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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Sprache: Englisch
Translated into seven languages, Cotton and Williams' Practical Gastrointestinal Endoscopy has for the last 25 years been the basic primer for endoscopy around the world, providing clear, clinical and practical guidance on the fundamentals of endoscopy practice, from patient positioning and safety, how to perform different endoscopic procedures, and the latest in therapeutic techniques and advances in technology.
It's key strength and reason for its popularity is its step-by-step, practical approach, especially with the use of outstanding colour artwork to illustrate the right and wrong ways to perform endoscopy. Add to this the weight and expertise of its author team, led by Peter Cotton and Christopher Williams, and the final result is an essential tool for all gastroenterologists and endoscopists, particularly trainees looking to improve their endoscopic technique.
Joining Peter Cotton, Christopher Williams and Brian Saunders in the seventh edition are two exciting stars in UK and US endoscopy, Adam Haycock and Jonathan Cohen. New to this edition are:
- Approximately 35 high-quality videos illustrating optimum endoscopy practice, all referenced via “video eyes” in the text
- Self-assessment MCQs to test main learning points
- An online clinical photo imagebank to complement the line illustrations, perfect for downloading into scientific presentations
- Key learning points in every chapter
- Much more information on mucosal resection techniques and small bowel endoscopy—for capsule and “deep” enteroscopy
- The latest recommendations and guidelines from the ASGE, ASG, UEGW and BSG.
Cotton and Williams' Practical Gastrointestinal Endoscopy, seventh edition is fully modernised, masterful as ever, and once again, the number one endoscopy manual for a whole new generation of gastroenterologists and endoscopists.
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Veröffentlichungsjahr: 2013
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Table of Contents
Title page
Copyright page
List of Video Clips
Preface to the Seventh Edition
Preface to the First Edition
Acknowledgments
About the Companion Website
CHAPTER 1: The Endoscopy Unit, Staff, and Management
Endoscopy units
Staff
Management, behavior, and teamwork
Documentation and quality improvement
Educational resources
CHAPTER 2: Endoscopic Equipment
Endoscopes
Endoscopic accessories
Ancillary equipment
Electrosurgical units
Lasers and argon plasma coagulation
Equipment maintenance
Infection control
Cleaning and disinfection
CHAPTER 3: Patient Care, Risks, and Safety
Patient assessment
Patient education and consent
Physical preparation
Monitoring
Medications and sedation practice
Recovery and discharge
Managing an adverse event
CHAPTER 4: Upper Endoscopy: Diagnostic Techniques
Patient position
Endoscope handling
Passing the endoscope
Routine diagnostic survey
Problems during endoscopy
Recognition of lesions
Specimen collection
Diagnostic endoscopy under special circumstances
CHAPTER 5: Therapeutic Upper Endoscopy
Benign esophageal strictures
Achalasia
Esophageal cancer palliation
Gastric and duodenal stenoses
Gastric and duodenal polyps and tumors
Foreign bodies
Acute bleeding
Enteral nutrition
CHAPTER 6: Colonoscopy and Flexible Sigmoidoscopy
History
Indications and limitations
Informed consent
Contraindications and infective hazards
Patient preparation
Medication
Equipment—present and future
Anatomy
Insertion
Handling—“single-handed,” “two-handed,” or two-person?
Sigmoidoscopy—accurate steering
Endoscopic anatomy of the sigmoid and descending colon
Sigmoidoscopy—the bends
Sigmoidoscopy—the loops
Diverticular disease
Descending colon
Splenic flexure
Transverse colon
Hepatic flexure
Ascending colon and ileo-cecal region
Examination of the colon
Stomas
Pediatric colonoscopy
Per-operative colonoscopy
CHAPTER 7: Therapeutic Colonoscopy
Equipment
Polypectomy
Other therapeutic procedures
CHAPTER 8: Resources and Links
Websites
Epilogue: The Future? Comments from the Senior Authors
Intelligent endoscopes
Colonoscopy—boon or bubble?
Advanced therapeutics, cooperation, and multidisciplinary working
Quality and teaching
Index
This edition first published 2014© 1980, 1982, 1990, 1996, 2003 by Blackwell Publishing Ltd, 2008 by Peter B Cotton, Christopher B Williams, Robert H Hawes and Brian P Saunders, 2014 by John Wiley & Sons, Ltd.
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Library of Congress Cataloging-in-Publication Data
Haycock, Adam, author.
Cotton and Williams’ practical gastrointestinal endoscopy : the fundamentals / Adam Haycock, Jonathan Cohen, Brian P. Saunders, Peter B. Cotton, Christopher B. Williams ; videos supplied by Stephen Preston.—7th edition.
p. ; cm.
Practical gastrointestinal endoscopy
Preceded by: Practical gastrointestinal endoscopy / Peter B. Cotton . . . [et al.]. 6th ed. 2008.
Includes bibliographical references.
ISBN 978-1-118-40646-5 (cloth)
I. Cohen, Jonathan, 1964– author. II. Saunders, Brian P., author. III. Cotton, Peter B., author. IV. Williams, Christopher B. (Christopher Beverley), author. V. Title. VI. Title: Practical gastrointestinal endoscopy.
