- Email: [email protected]
Unsedated ultrathin EGD
EDITORIAL
Unsedated ultrathin EGD Upper GI endoscopy without administration of conscious sedation has been used since the introduction of flexible upper GI endoscopy by Hirschowitz in 1957.1 Performing an unsedated diagnostic examination remains the rule rather than the exception throughout most of the world. In the United States, however, conscious sedation for upper endoscopy remains the standard of practice. There are myriad issues that contribute to this, but patient and physician expectations drive the use of sedation. Despite the introduction of sophisticated monitoring techniques, sedation-related cardiopulmonary complications comprise the majority of morbidity and mortality rates associated with upper GI endoscopy.2-5 When the economic burden of sedated endoscopy is calculated, both direct and indirect costs must be considered. These include but are not limited to the costs of (1) periprocedural and intraprocedural monitoring and need for a second nurse/technician during the procedure, (2) the need for postprocedural recovery in progressively busier endoscopy suites, (3) the postprocedure effect of sedation with loss of productivity of the patient and the escort responsible for transportation and immediate care. Although the combined financial impact of these factors has not been directly addressed, it seems that unsedated upper GI endoscopy can potentially result in a significant reduction in combined procedurerelated costs. The introduction of the unsedated transnasal approach to upper GI endoscopy (T-EGD) in 19946 revitalized interest in unsedated endoscopy in large part because of the availability of significantly slimmer and higher-quality endoscopes. Moreover, over the last 10 years multiple studies have addressed the advantages and disadvantages of the unsedated approach.7-12 These studies have generally either evaluated the use of the slimmer or ultrathin endoscopes through the conventional transoral route with and without conscious sedation or compared the unsedated T-EGD with transoral sedated or unsedated EGD. The largest study to date13 comparing transoral EGD and T-EGD with a 4-mm endoscope concluded that the transnasal route was one of the factors associated with good tolerance of unsedated endoscopy. However, such a definitive finding is not uniformly reported. The reasons for this discrepancy are not
clear, but it is likely that cultural expectations or inclusion of procedures performed before the endoscopists had yet mastered the transnasal technique may have contributed to the unfavorable results. The diagnostic yield of transnasal unsedated upper GI endoscopy has been found to be similar to conventional sedated EGD in evaluation of Helicobacter pylori diagnosis and eradication,14 detection and grading of esophageal varices,15 and detection of Barrett’s metaplasia and dysplasia.16 Similarly, transoral ultrathin EGD has been shown to have comparable diagnostic yield and tolerability with that of conventional EGD.17 Both techniques have been performed with the patient in the upright sitting position or left lateral decubitus position, depending
Widespread use of unsedated techniques will require acceptance by patients and physicians, comfort and expertise with these techniques by endoscopists, and potential financial and quality-of-life incentives (eg, more rapid room turnover, no work loss for patients).
Copyright ª 2006 by the American Society for Gastrointestinal Endoscopy 0016-5107/$32.00 doi:10.1016/j.gie.2006.07.037
on the endoscopists’ preference. The use of transnasal unsedated endoscopy has now been extended to placement of feeding tubes in critically ill patients18-20 with reduction in procedure time and enhanced safety and diminished medication requirements compared with the transoral approach,20 with comparable results to fluoroscopic techniques for feeding tube placement.21 Despite these advances, the GI community has not yet embraced this approach for multiple reasons, one of them being that it requires more expertise and skill. Although transoral unsedated endoscopy with ultrathin endoscopes does not involve significant change in a familiar technique, it has been our experience that there is a significant learning curve for mastering the transnasal technique, albeit steep, even for very experienced endoscopists. The transnasal unsedated approach requires familiarity with nasal and pharyngeal anatomy and expertise with transnasal intubation and nasopharyngeal advancement of the endoscope in the upright position. In contrast to the gastroenterology community’s reluctance to embrace these unsedated techniques, transnasal unsedated esophagoscopy has gained wide popularity as
874 GASTROINTESTINAL ENDOSCOPY Volume 64, No. 6 : 2006
www.giejournal.org
Saeian & Shaker
Editorial
