ERCP in Children

Patient and Family Preparation

Preparation for high-risk procedures in children involves preparing both the child and the parents or guardians. This process may resemble preparation for adults who are elderly or disabled and dependent on the assistance of family for medical decision making. The current and past medical history must be carefully reviewed to include prior anesthesia and operative history, current medications, and allergies to medications, contrast agents, and latex. Problems that may have followed a prior similar procedure should be reviewed to identify opportunities for improvement or risk reduction. Additional vulnerabilities that are unique or more common in children include behavioral issues such as exaggerated fears, emotional lability, oppositional behavior, occult metabolic or hematologic conditions, undiscovered congenital abnormalities, and thermal instability in young infants. A detailed family history assumes greater importance for young children undergoing their first procedure, because anesthetic risk attributable to hereditary conditions such as malignant hyperthermia or other metabolic disorders may be revealed.

Infants are unusually sensitive to seemingly minor hemorrhage because of their small total circulating blood volume. Supportive blood products should be held in reserve for procedures in which significant bleeding may develop. Infants are also more vulnerable to compromised ventilation when excessive insufflation restricts movement of the diaphragm or an endoscope compresses the relatively soft trachea.

Older children and adolescents may join their parents in the process of obtaining informed consent for a procedure. The parents must understand the potential risks, benefits, and alternatives and be offered additional consultation with a surgeon or interventional radiologist when appropriate. Families are most reassured by a team management approach.

Procedure Environment

The procedure environment must have equipment and staff available to support complex therapeutic procedures and adverse events that might arise. Busy adult endoscopy units have highly experienced staff who can anticipate and efficiently assist with the technical aspects of ERCP. Pediatric units and their staff are disadvantaged by the relative infrequency of this procedure. Periodic review of basic principles, hands-on simulation, and consistent staff participation can build and reinforce skills and improve teamwork in a pediatric unit. Ideally, recovery unit nurses with pediatric experience should be available to recognize emerging problems and expedite supportive care. Although ERCP can be performed safely on an ambulatory or outpatient basis, overnight hospital admission for observation of children is advisable because the signs and symptoms of adverse events can evolve many hours after the procedure and may not be reliably reported or recognized early by a child. Immediate access to subspecialty consultation by pediatric anesthesiologists, gastroenterologists, surgeons, and radiologists is essential when providing safe and effective care.

Endoscopist

Who should perform pediatric ERCP relates to issues of skill, knowledge, and environment. High-volume ERCP and advanced endoscopic skills reside within adult medicine centers of excellence supported by experienced assistants with abundant accessories, ensuring the likelihood of technical success. However, technical success alone may not be sufficient for optimal care of children. Pediatricians have important clinical knowledge about when and how to use ERCP in a particular child or situation, but they may be excluded from important decision making once a child is transferred to an adult medicine facility. Endoscopists who have an adult practice are reluctant to perform ERCP in a pediatric facility where properly trained assistants and an adequate inventory of accessories may be lacking. Adult and pediatric endoscopists must consider these factors and the availability of alternative therapy before embarking on ERCP in pediatric patients.

Pediatric endoscopists who seek training in ERCP require either supplemental training with adult patients or a very long training period with pediatric patients to achieve experience with several hundred procedures, a number shown to correlate with achieving technical success in adult patients. The volume and complexity of cases required to achieve a comparable level of initial competence and, importantly, to maintain competence in pediatric ERCP are unknown. A special interest group (SIG) of pediatric endoscopists performing ERCP in tertiary care centers around the world was recently formed under the sponsorship of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN). Members of this SIG are collaborating on a prospective multicenter database that will soon provide information about technical success and clinical outcomes when ERCP is performed by pediatric endoscopists.

Sedation

Most pediatric gastroenterologists prefer general anesthesia or deep sedation for technically challenging procedures in children. This is similar to a trend toward more frequent use of deep sedation and anesthesia in adults undergoing particularly uncomfortable or lengthy endoscopic procedures. Although ERCP in older children and adolescents may be performed successfully with intravenous moderate sedation, general anesthesia with endotracheal intubation affords safer airway management with assured analgesia and hypnosis during a potentially lengthy or difficult procedure. Once the airway has been secured, either prone or supine positioning can be safely used; when the prone position is selected, adequate use of padding and bolsters allows for sufficient chest excursion and reduced abdominal compression.

Fluoroscopy (see Chapter 3 )

Children are more vulnerable than adults to radiation injury during fluoroscopy. They are more sensitive to the effects of radiation, have a longer life expectancy than adults during which the long-term adverse events from exposure (stochastic effects) such as cancer may evolve, and may receive unnecessary high-dose radiation exposure if equipment is not adjusted for a smaller body. Therefore the assistance of a radiation technologist with pediatric experience for equipment support and the availability of a radiologist with pediatric training for consultation are critically important for safe and effective fluoroscopy during ERCP. The desire for high-resolution imaging must be balanced against the risk of greater radiation exposure to the child.