[DNLM: 1. Gastrointestinal Diseases–diagnosis. 2. Endoscopy–methods. 3. Gastrointestinal Diseases–surgery. WI 141]
RC804.G3
616.3'307545–dc23
2013041985
A catalogue record for this book is available from the British Library.
Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.
Cover image: background image from the authors, inset images by David Gardner
Cover design by Sarah Dickinson
List of Video Clips
Chapter 1
Video 1.1 The endoscopy unit: A virtual tour
Chapter 4
Video 4.1 Endoscopic view of direct vision insertion
Video 4.2 Full insertion and examination
Chapter 6
Video 6.1 History of colonoscopy
Video 6.2 Variable shaft stiffness
Video 6.3 ScopeGuide magnetic imager: The principles
Video 6.4 Embryology of the colon
Video 6.5 Insertion and handling of the colonoscope
Video 6.6 Steering the colonoscope
Video 6.7 Magnetic imager: An easy spiral loop
Video 6.8 Sigmoid loops
Video 6.9 Magnetic imager: Short and long “N”-loops
Video 6.10 Magnetic imager: “Alpha” spiral loops
Video 6.11 Magnetic imager: “Lateral view” spiral loop
Video 6.12 Magnetic imager: Flat “S”-loop in a long sigmoid
Video 6.13 Descending colon
Video 6.14 Splenic flexure
Video 6.15 Transverse colon
Video 6.16 Magnetic imager: Shortening transverse loops
Video 6.17 Magnetic imager: Deep transverse loops
Video 6.18 Magnetic imager: “Gamma” looping of the transverse colon
Video 6.19 Hepatic flexure
Video 6.20 Ileo-cecal valve
Video 6.21 Examination
Video 6.22 Normal appearances
Video 6.23 Abnormal appearances
Video 6.24 Post surgical appearances
Video 6.25 Infective colitis
Video 6.26 Crohn's Disease
Chapter 7
Video 7.1 Stalked polyps
Video 7.2 Small polyps
Video 7.3 Polypectomy: EMR
Video 7.4 Piecemeal polypectomy
Video 7.5 Endoloop
Video 7.6 Tattoo
Video 7.7 Postpolypectomy bleed with therapy
Video 7.8 APC for angiodysplasia and polyp eradication
Preface to the Seventh Edition
Gastrointestinal endoscopy continues to evolve and has seen a steady increase in demand, complexity, and innovation in what it is possible to do with an endoscope. It is now the undoubted investigation of choice for the GI tract, although there is no room for complacency. Parallel improvements in imaging capabilities such as MRCP and CT colonography are now impacting on the “diagnostic” endoscopy workload, and much of the current emphasis is on advancing endoluminal, transluminal, and hybrid therapeutic techniques.
The ongoing adoption of national bowel cancer screening programs has driven up standards for endoscopists across the board. Increasing recognition of the importance of identifying even small, subtle premalignant dysplastic lesions and the ability to provide complex therapeutic intervention in both the upper and lower GI tract has made the learning process even more lengthy and difficult for those new to the field. Accordingly, the “fundamentals” no longer refers solely to basic or simple procedures, if indeed it ever did. In this era of increasing complexity of endoscopy and increasing attention to quality performance, the fundamental skills that constitute the foundation of all endoscopic practice have never been more important to master.
In line with the last edition, we have limited this book to the most common diagnostic and therapeutic “upper” and “lower” GI procedures, reserving more advanced techniques such as ERCP and EUS for others to cover. What is new to this edition is acknowledgement of the enormous impact of the Internet and electronic “e-learning.” This edition is supported by a selection of online multimedia images and clips, which are signposted in the text and referenced at the end of each chapter. To allow for greater use of mobile platforms, each chapter has been reconfigured into a more easily digestible “bite-sized” chunk with its own key learning points and searchable keywords. Multiple-choice questions (MCQs) are also available online to allow self-assessment and consolidate learning.
We also formally acknowledge with this edition what has been common parlance for years—that this book is “Cotton and Williams′” fundamentals of gastrointestinal endoscopy, sharing personal opinions, tips, and tricks gained over many years. Although this is the last edition in which these two pioneering authors will actively participate, this textbook will remain a practical guide squarely based on their practice and principles. It has been our privilege to work with them to produce this edition, and we are honored to have been asked to sustain this important effort in the future.
Practical Gastrointestinal Endoscopy: The Fundamentals aims to complement rather than replace more evidence-based recommendations and guidelines produced by national societies. It remains focused on helping those in the first few years of experience to move more quickly up the learning curve toward competency. We hope that it will inspire trainees to attain the levels of excellence represented by those individuals from whom the book takes its name.
Adam Haycock
Jonathan Cohen
Brian P Saunders
Preface to the First Edition
This book is concerned with endoscopic techniques and says little about their clinical relevance. It does so unashamedly because no comparable manual was available at the time of its conception and because the explosive growth of endoscopy has far outstripped facilities for individual training in endoscopic technique. For the same reason we have made no mention of rigid endoscopes (oesophagoscopes, sigmoidoscopes and laparoscopes) which rightly remain popular tools in gastroenterology, nor have we discussed the great potential of the flexible endoscope in gastrointestinal research.