an office procedure among otolaryngologists for examination of the esophagus and the pharynx and larynx in patients with reflux-related symptoms.22,23 The reason for this difference seems to be the familiarity of these specialists with transnasal passage of the endoscope in an unsedated patient and familiarity with the anatomy of the aerodigestive tract and its endoscopic evaluation. The office-based aspect of their practice also lends itself well to this approach. In final analysis, widespread use of unsedated techniques will require acceptance by patients and physicians, comfort and expertise with these techniques by endoscopists, and potential financial and quality-of-life incentives (eg, more rapid room turnover, no work loss for patients). Patient acceptance will depend heavily on proper education about the procedure and information on its comparative risks and benefits. To date, this type of patient education has not been systematically used. Endoscopists’ preference and comfort are more complex and depend on a number of factors, such as the availability of the proper setup and personnel for unsedated EGD, time required for the procedure, and adequate training, especially if the transnasal technique is chosen. These may be the main reasons for the higher popularity of this technique by otolaryngologists compared with gastroenterologists. In this issue of Gastrointestinal Endoscopy Horiuchi and Nakayama24 report on a fundamental and recognized aspect of unsedated endoscopy, namely, the effect of endoscope diameter on acceptability of and tolerance by patients. Size does indeed matter. Their multifaceted study shows that unsedated endoscopy by the transoral route using an endoscope with a 5.2-mm diameter performs equally well but is significantly better tolerated than either a 6.5-mm diameter or a sedated examination with a 9.0-mm endoscope. The latter comparison may be particularly prone to the potential of recall bias because patients were asked to compare the procedure to one performed some 18 months earlier. All endoscopes had similar optical quality. These findings corroborate previous reports that compared the acceptability of 5.3-mm and 5.9-mm diameter endoscopes according to the unsedated transnasal technique of EGD.8 The lack of a difference in the willingness of the patient to repeat the same procedure (90% vs 83%, P Z.52) with the 5.2-mm versus the 6.5-mm diameter endoscope does not suggest a significant advantage. This lack of difference may in part be due to the fact that the 6.5-mm endoscope is itself of significantly smaller diameter than standard endoscopes (eg, 9.0-9.8 mm). Although extrapolation of these findings to the U.S. population may not be valid, the study by Garcia et al17 performed in California in which only 18 of 80 patients were of Asian descent reported that patients were just as willing to undergo repeat examination with unsedated ultrathin endoscopy as with sedated standard endoscopy. Whether the transnasal or transoral route of intubation is used, the diameter of the endoscope has now been shown
in several studies to be the single most important factor in patient comfort and therefore tolerance of the procedure. Subsequent willingness to undergo repeat examination also follows this paradigm. From the endoscopist’s perspective, the optical quality of the instrument, ease and adequacy of suctioning mechanism, and ability to obtain adequate biopsy specimens are important issues. The use of even smaller, battery-powered instruments has been limited in part as a result of poor optical quality and thus far remains of unclear benefit. Optical quality of ultrathin scopes as slim as 4.8 mm is now comparable to larger endoscopes used for conventional upper endoscopy. However, the suctioning capability of the ultrathin endoscopes is much weaker. In addition, the air/water and biopsy channels are shared in some of the endoscopes, which poses difficulty in visualization during biopsy specimen acquisition, particularly near the gastroesophageal junction. Resolving these shortcomings will undoubtedly enhance ease of operation.
www.giejournal.org
Volume 64, No. 6 : 2006 GASTROINTESTINAL ENDOSCOPY 875
DISCLOSURE The authors have no financial arrangements (eg, consultancies, stock ownership, equity interests, patent-licensing arrangements, research support, major honoraria, etc) with a company whose product figures prominently in this article or with a company making a competing product except as disclosed on a separate attachment. Kia Saeian, MD Reza Shaker, MD MCW Dysphagia Institute Division of Gastroenterology and Hepatology Medical College of Wisconsin Milwaukee, Wisconsin, USA
REFERENCES 1. Modlin IM. The evolution of therapy in gastroenterology: a vintage of digestion. Montreal, Canada: Axcan Pharma; 2002. 2. Bell GD. Review article: premedication and intravenous sedation for upper gastrointestinal endoscopy. Aliment Pharmacol Ther 1990;4: 103-22. 3. O’Connor KW, Jones S. Oxygen desaturation is common and clinically underappreciated during elective endoscopic procedures. Gastrointest Endosc 1990;36:S2-4. 4. Scott-Coombes DM, Thompson JN. Hypoxia during upper gastrointestinal endoscopy is caused by sedation. Endoscopy 1993;25:308-9. 5. Lieberman DA, Wuerker CK, Katon RM. Cardiopulmonary risk of esophagogastroduodenoscopy: role of endoscope diameter and systemic sedation. Gastroenterology 1985;88:468-72. 6. Shaker R. Unsedated trans-nasal pharyngoesophagogastroduodenoscopy (T-EGD): technique. Gastrointest Endosc 1994;40:346-8. 7. Dean R, Dua K, Massey B, et al. A comparative study of unsedated transnasal esophagogastroduodenoscopy and conventional EGD. Gastrointest Endosc 1996;44:422-4.
