Equipment
Endoscope (side- or forward-viewing)
The standard endoscope for ERCP is the therapeutic side-viewing duodenoscope, which has a side-viewing objective lens, a tip with four-way angulation capability, a side-positioned air/water nozzle, a 4.2-mm instrument channel, and a forceps elevator adjacent to the instrument channel outlet that allows fine linear instrument position changes (see the image below). In certain situations where a traditional duodenoscope is not suitable (eg, in patients with a Billroth II or a Roux-en-Y reconstruction), a forward-viewing endoscope may be tried instead. [37]
View of duodenoscope tip. Note that elevator is in closed position and is obscuring instrument channel from view.
Image-processing equipment
Appropriate endoscopic video processing equipment is needed in a procedure room that can also accommodate fluoroscopy. Most centers have a dedicated procedure room that incorporates either a permanent fluoroscopy table or a portable C-arm device, along with the video processing equipment specific to a particular brand of endoscope. Dual video monitors or split-screen capability must be available in the endoscopist's direct field of view; simultaneous fluoroscopic and endoscopic imaging is required for proper completion of ERCP (see the image below).
Fluoroscopic imaging in ERCP requires the injection of a radiopaque marker into either the biliary tree (cholangiography) or the pancreatic duct (pancreatography). Iodinated contrast agents are most commonly used, though noniodinated agents are also available. Undiluted contrast is appropriate for initial fluoroscopic images or when fine imaging details are desired (as in visualizing the pancreatic duct). Half-strength contrast is preferable for certain purposes, such as assessment for choledocholithiasis in a dilated bile duct.
Because of concerns over systemic uptake of iodinated contrast agents during ERCP, prophylactic steroid and diphenhydramine therapy before contrast administration is a common practice in patients with a history of hypersensitivity to such agents. Although prophylactic medication and substitution of noniodinated contrast are reasonable, a trial demonstrated no adverse reactions to iodinated contrast agents during ERCP in high-risk patients, suggesting that these preventive measures may be unnecessary in this patient population. [38]
Cannulation devices
Most endoscopists have adopted the sphincterotome as their primary cannulation device for ERCP, primarily because this device has the ability to cannulate both the biliary and pancreatic ductal system, as well as perform sphincterotomy, without having to be switched out. Most currently available sphincterotomes have multiple lumens that allow the passage of a guide wire or injection of contrast.
Current sphincterotomes also have a cutting wire of varying length that both allows coagulative cutting and has the ability to alter the curvature of the radiopaque tip of the device. Tension can be applied to the cutting wire via an operator-controlled handle, which causes the tip of the sphincterotome to bow (see the image below); this ability to bow and unbow the tip of the device can facilitate cannulation and cutting. Different tip diameters and degrees of taper are also available, depending on the clinical situation.
Once the sphincterotome is in the proper position, most endoscopists use a wire-guided approach to cannulation, in which a guide wire is passed through one of the sphincterotome lumens and into either the common bile duct (CBD) or the pancreatic duct before contrast injection. This approach not only facilitates acquisition of ductal access but also allows accessories to be more safely passed into the ductal system over the wire.
Many different guide wires are available from several different manufacturers. They vary with respect to diameter (0.018-0.035 mm), length (260-cm short wire or 450-cm long wire), degree of rigidity, outer coating material, tip angle, and even bending or coiling tendency with the application of pressure. By taking these characteristics into account, one can readily choose the appropriate wire for a specific situation.
The cannulation catheter is a more traditional tool, which some endoscopists still prefer to the sphincterotome. A cannulation catheter is similar to a sphincterotome in that it often contains multiple lumens for contrast injection or wire passage and a radiopaque tip. It differs from a sphincterotome in that it has no cutting wire but can include a specialized tip (eg, a ball tip or needle tip) that can facilitate passage of the catheter into a duct with a particular structural property.
