Biliopancreatic Endoscopy: Practical Application

This book aims to provide the basic technology and recent advances in biliopancreatic endoscopy. The method of Endoscopic retrograde cholangiopancreatography (ERCP) is popularly applied to enlarge the papillary orifice for removal of biliary and pancreatic stones, to relieve obstruction of distal bile duct or pancreatic duct by nasobiliary / nasopancreatic drainage or stenting, and to remove the premalignant tumor of papilla in recent four decades. The diagnostic role of ERCP is already replaced by the noninvasive images such as abdominal sonography, computed tomography, magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasonography (EUS).

This book will be contributed by the senior members of the Digestive Endoscopy Society of Taiwan (DEST) who are the leading ERCPists of the medical centers and teaching hospitals in Taiwan. There are 21 chapters, including the various techniques of therapeutic ERCP and EUS, how to approach the difficult cases and prevent complications. Recently, many new facilities and techniques develop to solve the difficult problems, but those new methods may have potential hazard to the patients, particularly in the inexperienced hands. We will share our clinical experience and comments on the recent literatures, to illustrate the standard operative procedures of biliopancreatic endoscopy, and focus on the patients’ safety as well as efficacy. We hope this book will be helpful for the readers in clinical application and facilitate the junior doctors to choose the cost-effective and safe procedure to help their patients in the future.

• Language: English
• Publisher: Springer
• Release date: Feb 2, 2018
• ISBN: 9789811043673

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© Springer Nature Singapore Pte Ltd. 2018

Kwok-Hung Lai, Lein-Ray Mo and Hsiu-Po Wang (eds.)Biliopancreatic Endoscopyhttps://doi.org/10.1007/978-981-10-4367-3_1

Fundamentals of ERCP: Indications, Equipment, and Preparation

Kwok-Hung Lai¹, ², ³  

(1)

Division of Gastroenterology and Hepatology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan

(2)

School of Medicine, National Yang-Ming University, Taipei, Taiwan

(3)

Department of Medicine, National Defense Medical Center, Taipei, Taiwan

Kwok-Hung Lai

Email: [e-mail]

Abstract

Endoscopic retrograde cholangiopancreatography (ERCP) is widespread use for the clinical management of biliopancreatic disease. Even the diagnosis of most biliopancreatic diseases can be established by noninvasive imaging modalities including computed tomography (CT scan), magnetic resonance imaging (MRI), or endoscopic ultrasonography (EUS); ERCP is still required for the study of sphincter function, observation of the intraductal lesions, acquisition of specimen for histological diagnosis, and further endoscopic treatment. ERCP is considered as an invasive procedure; the experience of endoscopists and working teams is the major factor influencing the success rate. A competent ERCP endoscopist is defined as completing a minimum of 200 procedures and achieving an overall biliary cannulation rate of at least 85% [1–3]. In the teaching hospitals, the ERCPs performed by supervised trainees were reported to be as safe as the competent ERCP endoscopists [4]. Some special techniques such as double guidewire method, precut sphincterotomy, pancreatic stenting, or rendezvous method with EUS can increase the success rate of difficult ERCP, but the complication rate is higher than conventional methods even performed by the experts [5]. Screening of the patients with appropriate indications, selection of suitable methods and equipment, and well preparation before the procedures are paramount for the safety and success of ERCP.

Keywords

IndicationContraindicationEquipmentPreparationEvaluation of patientEndoscopic retrograde cholangiopancreatographyERCPDuodenoscopeCholedochoscopeEchoendoscopeCannulaGuidewireSphincterotomeBalloonDilatorStentNasobiliary catheterBrushing catheterAccessoriesHistoryPhysical examinationLaboratory testInformed consentInstructionAntiplatelet therapyAnticoagulation therapyBleeding tendencyIntracardiac deviceContrast mediumAllergyPregnancyAntibiotic prophylaxisPremedicationSedationRadiation protection