Our concentration on techniques should not be taken to denote a lack of interest in results and real indications. As gastroenterologists we believe that procedures can only be useful if they improve our clinical management; clever techniques are not indicated simply because they are possible, and some endoscopic procedures will become obsolete with improvements in less invasive methods. Indeed we are moving into a self-critical phase in which the main interest in gastrointestinal endoscopy is in the assessment of its real role and cost-effectiveness.
Gastrointestinal endoscopy should be only one of the tools of specialists trained in gastrointestinal disease—whether they are primarily physicians, surgeons or radiologists. Only with broad training and knowledge is it possible to place obscure endoscopic findings in their relevant clinical perspective, to make realistic judgements in the selection of complex investigations from different disciplines, and to balance the benefits and risks of new therapeutic applications. Some specialists will become more expert and committed than others, but we do not favour the widespread development of pure endoscopists or of endoscopy as a sub-specialty.
Skilful endoscopy can often provide a definitive diagnosis and lead quickly to correct management, which may save patients from months or years of unnecessary illness or anxiety. We hope that this little book may help to make that process easier and safer.
April 1979
P.B.C., C.B.W.
Acknowledgments
The authors are grateful to the dedicated collaborators who have embellished or enabled the production of this book.
The skills of Steve Preston ([email protected]) produced the web videos and imagery. The artistry and great patience of David Gardner ([email protected]) has allowed upgrading of the drawings and figures in this edition and several previous ones. At Wiley publishers, the guidance of Oliver Walter, backed by Rebecca Huxley's formidable editorial talents, has made the production process almost enjoyable.
The authors also wish to register indebtedness to their respective life-partners (Cori, Sarah, Annie, Marion and Christina) for their unending support—despite intrusions into personal and family time.
About the Companion Website
This book is accompanied by a website:
www.wiley.com/go/cottonwilliams/practicalgastroenterology
The website includes:
37 videos showing procedures described in the bookAll videos are referenced in the text where you see this logo A clinical photo imagebank, consisting of an equivalent clinical photo for selected line illustrationsAn interactive “check your understanding” question bank (MCQs) to test main learning points in each chapterCHAPTER 1
The Endoscopy Unit, Staff, and Management
Most endoscopists, and especially beginners, focus on the individual procedures and have little appreciation of the extensive infrastructure that is now necessary for efficient and safe activity. From humble beginnings in adapted single rooms, most of us are lucky enough now to work in large units with multiple procedure rooms full of complex electronic equipment, with additional space dedicated to preparation, recovery, and reporting.
Endoscopy is a team activity, requiring the collaborative talents of many people with different backgrounds and training. It is difficult to overstate the importance of appropriate facilities and adequate professional support staff, to maintain patient comfort and safety, and to optimize clinical outcomes.
Endoscopy procedures can be performed almost anywhere when necessary (e.g. in an intensive care unit), but the vast majority take place in purpose-designed “endoscopy units.”
Endoscopy units
Details of endoscopy unit design are beyond the scope of this book, but certain principles should be stated.
There are two types of unit. Private clinics (called ambulatory surgical centers in the USA) deal mainly with healthy (or relatively healthy) outpatients, and should resemble cheerful modern dental suites. Hospital units have to provide a safe environment for managing sick inpatients, and also more complex procedures with a therapeutic focus, such as endoscopic retrograde cholangiopancreatography (ERCP). The more sophisticated units resemble operating suites. Units that serve both functions should be designed to separate the patient flows as far as possible.
The modern unit has areas designed for many different functions. Like a hotel or an airport (or a Victorian household), the endoscopy unit should have a smart public face (“upstairs”), and a more functional back hall (“downstairs”). From the patient's perspective, the suite consists of areas devoted to reception, preparation, procedure, recovery, and discharge. Supporting these activities are many other “back hall” functions, which include scheduling, cleaning, preparation, maintenance and storage of equipment, reporting and archiving, and staff management.
Procedure rooms
The rooms used for endoscopy procedures should:
not be cluttered or intimidating. Most patients are not sedated when they enter, so it is better for the room to resemble a modern dental office, or kitchen, rather than an operating room.be large enough to allow a patient stretcher/trolley to be rotated on its axis, and to accommodate all of the equipment and staff (and any emergency team), but also compact enough for efficient function.be laid out with function in mind, keeping nursing and doctor spheres of activity separate (Fig 1.1), and minimizing exposed trailing electrical cables and pipes (best by ceiling-mounted beams).Fig 1.1 Functional planning—spheres of activity.
Each room should have:
piped oxygen and suction (two lines);lighting planned to illuminate nursing activities but not dazzle the patient or endoscopist;video monitors placed conveniently for the endoscopist and assistants, but also allowing the patient to view, if wished;adequate counter space for accessories, with a large sink or receptacle for dirty equipment;storage space for equipment required on a daily basis;systems of communication with the charge nurse desk, and emergency call;disposal systems for hazardous materials.Patient preparation and recovery areas
Patients need a private place for initial preparation (undressing, safety checks, intravenous (IV) access), and a similar place in which to recover from any sedation or anesthesia. In some units these functions are separate, but can be combined to maximize flexibility. Many units have simple curtained bays, but rooms with solid side walls and a movable front curtain are preferable. They should be large enough to accommodate at least two people other than the patient on the stretcher, and all of the necessary monitoring equipment.
