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Impact of the supine position versus left horizontal position on colonoscopy insertion: a 2-center, randomized controlled trial
ORIGINAL ARTICLE
Impact of the supine position versus left horizontal position on colonoscopy insertion: a 2-center, randomized controlled trial Shengbing Zhao, MD,1,* Xia Yang, MD,1,2,* Qianqian Meng, MD,1,* Shuling Wang, MD,1,* Jun Fang, MD,3 Wei Qian, MD,1 Tian Xia, MD,1 Peng Pan, MD,1 Zhijie Wang, MD,1 Lun Gu, MD,1 Xin Chang, MD,1 Duowu Zou, MD, PhD,1,4 Zhaoshen Li, MD, PhD,1 Yu Bai, MD, PhD1 Shanghai; Wuhan, China
GRAPHICAL ABSTRACT
Background and Aims: Colonoscopy insertion is painful for some patients and is one of the main barriers to screening colonoscopy. Few studies have assessed the impact of the supine position (SP) on colonoscopy insertion, especially for unsedated patients. The aim of this randomized controlled trial was to clarify this issue. Methods: Unsedated patients were randomized to SP or left horizontal position (LHP) as the starting position of colonoscopy insertion. The primary outcome measure was cecal intubation time (CIT), and the secondary outcome measures were descending colon intubation time (DIT), pain score of patients, difficulty score according to the endoscopist, and patients’ acceptance of unsedated colonoscopy. Results: A total of 347 patients were randomized to the SP group (175) or the LHP group (172). The CIT in the SP group was significantly shorter than that in the LHP group (275.0 seconds [interquartile range (IQR), 234.0-328.5 seconds] versus 316.0 seconds [IQR, 261.0-370.0 seconds], P < .001). The DIT was also shorter in the SP group (64.5 seconds [IQR, 52.0-86.3 seconds] versus 74.0 seconds [IQR, 62.0-92.0 seconds], P Z .001). Compared with the LHP, the SP had a lower pain score (3.3 versus 3.9, P Z .002), a lower difficulty score (3.1 versus 3.7, P < .001), a lower frequency of position change (7.1% versus 38.0%, P < .001), and less need for abdominal compression (39.1% versus 45.5%, P Z .02). SP was the only modifiable and independent factor identified to reduce CIT and pain score and improve patients’ acceptance of unsedated colonoscopy. Conclusions: As an economical and convenient method, SP can reduce CIT, ease pain, and improve patients’ acceptance of unsedated colonoscopy. (Clinical trial registration number: NCT03289442.) (Gastrointest Endosc 2019;-:1-9.)
(footnotes appear on last page of article)
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INTRODUCTION Colorectal cancer (CRC) is one of the most commonly diagnosed malignancies worldwide, with the third highest morbidity and the second highest mortality.1 CRC screening has significantly reduced the incidence and mortality of CRC, and colonoscopy is generally recognized as the criterion standard. It is the most performed endoscopic procedure for CRC screening and surveillance.2-4 However, the participation rate of CRC screening and public acceptance of colonoscopy have often been suboptimal, although several efforts have been made.4-6 On the one hand, pain arising from colonoscopy, particularly during insertion, is one of the most important factors precluding the public from participating in screening.7,8 On the other hand, colonoscopy insertion is technically challenging and time consuming for inexperienced colonoscopists with looping occurring frequently, especially in the sigmoid, which increases the severity of pain and the risk of adverse events.9 Although propofol sedation can help ease discomfort during colonoscopy10 and is performed discretionarily for two-thirds of colonoscopies in the United States, the widespread use of sedation has been long criticized for the high cost of medical resources, time, and personnel, as well as the high risk of sedation-related and procedure-related adverse events,11,12 with great efforts made to reduce the number of colonoscopies with unnecessary anesthesia.13,14 Ideally, a high-quality, safe, and painless colonoscopy with no or minimal sedation is considered the optimal colonoscopy. Currently, unsedated colonoscopy is increasingly accepted and routinely performed in Europe and China,15,16 and a wealth of techniques and equipment have been introduced to facilitate insertion, ease pain, and reduce time, mainly for unsedated colonoscopy. However, these new techniques and equipment, including imaging devices,17 responsive insertion technology,18 doubleballoon endoscopy,19 variable-stiffness colonoscope,20 abdominal compression device,21 and water-exchange colonoscopy,16 showed conflicting findings on cecal intubation time (CIT) and procedure-related pain, or depended on expensive equipment, all of which limit their wide application.22 In addition, individual endoscopists were reported to be the most important modifiable factor associated with the pain of colonoscopy, and therefore more efforts are warranted to improve insertion skills and reduce the variation among endoscopists.10 Notably, changing the starting position of patients was considered to be able to alleviate discomfort and reduce time of insertion, and we also reported that the left tilt-down position (LTDP)23 could reduce CIT and pain, and potentially improve patients’ acceptance of unsedated colonoscopy because LTDP straightens the sigmoid and redundant colon and facilitates the fecal residue and fluid flowing away from the view of endoscopists compared with the left lateral horizontal position (LHP).23-25 Rationally, the supine position (SP) can also alleviate the disadvantages of LHP and is often used for
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position changes during insertion.26 However, the value of SP as the starting position has not been fully illustrated, especially for unsedated patients. Therefore, we conducted a 2-center randomized controlled trial (RCT) to explore the effect of SP on colonoscopy insertion.
