Renal Replacement Therapy
Kara Short
Daryl Ingram
Vincent Mortellaro
Traci Henderson
David Askenazi
Acute Renal Replacement Therapy
The two most common types of acute renal replacement therapy used in the neonatal population when management of electrolytes and/or fluid balance by less invasive means fails are peritoneal dialysis (PD) and continuous renal replacement therapy (CRRT). Variables to be considered when deciding between these modalities include:
ability to gain access (vascular for CRRT and peritoneal catheter for PD)
degree of fluid overload and/or electrolyte instability
goals of therapy
intoxication of a drug that can only be removed adequately by CRRT or hemodialysis (HD)
degree of uremia
condition of the abdomen, and
availability of resources/center experience (1).
Indications
1. In general, like any procedure, RRT is indicated when the potential benefits outweigh the potential risks of not performing the procedure. RRT should begin when one or more vital functions of the kidney are failing and that result is likely to impede vital organ function. The clinician should not wait for complete kidney failure to initiate RRT. This is analogous to intubation for respiratory support. One would not wait for complete respiratory failure to intubate, but would intubate a patient when impending respiratory failure is likely.
2. Specifically, RRT is indicated when conservative management has failed to adequately control any of the following conditions (2, 3):
a. Hypervolemia
b. Hyperkalemia
c. Hyponatremia
d. Refractory metabolic acidosis
e. Hyperphosphatemia
f. Inability to provide necessary blood products, drugs, and/or nutrition without progressive fluid overload
g. Toxicity of certain medications
Contraindications
Although not a true contraindication, PD for severe hyperammonemia does not provide adequate ammonia clearance. Thus, either high-dose CRRT or HD followed by CRRT is the modality of choice (6, 7). In the event that no HD or CRRT is available, starting PD while arranging transport to a medical center with HD and/or CRRT capabilities can be life saving (8). Contraindications to PD include any abdominal wall defects (omphalocele, gastroschisis), diaphragmatic or abdominal wall disruptions, perforated bowel due to necrotizing enterocolitis or other causes, acute abdomen, and/or recent surgery that disrupts the integrity of the peritoneum (9, 10). In babies with imminent or current intracranial hemorrhage, PD may be preferred as this procedure does not require anticoagulation (6).
Acute Peritoneal Dialysis
For a comprehensive discussion on guidelines for PD during AKI, the International Society of Peritoneal Dialysis provides specific, comprehensive guidelines which are beyond the scope of this chapter (9). For this chapter, we will discuss the issues pertinent to neonates. In neonates, acute PD is frequently preferred over intermittent HD and CRRT because it is technically easier to perform. Peritoneal surface area per kilogram of bodyweight is relatively larger in newborns and children than in adults. Therefore, PD usually allows
adequate clearance and removal of excess fluid. In addition, PD avoids the need for anticoagulation and maintenance of adequate vascular access, which are required for the other methods (11).
adequate clearance and removal of excess fluid. In addition, PD avoids the need for anticoagulation and maintenance of adequate vascular access, which are required for the other methods (11).
