- Email: [email protected]
Patient comfort during colonoscopy
Seminars in Colon and Rectal Surgery 28 (2017) 1–3
Contents lists available at ScienceDirect
Seminars in Colon and Rectal Surgery journal homepage: www.elsevier.com/locate/yscrs
Patient comfort during colonoscopy Shaun Brown, DO, FACSa, Charles B. Whitlow, MD, FACSb,n a b
William Beaumont Army Medical Center, El Paso, TX Department of Colon and Rectal Surgery, Ochsner Medical Center, New Orleans, LA
a b s t r a c t Patient comfort plays a role in acceptance of the procedure both initially and in surveillance. Unsedated colonoscopy should be offered to appropriate motivated patients and the use of some of the techniques discussed above (CO2 insufflation, water-aided colonoscopy, and smaller diameter scopes) may improve patient comfort during these exams. Likewise these techniques could allow for a decrease in the amount of sedation required for the exam and thus allow for fewer cardiopulmonary complications. Additional benefits beyond patient comfort may also impact the adaptation of these adjuncts. & 2017 Published by Elsevier Inc.
Introduction Colonoscopy is the most commonly performed colorectal cancer screening test performed in the United States and is the most common test for evaluating symptoms of the lower gastrointestinal tract. It is estimated that as many as 15 million colonoscopies are performed per year in this country.1 Patient comfort plays a role in acceptance of the procedure both initially and in surveillance. Additionally, it is affects the quality of the exam. This article discusses techniques that endoscopists can use to keep patients comfortable and in some cases may add to the quality of the procedure.
Sedation The vast majority of patients in the United States are administered sedation for colonoscopy. This is most commonly in the form of a combination of an opioid and a benzodiazepine (fentanyl and midazolam is the most commonly used combination in current use). Propofol use has increased in the past 5 years.2 Unsedated colonoscopy has the obvious advantages of decreased cost, absence of sedation complications, immediate return to normal function, and no need for an escort for transportation after the exam. While overall data demonstrates a lower cecal intubation rate (CIR) in unsedated patients, at least one study has shown the use of on demand sedation in these patients brings n Corresponding author at: Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA 70121. E-mail address: [email protected] (C.B. Whitlow).
http://dx.doi.org/10.1053/j.scrs.2016.11.004 1043-1489/& 2017 Published by Elsevier Inc.
the CIR up to the rate of patients who are sedated for the entire procedure.3,4 In two prospective studies 28–56% of patients offered unsedated colonoscopy elected to begin the exam unsedated and over 80% of patients completed the exam unsedated.3,4 Experienced endoscopists who are comfortable with the increased amount of time and communication these exams require should consider offering this option to motivated patients—however, arrangements for sedation should be available if patient discomfort precludes a safe and complete exam. The choice of benzodiazepine/opioid vs. propofol has several issues to consider. Included in this are cost, personnel requirements, speed of recovery, complication rates and patient/physician satisfaction. In general, the benzodiazepine/opioid is equated with minimal moderated sedation while propofol is used for deep sedation or even general anesthesia. Propofol is associated with a quicker, more reliable onset, shorter recovery times, improved patient and physician satisfaction and is especially useful in difficult to sedate patents—such as those on anxiolytic, antidepressant, or narcotics. The disadvantages of propofol are the increased overall cost of the drug and personnel required to administer and monitor its use. There is an FDA black box warning for propofol that stating that only persons trained in administering general anesthesia and not directly involved in the performance of the procedure should administer propofol. Therefore there is usually an anesthesiologist or nurse anesthetist present when propofol is used for procedural sedation. Local state licensing boards and hospital privileging have a great effect on how propofol is used in colonoscopy at a particular institution. The authors' personal experience with propofol has been that it provides excellent and safe sedation; however, patients require airway attention more frequently and positional changes are more
2
S. Brown, C.B. Whitlow / Seminars in Colon and Rectal Surgery 28 (2017) 1–3
difficult and are associated with an annoying cough. The benzodiazepine/opioid combination is still an acceptable technique for sedation but does result in slower return to baseline function and discharge, which can decrease efficiency of busy endoscopy units. The overall economic arguments for a particular model of procedural sedation are rapidly changing and are beyond the scope of this article, but definitely enter into local decision making.