The “prep-recovery bays” should be adjacent to a central nursing workstation. Like the bridge of a ship, it is where the nurse captain of the day controls and steers the whole operation, and from which recovering patients can be monitored.
All units should have at least one completely private room for sensitive interviews/consultations before and after procedures.
Equipment management and storage
There must be designated areas for endoscope and accessory reprocessing, and storage of medications and all equipment, including an emergency resuscitation cart. Many units also have fully equipped mobile carts to travel to other sites when needed.
Staff
Specially trained endoscopy assistants have many important functions. They:
prepare patients for their procedures, physically and mentally;set up all necessary equipment;assist endoscopists during procedures;monitor patients' safety, sedation, and recovery;clean, disinfect, and process equipment;maintain quality control.Most endoscopy assistants are trained nurses, but technicians and nursing aides also have roles (e.g. in equipment processing). Large units need a variety of other staff, to handle reception, transport, reporting, and equipment management, including informatics.
Members of staff need places to store their clothes and valuables, and a break area for refreshments and meals.
Procedure reports
Usually, two reports are generated for each procedure—one by the nurses and one by the endoscopist.
Nurse's report
The nurse's report usually takes the form of a preprinted “flow sheet,” with places to record all of the pre-procedure safety checks, vital signs, use of sedation/analgesia and other medications, monitoring of vital signs and patient responses, equipment and accessory usage, and image documentation. It concludes with a copy of the discharge instructions given to the patient.
Endoscopist's report
In many units, the endoscopist's report is written or dictated in the procedure rooms. In larger ones, there may need to be a separate area designed for that purpose.
The endoscopist's report includes the patient's demographics, reasons for the procedure (indications), specific medical risks and precautions, sedation/analgesia, findings, diagnostic specimens, treatments, conclusions, follow-up plans, and any unplanned events (complications). Endoscopists use many reporting methods—handwritten notes, preprinted forms, free dictation, and computer databases.
The paperless endoscopy unit
Eventually all of the documentation (nursing, administrative, and endoscopic) will be incorporated into a comprehensive electronic management system. Such a system will substantially reduce the paperwork burden, and increase both efficiency and quality control.
Management, behavior, and teamwork
Complex organizations require efficient management and leadership. This works best as a collaborative exercise between the medical director of endoscopy and the chief nurse or endoscopy nurse manager. The biggest units will also have a separate administrator. These individuals must be skilled in handling people (doctors, staff, and patients), complex equipment, and significant financial resources. They must develop and maintain good working relationships with many departments within the hospital (such as radiology, pathology, sterile processing, anesthesia, bioengineering), as well as numerous manufacturers and vendors. They also need to be fully cognizant of all of the many local and national regulations that now impact on endoscopy practice.
The wise endoscopist will embrace the team approach, and realize that maintaining an atmosphere of collegiality and mutual respect is essential for efficiency, job satisfaction, and staff retention, and for optimal patient outcomes.
It is also essential to ensure that the push for efficiency does not drive out humanity. Patients should not be packaged as mere commodities during the endoscopy process. Treating our customers (and those who accompany them) with respect and courtesy is fundamental. Always assume that patients are listening, even if apparently sedated, so never chatter about irrelevances in their presence. Never eat or drink in patient areas. Background music is appreciated by many patients and staff.
Documentation and quality improvement
The agreed policies of the unit (including regulations dictated by the hospital and national organizations) are enshrined in an Endoscopy Unit Procedure Manual. This must be easily available, constantly updated, and frequently consulted.
Day-to-day documentation includes details of staff and room usage, disinfection processes, medications, instrument and accessory use and problems, as well as the procedure reports.
A formal quality assessment and improvement process is essential for maximizing the safety and efficiency of endoscopy services. Professional societies have recommended methods and metrics. The American Society for Gastrointestinal Endoscopy (ASGE) has incorporated these into its Endoscopy Unit Recognition Program, and the benefit of concentrating on and documenting quality is well exemplified by the success of the Global Rating Scale project in the UK.
Educational resources
Endoscopy units should offer educational resources for all of its users, including patients, staff, and doctors. Clinical staff need a selection of relevant books, atlases, key reprints, and journals, and publications of professional societies. Increasingly, many of these materials are available online, so that easy Internet access should be available. Many organizations produce useful educational videotapes, CD-ROMs, and DVDs.
Teaching units will need to embrace computer simulators, which are becoming valuable tools for training (and credentialing).
Further reading
Armstrong D, Barkun A, Cotton PB et al. Canadian Association of Gastroenterology consensus guidelines on safety and quality indicators in endoscopy. Can J Gastroenterol 2012; 26: 17–31.
ASGE Quality Assurance In Endoscopy Committee, Petersen BT, Chennat J et al. Multisociety guideline on reprocessing flexible gastrointestinal endoscopes. Gastrointest Endosc 2011; 73: 1075–84.
Cotton PB. Quality endoscopists and quality endoscopy units. J Interv Gastroenterol 2011; 1: 83–7.
Cotton PB, Bretthauer M. Quality assurance in gastroenterology. Best Pract Res Clin Gastroenterol 2011; 25: 335–6.