Introduction

Endoscopic retrograde cholangiopancreatography (ERCP) is widespread use for the clinical management of biliopancreatic disease. Even the diagnosis of most biliopancreatic diseases can be established by noninvasive imaging modalities including computed tomography (CT scan), magnetic resonance imaging (MRI), or endoscopic ultrasonography (EUS); ERCP is still required for the study of sphincter function, observation of the intraductal lesions, acquisition of specimen for histological diagnosis, and further endoscopic treatment. ERCP is considered as an invasive procedure; the experience of endoscopists and working teams is the major factor influencing the success rate. A competent ERCP endoscopist is defined as completing a minimum of 200 procedures and achieving an overall biliary cannulation rate of at least 85% [1–3]. In the teaching hospitals, the ERCPs performed by supervised trainees were reported to be as safe as the competent ERCP endoscopists [4]. Some special techniques such as double guidewire method, precut sphincterotomy, pancreatic stenting, or rendezvous method with EUS can increase the success rate of difficult ERCP, but the complication rate is higher than conventional methods even performed by the experts [5]. Screening of the patients with appropriate indications, selection of suitable methods and equipment, and well preparation before the procedures are paramount for the safety and success of ERCP.

Indications and Contraindications

The indications for ERCP are assessment and treatment of biliary obstruction due to common bile duct stones, benign and malignant biliary stricture, sphincter of Oddi dysfunction, recurrent pancreatitis and its complication such as stricture, stones and pseudocyst formation, ampullary tumor, and postoperative biliary leakage. The indications and types of diagnostic and therapeutic ERCP are shown in Table 1. In the patients with pancreatic and biliary cancers, ERCP is only indicated for histological diagnosis and palliative treatment of biliary obstruction when surgery is not elected. Preoperative ERCP is not required in patients undergoing cholecystectomy if there is low probability of concomitant choledocholithiasis [6, 7]. In patients with clinically suspected type 2 or 3 sphincter of Oddi dysfunction, sphincter of Oddi manometry (SOM) may be indicated after diagnostic ERCP. Bile collection for microscopic examination of crystals and parasitic ova is suggested in endemic area or clinically suspicion of stones but negative ERCP.

Table 1

Indications of diagnostic and therapeutic ERCP

The absolute contraindications include patients’ refusal, unstable cardiopulmonary, neurological or cardiovascular condition, pharyngeal or esophageal obstruction, and suspected hollow organ perforation. Relative contraindications include severe coagulopathy, pregnancy, known to have structural abnormality of upper gastrointestinal tract (e.g., stricture of esophagus, pyloric obstruction, paraesophageal herniation or volvulus, etc.), prior history of anaphylactic reaction of contrast media, inadequate preparation for endoscopic therapy, and inadequate surgical backup.

Equipment

Side-view duodenoscope with a biopsy channel ≥3.2 mm is recommended for routine ERCP. Therapeutic duodenoscope with a larger biopsy channel ≥4.2 mm is needed for special purposes such as large plastic stent insertion (≥10 Fr), mechanical lithotripsy, or choledochoscopic examination. Therapeutic end-view endoscopes, enteroscopes with/without balloon assistance, or colonoscopes can be used for patients with surgically altered anatomy. Besides the baby and spyglass choledochoscope, the ultraslim gastroscope can also be used to examine the bile duct through the enlarged papillary orifice. Therapeutic curvilinear echoendoscope is needed for EUS-guided procedures [8, 9].

