Factors Predicting the Possibility of Conducting Colonoscopy Without Sedation

• Introduction
• Materials and Methods
• Evaluation of Success Rates in Colonoscopy
• Results
• Discussion
• References

Background and Study Aims: Colonoscopy without sedation costs less than sedated colonoscopy. The aims of the present study were to determine the percentage of patients who can successfully undergo nonsedated colonoscopy and to identify factors capable of predicting whether a colonoscopy can be completed without sedation.

Patients and Methods: Demographic, clinical, and colonoscopy-related data were prospectively recorded for consecutive patients undergoing colonoscopy by an experienced endoscopist in a single private practice setting. All of the colonoscopies routinely began without sedation, unless sedation was specifically requested by the patient. Sedation was given when requested by the patient if significant discomfort occurred during the procedure. To determine factors making it more likely that nonsedated colonoscopy would be possible, age, sex, presence of diverticulosis, prior colonic surgery, prior colonoscopy, and the time required to complete the colonoscopy were evaluated using a multivariate logistic regression analysis.

Results: Five patients asked to have sedation before the procedure. Of 173 patients in whom colonoscopy was started without sedation, 159 (91.9 %) required no sedation. Complete colonoscopy was achieved in 152 of the 173 initially nonsedated patients (87.9 %) and in 167 of the total of 178 patients (93.8 %). Multivariate logistic regression analysis showed that male sex (odds ratio 5.9; 95 % CI, 1.7 to 21.4) and a prior segmental colonic resection (odds ratio 6.2; 95 % CI, 0.8 to 48.9) were associated with an ability to complete the colonoscopy procedure without sedation.

Conclusions: The vast majority of patients undergoing colonoscopy procedures conducted by an experienced endoscopist do not require sedation. Male sex, segmental colonic resection, and probably experience in lower gastrointestinal endoscopy on the part of the patient, are predictive factors for successful colonoscopy without sedation.

Introduction

Colonoscopy is traditionally performed with conscious sedation in certain countries [1] [2] . This is because air insufflation into the colon and loop formation may cause visceral pain of varying intensity. Conscious sedation has the advantages that the examination is well accepted and tolerated by the patients, as the sedation blunts the sensation of intraprocedural pain and induces retrograde amnesia for painful stimuli [3]. However, colonoscopy with conscious sedation definitely increases the cost of the procedure, since it includes administration of premedication and requires a properly staffed and equipped recovery area. In addition, the patient cannot return immediately to normal everyday activities after the procedure, and cannot drive when returning home and may need to be accompanied by a friend or relative, implying a further loss of working hours.

In a period in which we are “struggling toward easier endoscopy” [4] - i.e., less costly endoscopy - nonsedated colonoscopy is a cost-effective approach, since sedation adds to the cost of the examination. In certain European countries, including Finland, Germany, and Greece sedation is not routinely used for colonoscopy [3] [5] [6] [7] , and patients do not usually expect to be sedated during the procedure. The usual standard of care in Greece is that most patients are not given sedation for upper or lower gastrointestinal endoscopy [7] [8] [9] , but a small percentage of patients may request preprocedural sedation or ask to be sedated during colonoscopy. The objectives of this prospective study were therefore to determine the percentage of patients who can successfully undergo colonoscopy without sedation and to identify factors capable of predicting whether a colonoscopy can be completed without sedation.

Materials and Methods

Consecutive colonoscopies performed in a single private practice setting were studied prospectively. Only the first colonoscopy was evaluated for patients who underwent repeated colonoscopies in this private setting during the study period. The colonoscopies were carried out by the author, a senior gastroenterologist who completed his fellowship in gastroenterology in 1979. He is head of a university-based gastroenterology unit in the largest hospital in Athens, and has the university's permission to carry out private consultation and endoscopy outside of the hospital's eight hours per week. He is experienced in most diagnostic and therapeutic endoscopic procedures, including upper and lower gastrointestinal and endoscopic cholangiopancreatography. His experience in colonoscopy exceeds three thousand diagnostic and therapeutic procedures [7].