Fluoroscopy for pediatric ERCP may be performed using a fixed table in a dedicated fluoroscopy suite or a portable C-arm in a separate procedure room. The advantages of the C-arm device are portability, lower cost, and easier oblique imaging. Modern digital devices provide excellent image quality. The x-ray equipment should be adjusted to accommodate the smaller body of a young child and reduce the radiation dose rate. Shielding of reproductive organs is important and should be performed for all patients. Good fluoroscopic technique by the examiner can minimize radiation exposure to the child and to personnel (see also Chapter 3 ). The following rules or principles will help advance this goal: (1) position the child so that the beam takes the shortest distance through the body—that is, avoid unnecessary oblique projection; (2) position the image intensifier or receptor above the patient; (3) minimize the distance of the intensifier and maximize the distance of the x-ray tube to the child's body; (4) use the least magnification necessary and use field collimators to focus on areas of interest; (5) avoid the use of a grid; (6) minimize beam-on time and use the slowest pulse rates that produce acceptable imaging for a given task; and (7) use the “last image hold” feature when capturing images to avoid additional exposure. Either low-osmolar nonionic or high-osmolar water-soluble contrast media in the range of 150 to 300 mg/mL may be used.

Supplemental Medications

Drug dosing for children is based on units per kilogram body weight ranging up to maximum adult doses. In addition to limited use for endocarditis prophylaxis, antibiotics are recommended for high-grade biliary or pancreatic duct obstruction, biliary or pancreatic duct disruption, and pancreatic fluid collections (see also Chapter 10 ). Ampicillin/sulbactam (100 to 200 mg/kg/day intravenous [IV] divided every 6 hours, maximum 4 g sulbactam per day), a broad-spectrum cephalosporin such as cefazolin (50 to 100 mg/kg/day IV divided every 8 hours, maximum 6 g/day), or a fluoroquinolone such as ciprofloxacin (20 to 30 mg/kg/day IV divided every 12 hours, maximum 800 mg/day) is usually adequate. Intravenous glucagon can be used to briefly reduce duodenal contractions during cannulation. A dose of 0.25 to 0.5 mg IV is appropriate for most ages and can be repeated. Intravenous secretin 0.2 mcg/kg may be used to facilitate successful cannulation of the minor papilla (see Chapter 21 ). The efficacy of rectal indomethacin for prevention of post-ERCP pancreatitis in children has not been studied. However, given the low risk of single-dose administration and the potential benefit extrapolated from adult data (see Chapter 8 ), rectal indomethacin should be considered for use in children. This author uses the dose of rectal indomethacin, 2 mg/kg (maximum 100 mg), for all children undergoing ERCP unless performed during an episode of acute pancreatitis. This can be achieved by cutting 50 mg rectal suppositories and using 2 mL of a 5 mg/mL liquid oral suspension for rectal administration in children under 10 kg.

Endoscopic Equipment

Although there are no duodenoscopes specifically designed for use in children, patients of all ages and sizes, including full-term neonates, can undergo diagnostic and therapeutic ERCP using duodenoscopes that are commercially available. Standard diagnostic duodenoscopes with insertion tube diameters in the range of 11 to 12 mm can be used effectively in children older than 2 years and with difficulty between 1 and 2 years of age. These endoscopes generally have operating channels that will accommodate catheters and stents up to 7 to 8 Fr, which is adequate for most interventions. Whereas “therapeutic” duodenoscopes containing operating channels in excess of 4 mm are needed to place 10-Fr stents, such large endoprostheses are rarely needed in young children. These larger endoscopes are easily used in most adolescents.

Neonates and infants require a small-diameter instrument in the range of 7 to 8 mm that will pass easily through the pylorus and allow effective positioning of the tip adjacent to the major papilla. Currently, there is only one commercially available duodenoscope suitable for use in small infants, the PJF-160 (Olympus America, Inc., Lehigh Valley, PA). This endoscope has a working length of 1240 mm, a maximum distal tip diameter of 7.5 mm, an operating channel diameter of 2.0 mm, an elevator, and a noninsulated metal tip. The length is poorly suited for use in small infants ( Fig. 29.1 ). Basic diagnostic and therapeutic maneuvers are possible with this endoscope, although the repertoire of available accessories that will fit through the small operating channel is limited. Catheter tips that taper to a diameter of 3 to 4 Fr are helpful in order to selectively cannulate biliary and pancreatic ducts in infants. However, deep selective cannulation into normal ducts is not always possible in young infants because of their narrow caliber. An ultratapered (3.5 Fr) cannula, a retrieval balloon catheter, and a wire basket catheter that will fit the 2.0-mm channel of the PJF-160 duodenoscope are available from Olympus. Other highly tapered cannulas such as the precurved Glo-Tip (GT-5-4-3) (Cook Endoscopy, Winston-Salem, NC) may be used. A tapered-tip sphincterotome catheter with a short cutting wire such as the UTS-15 (Cook Endoscopy) can be advanced with some resistance through the operating channel of the PJF-160 endoscope. Olympus does not endorse the use of this endoscope for sphincterotomy because of the potential risk of thermal injury from electrical current conducted through the metal tip. Nonetheless, this author and others have used this instrument for sphincterotomy without incident.

Equipment for irrigation and hemostasis must be readily available when performing therapeutic ERCP. The 2.0-mm operating channel of the PJF-160 endoscope is too narrow for hemostatic clip devices and bipolar cautery probes, but small-diameter (1.8 mm) sclerotherapy catheters (Boston Scientific Corp., Marlborough, MA) and small-diameter (1.5 mm) argon plasma coagulation catheters (Erbe USA, Inc., Marietta, GA) can be used for injection and cautery hemostasis, respectively.

CO ₂ insufflation substituted for air insufflation may reduce the risk of abdominal distension in infants and air embolism. Although air embolism is rarely reported in pediatric endoscopy, CO ₂ embolism may be better tolerated based on animal studies. This author uses CO ₂ insufflation for all ERCPs.