CO2 insufflation colonoscopy Comfort during and after colonoscopy is major issue influencing patient tolerance and compliance with screening recommendations. Several procedural adjuncts have been described to decrease pain, reduce the amount of sedation required, or enable performance of unsedated colonoscopy. The two techniques that seem to have attracted the most attention are CO2 insufflation and water-aided colonoscopy. Adequate distention of the lumen during colonoscopy is required for good visibility. As much as 8–17 L of room air may be instilled during a procedure, compared to the 0.7–1.0 L per day that is naturally produced in the gastrointestinal tract.5 Room air is poorly absorbed from the colon. While a significant portion of this air is removed via suction during the withdrawal phase of the procedure a substantial amount remains.6 CO2 is absorbed from the colon 160 times faster than nitrogen and 12 times faster than oxygen, which are the two main elements of air.7 This rapid absorption is the mechanism by which CO2 insufflation is believed to decrease pain from colonoscopy. This technique requires a CO2 regulator and a source of the gas–gas line or refillable cylinders. CO2 insufflation is an add-on purchase the manufactures do not widely promote. This may be one reason this technique has not been widely adapted. Memon et al.8 performed a systemic review and meta-analysis of 24 randomized trials with 3996 patients comparing CO2 vs. air insufflation (AI). Procedural sedation included unsedated patients, minimal sedation, and conscious sedation. Cecal intubation rates (CIR) and cecal intubation times (CIT) were similar for the two groups. The methodology in this study involved comparing patient with any pain (visual analog score [VAS] 4 0) to those with no pain. Using these criteria they found a benefit with regards to pain during the procedure, and at 15 min, 30 min–2 h, 6 h, 24 h postprocedure. There were no differences in complications and endtidal CO2 levels were similar during and after the procedure. The authors concluded that CO2 instead of air should be routinely utilized for colonoscopy. There has been no report that demonstrated an increased complication rate for CO2 colonoscopy. The additional cost includes the gas regulator that is connected to the colonoscope and the cost of CO2. Data in regards to the overall cost is limited, however, Yamano et al.5 analyzed the cost difference between the two types of insufflation. According to these authors, the total cost of endoscopy with CO2 increases 2.5% per colonoscopy (400 Yen or $3.8 U.S. dollars). The benefits for routine screening colonoscopy appear to be minimal and it does not appear to increase the ability to perform unsedated colonoscopy. However, for patient with suspected obstruction or intestinal distention pre-procedure, CO2 is an excellent option. It may also have benefit in cases in which advanced polyp resection techniques (endoscopic mucosal resection, endoscopic submucosal dissection) are used as well as intraoperative colonoscopy. Water-aided colonoscopy Two types of water-aided colonoscopy have been described, water immersion (WI) and water exchange (WE). Water
immersion is best described as water infusion as an adjunct to air insufflation.9 Suction of residual feces during insertion is not described as an integral component of WI, and residual air is not removed because the air compartment is used to facilitate advancement.10 In this technique water is infused during insertion of the colonoscope and is removed during scope withdrawal. After cecal/ileal intubation the water is removed and gas insufflation is used for withdrawal, mucosal inspection and any biopsy or polypectomy that need to be performed. Water exchange is a modification of water immersion that minimizes distention through airless insertion (turning off insufflation, suctioning all residual air pockets) and maximizing cleanliness while advancing to the cecum. The rationale is that insufflated gas quickly travels to the cecum, which lengthens the colon and sharpens the angulation of the flexures.9 Several randomized trials have been performed comparing water immersion or water exchange to air insufflation. A systematic review of these studies was published in 2012.9 Eight of the studies compared water immersion, four compared water exchange. Sedation protocols included no sedation, “minimal” sedation for premedication and on-demand sedation. In the water immersion studied all but one showed a statistically significant reduction in pain scores. It should be noted that in only 2 studies the mean pain score was over 5 and the absolute mean reduction was less than 2 on a 10-point VAS for all studies. In the water exchange studies the differences in pain scores were more pronounced. Cadoni et al. performed a randomized prospective patient blinded study comparing unsedated colonoscopy utilizing WE vs. WI vs. CO2 vs. and air insufflation. WE was associated with less insertional pain and a greater percentage of patients that reported a painless colonoscopy, however, only 12.9% of patients reported a painless procedure.11 There was no difference between groups in regards to willingness to repeat the examination, or overall satisfaction. This bears the question whether the difference in the VAS is clinically relevant for the patients. Another randomized trial of WE vs. WI vs. AI during minimal sedation colonoscopy demonstrated a higher percentage of painless insertion in the WE group (61% WE vs. 43% WI vs. 30% AI).12 While there was no difference in ADR between groups, WE was associated with a higher ADR rate for right-sided polyps. Of note, procedures utilizing WE resulted in a longer insertion time to cecum (16.4 min WE vs. 5.7 min WI vs. 6.3 min AI). The authors concluded that the longer procedure time associated with WE was the result of suctioning dirty water and air pockets, which is time consuming. There is a learning curve with water exchange colonoscopy and this technique may result in longer procedure times, but there is no special equipment required beyond the standard high volume irrigator that is widely available. Both CO2 insufflation and water-aided colonoscopy may be useful adjuncts in patients who desire unsedated or minimal sedation procedures. The possible benefit in adenoma detection rate with water-aided colonoscopy warrants further study.
