these landmarks, the inferior epigastric artery should not be punctured.
Sedation and analgesia for bedside insertion in children can be the greatest risk, and so appropriate facilities and staff must be available.
The following procedure is recommended when inserting a bedside PD catheter, with staff well trained on sterile procedures for all components of PD:
sterile garments worn by staff;
sterile drapes;
all components and connections opened on a sterile tray;
add povidone iodine dressing to PD connections;
closed sterile system of tubing, PD fluid and PD catheter.
Prophylactic antibiotics prior to catheter insertion are recommended. A closed delivery system with a Y connection should be used. A system using buretrols to measure fill and drainage volumes should be used when performing manual PD in small children. In resource limited settings, an open system with spiking of bags may be used.
The decision of which antibiotic to use is dependent on local bacterial susceptibilities, timing of the procedure and availability.
Automated peritoneal dialysis is suitable for the management of paediatric AKI, except in neonates.
Dialysis Solutions
The acute peritoneal solution should include dextrose in a concentration designed to achieve the target ultrafiltration.
Once potassium levels fall below 4 mmol/l, potassium should be added using sterile technique. If the potassium cannot be measured, it can be added after 12 hours of continuous PD to achieve a level of 3-4 mmol/l.
Serum concentrations of electrolytes should be measured 12-hourly for the first 24 h and daily once stable. In resource poor settings, if practical, sodium and potassium should be measured daily.
For hepatic dysfunction, hemodynamic instability and persistent/worsening metabolic acidosis, it is preferable to use bicarbonate containing solutions, with lactate containing solutions as an alternative.
Commercially prepared solutions should be used. Locally prepared solutions made in an approved and certified aseptic unit/pharmacy may be used, with careful observation of sterile preparation procedures and patient outcomes. The third preferred option is solutions prepared in a clean environment with a minimum number of punctures and the least number of steps. This fluid should be used immediately.
Prescription of Acute PD
The initial fill volume should be 10–20 ml/kg to minimize the risk of dialysate leakage; a gradual increase to 30–40 ml/kg (800–1100 ml/m2) may be made.
The initial exchange duration should be every 60–90 min; a gradual increase can occur as fluid and solute removal targets are achieved. In neonates and small infants, the cycle duration may need to be reduced.
Close monitoring of total fluid intake and output is mandatory, with a goal to achieve and maintain normotension and euvolemia.
Acute PD should be continuous throughout the full 24-h period for the initial 1–3 days of therapy. There should be close monitoring, where available, of drug dosages and levels.
Continuous Flow PD
CFPD can be a treatment option when an increase in solute clearance and ultrafiltration is desired but cannot be achieved with standard acute PD.
This technique should be considered experimental.
CFPD can be used for children with AKI when the use of only very small fill volumes is preferred.
Complications
Potential complications associated with the use of PD for management of AKI in children are peritonitis, mechanical complications, protein loss, and hyperglycaemia.
