Chapter 2 Gastrointestinal Endoscopy
Instrumentation, Handling Technique, Training, and Implementation in Practice
Endoscopic equipment is no longer considered a luxury that only large referral centers or veterinarians practicing in affluent areas can justify purchasing. A variety of quality instruments, both new and used, are available. This chapter is concerned with key aspects to be considered in the purchase of an endoscope, the technical points of maneuvering an endoscope, steps toward gaining proficiency in operating an endoscope so that thorough examinations can be consistently performed (i.e., gaining proper training), and recommendations for increasing the use of endoscopy in the practice setting (recognizing indications for endoscopy and marketing the procedure successfully). Proper maintenance to promote the maximum life span of the equipment was discussed in Chapter 1. While there are now many small animal and mixed practices that have purchased endoscopes, there are also many practices that still vastly underutilize their equipment. Patient care can be clearly enhanced through earlier and more frequent use of endoscopy. Recognition of the many potential applications for the use of flexible endoscopy instrumentation is essential (Box 2-1), and success in fully implementing endoscopy services into the practice’s core procedures program depends on the veterinarian’s ability to effectively educate clients about the value of endoscopy as a diagnostic procedure and to make clear and effective recommendations on proper diagnostic assessment.
BOX 2-1 Applications for Flexible Endoscopy (Areas of Examination and Procedures)
Subsequent chapters on the digestive system deal individually with the technical points of examining the esophagus, stomach, duodenum, ileum, and colon. The beginner learning to perform GI endoscopy naturally gives more thought to trying to move the instrument from one point to another than to careful gross examination and diagnosis of the areas being traversed. As the endoscopist becomes more skilled, an almost effortless maneuvering of the endoscope becomes second nature and the greater part of the time used to perform an examination is taken up with careful observation and synthesis of findings in relation to the clinical problem and prior experience. As the reader will find on review of the subsequent digestive system chapters, a combination of impressions from observation and microscopic review of biopsy samples is often needed for definitive diagnosis (see Chapter 8 for details on gross assessment and pathology). Because many disorders affect the upper and lower GI tract, a variety of appearances may be seen with an endoscope. The GI chapters carefully review the technical points of maneuvering the endoscope through these areas and provide an atlas of the things to be “seen” by the endoscopist. Indeed, upper GI endoscopy and colonoscopy are a primary means of physical diagnosis for the gastroenterologist.
The Decision to Purchase an Endoscope
For the veterinarian, the selection of equipment to be used for performing endoscopy often depends on its versatility of application, durability, and expense. Many practices, recognizing the full range of capabilities of endoscopy, have been able to financially justify the purchase of high-quality endoscopy equipment. A single scope can be used for a variety of GI and respiratory procedures. In addition, the availability of an endoscope often allows earlier access to examination of the GI tract than if surgery is the only other alternative. Clients almost always opt to have a less invasive procedure performed if the capabilities are present, and they often consent to this type of procedure much sooner than they would to surgery. Therefore, when consideration is given to the purchase of an endoscope, the most important factors to be reviewed should be the probable frequency of usage and versatility of the endoscope rather than the purchase price. Other important considerations are the quality of the optical system, the length and diameter of the insertion tube, the diameter of the instrument channel, and ease of operating the endoscope. Significant differences exist! Too frequently veterinarians rank a lower purchase price as one of the most important factors. This can be a significant mistake because even the most skilled endoscopist may find performing a complete examination and making the correct diagnosis difficult while using an endoscope of poor quality. High-quality endoscopy equipment will pay for itself in most practices in 1 to 3 years, as long as it is used as often as it can and should be. With proper care an endoscope should last many more years.
Training
Skills training should include proper handling techniques, maneuvering the endoscope through the upper GI tract smoothly and efficiently, techniques for traversing the pyloric canal to enter the duodenum, colonoscopy and ileoscopy, biopsy techniques, and foreign body retrieval. There is significant value in taking another course to fine-tune the necessary skill set after a period of time spent working on cases at one’s practice. This is an excellent opportunity to work with experienced instructors to correct any “bad habits” that may have been picked up and to simply continue practicing with the aid of experienced coaches. Endoscopy courses are advertised through university websites, brochures, seminars, and some of the endoscope company websites (e.g., www.lifelearn.com, www.ksvea.com, www.vetmed.wsu.edu, www.vet.uga.edu, www.cvmbs.colostate.edu).