Colonoscope type/size Colonoscope diameters typically vary from 11.3 to 13.2 mm and a 9.7-mm ultrathin videocolonoscope is now available. While some have found a decrease in pain in unsedated exams, Chen et al.13 did not demonstrate any difference in pain when comparing colonoscopies performed using in scopes of 11.3 mm, 12.2 mm or 13.2 mm. While pain may not be improved, smaller scopes may allow for completion of difficult scopes, even those in which an adult scope has been previously used unsuccessfully. Another feature of some of the most current colonoscopes is the variable
S. Brown, C.B. Whitlow / Seminars in Colon and Rectal Surgery 28 (2017) 1–3
stiffness function. In at least two studies fewer patients experienced moderate or severe pain in unsedated colonoscopies compared to a standard colonoscope.13,14
Patient position The standard starting position for colonoscopy is with the patient in the left-lateral position. Patients are then moved to alternate positions, most commonly supine, as needed to complete the exam. Several authors have advocated other positions. Uddin et al.15 described putting patients with a BMI 4 30 in the prone position. These patients were sedated and no difference in pain was noted, however, cecal intubation times were lower and less repositioning was needed for prone patients. Vergis et al. compared starting the exam right-side down vs. left-side down and reported decreased cecal intubation times and increased patient comfort for patients started in the right-side down position. Benefit was greatest in female patients with prior non-colonic abdominal surgery.16
Miscellaneous Another colonoscope adaptation that has been investigated is magnetic endoscopic imaging. A computerized image of the colonoscope is generated by detection of electromagnetic fields generated by coils in the colonoscope and adjacent to the patient. There is no data indicating patients have lower pain scores or require less sedation. What benefit there is to this technique appears mostly related to training endoscopists.13,17,9 Various medical adjuncts have been studied for increasing patient comfort. Maslekar et al.18 reported lower pain scores for patients receiving nitrous oxide vs. midazolam-fentanyl but another study found that it is not an effective substitute for benzodiazepine/opioid sedation. Glucagon was once routinely used in colonoscopy.19 A 2013 study found a statistically significant decrease in pain scores but the clinical difference was less than 1.7 on a 10 point visual analog scale.20 Church demonstrated equivalent efficacy of warm water vs. glucagon for reducing colonic spasm.21 Hyoscyamine and scopolamine have both been studied and failed to show significant changes in patient comfort.
Conclusion It seems unlikely that a substantial number of patients in the United States will be willing to undergoing unsedated colonoscopy in the current healthcare system. Economic factors could make unsedated colonoscopy attractive to some but many patients would simply choose not to undergo the procedure if sedation were not offered. Unsedated colonoscopy should be offered to appropriate motivated patients and the use of some of the techniques discussed above (CO2 insufflation, water-aided colonoscopy, and smaller diameter scopes) may improve patient comfort during these exams. Likewise these techniques could allow for a decrease in the amount of sedation required for the exam and thus
3
allow for fewer cardiopulmonary complications. Additional benefits beyond patient comfort may also impact the adaptation of these adjuncts. The choice between propofol vs. benzodiazepine/ opioid for sedation for a colonoscopy is dependent on a variety of factors.