Bowel preparation for the colonoscopy procedures was carried out with 4 l polyethylene glycol in the morning, and the examinations were performed between 17.00 h and 19.30 h on the same day. Before the examination, the patients' demographic characteristics (age, sex) and medical history were recorded, including the indication for colonoscopy, prior colonic surgery, and experience with rigid or flexible sigmoidoscopy or colonoscopy. Unless sedation was specifically requested by the patient, the colonoscopies were commenced without sedation. If significant discomfort occurred, the patient was sedated (with intravenous midazolam in 2.5-mg increments) on request during the procedure. The study was conducted in accordance with the Helsinki declaration on human rights; approval by an institutional review board was not regarded as being necessary, since the study was prospectively collecting information from colonoscopies conducted in the same way that they are routinely performed by most gastroenterologists in Greece - i.e., without sedation.

The colonoscopies were carried out using a Fujinon EC-200LR video colonoscope with the “singlehanded” technique, without the aid of radiographic screening or a stiffening overtube. All of the procedures were conducted with one nurse assistant present. A heparinized intravenous cannula was placed in the patient's forearm for use in case the patient requested sedation during the examination. Heart rate and peripheral oxygen saturation were monitored using a pulse oximeter, and events that occurred were recorded so as to be able to identify the main reason for discontinuation of the procedure if it occurred. These events included arterial oxygen desaturation (< 90 %), vasovagal reaction defined by bradycardia (< 45 beats/min), and hypotension (defined by a reduction in systolic blood pressure to below 90 mmHg). Intolerance to the procedure by the patient (anxiety, abdominal discomfort, or pain) was also recorded, as well as the quality of the preparation, which was described using a three-grade scale (excellent, satisfactory, or bad). Bad preparation quality was defined by the presence of solid or viscous fecal material in the bowel lumen, prohibiting thorough inspection of the colonic mucosa.

The length of intubated colon was determined by noting characteristic anatomical sites in the colon. Total colonoscopy was defined by confirmation of intubation of the cecum, identification of the ileocecal valve, or intubation of the terminal ileum or an ileocolonic anastomosis. The time required to advance and withdraw the scope was separately recorded using a stopwatch.

Evaluation of Success Rates in Colonoscopy

Colonoscopies were considered to have been successful if the cecum or ileum, or an ileocolonic anastomosis, was intubated. They were considered unsuccessful if they were not completed due to technical inability to advance the scope, when there was a tumor occluding the bowel lumen, or if the patient was unable to tolerate the procedure. The overall success rate of colonoscopy and the success rate in nonsedated patients were separately calculated after exclusion of patients with poor colonic preparation.

Statistical analysis. All of the data collected were stored using database software and analyzed by using the Statistical Package for the Social Sciences program (SPSS Inc., Chicago, Illinois, USA). Data in the text are presented as median with ranges. Percentages are given with a 95 % confidence interval (CI). Qualitative data were assessed using the chi-squared test with the Yates correction, as appropriate. Numerical data were analyzed using the nonparametric Mann-Whitney U test. Multivariate logistic regression analysis, with a stepwise selection criterion of < 0.05 for entering the model and a removal criterion of likelihood ratio of > 0.1 were used to identify variables associated with nonsedated colonoscopy. The independent variable was “sedation” (yes: 1, no: 0) and the dependent variables were “sex” (male: 1, female: 0), “age,” “history of prior colon resection” (yes: 1, no: 0), “prior colonoscopy” (yes: 1, no: 0) and “diverticulosis” (yes: 1, no: 0). A P value of less than 0.05 was regarded significant.