Editorial
Saeian & Shaker
8. Craig A, Hanlon J, Dent J, et al. A comparison of transnasal and transoral endoscopy with small-diameter endoscopes in unsedated patients. Gastrointest Endosc 1999;49:292-6. 9. Zaman A, Hahn M, Hapke R, et al. A randomized trial of peroral versus transnasal unsedated endoscopy using an ultrathin videoendoscope. Gastrointest Endosc 1999;49:279-84. 10. Dumortier J, Ponchon T, Scoazec JY, et al. Prospective evaluation of transnasal esophagogastroduodenoscopy: feasibility and study on performance and tolerance. Gastrointest Endosc 1999;49:285-91. 11. Roy JF, Deforest D, Marek TA. Prospective comparison of nasal versus oral indertion of a thin video endoscope in healthy volunteers. Endoscopy 1996;28:422-4. 12. Sorbi D, Gostout CJ, Henry J, et al. Unsedated small-caliber esophagogastroduodenoscopy (EGD) versus conventional EGD: a comparative study. Gastroenterology 1999;117:1301-7. 13. Thota PN, Zuccaro G Jr, Vargo JJ II, et al. A randomized prospective trial comparing unsedated esophagoscopy via transnasal and transoral routes using a 4-mm video endoscope with conventional endoscopy with sedation. Endoscopy 2005;37:559-65. 14. Saeian K, Townsend WF, Rochling FA, et al. Unsedated transnasal EGD: an alternative approach to conventional esophagogastroduodenoscopy for documenting Helicobacter pylori eradication. Gastrointest Endosc 1999;49:297-301. 15. Saeian K, Staff D, Knox J, et al. Unsedated transnasal endoscopy: a new technique for accurately detecting and grading esophageal varices in cirrhotic patients. Am J Gastroenterol 2002;97:2246-9.
16. Saeian K, Staff DM, Vasilopoulos S, et al. Unsedated transnasal endoscopy accurately detects Barrett’s metaplasia and dysplasia. Gastrointest Endosc 2002;56:472-8. 17. Garcia RT, Cello JP, Nguyen MH, et al. Unsedated ultrathin EGD is well accepted when compared with conventional sedated EGD: a multicenter randomized trial. Gastroenterology 2003;125:1606-12. 18. Dranoff JA, Angood PJ, Topazian M. Transnasal endoscopy for enteral feeding tube placement in critically ill patients. Am J Gastroenterol 1999;94:2902-4. 19. O’Keefe SJ, Foody W, Gill S. Transnasal endoscopic placement of feeding tubes in the intensive care unit. JPEN J Parenter Enteral Nutr 2003; 27:349-54. 20. Kulling D, Bauerfeind P, Fried M. Transnasal versus transoral endoscopy for the placement of nasoenteral feeding tubes in critically ill patients. Gastrointest Endosc 2000;52:506-10. 21. Fang JC, Hilden K, Holubkov R, et al. Transnasal endoscopy vs fluoroscopy for the placement of nasoenteric feeding tubes in critically ill patients. Gastrointest Endosc 2005;62:661-6. 22. Aviv JE, Takoudes TG, Ma G, et al. Office-based esophagoscopy: a preliminary report. Otolaryngol Head Neck Surg 2001;125:170-5. 23. Postma GN, Cohen JT, Belafsky PC, et al. Transnasal esophagoscopy: revisited (over 700 consecutive cases). Laryngoscope 2005;115: 321-3. 24. Horiuchi A, Nakayama Y. Unsedated ultrathin EGD by using a 5.2-mm– diameter videoscope: evaluation of acceptability and diagnostic accuracy. Gastrointest Endosc 2006;64:868-73.