METHODS Overview We conducted the RCT between August 2017 and January 2018 in 2 digestive endoscopy centers, as introduced previously.23,27,28 The study protocol was approved by the ethics committees of both hospitals, and informed consent was acquired from all participants. The trial was registered at ClinicalTrials.gov (identifier, NCT03289442). Professors Z.S. Li, Y. Bai, D.W. Zou, and co-authors had full access to the study data, and the final manuscript was reviewed and approved by all authors.
Participants Consecutive adult outpatients with indications of CRC screening, surveillance, and diagnostic examinations for colonoscopy were invited to participate in the study by the 3 endoscopists (Y.B, X.Y., and J.F.). Patients younger than 18 years or older than 75 years, those who did not provide informed consent, pregnant women, and those with histories of colonic resection, severe cardiopulmonary and renal diseases, major psychiatric disorders, therapeutic colonoscopy, or any contraindications for colonoscopy were excluded.
Randomization Patients were randomized to SP or LHP with stratification according to the centers. The randomization list generated by the Center for Clinical Epidemiology and Evidence-Based Medicine (Second Military Medical University/Naval Medical University, Shanghai, China) was put into sealed opaque envelopes, which were opened at the start of the colonoscopy. The person generating the list did not participate in data acquisition and analysis.
Bowel preparation and intervention procedures All patients received the same split-dose bowel preparation with 3 L of polyethylene glycol (Wanhe Pharmaceutical Co, Ltd, China or Tianjin Beaufour Ipsen, Pharmaceutical Co, Ltd, China), as described previously.23,27,28 No hyoscine was used in the study. High-resolution colonoscopes (CF-Q290 or CF-Q260, Olympus) without endoscopic attachments, image devices, or water immersion/exchange were used, using carbon dioxide as the standard gas for insufflation. At the start of the colonoscopy, patients in the SP group were instructed to lie in a supine position to receive inspection (or first in a left position to seek the entrance for the colonoscope and immediately transfer
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Supine position for colonoscopy insertion
Figure 1. A, The supine position. B, The left lateral horizontal position.
to the supine position depending on the preference of the colonoscopist); patients in the LHP group were positioned in the left lateral horizontal position (Fig. 1). The colonoscopists were required not to take biopsy samples or resect polyps and insufflate the colon with as little gas as possible during insertion so that they could identify the direction of insertion to reduce pain and the risk of adverse events during insertion. The application of loop reduction, position change, and abdominal compression depended on the preferences of colonoscopists. The time to the descending colon and cecum was recorded. Insertion difficulty and pain were assessed by the endoscopists and patients as soon as the cecum was reached. No colonoscopist had previously performed colonoscopy with the supine starting position, and no trainees participated in the RCT.
scopists were unable to complete the insertion; (5) the need for position change and abdominal compression during insertion; and (6) rates of adverse events, including aspiration pneumonia, perforation, splenic injury/rupture, and death, which required hospitalization within 30 days of the colonoscopy.29
Sample size calculation A pilot study was conducted to find that SP could reduce CIT by 30 seconds; the mean CIT was 5.3 minutes with a standard deviation (SD) of 1.6 minutes. A sample size of 161 patients in each group was estimated to provide a power of 80% and a Z 0.05 to detect a 30-second difference in CIT between the SP and LHP groups.