Therapeutic accessories
Once access to either the biliary or the pancreatic ductal system is gained, various accessories can be passed over the wire for use in therapeutic interventions. These accessories include tools that are specific to a certain indication, such as stone extraction balloons (see the video below) or baskets (see the first image below), stricture dilating balloons or catheters (see the second image below), stents of various types (see the third image below), cytopathology brushes, and even cholangioscopes for intraductal visualization.
Biliary stents. Upper stent is plastic stent; lower stent is self-expanding metal stent (SEMS).
Protective gear
All personnel within the ERCP procedural area should be protected from the scattered radiation produced by the fluoroscopy unit. Standard protective apparel includes a lead apron and a thyroid shield with a lead thickness of 0.2-0.5 mm. Two-piece lead apparel in the form of a skirt and vest is also available, depending on the wearer's preference. The use of leaded radiation safety glasses is also advocated; repeated radiation exposure to the eye can be hazardous. [39]
Additional protective gear recommended for use during ERCP includes a face shield, surgical gloves and gown, and shoe covers if desired.
Patient Preparation
Anesthesia
Acceptable regimens for achieving adequate sedation in patients undergoing ERCP vary by medical center and by provider and may also be dictated by the laws pertaining to anesthetic administration in a certain geographic region. The most common sedation protocol includes the use of a nurse-administrated or physician-administered intravenous (IV) benzodiazepine (eg, midazolam) along with an IV narcotic (eg, meperidine).
Meperidine is commonly used because of its longer half-life and deeper sedative properties and because of the traditional belief that other narcotic agents (eg, fentanyl or morphine) may be associated with contraction of the sphincter of Oddi. A prospective, randomized, double-blinded trial demonstrated no difference in papillary cannulation rates between patients receiving propofol plus fentanyl and those receiving propofol alone. [40] Thus, fentanyl may be a reasonable alternative to meperidine, especially in patients who are allergic to meperidine.
For patients in whom deep sedation may be difficult to achieve with this approach (eg, those who use recreational or medicinal narcotics, alcohol, or sedatives and those who have a history of difficult sedation), general anesthesia should be considered. Many medical centers use an anesthetist to administer a general anesthetic agent (eg, propofol) in this scenario.
Certain states also allow trained nurses or gastrointestinal (GI) endoscopists to administer propofol. This trend may increase, now that nurse-administered propofol has been shown to be as safe as administration of midazolam plus meperidine for therapeutic endoscopic procedures. [41] The benefits of propofol, as compared with other agents, include rapid onset of action, deep sedation, and relatively rapid recovery.
Regardless of the anesthetic regimen, sedated patients are typically monitored by a nurse for respiratory and cardiovascular status during ERCP. Any of the agents mentioned above can be associated with respiratory or cardiovascular compromise; thus, antagonist agents (eg, naloxone for narcotics and flumazenil for benzodiazepines) should be readily available to the monitoring personnel. Antimotility medications (eg, glucagon) are also commonly used during ERCP to decrease bowel contractions/motility and facilitate proper visualization and cannulation of the ampulla in a patient with brisk duodenal peristalsis.
Positioning
The prone position (see the image below) is standard for ERCP because it offers the best access for anterior-posterior fluoroscopic imaging.
Some endoscopists prefer the semiprone position (see the image below). Although this position may not yield optimal image quality, it may be preferable for certain patients (eg, those who are obese or have respiratory compromise). Some endoscopists also find it easier to pass the duodenoscope into the small bowel while the patient is in this position.
The supine position (see the image below) may also be used for ERCP. Indications for the use of this position include endoscopist preference, comorbid conditions, pregnancy, and any factor that necessitates closer airway monitoring during the procedure.
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View of duodenoscope tip. Note that elevator is in closed position and is obscuring instrument channel from view.
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Fluoroscopy table and dual-screen procedure monitors.
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Sphincterotome in bowed position.
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Two different sizes of biliary stone baskets.
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Biliary stricture–dilating balloon catheter.