876 GASTROINTESTINAL ENDOSCOPY Volume 64, No. 6 : 2006
www.giejournal.org
Unsedated ultrathin EGD Upper GI endoscopy without administration of conscious sedation has been used since the introduction of flexible upper GI endoscopy by Hirschowitz in 1957.1 Performing an unsedated diagnostic examination remains the rule rather than the exception throughout most of the world. In the United States, however, conscious sedation for upper endoscopy remains the standard of practice. There are myriad issues that contribute to this, but patient and physician expectations drive the use of sedation. Despite the introduction of sophisticated monitoring techniques, sedation-related cardiopulmonary complications comprise the majority of morbidity and mortality rates associated with upper GI endoscopy.2-5 When the economic burden of sedated endoscopy is calculated, both direct and indirect costs must be considered. These include but are not limited to the costs of (1) periprocedural and intraprocedural monitoring and need for a second nurse/technician during the procedure, (2) the need for postprocedural recovery in progressively busier endoscopy suites, (3) the postprocedure effect of sedation with loss of productivity of the patient and the escort responsible for transportation and immediate care. Although the combined financial impact of these factors has not been directly addressed, it seems that unsedated upper GI endoscopy can potentially result in a significant reduction in combined procedurerelated costs. The introduction of the unsedated transnasal approach to upper GI endoscopy (T-EGD) in 19946 revitalized interest in unsedated endoscopy in large part because of the availability of significantly slimmer and higher-quality endoscopes. Moreover, over the last 10 years multiple studies have addressed the advantages and disadvantages of the unsedated approach.7-12 These studies have generally either evaluated the use of the slimmer or ultrathin endoscopes through the conventional transoral route with and without conscious sedation or compared the unsedated T-EGD with transoral sedated or unsedated EGD. The largest study to date13 comparing transoral EGD and T-EGD with a 4-mm endoscope concluded that the transnasal route was one of the factors associated with good tolerance of unsedated endoscopy. However, such a definitive finding is not uniformly reported. The reasons for this discrepancy are not
clear, but it is likely that cultural expectations or inclusion of procedures performed before the endoscopists had yet mastered the transnasal technique may have contributed to the unfavorable results. The diagnostic yield of transnasal unsedated upper GI endoscopy has been found to be similar to conventional sedated EGD in evaluation of Helicobacter pylori diagnosis and eradication,14 detection and grading of esophageal varices,15 and detection of Barrett’s metaplasia and dysplasia.16 Similarly, transoral ultrathin EGD has been shown to have comparable diagnostic yield and tolerability with that of conventional EGD.17 Both techniques have been performed with the patient in the upright sitting position or left lateral decubitus position, depending
Widespread use of unsedated techniques will require acceptance by patients and physicians, comfort and expertise with these techniques by endoscopists, and potential financial and quality-of-life incentives (eg, more rapid room turnover, no work loss for patients).
Copyright ª 2006 by the American Society for Gastrointestinal Endoscopy 0016-5107/$32.00 doi:10.1016/j.gie.2006.07.037
on the endoscopists’ preference. The use of transnasal unsedated endoscopy has now been extended to placement of feeding tubes in critically ill patients18-20 with reduction in procedure time and enhanced safety and diminished medication requirements compared with the transoral approach,20 with comparable results to fluoroscopic techniques for feeding tube placement.21 Despite these advances, the GI community has not yet embraced this approach for multiple reasons, one of them being that it requires more expertise and skill. Although transoral unsedated endoscopy with ultrathin endoscopes does not involve significant change in a familiar technique, it has been our experience that there is a significant learning curve for mastering the transnasal technique, albeit steep, even for very experienced endoscopists. The transnasal unsedated approach requires familiarity with nasal and pharyngeal anatomy and expertise with transnasal intubation and nasopharyngeal advancement of the endoscope in the upright position. In contrast to the gastroenterology community’s reluctance to embrace these unsedated techniques, transnasal unsedated esophagoscopy has gained wide popularity as
874 GASTROINTESTINAL ENDOSCOPY Volume 64, No. 6 : 2006
www.giejournal.org
Saeian & Shaker
Editorial
