CAPD is the most widely used dialysis technique in the world due to its simplicity and low cost, although it is not the technique of choice in France. With this techniquen no cycler is used. The dialysate in a bag suspended from a gallows is infused into the patient, who disconnects during the stasis phase and reconnects for the drainage phase (Figure 3)

In pediatrics, the child benefits from four to six cycles a day, usually performed by the parents, which means that the parents must be involved throughout the 24 hours. This dialysis method is ill-suited to individualized prescriptions. It requires a small number of daily cycles, with long stasis times, which limits UF in general but improves sodium and phosphate extraction. In addition, dialysis performed in the orthostatic position leads to the prescription of smaller intraperitoneal volumes due to poorer tolerance than in the supine position, in conjunction with increased IPP. Finally, we must also take into account the risk of infection secondary to repeated manipulations and the constraints this implies for the child and their parents. It should be noted that CAPD can also be performed on newborns, notably with the use of very small volumes, via the burette system (not currently available on a retrocedible basis).

APD uses a machine called a cycler. Dialysis is carried out at home, during the night, possibly leaving the patient with daytime stasis. The session generally lasts 8 to 11 hours, depending on the child’s needs and constraints (schooling), with several consecutive cycles. There are several types of APD, detailed in Figure 4 below.

Intermittent PD consists of several consecutive overnight cycles. Continuous cyclic PD (CCPD) involves a nocturnal session, plus a long daytime stasis (icodextrin or glucose-based solutions) after the last overnight injection. Fluctuating PD involves several partial drainages, as well as complete drainage after a certain number of cycles. Lastly, adapted PD makes it possible to vary times and volumes during a dialysis session, thereby increasing UF and sodium extraction while maintaining the same total dialysate volume and overall dialysis time [23]. In practice, adapted APD is often prescribed in the form of a repeated alternation of a short cycle followed by a long cycle.

Dialysate is a sterile solution of water, buffer, and osmotic agent. Isotonic dialysate (1.5% glucose concentration) is most often used. A hypertonic solution is used when it is necessary to increase the UF. Dialysates will eventually lead to alteration of the peritoneal membrane, and excessive use of hypertonic dialysate, lactate buffers, and non-biocompatible solutions will increase this alteration. It is therefore preferable to use a biocompatible dialysate in children whenever possible (not always available in all countries), with a neutral pH and a bicarbonate buffer to preserve the peritoneal membrane. The use of a dialysate containing icodextrin enables UF to be preserved during long stasis (diurnal stasis).

Stasis time plays an important role in the effectiveness of prescribed exchanges. Purification depends on the length of the cycle: the longer the stasis time, the better the purification, since it gives time for exchanges to take place, particularly for “large” molecules such as phosphate. Too long a stasis time will result in a reduction in UF due to loss of the dialysate’s osmotic power (glucose reabsorption). A short stasis time will conserve UF but will result in less purification. The definition of optimal times depends on individual characteristics, as revealed by PET test of the peritoneal membrane [24]. PET can be used to assess urea saturation and glucose desaturation levels in the dialysate. The area under the curve, which crosses the saturation and desaturation rates, defines the APEX (Accelerated Peritoneal Equilibration eXamination) time [25]. This time theoretically defines an optimum contact time to ensure optimal UF and urea purification for a defined intraperitoneal volume [26]. Figure 5 summarizes these outlines for a PD prescription.

The intraperitoneal volume is prescribed according to the child’s body surface area. It is gradually increased to avoid dialysate leakage and improve dialysis tolerance. The volume prescribed is generally 30–50 mL/kg or 600–800 mL/m2 for children under 2 years of age, and from 1,000 to 1,200–1,400 mL/m2 for children over 2 years of age [5]. A large volume leads to greater capillary recruitment and better purification. However, too large a volume can lead to patient discomfort and retrofiltration.

In CAPD, “effective” volumes are between 900 and 1,100 mL/m2 . Daytime volumes are lower than night-time volumes (around 800–1,000 mL/m2 vs. 1,000–1,400 mL/m2) to avoid mechanical complications. IPP measurement is a valuable aid in determining maximum peritoneal volume. Under no circumstances should the IPP exceed 18 cm H2O, as this would expose the child to mechanical complications (hernia, respiratory difficulties, etc.). In practice, the acceptable IPP is 12 to 14 cm H2O for children over 2 years of age, and 8 to 10 cm for children under 2.

As with adults, hernias are the most frequent “mechanical” complications in PD, especially so in younger children, as the peritoneovaginal canal persists until the age of 2 [27]. Peritoneal dialysis catheter malfunction may be secondary to catheter displacement, kinking, or obstruction. Depending on the etiology, laxative treatment, surgical repositioning of the catheter, or fibrinolytic therapy may be suggested.

Dialysate leakage around the catheter or into the abdominal wall occurs more frequently in children weighing less than 10 kg [28]. The use of large volumes of dialysate within 2 weeks of catheter insertion is a contributing factor. Extrusion of a catheter sleeve is a frequent complication that can lead to local inflammation and increase the risk of infection.

Other rarer mechanical complications include hydrothorax, hemoperitoneum, pneumoperitoneum, or chyloperitoneum [29,30]. Abdominal pain at the time of infusion is more frequent with acid PH dialysates buffered by lactate [31].

Pain during drainage may be secondary to the fact that the chosen catheter is long or poorly positioned, inducing a sensation of heaviness and pelvic irritation. Pain during the drainage phase is more frequent in APD than in CAPD due to the hydrostatic pressure induced by the cycler at the start of the drainage phase. Infusion and drainage speed must be optimized according to age when prescribing limits on the cycler software [32].

Tunnelitis is defined by the presence of redness, swelling, and tenderness along the subcutaneous path of the catheter. Catheter emergence infection is defined by the presence of a purulent discharge at the catheter-skin interface [34]. Staphylococci are responsible for the majority of catheter emergence infections, followed by Pseudomonas aeruginosa. Risk factors associated with a higher incidence of catheter infection are poor local care, catheter compression, bathing, the presence of animals (especially during dialysis hook-up), and poor catheter handling. Thus, therapeutic education of the family is crucial to avoid these infections.

In order to prevent and treat catheter-related infections more effectively, new recommendations were issued in 2024 [18]. They reiterate the main principles of asepsis: antibiotic prophylaxis should be administered at the time of catheter insertion, and careful catheter care should be practiced. As no antiseptic solution has been shown to be superiorly effective in preventing catheter-related infections, the application of an antibiotic (mupirocin) to the exit port may be suggested. In the event of infection, the dressing should be changed daily. Nasal carriage of Staphylococcus aureus should be treated with mupirocin. The choice, duration, and route of antibiotic administration will be adapted on a case-by-case basis, in line with new recommendations.

Peritoneal fluid infection is the main complication of PD and may lead to the technique being abandoned if episodes are repeated. It is a diagnostic and therapeutic emergency. Signs suggestive of peritonitis include cloudy drainage fluid and/or pain and/or difficulty infusing and/or draining dialysate. Abdominal pain and fever are inconstant. Peritonitis is most often of bacterial origin (sometimes mycotic, viral, or parasitic). Positive diagnosis is confirmed by Sero hematological analysis of the dialysis fluid, which reveals more than 100 leukocytes/mm3, over 50% of which are neutrophils. The most common germs are staphylococci, BGN, and enterococci. Management is hospital-based, with the start of probabilistic intraperitoneal antibiotic therapy with a C3G anti-pyocyanic agent (ceftazidime or aminoside), with or without an anti-staphylococcal glycopeptide (vancomycin or teicoplanin), to be adapted subsequently [34].