Results

The study included 182 consecutive patients (89 men, 93 women; mean age 54, range 17 - 84). They were all Greeks who had lived in Greece since birth. The indications for colonoscopy are shown in Table [1]. In four patients (2.2 %; 95 % CI, 0.6 to 5.5 %), the quality of colon preparation was poor, and they were therefore excluded from further analysis. Five women patients (2.8 %; 95 % CI, 0.9 to 6.3 %) requested preprocedural conscious sedation, and the colonoscopy started without sedation in 173 patients. Forty-five of the 178 patients (25.3 %; 95 % CI, 19.1 to 32.3 %) had a history of colonic surgery, including 34 with sigmoid colectomy and 11 with right hemicolectomy. Eighty-one patients (45.5 %; 95 % CI, 38.0 to 53.1 %) had experience of rigid or flexible sigmoidoscopy or colonoscopy. Of the 173 patients who started colonoscopy without sedation, 14 (8.1 %) asked to be sedated during the procedure and 159 (91.9 %; 95 % CI, 86.8 to 95.5 %) had colonoscopy without sedation. Overall, total colonoscopy was achieved in 167 of the 178 patients (93.8 %; 95 % CI, 89.2 to 96.9 %). Colonoscopy without sedation was completed in 152 of 183 patients (83.1 %; 95 % CI, 76.8 to 88.2 %) and colonoscopy with preprocedural sedation (n = 5) or sedation during the procedure (n = 14) was completed in 15 of 19 patients (78.9 %; 95 % CI, 54.4 to 94.0 %) (Table [2]). The reasons for incomplete colonoscopy procedures are shown in Table [3]. Adverse effects occurred in five patients, four in the nonsedated group and one in the sedated one. Three of these patients had short oxygen desaturation events and two had vasovagal reactions not requiring early termination of the endoscopy.

The demographic, clinical, and procedure-related data for the 178 patients are given in Table [2], separately for patients who had unsedated colonoscopy and for those who received sedation. The univariate analysis did not show any statistically significant difference between the sedated and nonsedated patients with regard to insertion and total procedure times, age, history of a prior colon resection, or diverticulosis. By contrast, significantly more men than women, as well as patients who had experience with any kind of lower gastrointestinal endoscopy, did not require sedation (Table [2]). However, when these variables were assessed using multivariate logistic regression analysis, male sex (odds ratio 5.9; 95 % CI, 1.7 to 21.4; significance of likelihood ratio statistic < 0.002) and a prior segmental colonic resection (odds ratio 6.2; 95 % CI, 0.8 to 48.9; significance of likelihood ratio statistic < 0.03) were associated with completion of colonoscopy without sedation. Twenty-nine of the 159 patients (18.2 %) who had nonsedated colonoscopy were advised to have a follow-up colonoscopy. They all accepted, and had the endoscopy repeated without sedation.

Discussion

The demand for total colonoscopy has increased during the last decade, since its introduction as the most specific examination for the prevention of colon cancer [10]. An expert multidisciplinary panel has recently suggested that people at average risk for colon cancer - i.e., asymptomatic individuals older than 50 years with no other risk factors - should have total colonoscopy every ten years [10]. Colonoscopy performed with conscious sedation is not a cost-effective approach for screening purposes. The only reason favoring conscious sedation is that colonoscopy may cause abdominal pain to the patient, resulting in early termination of the examination and avoidance of a follow-up colonoscopy if indicated.

Colonoscopy is customarily conducted with sedation in the USA and UK [1] [2] [3] [4] , but is carried out without sedation in most patients in continental European countries such as Germany, Finland, and Greece [5] [6] [7] . A few published reports have studied the success rate of nonsedated colonoscopy. They have shown that an experienced endoscopist can successfully perform colonoscopy without sedation in more than 82 % of patients [5] [6] [7] [11] [12] [13] . In the present study, 88 % of the patients required no sedation to enable them to complete colonoscopy, and this figure is in agreement with the experience of other investigators [5] [6] [11] [14] . This success rate is lower than that reported for sedated patients (95 %) [15] [16] . However, when patients who requested sedation during the procedure were added, the total colonoscopy success rate increased in our study to 94 %, a figure within the range of reported cecal intubation rates for a colonoscopy service in the 1990s [15] [17] .