References 1. Cohen LB, Wecsler JS, John N, et al. Endoscopic sedation in the United States: results from a nationwide survey. Am J Gastroenterol. 2006;101(5):967–974. 2. Childers RE, Williams JL, Sonnenberg A. Practice patterns of sedation for colonoscopy. Gastrointest Endosc. 2015;82(3):503–511. 3. Paggi S, Rondonotti E, Amato A, et al. Resect and discard strategy in clinical practice: a prospective cohort study. Endoscopy. 2012;44(10):899. 4. Petrini JL, Egan JV, Hahn WV. Unsedated colonoscopy: patient characteristics and satisfaction in a community-based endoscopy unit. Gastrointest Endosc. 2009;69(3):567–572. 5. Yamano HO, Yoshikawa K, Kimura T, et al. Carbon dioxide insufflation for colonoscopy: evaluation of gas volume, abdominal pain, examination time and transcutaneous partial CO2 pressure. J Gastroenterol. 2010;45(12):1235–1240. 6. Sumanac K, Zealley I, Fox BM, et al. Minimizing postcolonoscopy abdominal pain by using CO2 insufflation: a prospective, randomized, double blind, controlled trial evaluating a new commercially. Gastrointest Endosc. 2002;56(2): 190–194. 7. Saltzman HA, Sieker HO. Intestinal response to changing gaseous environments: normobaric and hyperbaric observations. Ann N Y Acad Sci. 1968;150 (1):31–39. 8. Memon M, Memon B, Yunus R, Khan S. Carbon dioxide versus air insufflation for elective colonoscopy: a meta-analysis and systematic review of randomized controlled trials. Surg Laparosc. 2016;26(15):102–116. 9. Leung FW, Amato A, Ell C, et al. Water-aided colonoscopy: a systematic review. Gastrointest Endosc. 2012;76(3):657–666. 10. Radaelli F, Paggi S, Amato A, Terruzzi V. Warm water infusion versus air insufflation for unsedated colonoscopy: a randomized, controlled trial. Gastrointest Endosc. 2010;72(4):701–709. 11. Cadoni S, Falt P, Gallittu P, et al. Water exchange is the least painful colonoscope insertion technique and increases completion of unsedated colonoscopy. Clin Gastroenterol Hepatol. 2015;13(11):1972–1980. 12. Hsieh YH, Koo M, Leung FW. A patient-blinded randomized, controlled trial comparing air insufflation, water immersion, and water exchange during minimally sedated colonoscopy. Am J Gastroenterol. 2014;109(9):1390–1400. 13. Chen PJ, Shih YL, Chu HC, Chang WK, Hsieh TY, Chao YC. A prospective trial of variable stiffness colonoscopes with different tip diameters in unsedated patients. Am J Gastroenterol. 2008;103(6):1365–1371. 14. Ogawa T, Ohda Y, Nagase K, et al. Evaluation of discomfort during colonoscopy with conventional and ultrathin colonoscopes in ulcerative colitis patients. Dig Endosc. 2015;27(1):99–105. 15. Uddin FS, Iqbal R, Harford WV, et al. Prone positioning of obese patients for colonoscopy results in shortened cecal intubation times: a randomized trial. Dig Dis Sci. 2013;58(3):782–787. 16. Vergis N, McGrath AK, Stoddart CH, Hoare JM. Right Or Left in COLonoscopy (ROLCOL) &quest: a randomized controlled trial of right-versus left-sided starting position in colonoscopy. Am J Gastroenterol. 2015;110(11):1576–1581. 17. Teshima CW, Zepeda-Gómez S, AlShankiti SH, Sandha GS. Magnetic imagingassisted colonoscopy vs conventional colonoscopy: a randomized controlled trial. World J Gastroenterol. 2014;20(36):13178–13184. 18. Maslekar S, Gardiner A, Hughes M, Culbert B, Duthie GS. Randomized clinical trial of Entonoxs versus midazolam–fentanyl sedation for colonoscopy. Br J Surg. 2009;96(4):361–368. 19. Løberg M, Furholm S, Hoff I, Aabakken L, Hoff G, Bretthauer M. Nitrous oxide for analgesia in colonoscopy without sedation. Gastrointest Endosc. 2011;74(6): 1347–1353. 20. Tamai N, Matsuda K, Sumiyama K, Yoshida Y, Tajiri H. Glucagon facilitates colonoscopy and reduces patient discomfort: a randomized double-blind controlled trial with salivary amylase stress analysis. Eur J Gastroenterol Hepatol. 2013;25(5):575–579. 21. Church JM. Warm water irrigation for dealing with spasm during colonoscopy: simple, inexpensive, and effective. Gastrointest Endosc. 2002;56(5):672–674.