Cotton PB, Barkun A, Hawes RH, Ginsberg G (eds) Efficiency in Endoscopy. Gastrointestinal Endoscopy Clinics of North America, Vol. 14(4) (series ed. Lightdale CJ). Philadelphia: WB Saunders, 2004.
Faigel DO, Cotton PB. The London OMED position statement for credentialing and quality assurance in digestive endoscopy. Endoscopy 2009; 41: 1069–74.
Global Rating Scale. (available online at www.globalratingscale.com).
JAG (British Joint Advisory Group on GI Endoscopy). (available online at http://www.thejag.org.uk/AboutUs/DownloadCentre.aspx).
Petersen B, Ott B. Design and management of gastrointestinal endoscopy units. In: Advanced Digestive Endoscopy e-book/annual: Endoscopic Practice and Safety. Blackwell Publishing, 2008. (available online at www.gastrohep.com).
Now check your understanding—go to www.wiley.com/go/cottonwilliams/practicalgastroenterology
CHAPTER 2
Endoscopic Equipment
Endoscopes
There are many different endoscopes available for various applications, and several manufacturers, but they all have common features. There is a control head with valves (buttons) for air insufflation and suction, a flexible shaft (insertion tube) carrying the light guide and one or more service channels, and a maneuverable bending section at the tip. An umbilical or universal cord (also called “light guide connecting tube”) connects the endoscope to the light source and processor, air supply, and suction (Fig 2.1). Illumination is provided from an external high-intensity source through one or more light-carrying fiber bundles.
Fig 2.1 Endoscope system.
The image is captured with a charge-coupled device (CCD) chip, transmitted electronically, and displayed on a video monitor. Individual pixels (photo cells) in the CCD chips can respond only to degrees of light and dark. Color appreciation is arranged by two methods. So-called “color CCDs” have their pixels arranged under a series of color filter stripes (Fig 2.2). By contrast, “monochrome CCDs” (or, more correctly, sequential system CCDs) use a rotating color filter wheel to illuminate all of the pixels with primary color strobe-effect lighting (Fig 2.3). This type of chip can be made smaller, or can give higher resolution, but the system is more expensive because of the additional mechanics and image-processing technology.
Fig 2.2 Static red, green, and blue filters in the “color” chip.
Fig 2.3 Sequential color illumination.
“Electronic chromoendoscopy” systems are now standard in many endoscopes, allowing enhancement of aspects of the surface of the gastrointestinal mucosa. Narrow band imaging (NBI; Olympus Corporation) uses optical filters to select certain wavelengths of light, which correspond to the peak light absorption of hemoglobin, enhancing the visualization of blood vessels and certain surface structures. The Fuji Intelligent Chromo Endoscopy (FICE; Fujinon Endoscopy) and i-Scan (Pentax Medical) systems take ordinary endoscopic images and digitally process the output to estimate different wavelengths of light, providing a number of different imaging outputs. Autofluorescence imaging can detect endogenous fluorophores, a number of which occur in the gastrointestinal tract. Two systems now also allow magnification of the endoscopic image down to the cellular level: termed confocal microscopy (Pentax Medical, Mauna Kea Technologies). Blue laser light is focused on the desired tissue after injecting fluorescent materials, which become excited by the laser light and are detected at defined horizontal levels.
Tip control
The distal bending section (10 cm or so) and tip of the endoscope is fully deflectable, usually in both planes, up to 180° or more. Control depends upon pull wires attached at the tip just beneath the outer protective sheath, and passing back through the length of the instrument shaft to the two angulation control wheels (for up/down and right/left movement) on the control head (Fig 2.4). The wheels incorporate a friction braking system, so that the tip can be fixed temporarily in any desired position. The instrument shaft is torque stable, so that rotating movements applied to the head are transmitted to the tip when the shaft is relatively straight.
Fig 2.4 Basic design—control head and bending section.
Instrument channels and valves
The internal anatomy of endoscopes is complex (Fig 2.5). The shaft incorporates a biopsy/suction channel extending from the entry “biopsy port” to the tip of the instrument. The channel is usually about 3 mm in diameter, but varies from 1 to 5 mm depending upon the purpose for which the endoscope was designed (from neonatal examinations to major therapeutic procedures). In some instruments, especially those with lateral-viewing optics, the tip of the channel incorporates a deflectable elevator or bridge (see Fig 2.7), which permits directional control of forceps and other accessories independent of the instrument tip. This elevator is controlled by an additional thumb lever. The biopsy/suction channel is used also for aspirating secretions: an external suction pump is connected to the universal cord near to the light source, and suction is diverted into the instrument channel by pressing the suction valve. Another small channel allows the passage of air to distend the organ being examined. The air is supplied from a pump in the light source and is controlled by another valve. For colonoscopy, the air insufflation system can be modified to CO2 rather than room air and has been shown to lessen abdominal distension and pain after colonoscopy. The air system also pressurizes the water bottle, so that a jet of water can be squirted across the distal lens to clean it.
Fig 2.5 The internal anatomy of a typical endoscope.
Different instruments
The endoscopy unit must have a selection of endoscopes for specific applications. These may differ in length, size, stiffness, channel size and number, sophistication, and distal lens orientation. Most endoscopies are performed with instruments providing direct forward vision, via a wide-angle lens (up to 130°) (Fig 2.6). However, there are circumstances in which it is preferable to view laterally, particularly for endoscopic retrograde cholangiopancreatography (ERCP) (Fig 2.7).