an office procedure among otolaryngologists for examination of the esophagus and the pharynx and larynx in patients with reflux-related symptoms.22,23 The reason for this difference seems to be the familiarity of these specialists with transnasal passage of the endoscope in an unsedated patient and familiarity with the anatomy of the aerodigestive tract and its endoscopic evaluation. The office-based aspect of their practice also lends itself well to this approach. In final analysis, widespread use of unsedated techniques will require acceptance by patients and physicians, comfort and expertise with these techniques by endoscopists, and potential financial and quality-of-life incentives (eg, more rapid room turnover, no work loss for patients). Patient acceptance will depend heavily on proper education about the procedure and information on its comparative risks and benefits. To date, this type of patient education has not been systematically used. Endoscopists’ preference and comfort are more complex and depend on a number of factors, such as the availability of the proper setup and personnel for unsedated EGD, time required for the procedure, and adequate training, especially if the transnasal technique is chosen. These may be the main reasons for the higher popularity of this technique by otolaryngologists compared with gastroenterologists. In this issue of Gastrointestinal Endoscopy Horiuchi and Nakayama24 report on a fundamental and recognized aspect of unsedated endoscopy, namely, the effect of endoscope diameter on acceptability of and tolerance by patients. Size does indeed matter. Their multifaceted study shows that unsedated endoscopy by the transoral route using an endoscope with a 5.2-mm diameter performs equally well but is significantly better tolerated than either a 6.5-mm diameter or a sedated examination with a 9.0-mm endoscope. The latter comparison may be particularly prone to the potential of recall bias because patients were asked to compare the procedure to one performed some 18 months earlier. All endoscopes had similar optical quality. These findings corroborate previous reports that compared the acceptability of 5.3-mm and 5.9-mm diameter endoscopes according to the unsedated transnasal technique of EGD.8 The lack of a difference in the willingness of the patient to repeat the same procedure (90% vs 83%, P Z.52) with the 5.2-mm versus the 6.5-mm diameter endoscope does not suggest a significant advantage. This lack of difference may in part be due to the fact that the 6.5-mm endoscope is itself of significantly smaller diameter than standard endoscopes (eg, 9.0-9.8 mm). Although extrapolation of these findings to the U.S. population may not be valid, the study by Garcia et al17 performed in California in which only 18 of 80 patients were of Asian descent reported that patients were just as willing to undergo repeat examination with unsedated ultrathin endoscopy as with sedated standard endoscopy. Whether the transnasal or transoral route of intubation is used, the diameter of the endoscope has now been shown
in several studies to be the single most important factor in patient comfort and therefore tolerance of the procedure. Subsequent willingness to undergo repeat examination also follows this paradigm. From the endoscopist’s perspective, the optical quality of the instrument, ease and adequacy of suctioning mechanism, and ability to obtain adequate biopsy specimens are important issues. The use of even smaller, battery-powered instruments has been limited in part as a result of poor optical quality and thus far remains of unclear benefit. Optical quality of ultrathin scopes as slim as 4.8 mm is now comparable to larger endoscopes used for conventional upper endoscopy. However, the suctioning capability of the ultrathin endoscopes is much weaker. In addition, the air/water and biopsy channels are shared in some of the endoscopes, which poses difficulty in visualization during biopsy specimen acquisition, particularly near the gastroesophageal junction. Resolving these shortcomings will undoubtedly enhance ease of operation.
www.giejournal.org
Volume 64, No. 6 : 2006 GASTROINTESTINAL ENDOSCOPY 875
DISCLOSURE The authors have no financial arrangements (eg, consultancies, stock ownership, equity interests, patent-licensing arrangements, research support, major honoraria, etc) with a company whose product figures prominently in this article or with a company making a competing product except as disclosed on a separate attachment. Kia Saeian, MD Reza Shaker, MD MCW Dysphagia Institute Division of Gastroenterology and Hepatology Medical College of Wisconsin Milwaukee, Wisconsin, USA
REFERENCES 1. Modlin IM. The evolution of therapy in gastroenterology: a vintage of digestion. Montreal, Canada: Axcan Pharma; 2002. 2. Bell GD. Review article: premedication and intravenous sedation for upper gastrointestinal endoscopy. Aliment Pharmacol Ther 1990;4: 103-22. 3. O’Connor KW, Jones S. Oxygen desaturation is common and clinically underappreciated during elective endoscopic procedures. Gastrointest Endosc 1990;36:S2-4. 4. Scott-Coombes DM, Thompson JN. Hypoxia during upper gastrointestinal endoscopy is caused by sedation. Endoscopy 1993;25:308-9. 5. Lieberman DA, Wuerker CK, Katon RM. Cardiopulmonary risk of esophagogastroduodenoscopy: role of endoscope diameter and systemic sedation. Gastroenterology 1985;88:468-72. 6. Shaker R. Unsedated trans-nasal pharyngoesophagogastroduodenoscopy (T-EGD): technique. Gastrointest Endosc 1994;40:346-8. 7. Dean R, Dua K, Massey B, et al. A comparative study of unsedated transnasal esophagogastroduodenoscopy and conventional EGD. Gastrointest Endosc 1996;44:422-4.