Contents lists available at ScienceDirect
Seminars in Colon and Rectal Surgery journal homepage: www.elsevier.com/locate/yscrs
Patient comfort during colonoscopy Shaun Brown, DO, FACSa, Charles B. Whitlow, MD, FACSb,n a b
William Beaumont Army Medical Center, El Paso, TX Department of Colon and Rectal Surgery, Ochsner Medical Center, New Orleans, LA
a b s t r a c t Patient comfort plays a role in acceptance of the procedure both initially and in surveillance. Unsedated colonoscopy should be offered to appropriate motivated patients and the use of some of the techniques discussed above (CO2 insufflation, water-aided colonoscopy, and smaller diameter scopes) may improve patient comfort during these exams. Likewise these techniques could allow for a decrease in the amount of sedation required for the exam and thus allow for fewer cardiopulmonary complications. Additional benefits beyond patient comfort may also impact the adaptation of these adjuncts. & 2017 Published by Elsevier Inc.
Introduction Colonoscopy is the most commonly performed colorectal cancer screening test performed in the United States and is the most common test for evaluating symptoms of the lower gastrointestinal tract. It is estimated that as many as 15 million colonoscopies are performed per year in this country.1 Patient comfort plays a role in acceptance of the procedure both initially and in surveillance. Additionally, it is affects the quality of the exam. This article discusses techniques that endoscopists can use to keep patients comfortable and in some cases may add to the quality of the procedure.
Sedation The vast majority of patients in the United States are administered sedation for colonoscopy. This is most commonly in the form of a combination of an opioid and a benzodiazepine (fentanyl and midazolam is the most commonly used combination in current use). Propofol use has increased in the past 5 years.2 Unsedated colonoscopy has the obvious advantages of decreased cost, absence of sedation complications, immediate return to normal function, and no need for an escort for transportation after the exam. While overall data demonstrates a lower cecal intubation rate (CIR) in unsedated patients, at least one study has shown the use of on demand sedation in these patients brings n Corresponding author at: Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA 70121. E-mail address: [email protected] (C.B. Whitlow).
http://dx.doi.org/10.1053/j.scrs.2016.11.004 1043-1489/& 2017 Published by Elsevier Inc.
the CIR up to the rate of patients who are sedated for the entire procedure.3,4 In two prospective studies 28–56% of patients offered unsedated colonoscopy elected to begin the exam unsedated and over 80% of patients completed the exam unsedated.3,4 Experienced endoscopists who are comfortable with the increased amount of time and communication these exams require should consider offering this option to motivated patients—however, arrangements for sedation should be available if patient discomfort precludes a safe and complete exam. The choice of benzodiazepine/opioid vs. propofol has several issues to consider. Included in this are cost, personnel requirements, speed of recovery, complication rates and patient/physician satisfaction. In general, the benzodiazepine/opioid is equated with minimal moderated sedation while propofol is used for deep sedation or even general anesthesia. Propofol is associated with a quicker, more reliable onset, shorter recovery times, improved patient and physician satisfaction and is especially useful in difficult to sedate patents—such as those on anxiolytic, antidepressant, or narcotics. The disadvantages of propofol are the increased overall cost of the drug and personnel required to administer and monitor its use. There is an FDA black box warning for propofol that stating that only persons trained in administering general anesthesia and not directly involved in the performance of the procedure should administer propofol. Therefore there is usually an anesthesiologist or nurse anesthetist present when propofol is used for procedural sedation. Local state licensing boards and hospital privileging have a great effect on how propofol is used in colonoscopy at a particular institution. The authors' personal experience with propofol has been that it provides excellent and safe sedation; however, patients require airway attention more frequently and positional changes are more
2
S. Brown, C.B. Whitlow / Seminars in Colon and Rectal Surgery 28 (2017) 1–3
difficult and are associated with an annoying cough. The benzodiazepine/opioid combination is still an acceptable technique for sedation but does result in slower return to baseline function and discharge, which can decrease efficiency of busy endoscopy units. The overall economic arguments for a particular model of procedural sedation are rapidly changing and are beyond the scope of this article, but definitely enter into local decision making.