It may be argued that patients are less willing to accept nonsedated colonoscopy. However, most of the studies on this topic have been carried out in countries in which colonoscopy is traditionally performed with conscious sedation and patients expect to be sedated during the examination [4] [12] [18] [19] [20] . In contrast to this belief, Eckardt et al. have shown that colonoscopy without sedation does not cause more discomfort than a barium enema [21], and Ristikankare et al. have suggested that “routinely administered sedation does not markedly increase patients' tolerance to the procedure” [5]. Flexible sigmoidoscopy is carried out in nonsedated patients, and an experienced endoscopist usually examines the descending colon and often may intubate the transverse colon using the 60-cm sigmoidoscope. When it is accepted that passing the sigmoid is the part of the examination that may cause most pain to the patient [16], there is some contradiction between the expectation that flexible sigmoidoscopy can be performed without sedation and the view that all patients undergoing colonoscopy need to be sedated.

The data from the present study show that significantly more Greek women than men request preprocedural medication or sedation during the examination. Recent studies have suggested that men are more likely than women to consent to unsedated colonoscopy [18] [19] , and that female sex and preexisting abdominal pain are predictors for a need for sedated colonoscopy [13] [20] [22] . These results are in agreement with those of another study suggesting that colonoscopy is more difficult and painful in women than in men [23]. Irritable bowel syndrome is 2.4 times more common in women than in men [24]. In addition, gynecological diseases, pelvic surgery [21], and endometriosis may lead to the formation of adhesions between the sigmoid colon and the peritoneum. These factors may be related to pain being induced during colonoscopy [23], and may explain why women more often request sedation than men.

Patients undergoing sedated colonoscopy are dissatisfied by the length of the examination (> 60 minutes) [25]. The duration of the procedure might therefore affect patients' decision to ask for sedation during the examination, as a lengthy examination may result in excessive air insufflation into the colon, loop formation, and abdominal pain. However, as reported by Hoffman et al. [14], the duration of the procedure is not a predictor for future sedation preference; nor did it predict whether patients would request sedation during colonoscopy in the present study. The median insertion time and total procedure time were two minutes longer in the sedated patients compared with the nonsedated patients - probably reflecting the time taken to administer intravenous sedation.

The age of the patient may also influence the preference for sedation. Three published studies have suggested that age is not a predictor for sedation preference [14] [21] [22] , but Rex et al. have shown that increasing age is associated with willingness to try colonoscopy without sedation [20]. Although the mean age of the patients who asked for sedation in the present study was six years lower than that of the patients who had nonsedated colonoscopy, the difference was not statistically significant. However, a prior segmental colonic resection favored successful colonoscopy without sedation in these patients. This is probably because colonoscopy is easier after sigmoid colectomy [23], since there is no sigmoid loop that may cause pain during the examination.

Contrary to recent reports [14] [22] , the present data suggest that there is a preference for nonsedated colonoscopy when patients have prior experience of lower gastrointestinal endoscopy. There are confounding factors that may be related to this finding. Patients with inflammatory bowel disease and those with a segmental colonic resection represent subgroups who usually have experience of lower gastrointestinal endoscopy, and in these patients the colon is more easily examined [23]. Another group includes patients undergoing colonoscopy for postpolypectomy screening and those who have first-degree relatives with colon cancer. These patients are psychologically prepared for a need to repeat the examination, and they may therefore be more tolerant to undergoing colonoscopy without sedation.

The present study was carried out in Greece, where it is not routine to sedate patients for colonoscopy. It might therefore be argued that the results are potentially biased, as they reflect the cultural expectations of Greek patients and may not apply in other countries. However, data from Germany [6] and Finland [5] support the results. Even recently published studies from the United States show that nonsedated colonoscopy is well accepted by many patients [12] [13] [14] [20] .