Accessories including cannulas, guidewires, sphincterotomes, balloons or tapered dilators, baskets, lithotripters, plastic or metallic stents, nasobiliary catheters, brushing catheters, or injection needles should be prepared according to the therapeutic purposes. The basic technology of ERCP is selective cannulation and guidewire insertion. Most of the therapeutic ERCP procedures are performed through the guidewires. Cannulas, guidewires, and sphincterotomes are the frequently used accessories for therapeutic ERCP. Each item of accessory devices has many types, with different sizes, functions, and prices. The selection of accessories for cannulation depends on the endoscopists’ preference and financial consideration. The size and length of accessory devices must fit the endoscope, particularly the colonoscope or enteroscope with smaller working channel and longer length which was used for the patient with surg ically altered anatomy. The success rate of selective bile duct cannulation using a standard catheter with or without guidewire ranged from 66 to 81.7%, whereas the success rate by using a sphincterotome with a guidewire ranged from 84 to 97% [8, 10]. The standard catheter with or without a guidewire are limited in their ability to vary the angle to gain access into the desired duct. Although the distal end of catheter can be manipulated to make a curve before cannulation, it is sometimes difficult to selective cannulation in the patient with a prominent native papilla and its orifice faced downwardly. Although routine use of a sphincterotome with guidewire for initial cannulation and native papilla can achieve a higher success rate of selection cannulation, it may increase the medical expense if the patient is not planned for subsequent sphincterotomy. The catheter or sphincterotome with a smaller tapered tip (3 or 3.5 Fr) may improve ductal access in the minor papilla or major papilla with a small orifice. Some small tapered catheter or sphincterotomes only accommodate to a smaller caliber guidewire (0.018–0.025 in). Exchanging to a conventional catheter and larger guidewire (0.035 in.) or using a stronger 0.025 in. guidewire (e.g., Visiglide 2, Jagwire stiff) after selective cannulation may be needed if it is followed by a stent insertion or balloon dilation through a stricture or stenotic papilla. Needle knife sphincterotome should be prepared for precut sphincterotomy or fistulotomy in the patients with difficult selective cannulation of bile duct or endoscopic drainage of pancreatic pseudocyst [8–11]. Some catheters or sphincterotomes with special designs such as multiple lumens, swing tip, metal tip, dome tip, clevercut (coating of proximal cutting wire), short wire system, and preloaded with guidewire are available, but their list prices are higher than conventional accessories [10]. Several types of three lumen, water-perfused manometry catheter with a tip diameter 3.5 Fr and three side ports above the tip with 2 mm apart are used for SOM. The catheter is connected with a perfusion pump-transducer recording system for pressure measurement. Some manometry catheter can accommodate with a 0.018 in. guidewire to facilitate cannulation and maintain the duct position. A modified catheter (Lehman type) scarifies one port to allow continuous aspiration during perfusion manometry to reduce the risk of pancreatitis. The solid-state manometry catheters with three piezoelectric pressure transducers which do not use water perfusion are available. The solid-state manometry catheters can accommodate a 0.018 in. guidewire and have a radiopaque metal tip to facilitate cannulation and identify the location of catheter without contrast injection. Although the solid-state catheter is more expensive than perfusion catheter, it can be reused for 50 procedures [8, 12].

During an ERCP procedure, guidewires are used for support catheter replacement, stenting, and cytological test. They also can help for selective cannulation of bile duct. Most of the available guidewires are smooth and hydrophilic. It is necessary to flush water through all dry or contrast-filled devices before insertion of guidewire to reduce friction and facilitate guidewire passage. Endoscopists should confirm the intactness of coated guidewire before wire-guided sphincterotomy to avoid transmission of electric current to bile duct through the guidewire. Guidewire-related perforation may occur due to forcing the entry of guidewire in the patients with difficult cannulation, ampullary edema, severe biliary stricture, electric burn through the damage guidewire, or fracture of guidewire. The retroperitoneal microperforation induced by guidewire is usually asymptomatic, but fever and abdominal pain may develop in some cases [13, 14].

Endoscopic balloon dilation is the alternative method to enlarge the papillary orifice and is popularly used in Asian countries [15]. Various balloon dilators can be used to dilate the stricture of bile duct or pancreatic duct also. The diameter and length of balloon should be prepared according to the maximal bile duct or pancreatic duct size. The injection pressure and size of balloon inflation should follow the instruction of manufacturer or the fluoroscopic image.

Multiple formed stones without distal bile duct stricture can be retrieved by balloon catheters after enlargement of papillary orifice. Balloon catheters may also be used for occlusion cholangiogram or testing the adequacy of sphincterotomy. Endoscopists should avoid excessive contrast media injection, and the contrast media must be drained out after occlusion cholangiography, particularly in patients with biliary obstruction or stricture. The loose pigmented stones or big stones with tapered distal bile duct can be retrieved by a basket or lithotripter. In the patient with discrepancy between the size of stone and distal bile duct, the stone should be fragmented by a lithotripter before retrieval to avoid stone entrapped in the basket, particularly using the eight-wire or helical basket. In patients with multiple large radiopaque hard stones, electrohydraulic/laser lithotripsy or surgical intervention rather than mechanical lithotripsy is recommended. Besides the through-the-endoscope lithotripsy basket, the Soehendra external lithotripter should be prepared to rescue the entrapped basket [8, 9].

Other essential accessories used for biliopancreatic endoscopy including draining devices such as plastic or metallic stents and nasobiliary or nasopancreatic catheters, hemostatic devices such as injection needle and hemoclips (also used for closure of perforated hole), and tissue sampling devices such as biopsy forceps and cytobrush should also be available before ERCP.