CO2 insufflation colonoscopy Comfort during and after colonoscopy is major issue influencing patient tolerance and compliance with screening recommendations. Several procedural adjuncts have been described to decrease pain, reduce the amount of sedation required, or enable performance of unsedated colonoscopy. The two techniques that seem to have attracted the most attention are CO2 insufflation and water-aided colonoscopy. Adequate distention of the lumen during colonoscopy is required for good visibility. As much as 8–17 L of room air may be instilled during a procedure, compared to the 0.7–1.0 L per day that is naturally produced in the gastrointestinal tract.5 Room air is poorly absorbed from the colon. While a significant portion of this air is removed via suction during the withdrawal phase of the procedure a substantial amount remains.6 CO2 is absorbed from the colon 160 times faster than nitrogen and 12 times faster than oxygen, which are the two main elements of air.7 This rapid absorption is the mechanism by which CO2 insufflation is believed to decrease pain from colonoscopy. This technique requires a CO2 regulator and a source of the gas–gas line or refillable cylinders. CO2 insufflation is an add-on purchase the manufactures do not widely promote. This may be one reason this technique has not been widely adapted. Memon et al.8 performed a systemic review and meta-analysis of 24 randomized trials with 3996 patients comparing CO2 vs. air insufflation (AI). Procedural sedation included unsedated patients, minimal sedation, and conscious sedation. Cecal intubation rates (CIR) and cecal intubation times (CIT) were similar for the two groups. The methodology in this study involved comparing patient with any pain (visual analog score [VAS] 4 0) to those with no pain. Using these criteria they found a benefit with regards to pain during the procedure, and at 15 min, 30 min–2 h, 6 h, 24 h postprocedure. There were no differences in complications and endtidal CO2 levels were similar during and after the procedure. The authors concluded that CO2 instead of air should be routinely utilized for colonoscopy. There has been no report that demonstrated an increased complication rate for CO2 colonoscopy. The additional cost includes the gas regulator that is connected to the colonoscope and the cost of CO2. Data in regards to the overall cost is limited, however, Yamano et al.5 analyzed the cost difference between the two types of insufflation. According to these authors, the total cost of endoscopy with CO2 increases 2.5% per colonoscopy (400 Yen or $3.8 U.S. dollars). The benefits for routine screening colonoscopy appear to be minimal and it does not appear to increase the ability to perform unsedated colonoscopy. However, for patient with suspected obstruction or intestinal distention pre-procedure, CO2 is an excellent option. It may also have benefit in cases in which advanced polyp resection techniques (endoscopic mucosal resection, endoscopic submucosal dissection) are used as well as intraoperative colonoscopy. Water-aided colonoscopy Two types of water-aided colonoscopy have been described, water immersion (WI) and water exchange (WE). Water
immersion is best described as water infusion as an adjunct to air insufflation.9 Suction of residual feces during insertion is not described as an integral component of WI, and residual air is not removed because the air compartment is used to facilitate advancement.10 In this technique water is infused during insertion of the colonoscope and is removed during scope withdrawal. After cecal/ileal intubation the water is removed and gas insufflation is used for withdrawal, mucosal inspection and any biopsy or polypectomy that need to be performed. Water exchange is a modification of water immersion that minimizes distention through airless insertion (turning off insufflation, suctioning all residual air pockets) and maximizing cleanliness while advancing to the cecum. The rationale is that insufflated gas quickly travels to the cecum, which lengthens the colon and sharpens the angulation of the flexures.9 Several randomized trials have been performed comparing water immersion or water exchange to air insufflation. A systematic review of these studies was published in 2012.9 Eight of the studies compared water immersion, four compared water exchange. Sedation protocols included no sedation, “minimal” sedation for premedication and on-demand sedation. In the water immersion studied all but one showed a statistically significant reduction in pain scores. It should be noted that in only 2 studies the mean pain score was over 5 and the absolute mean reduction was less than 2 on a 10-point VAS for all studies. In the water exchange studies the differences in pain scores were more pronounced. Cadoni et al. performed a randomized prospective patient blinded study comparing unsedated colonoscopy utilizing WE vs. WI vs. CO2 vs. and air insufflation. WE was associated with less insertional pain and a greater percentage of patients that reported a painless colonoscopy, however, only 12.9% of patients reported a painless procedure.11 There was no difference between groups in regards to willingness to repeat the examination, or overall satisfaction. This bears the question whether the difference in the VAS is clinically relevant for the patients. Another randomized trial of WE vs. WI vs. AI during minimal sedation colonoscopy demonstrated a higher percentage of painless insertion in the WE group (61% WE vs. 43% WI vs. 30% AI).12 While there was no difference in ADR between groups, WE was associated with a higher ADR rate for right-sided polyps. Of note, procedures utilizing WE resulted in a longer insertion time to cecum (16.4 min WE vs. 5.7 min WI vs. 6.3 min AI). The authors concluded that the longer procedure time associated with WE was the result of suctioning dirty water and air pockets, which is time consuming. There is a learning curve with water exchange colonoscopy and this technique may result in longer procedure times, but there is no special equipment required beyond the standard high volume irrigator that is widely available. Both CO2 insufflation and water-aided colonoscopy may be useful adjuncts in patients who desire unsedated or minimal sedation procedures. The possible benefit in adenoma detection rate with water-aided colonoscopy warrants further study.