Fig 2.6 The tip of a forward-viewing endoscope.
Fig 2.7 A side-viewer with a deflectable elevator.
The overall diameter of an endoscope is a compromise between engineering ideals and patient tolerance. The shaft must contain and protect many bundles, wires, and tubes, all of which are stronger and more efficient when larger (Fig 2.5). A colonoscope can reasonably approach 15 m in diameter, but this size is acceptable in the upper gut only for specialized therapeutic instruments.
Routine upper endoscopy is mostly performed with instruments of 8–11 mm diameter. Smaller endoscopes are available; they are better tolerated by all patients and have specific application in children. Some can be passed through the nose rather than the mouth. However, smaller instruments inevitably involve some compromise in durability, image quality, maneuverability, biopsy size, and therapeutic potential.
Several companies now produce a full range of endoscopes at comparable prices. However, light sources and processors produced by different companies are not interchangeable, so that most endoscopy units concentrate for convenience on equipment from a single manufacturer. Endoscopes are delicate, and some breakages are inevitable. Careful maintenance and close communication, repair, and back-up arrangements with an efficient company are necessary to maintain an endoscopy service. The quality of that support is often a crucial factor affecting the choice of company.
Endoscopic accessories
Many devices can be passed through the endoscope biopsy/suction channel for diagnostic and therapeutic purposes.
Biopsy forceps consist of a pair of sharpened cups (Fig 2.8), a spiral metal cable, a pull wire, and a control handle (Fig 2.9). Their maximum diameter is limited by the size of the channel, and the length of the cups by the radius of curvature through which they must pass in the instrument tip. When taking biopsy specimens from a lesion that can only be approached tangentially (e.g. the wall of the esophagus), forceps with a central spike may be helpful; however, these do present a significant puncture hazard for staff.Cytology brushes have a covering plastic sleeve to protect the specimen during withdrawal (Fig 2.10).Flexible needles are used for injections and for sampling fluids and cells.Fluid-flushing devices. Most instruments have a flushing jet channel to keep the lens clean. Fluids can also be forcibly flushed through the instrumentation channel with a large syringe or a pulsatile electric pump, with a suitable nozzle inserted into the biopsy port. For more precise aiming, a washing catheter can be passed down the channel to clean specific areas of interest, or to highlight mucosal detail by “dye spraying” (using a nozzle-tipped catheter).Fig 2.8 Biopsy cups open.
Fig 2.9 Control handle for forceps.
Fig 2.10 Cytology brush with outer sleeve.
Ancillary equipment
Suction traps (fitted temporarily into the suction line) can be used to take samples of intestinal secretions and bile for microbiology, chemistry, and cytology (Fig 2.11; see also Fig 7.27).Biteguards are used to protect the patient's teeth and the endoscope. Some guards have straps, to keep them in place, and oxygen ports.Overtubes are flexible plastic sleeves that cover the endoscope shaft and act as a conduit for repeated intubations, or to facilitate therapeutic procedures such as the extraction of a foreign body and hemostasis (Fig 2.12).Caps of various shapes can be attached to the tip of the endoscope to facilitate various procedures, such as banding and mucosal resection, dissection, etc.Stretchers/trolleys. Endoscopy is normally performed on a standard transportation stretcher. This should have side rails, and preferably allow height adjustment. The ability to tilt the stretcher head down may be helpful in emergencies.Image documentation. Videoscopes capture images digitally, which can then be enhanced, stored, transmitted, and printed. Video sequences can be recorded on tape or digitally.Sedation and monitoring. All patients require regular monitoring during an endoscopy with pulse oximetry as a minimum. Many units also have the facility for continuous blood pressure monitoring and electrocardiography, particularly for deeply sedated patients. Appropriate resuscitation equipment must be available, including oral airways, oxygen delivery systems, and wall suction.Fig 2.11 A suction trap to collect fluid specimens.
Fig 2.12 An overtube with biteguard over a rubber lavage tube.
Electrosurgical units
Any electrosurgical unit can be used for endoscopic therapy if necessary, but purpose-built isolated-circuit and “intelligent” units have major advantages in safety and ease of use. Units should have test circuitry and an automatic warning system or cut-out in case a connection is faulty or the patient plate is not in contact. Most units have separate “cut” and “coagulate” circuits, which can often be blended to choice. For flexible endoscopy, low-power settings are used (typically 15–50 W). However, an “auto-cut” option is increasingly popular. This uses an apparently higher power setting but gives good control of tissue heating and cutting, because the system automatically adjusts power output according to initial tissue resistance and increasing resistance during coagulation and desiccation.
The type of current is generally less important than the amount of power produced, and other physical factors such as electrode pressure or snare-wire thickness and squeeze are more critical. High settings (high power) of coagulating current provide satisfactory cutting characteristics, whereas units with output not rated directly in watts can be assumed to have “cut” power output much greater than that of “coag” at the same setting. The difference in current type used is therefore often illusory. If in doubt, pure coagulating current alone is considered by most expert endoscopists to be safer and more predictable, giving “slow cook” effect and maximum hemostasis.