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Prone position.
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Semiprone position.
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Supine position.
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Endoscopic view of major duodenal papilla.
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Cholangiogram. Note (a) duodenoscope positioned in duodenum with tip at distal aspect of common bile duct and (b) moderately dilated bile duct.
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Biliary stents. Upper stent is plastic stent; lower stent is self-expanding metal stent (SEMS).
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Fluoroscopic image of plastic stent in bile duct. Also note guide wire adjacent to stent in bile duct.
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This video, captured via endoscopic retrograde cholangiopancreatography, shows side-viewing duodenoscope being inserted and advanced into stomach and duodenum. Scope is then reduced into short position, bringing ampulla into view. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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This video, captured via endoscopic retrograde cholangiopancreatography, shows engagement and cannulation of ampulla using biliary cannulation catheter. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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This video, captured via endoscopic retrograde cholangiopancreatography, shows sphincterotomy being performed. Sphincter of Oddi is being cut by using electrocautery applied to biliary cannulation catheter. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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This video, captured via endoscopic retrograde cholangiopancreatography, shows cannulation of ampulla. Guide wire is then advanced, as seen on fluoroscopy, and wire makes right turn into pancreatic duct. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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This video, captured via endoscopic retrograde cholangiopancreatography, shows cannulation of common bile duct (CBD). Dye is then injected, and CBD is seen on fluoroscopy; there are filling defects suggestive of stones within duct. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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This video, captured via endoscopic retrograde cholangiopancreatography, shows insertion of biliary extraction balloon over guide wire. Sweeps of common bile duct (CBD) are made with extraction balloon to remove stones, sludge, and debris from CBD. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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This video, captured via endoscopic retrograde cholangiopancreatography, shows placement of biliary stent into common bile duct. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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Endosonography-guided cholangiopancreatography. Used with permission from Baishideng Publishing Group, Inc (Fig 1 from Perez-Miranda M, de la Serna C, Diez-Redondo P, Vila JJ. Endosonography-guided cholangiopancreatography as a salvage drainage procedure for obstructed biliary and pancreatic ducts. World J Gastrointest Endosc. Jun 16 2010;2(6):212-22).
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Biliary obstruction secondary to chronic pancreatitis. Used with permission from the Johns Hopkins Division of Gastroenterology and Hepatology (www.hopkinsmedicine.org/gi). Illustration Copyright© 1998-2003 by The Johns Hopkins Health System Corporation and The Johns Hopkins University. Illustration created by Mike Linkinhoker.
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Technique for pancreatic stone extraction. Used with permission from the Johns Hopkins Division of Gastroenterology and Hepatology (www.hopkinsmedicine.org/gi). Illustration Copyright© 1998-2003 by The Johns Hopkins Health System Corporation and The Johns Hopkins University. Illustration created by Mike Linkinhoker.
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(A) Biliary sphincterotomy and stent placement; (B) corresponding endoscopic retrograde cholangiopancreatography (ERCP) film. Used with permission from the Johns Hopkins Division of Gastroenterology and Hepatology (www.hopkinsmedicine.org/gi). Illustration Copyright© 1998-2003 by The Johns Hopkins Health System Corporation and The Johns Hopkins University. Illustration created by Mike Linkinhoker.
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Pancreatic stent placement for pseudocyst drainage. Used with permission from the Johns Hopkins Division of Gastroenterology and Hepatology (www.hopkinsmedicine.org/gi). Illustration Copyright© 1998-2003 by The Johns Hopkins Health System Corporation and The Johns Hopkins University. Illustration created by Mike Linkinhoker.
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Side-viewing endoscope. Used with permission from the Johns Hopkins Division of Gastroenterology and Hepatology (www.hopkinsmedicine.org/gi). Illustration Copyright© 1998-2003 by The Johns Hopkins Health System Corporation and The Johns Hopkins University. Illustration created by Mike Linkinhoker.