Editorial
Saeian & Shaker
8. Craig A, Hanlon J, Dent J, et al. A comparison of transnasal and transoral endoscopy with small-diameter endoscopes in unsedated patients. Gastrointest Endosc 1999;49:292-6. 9. Zaman A, Hahn M, Hapke R, et al. A randomized trial of peroral versus transnasal unsedated endoscopy using an ultrathin videoendoscope. Gastrointest Endosc 1999;49:279-84. 10. Dumortier J, Ponchon T, Scoazec JY, et al. Prospective evaluation of transnasal esophagogastroduodenoscopy: feasibility and study on performance and tolerance. Gastrointest Endosc 1999;49:285-91. 11. Roy JF, Deforest D, Marek TA. Prospective comparison of nasal versus oral indertion of a thin video endoscope in healthy volunteers. Endoscopy 1996;28:422-4. 12. Sorbi D, Gostout CJ, Henry J, et al. Unsedated small-caliber esophagogastroduodenoscopy (EGD) versus conventional EGD: a comparative study. Gastroenterology 1999;117:1301-7. 13. Thota PN, Zuccaro G Jr, Vargo JJ II, et al. A randomized prospective trial comparing unsedated esophagoscopy via transnasal and transoral routes using a 4-mm video endoscope with conventional endoscopy with sedation. Endoscopy 2005;37:559-65. 14. Saeian K, Townsend WF, Rochling FA, et al. Unsedated transnasal EGD: an alternative approach to conventional esophagogastroduodenoscopy for documenting Helicobacter pylori eradication. Gastrointest Endosc 1999;49:297-301. 15. Saeian K, Staff D, Knox J, et al. Unsedated transnasal endoscopy: a new technique for accurately detecting and grading esophageal varices in cirrhotic patients. Am J Gastroenterol 2002;97:2246-9.
16. Saeian K, Staff DM, Vasilopoulos S, et al. Unsedated transnasal endoscopy accurately detects Barrett’s metaplasia and dysplasia. Gastrointest Endosc 2002;56:472-8. 17. Garcia RT, Cello JP, Nguyen MH, et al. Unsedated ultrathin EGD is well accepted when compared with conventional sedated EGD: a multicenter randomized trial. Gastroenterology 2003;125:1606-12. 18. Dranoff JA, Angood PJ, Topazian M. Transnasal endoscopy for enteral feeding tube placement in critically ill patients. Am J Gastroenterol 1999;94:2902-4. 19. O’Keefe SJ, Foody W, Gill S. Transnasal endoscopic placement of feeding tubes in the intensive care unit. JPEN J Parenter Enteral Nutr 2003; 27:349-54. 20. Kulling D, Bauerfeind P, Fried M. Transnasal versus transoral endoscopy for the placement of nasoenteral feeding tubes in critically ill patients. Gastrointest Endosc 2000;52:506-10. 21. Fang JC, Hilden K, Holubkov R, et al. Transnasal endoscopy vs fluoroscopy for the placement of nasoenteric feeding tubes in critically ill patients. Gastrointest Endosc 2005;62:661-6. 22. Aviv JE, Takoudes TG, Ma G, et al. Office-based esophagoscopy: a preliminary report. Otolaryngol Head Neck Surg 2001;125:170-5. 23. Postma GN, Cohen JT, Belafsky PC, et al. Transnasal esophagoscopy: revisited (over 700 consecutive cases). Laryngoscope 2005;115: 321-3. 24. Horiuchi A, Nakayama Y. Unsedated ultrathin EGD by using a 5.2-mm– diameter videoscope: evaluation of acceptability and diagnostic accuracy. Gastrointest Endosc 2006;64:868-73.
876 GASTROINTESTINAL ENDOSCOPY Volume 64, No. 6 : 2006
www.giejournal.org