Lasers and argon plasma coagulation
Lasers (particularly the neodymium-YAG and argon lasers) were introduced into endoscopy for treatment of bleeding ulcers, and for tumor ablation, because it seemed desirable to use a “no touch” technique. However, it has become clear that the same effects can be achieved with simpler devices, and that pressure (coaptation) may actually help hemostasis.
Argon plasma coagulation (APC) is easier to use and as effective as lasers for most endoscopic purposes. APC electrocoagulates, without tissue contact, by using the electrical conductivity of argon gas—a similar phenomenon to that seen in neon lights. The argon, passed down an electrode catheter (Fig 2.13a) and energized with an intelligent-circuitry electrosurgical unit and patient plate, ionizes to produce a local plasma arc—like a miniature lightning strike (Fig 2.13b). The heating effect is inherently superficial (2–3 mm at most, unless current is applied in the same place for many seconds), because tissue coagulation increases resistance and causes the plasma arc to jump elsewhere. However, APC action alone may be too superficial to debulk a larger lesion, requiring preliminary piecemeal snare-loop removal, with APC to electrocoagulate the base.
Fig 2.13 Argon plasma coagulation (APC).
Equipment maintenance
Endoscopes are expensive and complex tools. They should be stored safely, hanging vertically in cupboards through which air can circulate. Care must be taken when carrying instruments, as the optics are easily damaged if left to dangle or are knocked against a hard surface. The head, tip, and umbilical cord should all be held (Fig 2.14).
Fig 2.14 Carry endoscopes carefully to avoid knocks to the optics in the control head and tip.
The life of an endoscope is largely determined by the quality of maintenance. Complex accessories (e.g. electrosurgical equipment) must be checked and kept in safe condition. Close collaboration with hospital bioengineering departments and servicing engineers is essential. Repairs and maintenance must be properly documented.
Channel blockage
Blockage of the air/water (or suction) channel is one of the most common endoscope problems. Special “channel-flushing devices” are available, allowing separate syringe flushing of the air and water channels; they should be used routinely. When blockage occurs, the various systems and connections (instrument umbilical, water bottle cap or tube, etc.) must be checked, including the tightness and the presence of rubber O-rings where relevant. It is usually possible to clear the different channels by using the manufacturer's flushing device or a syringe with a suitable soft plastic introducer or micropipette tip. Water can be injected down any channel and, because water is not compressed, more force can be applied than with air. Remember that a small syringe (1–5 mL) generates more pressure than a large one, whereas a large one (50 mL) generates more suction. The air or suction connections at the umbilical, or the water tube within the water bottle, can be syringed until water emerges from the instrument tip. Care should be taken to cover or depress the relevant control valves while syringing. Another method for unclogging the suction channel is to remove the valve and apply suction directly at the port.
Infection control
There is a risk of transmitting infection in the endoscopy unit from patient to patient, patient to staff, and even from staff to patient. Universal precautions should always be adopted. This means assuming that all patients are infectious, even if there is no objective evidence. Infection control experts and equipment manufacturers should be welcomed as partners in minimizing infection risk; they should be invited to participate in developing unit policies and in monitoring their effectiveness through formal quality control processes. Infection control policies should be written down and understood by all staff.
Staff protection
Staff should be immunized against hepatitis; tuberculosis checks are mandatory in some units. Splashing with body fluids is a risk for staff in contact with patients and instruments. Gowns, gloves, and eye protection should be worn for these activities (Fig 2.15).
Fig 2.15 Gowns, gloves, and eye protection should be worn.
Other measures to reduce the risk of infection include:
frequent hand-washing;use of paper towels when handling soiled accessories;disposal of soiled items directly into a sink or designated area (not on clean surfaces);separate disposal of hazardous waste, needles, and syringes;covering skin breaks with a waterproof dressing;maintenance of good hygienic practice throughout the unit.Cleaning and disinfection
There are three levels of disinfection:
Endoscope reprocessing
Guidelines for cleaning and disinfecting endoscopes should be determined in each unit (and documented in the procedure manual) after consulting with manufacturers, infection control experts, and appropriate national advisory bodies. Endoscopists should be fully aware of their local practice, not least because they may be held legally responsible for any untoward event.
All advisory bodies require high-level disinfection of endoscopes and other equipment shortly after use.
How long a disinfected instrument remains fit for use after disinfection is an important issue, and still a matter for debate. Some authorities have recommended 4–7 days, but the reality depends on several factors. Endoscopes that contain retained moisture will rapidly become colonized by the rinsing water. Assiduous care must be taken in the drying process, and specially designed drying cabinets are available commercially. Local policy should be guided by national recommendations and can be validated by microbiological monitoring.
Formal cleaning and disinfection procedures should take place in a purpose-designed area. There should be clearly defined and separate clean and dirty areas, multiple worktops, and double sinks as well as a separate hand washbasin, endoscopic reprocessors (washing machines), and ultrasonic cleaners. An appropriately placed fume hood is also desirable.
Mechanical cleaning
The first and vitally important task in the disinfection process is to clean the endoscope and all of its channels, to remove all blood, secretions, and debris. Disinfectants cannot penetrate organic material.