Evaluation of Patients

History

Besides the experience of endoscopists, the condition of patients may also affect the success rate of ERCP. To review the background and clinical history of the patients is very important for selection of instruments and the procedures. The detailed history taking includes the presence of systemic diseases, prior gastric or biliary operation, menstrual period in female of childbearing age, implantation of cardiac pacemaker or defibrillator, history of food or drug allergy including egg and contrast media, and current use of anticoagulant, antiplatelet agents, or other drugs including vitamins, fish oil, or iron tablet. In addition, the habit of raw meat intake particularly freshwater fish is also the significant information to include the possibility of parasites infestation of hepatobiliary tract. If patients are terminally ill, endoscopists should discuss with the patients and their families for hospice care or invasive palliative procedures [16].

Physical Examinations

Endoscopists should perform a detailed physical examination including the general condition, vital signs, body weight, any operative scars, ecchymosis/petechia or edema in the skin, and thorough chest and abdominal examination. If the patient has significant cardiopulmonary disorder, they should be carefully monitored during ERCP with deep sedation. Otherwise, the patients are switched to conscious sedation or local anesthesia. In patients with hematological disorders, hepatic and renal failure, or presence of ecchymosis/petechia during physical examination, the bleeding risk during and after ERCP may be higher than normal. Hemostatic condition should be corrected to normal before ERCP and selection of procedures causing less bleeding such as endoscopic balloon dilation instead of sphincterotomy.

Laboratory Tests and Imaging Studies

The laboratory tests including complete blood count, biochemical tests such as liver and renal function, fasting blood sugar, or bacteriological studies are routine examination for clinical diagnosis and treatment. Additional tests should be performed based on the medical history, physical examination, and patient and procedural risk factors [17]. For coagulation tests including prothrombin time/international normalized ratio (INR) and partial thromboplastin time, bleeding time should be performed in the patients with clinical suspicion of bleeding tendency. Although preoperative chest radiography is generally suggested for patients older than 60 years of age, routine chest X-ray provides little help in the change of patient care preoperatively. However, a chest X-ray should be performed in patients with new respiratory signs or symptoms or decompensated heart failure. Electrocardiography is necessary in the patients who will receive deep sedation during endoscopy because some drugs such as droperidol are contraindicated in those with a prolonged QT interval. Pregnancy test may be considered in women of childbearing age who give an uncertain pregnancy history unless they have received hysterectomy or bilateral tubal ligation. Blood typing before endoscopy is indicated when a blood transfusion is considered in those patients with active bleeding or anemia [17].

Every endoscopist should review the diagnostic images including the plain KUB, CT scan, MRI, or prior cholangiograms preoperatively [16]. In the patients with a multiple large dense stones and narrow distal bile duct (Fig. 1), laparoscopic bile duct exploration rather than endoscopic treatment may be preferred. Incarceration of stone may occur in patients with anomalous connection of biliopancreatic junction or stricture of proximal bile duct; dilation of the bile duct before stone extraction is necessary.

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Fig. 1

(a) Right upper KUB showing three radiopaque densities at right upper abdomen. (b) Left upper pre-contrast CT scan showing a large very high attenuation stone in bile duct and gallbladder. (c) Right lower MRI showing a large stone with narrowing distal bile duct. (d) Left lower mechanical lithotripter has failed to fragment the radiopaque stone and the stone was entrapped

Preparation Before ERCP

Informed Consent

Biliopancreatic endoscopy is an invasive procedure. Endoscopists should obtain the written informed consent from the patients before the procedures. The informed consent process and treatment guideline may vary from the policy of each country. The details of informed consent should include (1) the medical diagnosis and treatment plan; (2) procedure name; (3) the type and risks of sedation; (4) the nature and procedure steps of the proposed procedure; (5) benefits, success rate, and potential complications of the procedures; (6) the next step of management if the procedure has failed or presence of complications; (7) prognosis and outcome if the procedure is not performed; and (8) the reasonable alternative treatment modalities [18].

ERCP is complicated and all information about the procedure should be explained by whom is responsible to the procedure. Malpractice lawsuits and claim related to the complications are sometimes the serious events for the endoscopists and hospital; it is necessary to help the patient and his/her family members to understand all the details preoperatively. The patient should have enough time to ask questions and to discuss with medical personnel who is responsible to the procedure before signing the document [6, 18].