Colonoscope type/size Colonoscope diameters typically vary from 11.3 to 13.2 mm and a 9.7-mm ultrathin videocolonoscope is now available. While some have found a decrease in pain in unsedated exams, Chen et al.13 did not demonstrate any difference in pain when comparing colonoscopies performed using in scopes of 11.3 mm, 12.2 mm or 13.2 mm. While pain may not be improved, smaller scopes may allow for completion of difficult scopes, even those in which an adult scope has been previously used unsuccessfully. Another feature of some of the most current colonoscopes is the variable
S. Brown, C.B. Whitlow / Seminars in Colon and Rectal Surgery 28 (2017) 1–3
stiffness function. In at least two studies fewer patients experienced moderate or severe pain in unsedated colonoscopies compared to a standard colonoscope.13,14
Patient position The standard starting position for colonoscopy is with the patient in the left-lateral position. Patients are then moved to alternate positions, most commonly supine, as needed to complete the exam. Several authors have advocated other positions. Uddin et al.15 described putting patients with a BMI 4 30 in the prone position. These patients were sedated and no difference in pain was noted, however, cecal intubation times were lower and less repositioning was needed for prone patients. Vergis et al. compared starting the exam right-side down vs. left-side down and reported decreased cecal intubation times and increased patient comfort for patients started in the right-side down position. Benefit was greatest in female patients with prior non-colonic abdominal surgery.16
Miscellaneous Another colonoscope adaptation that has been investigated is magnetic endoscopic imaging. A computerized image of the colonoscope is generated by detection of electromagnetic fields generated by coils in the colonoscope and adjacent to the patient. There is no data indicating patients have lower pain scores or require less sedation. What benefit there is to this technique appears mostly related to training endoscopists.13,17,9 Various medical adjuncts have been studied for increasing patient comfort. Maslekar et al.18 reported lower pain scores for patients receiving nitrous oxide vs. midazolam-fentanyl but another study found that it is not an effective substitute for benzodiazepine/opioid sedation. Glucagon was once routinely used in colonoscopy.19 A 2013 study found a statistically significant decrease in pain scores but the clinical difference was less than 1.7 on a 10 point visual analog scale.20 Church demonstrated equivalent efficacy of warm water vs. glucagon for reducing colonic spasm.21 Hyoscyamine and scopolamine have both been studied and failed to show significant changes in patient comfort.
Conclusion It seems unlikely that a substantial number of patients in the United States will be willing to undergoing unsedated colonoscopy in the current healthcare system. Economic factors could make unsedated colonoscopy attractive to some but many patients would simply choose not to undergo the procedure if sedation were not offered. Unsedated colonoscopy should be offered to appropriate motivated patients and the use of some of the techniques discussed above (CO2 insufflation, water-aided colonoscopy, and smaller diameter scopes) may improve patient comfort during these exams. Likewise these techniques could allow for a decrease in the amount of sedation required for the exam and thus
3
allow for fewer cardiopulmonary complications. Additional benefits beyond patient comfort may also impact the adaptation of these adjuncts. The choice between propofol vs. benzodiazepine/ opioid for sedation for a colonoscopy is dependent on a variety of factors.