Initial cleaning must be done immediately after the endoscope is removed from the patient.
Manual cleaning
After brushing:
Manual disinfection
Soak the instrument and accessories (such as valves) in the chosen disinfectant for the recommended contact time.
Disinfectants
Glutaraldehyde has been the most popular agent. It can destroy viruses and bacteria within a few minutes, is non-corrosive (to endoscopes), and has a low surface tension, which aids penetration. The length of contact time needed for disinfection varies according to the type of gluteraldehyde used, and the temperature. Guidelines vary between countries, but 20 minutes is commonly recommended. More prolonged soaking may be required in cases of known or suspected mycobacterial disease.
Glutaraldehyde does carry the risk of sensitization, and can cause severe dermatitis, sinusitis, or asthma among exposed staff. The risk increases with increasing levels and duration of exposure. Medical-grade latex gloves, or nitrile rubber gloves, should be worn, with goggles and/or a face mask to protect against splashes. Closed system reprocessors and fume hoods/extraction fans are important. Reprocessors should be self-disinfecting. The concentration of disinfectant should be monitored.
Peracetic acid, chlorine dioxide, Sterox and other agents have also been used for endoscope disinfection.
A sterile water supply (special filters may be needed) helps to reduce the risk of nosocomial infections.
Rinsing, drying, and storing
Following disinfection, reprocessors rinse the instruments internally and externally to remove all traces of disinfectant, using the all-channel irrigator. The air, water, and suction channels (and flushing and forceps elevation channels if fitted) are perfused with 70% alcohol and dried with forced air before storage. This must be done for all endoscopes processed either manually or by automated reprocessor (some reprocessors have this function as part of the cycle). Bacteria multiply in a moist environment, and the importance of drying instruments after disinfection cannot be overemphasized. Instruments should be hung vertically in a well-ventilated cupboard.
Accessory devices
Diagnostic and therapeutic devices (such as biopsy forceps) are critical accessories, and must be sterile. Many are now disposable. Reusable accessories, such as water bottles, are autoclaved or gas sterilized.
Quality control of reprocessing
Records should be kept of the disinfection process for every endoscope, including who cleaned it, when, and how. Records that link the endoscope with which the patient was examined should also be kept. Routine bacteriological surveillance of automatic disinfectors and endoscopes is recommended by some experts, but is not yet endorsed by the main national societies, and is not widely practiced. This should allow early detection of serious contaminating organisms such as Pseudomonas and atypical mycobacteria. Routine surveillance also allows the early detection of otherwise unrecognizable internal channel damage, reprocessing protocol errors, as well as any water and environmental contamination problems. The specter of prion-related disease may be raised in patients with degenerative neurological symptoms. As prion proteins are not inactivated by heat or current disinfection regimes, disposable accessories should be used with a back-up endoscope reserved for such suspect patients. Lymphoid tissue is a particular risk, so many units now advise against routine ileal biopsies, particularly of Peyer's patches, for fear of potential prion contamination of the instrument channels.
Remember, although most of the cleaning, disinfection, and maintenance activities are normally and appropriately delegated to the staff, it is the endoscopist who is responsible for ensuring that their equipment is safe to use. Endoscopists should know how to complete the process themselves, especially in some emergency situations where the usual endoscopy nurses may not be available.
Safety and monitoring equipment
It is now standard practice to monitor patients through the procedural process and to provide supplemental oxygen in many cases. The necessary equipment must be readily available in the procedure rooms and pre-recovery areas, along with an emergency resuscitation cart.
Further reading
ASGE Quality Assurance In Endoscopy Committee, Petersen BT, Chennat J. Multisociety guideline on reprocessing flexible gastrointestinal endoscopes: 2011. Gastrointest Endosc 2011; 73: 1075–84.
Beilenhoff U, Neumann CS, Rey JF et al. ESGE-ESGENA guideline: Cleaning and disinfection in gastrointestinal endoscopy. Endoscopy 2008; 40: 939–7.
Guidelines for Decontamination of Equipment for Gastrointestinal Endoscopy Updated by: Dr Miles Allison—BSG Endoscopy Committee—February 2013 (available online at http://www.bsg.org.uk/clinical-guidelines/endoscopy/guidelines-for-decontamination-of-equipment-for-gastrointestinal-endoscopy.html).
Petersen BT, Chennat J, Cohen J et al. Multisociety guideline on reprocessing flexible GI endoscopes: 2011. Infect Control Hosp Epidemiol 2011; 32: 527–37.
Rateb G, Sabbagh L, Rainoldi J et al. Reprocessing of endoscopes: results of an OMED-OMGE survey. Can J Gastroenterol 2005; WCOG abstracts. DR.1054. (available online at http://www.pulsus.com/WCOG/abs/DR.1054.htm).
Rutala WA, Weber DJ. Creutzfeldt–Jakob disease. Recommendations for disinfection and sterilization. Clin Infect Dis 2001; 32: 1348–56.
US Society for Gastrointestinal Nurses and Assistants resource. (available online at http://infectioncontrol.sgna.org/SGNAInfectionPreventionResources/tabid/55/Default.aspx).
Willis C. Bacteria-free endoscopy rinse water—a realistic aim? Epidemiol Infect 2006; 134: 279–84.
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