Instructions to the Patients

The patient should discontinue the antiplatelet agents or anticoagulant 5–7 days as possible before ERCP. Patients with high risk of thromboembolic events may follow the instruction from their attending physicians. Other medications such as vitamin E, fish oil, and iron tablet which may affect the blood coagulation or monitoring of postoperative bleeding should be stopped for 5 days. Usually, patients are advised not to drink or eat for 6–8 h before ERCP to reduce the chance of vomiting during the procedure. Antihypertensive agents are allowed to administer with small amount of water 3 h before ERCP. In diabetic patients, adjustment of the doses of oral hypoglycemic agents or insulin before examination is necessary [18–20].

Special Management for Prior Antiplatelet/Anticoagulation Therapy and Potential Bleeding Tendency

Antiplatelet and anticoagulant medicines are suggested to stop for at least 1 week before therapeutic endoscopy in most Eastern countries for fear of perioperative gastrointestinal bleeding after therapeutic procedures [19]. In Western guideline, patients with high risk for thromboembolism such as recent implantation of coronary stent, prosthetic valves with atrial fibrillation, acute coronary heart disease, prior history of thromboembolic events or after cardiac surgery, aspirin may be used. Other agents such as thienopyridines (clopidogrel, ticlopidine), warfarin, or anticoagulants should be held for 5–7 days. Bridging therapy with unfractionated heparin or low molecular weight heparin may be used if the INR is <2 in very high-risk patients. However, unfractionated heparin must be held for 4 h, and low molecular weight heparin held for 12–24 h before ERCP. Anticoagulant can be resumed again within 24 h if there is no evidence of procedure-related bleeding [16, 18, 19].

Besides current use of antiplatelet/anticoagulant agents, for patients with hematological disorders, severe liver disease, renal failure, history of recurrent gastrointestinal bleeding or hematuria without definite causes, and presence of bruises or petechia over the body and limbs, a complete coagulation screening and correction of hemostatic abnormality are necessary. Intravenous vitamin K should be given to patients with obstructive jaundice and abnormal prothrombin time/INR. The foods or drugs such as animal blood, iron tablets which may mask the post-ERCP monitoring of bleeding episodes, should be avoided or discontinued. Proton pump inhibitor administration must be continued in the patients with concomitant peptic ulcer disease [17].

Intracardiac Devices Implantation

Electrocautery during sphincterotomy may induce cardiac arrhythmia in some patients who have intracardiac devices implantation such as pacemakers and defibrillators. Consulting the cardiologist should be performed before therapeutic ERCP using electrocautery. Even some of the modern devices are unaffected by the electrocautery, or being protected by a magnet, preoperative checking of the function of cardiac device and EKG monitoring until the reprogramming of the intracardiac device after the electrocautery procedure are recommended [6, 21]. The use of magnet may be not suitable in some patients with cardiac devices. Switching to other non-electrocautery method such as balloon dilation to enlarge the papillary orifice is also advised.

Allergy to Contrast Media

The adverse reactions to contrast media used during ERCP are uncommon [16]. However, patients with a history of allergy-like reaction to contrast media are with fivefolds of risk of subsequent reactions. Endoscopists should explain the risk and management of the adverse reactions to the patients before ERCP. Pretreatment with oral or intravenous steroid plus antihistamine starting the day before ERCP may be helpful to reduce the possibility of reactions. In patients with severe hypertension, diabetes mellitus, peptic ulcer, or infectious diseases, steroid should be used cautiously [6, 22, 23].

Nonionic low-osmolality contrast media is reported to have lower incidence of allergy reaction and post-ERCP pancreatitis. It may be used in the patients with an allergy history. However, there is lack of evidence to support nonionic contrast media as a method to reduce ERCP complications. The price of nonionic contrast media is more expensive than the ionic contrast media; routine use of nonionic contrast media for ERCP is unnecessary [22, 23].

In the patients with an indication for therapeutic ERCP and a history of anaphylactic shock after contrast media injection, ERCP can be tried by nonradiation method without the use of contrast media if the patients are not suitable for other treatment modalities [24].