A. Equipment
(Figs. 59.1 and 59.2)
 FIGURE 59.1 A: IV pole (Fig. 59.2). B: Dianeal Peritoneal Dialysis Solution (Baxter, Deerfield, Illinois). C: Dialy-Nate Set with luer connections: Peritoneal Dialysis set for Neonates (Utah Medical Products, Inc. www.utahmed.com.), which includes a 150-mL inline burette set, a 3-way stopcock, coiled tubing, and a drainage bag. D: ExSept Plus, skin-exit site wound cleanser; electrolytically produced 0.114% sodium hypochlorite (Courtesy of Angelini Pharma). E: Effluent Sample Bag (Baxter, Deerfield, Illinois). F: MiniCap with Povidone-Iodine Solution (Baxter, Deerfield, Illinois). G: Beta-Cap Clamp. H: FlexiCap Disconnect Cap with Povidone-Iodine Solution (Baxter, Deerfield, Illinois). |
Sterile
1. Masks, drapes, gowns, and gloves
2. Chlorhexidine, povidone-iodine, or center-approved disinfectant scrub
3. 1% lidocaine without epinephrine
4. 3-mL syringe with 25-gauge needle
5. IV cutdown tray with no. 11 surgical blade
6. 3-0 Prolene sutures (either as part of cutdown tray or separately)
7. 22-gauge angiocatheter or a femoral catheter with guidewire
8. A temporary catheter such as a 14-gauge angiocatheter or one of the commercially available temporary dialysis catheters (e.g., a Trocath [Trocath Peritoneal Dialysis Center, Kendall McGaw Laboratories, Sabana Grande, Puerto Rico])
9. Dialysis solution (1.5%, 2.5%, or 4.25%)
a. Other concentrations can be made by manual mixing of standard solutions once the system is set up
 FIGURE 59.2 An assembled peritoneal dialysis circuit illustrates an IV pole (A) with Dianeal (B) attached to a Dialy-Nate Set (C). The patient line of the Dialy-Nate Set is attached to a Tenckhoff catheter exiting from the abdominal cavity of a doll, and the drain line of the Dialy-Nate Set has a bag at the end (located at the base of the crib). |
10. Heparin
11. In-line burette set
12. Ultra-Set continuous ambulatory peritoneal dialysis (CAPD) Disposable Disconnect Y-Set or Dialy-Nate Set (Utah Medical Products, Midvale, Utah) made for patients <10 kg or fill volumes <150 mL
13. MiniCap Extended Life PD Transfer Set with Twist Clamp (Baxter, Deerfield, Illinois)
14. Medicap with Povidone-Iodine Solution
15. FlexiCap Disconnect Cap with Povidone-Iodine Solution
Nonsterile
1. Waterproof tape.
2. Baby weighing scale with low resolution (e.g., Medela, which has a resolution of 2 g from 0 to 6,000 g) or a hanging scale.
3. HomeChoice Automated PD System (minimum fill volume 150 mL) or any other reliable fluid warmer, such as the Gay-Mar Blanketrol and heating blanket. An alternative approach is to utilize a pediatric cycler set. Experience in using this equipment is necessary. We recommend a commercially available cycler that provides a minimum fill volume of 50 mL with 10-mL increments.
B. Preprocedure Care
1. Obtain informed consent.
2. Check bodyweight and abdominal girth.
3. Check for infection at the insertion site.
4. Decompress the stomach.
5. Catheterize the bladder.
6. Place preweighed diaper under the patient.
Before assembly of system, wash hands and put on a mask. All connections should be made using sterile technique. Universal precautions should be observed (see Chapter 6). Keep all tubing clamped. See Figure 59.2 for connections.
7. Prepare irrigation fluids per type of PD catheter.
8. Dwell volume for infusion = 10 to 15 mL/kg.
a. Temporary catheter: Add 500 U of heparin to each 1 L of the dialysis solution. Start with 1.5% dialysate.
b. Tunneled Tenckhoff catheter Quinton Pediatric Tenckhoff Neonatal 31-cm catheter (Kendall Healthcare, Mansfield, Massachusetts). Add 250-U heparin to each 1 L of sodium chloride 0.9% solution. Add 200-mg/L cefazolin and 8-mg/L gentamicin to sodium chloride 0.9% solution. If patient is allergic to either of those antibiotics, use vancomycin 20 mg/L.
9. Warm a liter bag of dialysate (Dianeal or other), or a larger bag if 1-L dialysate is not available, by resting it on the heating surface of the HomeChoice Automated PD System (Baxter, Deerfield, IL). You may also warm the tubing system with the Gay-Mar warmer and can hang bags as they are. The temperature can be set between 35°C and 37°C. For a newborn, keep the temperature at 37°C (in older pediatric patients, the temperature is usually set to 36°C, and occasionally to 35°C if the environmental temperature is high).
