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Position change during colonoscopy: the oldest and best trick in the book

2015; Elsevier BV; Volume: 82; Issue: 3 Linguagem: Inglês

10.1016/j.gie.2015.03.1987

1097-6779

Ana Wilson, Brian P. Saunders,

Colorectal Cancer Surgical Treatments

Finding and removing polyps at screening colonoscopy is fundamental to effective colon cancer prevention and allows accurate risk stratification to inform safe future surveillance intervals. The adenoma detection rate (ADR) has emerged as the key performance indicator of quality colonoscopy, and any new technique that improves ADR is most welcome. In recent years, multiple new devices and technologies to enhance ADR have been described, although few have shown persistent practical benefits. Despite the quest for exciting new technology, basic aspects of colonoscopic technique should not be forgotten or undervalued when it comes to detecting polyps. In this issue of Gastrointestinal Endoscopy, Ball et al,1Ball A.J. Johal S.S. Riley S.A. Position change during colonoscope withdrawal increases polyp and adenoma detection in the right but not in the left side of the colon: results of a randomized controlled trial.Gastrointest Endosc. 2015; 82: 488-494Abstract Full Text Full Text PDF Scopus (19) Google Scholar in a randomized controlled trial, report the benefits of position change, a simple and cost-neutral intervention during colonoscope withdrawal. Position change during examination of the colon is not a new concept and was first used by radiologists during barium enemas and more recently at CT colonography. The authors determined that moving the patient facilitated adequate distension at different colonic segments, with gas always rising to the least dependent areas and fluid running away to more dependent areas (Fig. 1). Thus, the hepatic flexure (right side of the body) is best examined in the left lateral position, the transverse colon (anterior location in the body) in the supine position, and the splenic flexure and descending colon (left side of the body) in the right lateral position. At colonoscopy, adequate luminal distension is considered a prerequisite to ensure optimal views of colonic mucosa, and failure to achieve it may compromise detection. Considering the physical structure of the colon, it is hard to see how this can be achieved without some degree of position change during colonoscopic examination. If the patient is kept in the left lateral position for the entire procedure, the splenic flexure and descending colon areas will always be dependent and collapsed, limiting views. Continuous air insufflation might help maintain luminal patency to some extent, but air will naturally move away from the left side of the colon to the right, leading to a risk of over-distension and even barotrauma proximally. Previous work from our unit reported that position changes during colonoscope withdrawal improved luminal distension in the transverse colon, splenic flexure, and descending colon.2East J.E. Suzuki N. Arebi N. et al.Position changes improve visibility during colonoscope withdrawal: a randomized, blinded, crossover trial.Gastrointest Endosc. 2007; 65: 263-269Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar In a subsequent randomized back-to-back study, that effect translated into significantly improved ADRs in those colonic segments after a position change from left lateral to supine (for transverse colon) and right lateral for splenic flexure and descending colon.3East J.E. Bassett P. Arebi N. et al.Dynamic patient position changes during colonoscope withdrawal increase adenoma detection: a randomized, crossover trial.Gastrointest Endosc. 2011; 73: 456-463Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar Similar results were reported by Koksal et al,4Koksal A.S. Kalkan I.H. Torun S. et al.A simple method to improve adenoma detection rate during colonoscopy: altering patient position.Can J Gastroenterol. 2013; 27: 509-512PubMed Google Scholar who found that position changes led to a 9.8% increase in ADR in the transverse colon, splenic flexure, and descending and sigmoid colon, although this group used both supine and right lateral positions in the left side of the colon. A major advantage of the study by Ball et al1Ball A.J. Johal S.S. Riley S.A. Position change during colonoscope withdrawal increases polyp and adenoma detection in the right but not in the left side of the colon: results of a randomized controlled trial.Gastrointest Endosc. 2015; 82: 488-494Abstract Full Text Full Text PDF Scopus (19) Google Scholar is its design and statistical analysis—like all colonoscopy studies, by nature it is open and cannot be blinded and is therefore susceptible to researcher's bias. The crossover design in which patients were randomized in a 1:1 ratio to undergo colonoscopic withdrawal in either the supine position followed by position change and vice versa minimizes the bias of the "carryover effect" (ie, first withdrawal alerts the endoscopist to what she or he may see on the second withdrawal). In addition, the researchers used the Prescott test to compare differences in proportions, which, unlike the McNemar test, takes into account the "period effect" (referring to better outcomes that may occur during the second "period"). Contrary to findings by East et al,3East J.E. Bassett P. Arebi N. et al.Dynamic patient position changes during colonoscope withdrawal increase adenoma detection: a randomized, crossover trial.Gastrointest Endosc. 