Pregnancy

ERCP is not an absolute contraindication in pregnant women if the clinical indication is strong. But it is better to postpone ERCP until second trimester. Consulting obstetricians before ERCP is necessary to evaluate the general condition of the pregnant patients in any gestation stage. The indications of ERCP in pregnancy include biliary pancreatitis, symptomatic choledocholithiasis, cholangitis, and pancreatic or biliary injury. ERCP is contraindicated in placental abruption, imminent delivery, ruptured membrane, or poorly controlled eclampsia. Local anesthesia is preferred, but meperidine, small dose of midazolam, and propofol may be used for sedation in complicated procedures or nervous patients. Patients with pregnancy will be on left lateral position during ERCP. The drugs with category B should be used prudently during ERCP. The fetus should be protected by lead apron. The time of fluoroscopy and electrocautery should be shortened as possible. Hard copy of X-ray should be avoided. Although sphincterotomy is a safe procedure to the fetus, the electric current may transmit to the fetus through amniotic fluid. Nonradiation ERCP is another choice of treatment for the patients with pregnancy. It is performed by wire-guided method, and bile aspiration is used to confirm selective biliary cannulation, followed by sphincterotomy and/or balloon dilation to remove the bile duct stone. Clearance of bile duct can be confirmed by subsequent choledochoscopy or laboratory data. To perform the nonradiation ERCP, preoperative review of the anatomy of pancreatobiliary system through MRI is mandatory to avoid stone incarceration in the proximal duct. In the patients with unstable condition, two-stage method with temporary biliary drainage with a stent or nasobiliary catheter can shorten the procedure time, but it needs the second procedure for definite treatment [16, 24, 25].

Antibiotics Prophylaxis

In the patients with acute infection such as cholangitis or pancreatic abscess, appropriate antibiotics should be given according to the bacteriological studies until subsidence of symptoms after adequate biliary drainage. In patients without active infection before ERCP, there is no convincing evidence to support the role of routine periprocedural antibiotic administration in reducing the incidence of infectious complication after ERCP [26]. Even ERCP is not an aseptic procedure; the overall postprocedural infection rate was low (0.25%) despite limiting the antibiotic administration to 25% of the patients with probable incomplete endoscopic drainage or immunosuppression in a previous study [27]. The current guidelines for the indications of antibiotics prophylaxis before ERCP include (1) obstructed bile duct which may not be drained completely, e.g., hilar stricture, primary sclerosing cholangitis, and multiple big stones with distal bile duct stricture; (2) high-risk cardiac condition, e.g., prosthetic cardiac valve, history of endocarditis, and congenital heart disease; and (3) liver transplantation complicated with biliary stricture. In addition, antibiotics should be given immediately in patients without prophylaxis and incomplete drainage of the obstructed bile duct after ERCP. Antibiotics that cover biliary flora such as enteric gram-negative organisms should be used and continued after the procedure if biliary drainage is incomplete [26]. Addition of nonabsorbed aminoglycoside (e.g., gentamycin) to contrast media does not have significant advantage to prevent septic complications after ERCP [23, 28].

Premedication and Sedation

Antifoaming agents such as simethicone syrup 40 mg (2 cc) with small amount of water can be given orally to prevent gas bubble formation in stomach and duodenum. Intravenous injection of anticholinergic agents, e.g., scopolamine butylbromide 20–40 mg or glucagon 0.25–0.5 mg, to relax the gastrointestinal tract and sphincter of Oddi may be given prior to ERCP. In patient with glaucoma, tachyarrhythmia, benign prostate hypertrophy, or pregnancy, anticholinergic agents are contraindicated. For sphincter of Oddi manometry, those medications (such as sedatives, smooth muscle relaxants) which may influence the motility of sphincter should not be given. Rectal administration with indomethacin 100 mg within 30 min before ERCP is also suggested in some endoscopists for the purpose to prevent post-ERCP pancreatitis, but no or limited protective effect against post-ERCP pancreatitis are reported in some reports [29–31]. Routine rectal administration of rectal indomethacin before ERCP or after ERCP in high-risk patients (e.g., prolonged procedure, pancreatic duct manipulation, unsuccessful procedure, etc.) is still controversial.