Textbooks offer detailed descriptions of procedures and an array of normal and abnormal appearances for veterinarians to refer to in their own practice setting. Training CDs are also available (e.g., www.lifelearn.com). Please see the companion website for a demonstration of normal exam technique.
www.tamssmallanimalendoscopy.com
Successful Implementation and Marketing of Endoscopy Services
There are many indications for performing GI endoscopy in dogs and cats (Box 2-2), and these are discussed in subsequent chapters. A simple but often overlooked example of not recognizing indications is the need to check for esophagitis in patients with frequent vomiting. For example, some dogs and cats with a linear intestinal foreign body will develop esophagitis, sometimes of a moderate to severe degree, secondary to frequent vomiting of activated enzymes, acid, and toxins from the GI tract (the same can occur in animals vomiting frequently from any cause, including parvovirus enteritis and pancreatitis). Esophagitis causes significant pain, and significant injury can also result in fibrosis and even stricture formation (see Chapter 3).
One of the most important advantages of endoscopy is that it allows early examination of the GI tract. Too often patients with GI disorders do not have a definitive diagnosis established soon enough. It is still important to perform basic diagnostic tests and consider therapeutic dietary trials early in the clinical course, but sometimes the preliminary assessment coupled with various trial therapies goes on for far too long before more definitive diagnostic steps are taken. Although pet owners may be initially reluctant to consider a procedure like endoscopy, usually because of concerns related to the requirement for anesthesia or cost constraints, an important part of the marketing of endoscopy is to educate clients about the value of early examination, especially in patients with intermittent or early chronic vomiting (10 to 14 days or longer). Of course, routine baseline tests should be done first as part of the initial screening diagnostic plan (e.g., a complete blood count, complete biochemical profile, urinalysis, fecal examination [centrifugal flotation combined with a Giardia antigen test], abdominal radiographs, and dietary trials, as deemed appropriate). When a definitive diagnosis is established early it not only can decrease overall costs to the client but also, very importantly, can effect better patient care through an earlier determination of specific therapy for the patient’s condition. Further, endoscopy is a very successful method for removing foreign bodies from the upper GI tract of dogs and cats; its success rate is greater than 80% (see Chapter 7 for details on foreign body retrieval). Clients naturally are very pleased when foreign bodies can be removed via endoscopy at less cost and in a much less invasive way as compared with surgery.
Finally, other marketing techniques can include providing clients with a few representative photos from their pet’s procedure (see Chapter 1 for a discussion on image capture devices), using a library of photos (e.g., textbook atlas photos or photos from the hospital’s files) to explain the value of endoscopy, providing client handouts describing endoscopy for animals, and illustrating case reports in client newsletters or on examination room walls. The bottom line is that when the doctors and staff make recommendations with enthusiasm and conviction, the number of procedures that are done will increase significantly. For hospitals that do not offer endoscopy, this section provides many reasons to consider referral for endoscopy.
Selection of Endoscopic Instruments: Making the Correct Choice
Careful thought must be given to the insertion tube diameter and length of the endoscope. Until recently, most endoscopes used in veterinary practice were designed for use in humans and often classified as adult or pediatric. Insertion tube diameters of endoscopes manufactured for examination of the human upper GI tract range from 6.0 (pediatric size) to 12.8 mm and often have a working length of around 100 cm. Fiberscopes manufactured for veterinary use are available in an insertion tube diameter size as small as 7.8 mm. Smaller diameter video endoscopes with larger instrument channels (up to 2.8 mm) are now available (see Chapter 1 for mechanical details on fiberscopes and video endoscopes). Most endoscopes used currently in small animal practice are in the range of 7.8 to 9.8 mm (Figure 2-1), and even smaller diameter video endoscopes will be available in the future. The inner working channel diameter of the human and veterinary endoscopes varies based on insertion tube diameter but ranges from 2 to 2.8 mm.
The ideal working length of an endoscope for small animal practice is 140 cm because it provides sufficient length to reach the duodenum in the largest of dogs. A 100-cm scope, the type that is still commonly found in general small animal practices, is too short to reach the duodenum of larger dogs, which could include any dog weighing more than 27 kg (60 lbs). A 100-cm scope can actually be long enough to reach the duodenum of some dogs weighing 35 to 40 kg (77 to 90 lbs), but in dogs of certain breeds that weigh less, the length simply may be insufficient (Figure 2-2). There are significant differences among breeds, so for maximal versatility the longer scope is best. The 140-cm veterinary scopes have a small enough diameter (7.8 to 9 mm) that they can be used for duodenoscopy in most cats. Most specialty practices will maintain both a long scope and a shorter one of smaller diameter (e.g., 100 cm in length and 7.8 mm or less in diameter) to facilitate examination of the smallest cats and dogs. For practices that do not have a scope longer than 100 cm, referral should be considered if an upper small bowel examination will be needed for a large dog (Figure 2-3).