2011; 73: 456-463Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar examining the left side of the colon in the right lateral position did not significantly increase the proportion of patients with ≥ 1 polyps and ≥1 adenomas compared with the supine position (unlike in a study by East et al3East J.E. Bassett P. Arebi N. et al.Dynamic patient position changes during colonoscope withdrawal increase adenoma detection: a randomized, crossover trial.Gastrointest Endosc. 2011; 73: 456-463Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar when position change for the left side of the colon was right lateral versus left lateral). However, examining the right side of colon in the left lateral position rather than the supine position significantly increased the proportion of patients with ≥1 polyp and ≥1 adenoma, which was not seen in the study by East et al,3East J.E. Bassett P. Arebi N. et al.Dynamic patient position changes during colonoscope withdrawal increase adenoma detection: a randomized, crossover trial.Gastrointest Endosc. 2011; 73: 456-463Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar but the latter study again compared left lateral versus left lateral for the right side of the colon. This is of significance because colonoscopic miss rates for cancers are higher in the right side of the colon than the left, possibly because in the right side, serrated lesions tend to be flatter, more subtle, more numerous, and more difficult to detect. So why are position changes not universally used? An answer to this question may in part be related to varying practices regarding patient sedation. A nonsedated or lightly sedated patient is easy to move and can cooperate with the process. Deeply sedated or anesthetized patients must be physically manipulated, increasing the procedure time and needing significant coordination from endoscopy assistants. In the United Kingdom, light sedation or no sedation is the norm for colonoscopy. Patients are advised during the consent process that they will be asked to move position several times during the procedure and that their cooperation in this process is required. Having 2 monitors, 1 on each side of the procedure trolley, allows interested patients to continue to view their examination regardless of their position. This avoids the need to turn their heads back toward the main monitor to watch the "action" when in the right lateral position and inadvertently falling back into the supine position. Another perceived problem with position changes is that they may slow the colonoscopy process. However, in a study from Ou et al,5Ou G. Kim E. Lakzadeh P. et al.A randomized controlled trial assessing the effect of prescribed patient position changes during colonoscope withdrawal on adenoma detection.Gastrointest Endosc. 2014; 80: 277-283Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar it took, on average, just an additional 44 seconds to complete position changes per examination. Although not studied to date, subsequent polypectomy after optimizing patient position is likely to be a much quicker process, more than compensating for the added time to perform the move as well as enhancing control and safety. In conclusion, we agree with Ball et al1Ball A.J. Johal S.S. Riley S.A. Position change during colonoscope withdrawal increases polyp and adenoma detection in the right but not in the left side of the colon: results of a randomized controlled trial.Gastrointest Endosc. 2015; 82: 488-494Abstract Full Text Full Text PDF Scopus (19) Google Scholar that this simple, cost-neutral intervention enhances the colonoscopy examination. As such, it should be taught to trainees as part of the colonoscopy curriculum and be recorded prospectively as a quality indicator. Other proven detection interventions include optimizing bowel preparation, allowing adequate time for the examination (>6 minutes), using high-definition colonoscopes (recommended by the European Society of Gastrointestinal Endoscopy6Kaminski M.F. Hassan C. Bisschops R. et al.Advanced imaging for detection and differentiation of colorectal neoplasia: European Society of Gastrointestinal Endoscopy (ESGE) Guideline.Endoscopy. 2014; 46: 435-449Crossref PubMed Scopus (230) Google Scholar), and using dye spray application, although the latter has not caught on for routine colonoscopy because of increased time and costs. Use of "cuffs" or "caps" and the latest "blue light" technologies may also be beneficial, and several studies are underway to assess their utility; however, position change remains complementary to all these new technologies. Looking to the future, polyp detection may become automated and computer-aided with high-speed video processing targeting abnormal mucosal areas faster than the human eye. Until that day, a quality examination will involve multiple components: comprehensive bowel cleansing, careful colonoscope manipulation, adequate distension, and recognition by the endoscopist of the diverse variation in pathology appearance, to name a few. Position change is a small incremental way to ensure an optimal examination and, although easily forgotten in a technology-driven age, should be used as a tried and tested way to maximize patient care. The following authors disclosed financial relationships relevant to this publication: A. Wilson: Equipment support from Olympus; B. P. Saunders: Equipment support from Olympus, Aquilant, and Arc Medical; speaker for Olympus; advisory board member of Creo Medical. Position change during colonoscope withdrawal increases polyp and adenoma detection in the right but not in the left side of the colon: results of a randomized controlled trialGastrointestinal EndoscopyVol. 82Issue 3PreviewIt has been suggested that changing patient position during colonoscope withdrawal increases adenoma detection. The results of previous studies have been conflicting. Full-Text PDF