Important factors include comfort and satisfaction levels, as well as the willingness of the patient to return to the same endoscopist for colonoscopic surveillance examinations. Most clinical studies use pain charts and specially designed questionnaires to investigate these factors. However, patients participating in clinical trials may report levels of satisfaction and intensity of pain differently than they otherwise would, owing to the Hawthorne effect [26]. It has therefore been suggested that “data on pain and satisfaction levels and willingness to return to the same endoscopist should be accumulated by colonoscopists evaluating attempts at unsedated colonoscopy in clinical practice outside of clinical trials” [20]. The present study prospectively analyses data collected from colonoscopies as they are performed routinely in clinical practice in Greece. A pain score chart was therefore not used, and the patients were not asked whether they would be willing to repeat an unsedated colonoscopy. However, in practice all 29 patients who had nonsedated colonoscopy and were advised to have follow-up surveillance had the endoscopy repeated without sedation.

The use of colonoscopy without sedation cannot be generalized to include all patients. Anxious patients and those who experience discomfort or pain during the examination will certainly benefit from sedative premedication or sedation on demand during colonoscopy. In this study, the decision on whether to administer sedation and the timing of it were freely determined by the patient, and not by a third party or by the endoscopist - observer bias was therefore excluded.

In conclusion, colonoscopy with sedation being provided when requested by the patient during the examination is a cost-effective and safe approach for total colonoscopy. Although these conclusions are based on the fairly small number of patients included in the study, they show that in experienced hands the cecal intubation rate is as high as in sedated colonoscopy. Subset characteristics within the group that favored nonsedated colonoscopy were male sex, prior segmental colonic resection, and probably the patient's experience of lower gastrointestinal endoscopy.