References 1. Cohen LB, Wecsler JS, John N, et al. Endoscopic sedation in the United States: results from a nationwide survey. Am J Gastroenterol. 2006;101(5):967–974. 2. Childers RE, Williams JL, Sonnenberg A. Practice patterns of sedation for colonoscopy. Gastrointest Endosc. 2015;82(3):503–511. 3. Paggi S, Rondonotti E, Amato A, et al. Resect and discard strategy in clinical practice: a prospective cohort study. Endoscopy. 2012;44(10):899. 4. Petrini JL, Egan JV, Hahn WV. Unsedated colonoscopy: patient characteristics and satisfaction in a community-based endoscopy unit. Gastrointest Endosc. 2009;69(3):567–572. 5. Yamano HO, Yoshikawa K, Kimura T, et al. Carbon dioxide insufflation for colonoscopy: evaluation of gas volume, abdominal pain, examination time and transcutaneous partial CO2 pressure. J Gastroenterol. 2010;45(12):1235–1240. 6. Sumanac K, Zealley I, Fox BM, et al. Minimizing postcolonoscopy abdominal pain by using CO2 insufflation: a prospective, randomized, double blind, controlled trial evaluating a new commercially. Gastrointest Endosc. 2002;56(2): 190–194. 7. Saltzman HA, Sieker HO. Intestinal response to changing gaseous environments: normobaric and hyperbaric observations. Ann N Y Acad Sci. 1968;150 (1):31–39. 8. Memon M, Memon B, Yunus R, Khan S. Carbon dioxide versus air insufflation for elective colonoscopy: a meta-analysis and systematic review of randomized controlled trials. Surg Laparosc. 2016;26(15):102–116. 9. Leung FW, Amato A, Ell C, et al. Water-aided colonoscopy: a systematic review. Gastrointest Endosc. 2012;76(3):657–666. 10. Radaelli F, Paggi S, Amato A, Terruzzi V. Warm water infusion versus air insufflation for unsedated colonoscopy: a randomized, controlled trial. Gastrointest Endosc. 2010;72(4):701–709. 11. Cadoni S, Falt P, Gallittu P, et al. Water exchange is the least painful colonoscope insertion technique and increases completion of unsedated colonoscopy. Clin Gastroenterol Hepatol. 2015;13(11):1972–1980. 12. Hsieh YH, Koo M, Leung FW. A patient-blinded randomized, controlled trial comparing air insufflation, water immersion, and water exchange during minimally sedated colonoscopy. Am J Gastroenterol. 2014;109(9):1390–1400. 13. Chen PJ, Shih YL, Chu HC, Chang WK, Hsieh TY, Chao YC. A prospective trial of variable stiffness colonoscopes with different tip diameters in unsedated patients. Am J Gastroenterol. 2008;103(6):1365–1371. 14. Ogawa T, Ohda Y, Nagase K, et al. Evaluation of discomfort during colonoscopy with conventional and ultrathin colonoscopes in ulcerative colitis patients. Dig Endosc. 2015;27(1):99–105. 15. Uddin FS, Iqbal R, Harford WV, et al. Prone positioning of obese patients for colonoscopy results in shortened cecal intubation times: a randomized trial. Dig Dis Sci. 2013;58(3):782–787. 16. Vergis N, McGrath AK, Stoddart CH, Hoare JM. Right Or Left in COLonoscopy (ROLCOL) &quest: a randomized controlled trial of right-versus left-sided starting position in colonoscopy. Am J Gastroenterol. 2015;110(11):1576–1581. 17. Teshima CW, Zepeda-Gómez S, AlShankiti SH, Sandha GS. Magnetic imagingassisted colonoscopy vs conventional colonoscopy: a randomized controlled trial. World J Gastroenterol. 2014;20(36):13178–13184. 18. Maslekar S, Gardiner A, Hughes M, Culbert B, Duthie GS. Randomized clinical trial of Entonoxs versus midazolam–fentanyl sedation for colonoscopy. Br J Surg. 2009;96(4):361–368. 19. Løberg M, Furholm S, Hoff I, Aabakken L, Hoff G, Bretthauer M. Nitrous oxide for analgesia in colonoscopy without sedation. Gastrointest Endosc. 2011;74(6): 1347–1353. 20. Tamai N, Matsuda K, Sumiyama K, Yoshida Y, Tajiri H. Glucagon facilitates colonoscopy and reduces patient discomfort: a randomized double-blind controlled trial with salivary amylase stress analysis. Eur J Gastroenterol Hepatol. 2013;25(5):575–579. 21. Church JM. Warm water irrigation for dealing with spasm during colonoscopy: simple, inexpensive, and effective. Gastrointest Endosc. 2002;56(5):672–674.