ERCP is a time-consuming and unpleasant procedure; sedation and analgesia may be necessary. The methods of sedation during ERCP are individualized; it depends on the comorbidity of patients, availability of anesthesiologists or nurse anesthetists, experience of endoscopists, hospital policy, or the reimbursement from health insurance. ERCPs can be successfully performed under topical pharyngeal anesthesia and conscious sedation in previous reports [32, 33]. Topical pharyngeal sprays with xylocaine, tetracaine, or benzocaine are often used for local anesthesia. Good pharyngeal anesthesia is important to suppress gag reflux and facilitate insertion of endoscope, particularly in those patients under minimal or conscious sedation. Topical anesthetic agents have been reported with some serious adverse reactions such as aspiration, anaphylactoid reaction, and methemoglobinemia, but the incidence is low. Besides topical anesthesia of pharynx, opioids (e.g., meperidine 25–100 mg, fentanyl 25–100 μg) alone or with benzodiazepines (valium 2.5–10 mg, midazolam 1–2 mg) are the common medications used for sedation during ERCP [34–36]. The antagonists of opioids (naloxone) and benzodiazepine (flumazenil) should be available for sedation reversal if significant cardiorespiratory event develops during the ERCP procedure. The sedation reversal rate for ERCP is 1% [36]. Other medications such as diphenhydramine, promethazine, and droperidol have been used to potentiate the action of benzothiazepine, particularly in those patients who are difficult to sedate. Besides respiratory depression, some idiosyncratic reactions, such as irritability, involuntary muscle movement, seizure after midazolam administration, decrease heart rate, and muscle rigidity, after fentanyl administration have been reported [34–36, 38].

Deep sedation by propofol with anesthetic is administrated intravenously as a repeated bolus injection, continuous infusion, or a mixture of both. Deep sedation is suitable for difficult extraction of common bile duct stones. Similar to other sedatives, propofol may suppress the respiration and should be used carefully in patients with sleep apnea or concomitant with chronic cardiorespiratory diseases. Pain at the injection site is the frequent local complication after propofol injection. Propofol has a narrow therapeutic level and no available reverse agent. The incidence of adverse events was higher in patients sedated with propofol than other sedative agents [37]. Deep sedation should be performed by anesthesiologists or trained experts under close monitoring. General anesthesia with endotracheal intubation is sometimes necessary in patients difficult to sedate or having significant cardiorespiratory problem who will receive a longer ERCP procedure [34, 38].

All the endoscopic procedures under sedation should be closely monitored during ERCP until complete recovery. Direct observation of chest wall movement or respiration is difficult in patients on prone position in a dark endoscopic room under fluoroscopy. The response of patients, pulse rate, and oxygen saturation monitored by pulse oximeter are needed in minimal and conscious sedation. In prolonged procedure or deep sedation, capnography, EKG monitoring, and oxygen supplement are recommended [34, 35, 37].

Radiation Protection

Fluoroscopy is commonly used during ERCP, and the endoscopists should have the sense to protect themselves and the patients against ionizing radiation. Protection equipment include the lead shield (lead-containing glass or mobile screen), lead apron (0.5 mm thick, fully covered), lead glass, and thyroid shield. To wear the radiation dosimeter inside the apron is also important to detect the dosage of the personal radiation exposure. In a survey of the radiation exposure protection during ERCP, Only 47.4% and 55.3% of the health care providers prepare the lead eyeglass and lead shield, respectively. Only 37.8% and 61.9% of the ERCP endoscopists utilized the lead glass and lead shield, respectively [39]. However, 55% of the aprons were frontal cover-type which did not fully protect the back and the side of endoscopists. Twenty-three percent of endoscopists wore less protective apron (0.2 mm thick), and 75% of endoscopists did not monitor their own exposure dose of radiation during ERCP [40]. Education for irradiation hazard and preparation of complete radiation protection equipment for the ERCP endoscopists are essential in each hospital. In addition, coverage of reproductive organs by the lead apron is also recommended in the young patients and the pregnant women during the ERCP procedures.

Summary

The factors affecting the success and safety of ERCP are experience of endoscopists and their working team, appropriateness of indications, and perfection of preparation. The management of the patients with biliopancreatic disease is individualized. Endoscopists should review the detailed clinical history, physical, laboratory, and image findings before decision making in each patient. ERCP is an invasive and unpleasant procedure; all the decision should be fully explained to the patient and obtain the written consent before the procedure. Patients who were not feasible for ERCP should be considered for other alternative treatments such as surgical intervention. Patients with special conditions including concomitant systemic disease, potential bleeding tendency, pregnancy, intracardiac device implantation, and allergy to contrast media should be carefully investigated and managed before ERCP. Type of sedation is selected based on the complexity of the procedure, risks and tolerance of patients, and the reimbursement of insurance. The suitable equipment and accessories should be available before ERCP. There are many types of accessories in each item with various functions and prices; endoscopists should know how to choose the right accessories to help their patients without increasing the unnecessary medical expense. Radiation protection to the members of working team and patients is also an important issue for the health care providers.

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