References

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M.D. S. D. Ladas,

Clinic for Gastrointestinal Endoscopy

23 Sisini Street

115 28 Athens

Greece

Phone: + 30-1-7210213

Email: sdladas@hol.gr

References

• 1 British Society of Gastroenterology. Recommendations for standards of sedation and patient monitoring during gastrointestinal endoscopy.  Gut. 1991;  32 823-827
  PubMedSearch in Google Scholar
• 2 ASGE Guideline. Sedation and monitoring of patients undergoing gastrointestinal endoscopic procedures.  Gastrointest Endosc . 1995;  42 626-629
  PubMedSearch in Google Scholar
• 3 Williams CB. Comfort and quality in colonoscopy.  Gastrointest Endosc. 1994;  40 769-770
  PubMedSearch in Google Scholar
• 4 Mokhashi MS, Howes RH. Struggling toward easier endoscopy [editorial].  Gastrointest Endosc. 1998;  48 432-440
  PubMedSearch in Google Scholar
• 5 Ristikankare M, Haztikamen J, Heikkinen M, et al. Is routinely given conscious sedation of benefit during colonoscopy?.  Gastrointest Endosc. 1999;  49 566-572
  PubMedSearch in Google Scholar
• 6 Eckardt VF, Kanzler G, Schmitt T, et al. Complications and adverse effects of colonoscopy with selective sedation.  Gastrointest Endosc. 1999;  49 560-565
  PubMedSearch in Google Scholar
• 7 Tassios PS, Ladas SD, Grammenos I, et al. Acquisition of competence in colonoscopy: the learning curve of trainees.  Endoscopy. 1999;  31 702
  Thieme ConnectPubMedSearch in Google Scholar
• 8 Ladas SD, Raptis SA. Selection of patients for upper gastrointestinal endoscopy without sedation: the finger-throat test.  Ital J Gastroenterol. 1986;  18 162-165
  PubMedSearch in Google Scholar
• 9 Ladas SD, Giorgiotis C, Pipis P, et al. Sedation for upper gastrointestinal endoscopy: time for reappraisal? [letter].  Gastrointest Endosc. 1990;  36 417-418
  PubMedSearch in Google Scholar
• 10 Winawer SJ, Fletcher RH, Miller L, et al. Colorectal cancer screening: clinical guidelines and rationale.  Gastroenterology. 1997;  112 594-642
  CrossrefPubMedSearch in Google Scholar
• 11 Seow-Choen F, Leong AFPK, Tsang C. Selective sedation for colonoscopy.  Gastrointest Endosc. 1994;  40 661-664
  PubMedSearch in Google Scholar
• 12 Herman FN. Avoidance of sedation during total colonoscopy.  Dis Colon Rectum. 1990;  33 70-72
  PubMedSearch in Google Scholar
• 13 Cataldo PA. Colonoscopy without sedation: a viable alternative.  Dis Colon Rectum. 1996;  39 257-261
  PubMedSearch in Google Scholar
• 14 Hoffman MS, Besaw R, Menon P, et al. Colonoscopy without conscious sedation [abstract].  Gastrointest Endosc. 1997;  45 49
  PubMedSearch in Google Scholar
• 15 Marshall JB, Barthel JS. The frequency of total colonoscopy and terminal ileal intubation in the 1990s.  Gastrointest Endosc. 1993;  39 518-520
  PubMedSearch in Google Scholar
• 16 Williams CB, Waye JD. Colonoscopy and flexible sigmoidoscopy. In: Yamada T (ed). Textbook of gastroenterology. 2nd ed.  Philadelphia; Lippincott, 1995: 2571-2589
  Search in Google Scholar
• 17 Waye JD, Bashkoff E. Total colonoscopy: is it always possible?.  Gastrointest Endosc. 1991;  37 152-154
  CrossrefPubMedSearch in Google Scholar
• 18 Early DS, Saifuddin T, Marshall JB. Are patients willing to undergo colonoscopy without sedation? [abstract].  Gastrointest Endosc. 1998;  47 48
  PubMedSearch in Google Scholar
• 19 Rex D, Portish VL. Routine versus as needed sedation for colonoscopy in self-selected Americans [abstract].  Gastrointest Endosc. 1998;  47 58
  PubMedSearch in Google Scholar
• 20 Rex DK, Imperiale TF, Portish V. Patients willing to try colonoscopy without sedation: associated clinical factors and results of a randomized controlled trial.  Gastrointest Endosc. 1999;  49 554-559
  PubMedSearch in Google Scholar
• 21 Eckardt VF, Kanzier G, Willems D, et al. Colonoscopy without premedication versus barium enema: a comparison of patient discomfort.  Gastrointest Endosc. 1996;  44 177-180
  PubMedSearch in Google Scholar
• 22 Rahmaani E, Rex DK, Ruppp TH, Lehman GA. Is routine sedation during colonoscopy necessary? [abstract].  Gastrointest Endosc. 1995;  41 327
  PubMedSearch in Google Scholar
• 23 Hull T, Church JM. Colonoscopy: how difficult, how painful?.  Surg Endosc. 1994;  7 784-787
  PubMedSearch in Google Scholar
• 24 Everhart JE, Renault PF. Irritable bowel syndrome in office-based practice in the United States.  Gastroenterology. 1991;  100 998-1005
  PubMedSearch in Google Scholar
• 25 Schutz SM, Lee JG, Schmitt CM, et al. Clues to patient dissatisfaction with conscious sedation for colonoscopy.  Am J Gastroenterol. 1994;  89 1476-1479
  PubMedSearch in Google Scholar
• 26 Kramer MS. Clinical epidemiology and biostatistics.  Berlin; Springer, 1988: 125-128
  Search in Google Scholar

M.D. S. D. Ladas,

Clinic for Gastrointestinal Endoscopy

23 Sisini Street

115 28 Athens

Greece

Phone: + 30-1-7210213

Email: sdladas@hol.gr