10. Spike the Dialy-Nate Set (Utah Medical Products, Midvale, Utah) into the dialysate (Dianeal or other).
11. Prime the circuit in a sterile fashion, clamp, and cap the end of the transfer set.
12. Connect the short-arm end of the Dialy-Nate Set to the twist clamp end of a MiniCap Extended Life PD Transfer Set with Twist Clamp (Baxter, Deerfield, Illinois). After surgical placement of the PD catheter, a sterile drainage bag is generally connected to the catheter. As PD is initiated, the Dialy-Nate Set is attached and the drainage bag discarded by a trained dialysis nurse.
C. Placement of a PD Catheter
The ideal technique is surgical insertion of a permanent PD catheter, which can be placed by an experienced surgeon in the neonatal intensive care unit (12). Catheters placed to exit the skin in a caudal direction carry a lower risk of peritonitis. The catheter is tunneled from the peritoneum to an exit site on the skin, which usually works well and leaks infrequently.
1. Monitor vital signs.
2. Sedate/anesthetize infant in supine position.
3. Scrub using sterile surgical procedure.
4. Prepare the skin of the abdomen (see Chapter 6).
5. Drape to expose the entire abdomen.
6. Elevate the umbilicus with two Addison graspers and incise the umbilicus with a no. 11 blade to enter into the peritoneal cavity.
7. Place a 5-mm Step trocar into the peritoneum and gain pneumoperitoneum with insufflation set based on the child’s size; insert a 5- or 4-mm 30° laparoscope.
8. On the left side of the abdomen at the lateral rectus muscle border use a no. 11 blade to incise the abdominal wall with a 2-cm incision; perform a 1-cm incision mirrored on the right side of the abdomen.
9. Use a hemostat to dilate the incision on the left, then with a laparoscopic grasper in the right side incision; feed the Tenckhoff catheter through the dilated left incision into the abdomen making sure the distal cuff is below the abdominal wall fascia but still extraperitoneal.
10. Use the right-sided grasper to place the catheter into the pelvis behind the bladder/uterus and in the pouch of Douglas.
11. Most catheters have a colored strip for orientation; take note if the strip is anterior or posterior for the intra-abdominal catheter as maintaining this orientation for the tunneled portion will keep the catheter from flipping out of the pelvis.
12. Remove the right-sided grasper; from the left side, use a hemostat to create a curved subcutaneous tunnel that will accept the proximal cuff; the tract will extend from the incision medially arching over the umbilicus.
13. In the right-sided incision, close abdominal wall fascia with a 3-0 Vicryl suture. Then pass a curved tendon grasper through the subcutaneous tissues medially arching over the top of the umbilicus, through the previously created left-sided tunnel and out the left-sided incision.
14. Orient the catheter with the strip in the proper position and then pull the catheter to the right-sided incision with the tendon grasper. Use a hemostat to assist the proximal cuff into subcutaneous tunnel and into proper position.
15. A correctly placed catheter will have a gentle curve from one side of the abdomen to the other over top of the umbilicus with no kinking. The proximal cuff will be situated in the subcutaneous tissues of the left side of the abdomen while the distal cuff will be located in the subfascial plane outside of the peritoneal lining. The colored strip on the catheter will be in the same orientation through its course to prevent any catheter twist that
could result in obstruction or flipping of the catheter outside of the pelvis. The catheter course should have at least 1 cm of subcutaneous distance between its course and the umbilical stalk. If a gastrostomy tube is present, the catheter will need a similar buffer of soft tissue.
could result in obstruction or flipping of the catheter outside of the pelvis. The catheter course should have at least 1 cm of subcutaneous distance between its course and the umbilical stalk. If a gastrostomy tube is present, the catheter will need a similar buffer of soft tissue.
16. Close the left-sided incision with running subcuticular 4-0 Monocryl suture. Remove the trocar from the umbilicus; close the umbilical fascia with 2-0 or 0 Vicryl depending on the child’s size. Close umbilical skin incision with a 4-0 Monocryl.
17. Place catheter metal fittings on the catheter and fasten them. Attach the connection tubing and test the catheter with saline. Saline should freely and quickly flow through the catheter into the abdomen and should drain as promptly.
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