Statistical analysis Outcome measures The outcome measures were the same as described previously.23 The primary outcome was CIT, which was confirmed by identifying the characteristic anatomic landmarks of the triradiate fold, appendiceal orifice, and ileocecal valve. The secondary outcome measures were (1) descending colon intubation time (DIT), which was identified by the presence of the straight colonic lumen and affirmed by an independent observer; (2) patients’ pain score using a 10-cm visual analog scale (VAS), in which a score of 0 denoted no pain and a score of 10 denoted unbearable pain; (3) patients’ acceptance of unsedated or sedated colonoscopy for future colonoscopies; (4) difficulty score for colonoscopy insertion assessed by the endoscopist, as measured by VAS in which a score of 0 represented no technical challenge and a score of 10 represented an extreme technical challenge such that endowww.giejournal.org
The analyses were performed according to intention-totreat analysis (patient characteristics, endoscopist characteristics, and indications) and per-protocol analysis (withdrawal time, polyp/adenoma detection, insertion time, and pain/difficulty score). Continuous variables were expressed as mean with ranges (SD) or median with the interquartile range and were compared using the Student t test or the Mann-Whitney non-parametric test when appropriate. Categorical data were analyzed using the chi-squared test. P values <.05 were considered to be statistically significant, and all tests were 2-sided. Multiple linear regression and multivariate logistic regression were performed using the following variables: age, gender, body mass index (BMI) (18.5 kg/m2 < BMI < 28 kg/m2, BMI >28 kg/m2, or BMI <18.5 kg/m2), the presence or absence of previous abdominal surgery and pelvic surgery, previous colonoscopy, history of previously incomplete colonoscopy, colonic diverticulum, experience Volume
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Assessed for eligibility (n=420)
Enrollment (n=347)
Excluded (n = 73) 1. Declined consent (n = 30) 2. Age <18 or >75 years (n = 14) 3. Urgent/therapeutic colonoscopy (n = 3) 4. Colonic resection (n = 7) 5. Others (n = 19)
Randomization
Allocation
Allocated to supine position (N=175)
Allocated to left lateral horizontal position (N=172)
Analysis Per-protocol analysis (n=169)
Per-protocol analysis (n=163)
Excluded(n=6) Obstructive disease (n=4) Intolerant abdominal pain (n=2)
Excluded(n=9) Poor bowel preparation (n=3) Obstructive disease (n=4) Intolerant abdominal pain (n=2)
Figure 2. Flowchart of the enrollment process.
of endoscopist, indications, bowel preparation quality, and the starting position. The model was built using stepwise regression. All statistical analyses were performed using SPSS Statistics v22 (IBM, Chicago, Ill).
RESULTS Enrollment and baseline characteristics Overall, 420 consecutive patients referred to the 2 centers were invited to participate and 73 patients were excluded for refusal, not within the required age range, urgent/therapeutic colonoscopy, colonic resection, and other reasons. Finally, 347 patients were randomized to SP (175) and LHP (172); 15 (4.3%) colonoscopies failed to reach the cecum for obstructive diseases (8), intolerant pain (4), and poor bowel preparation (3) (Fig. 2). The baseline characteristics were well balanced in the 2 groups (Table 1).
Primary outcomes and subgroup analysis CIT in the SP group was significantly shorter than that in the LHP group (275.0 seconds [interquartile range (IQR), 234.0-328.5 seconds] versus 316.0 seconds [IQR, 4 GASTROINTESTINAL ENDOSCOPY Volume
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261.0-370.0 seconds], P < .001, Table 2). Patients with Boston Bowel Preparation Scale (BBPS) score 6 showed a significant reduction in CIT (270.0 seconds [IQR, 230.5323.0 seconds] versus 313.5 seconds [IQR, 262.5-350.5 seconds], P < .001), but those with BBPS score <6 did not reach a significant difference (P Z .22, Table 2). Only male patients and endoscopists who had performed 1000 to 3000 procedures showed a shorter CIT in the SP group (both P < .001, Figs. 3 and 4), but the difference for female patients and endoscopists with more or fewer procedures was not statistically significant (P Z .43, P Z .14, and P Z .91, respectively; Figs. 3 and 4).
Secondary outcomes Compared with the LHP group, a shorter DIT was also observed in the SP group (64.5 seconds [IQR, 52.0-86.3 seconds] versus 74.0 seconds [IQR, 62.0-92.0 seconds], P Z .001, Table 2). The pain score in the SP group was lower than that in the LHP group (3.3 [SD, 1.6] versus 3.9 [SD, 1.7], P Z .002; Table 2) and the decrease in pain score was significant for males but not for females (P Z .001 and P Z .26, respectively; Fig. 5). The www.giejournal.org
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Supine position for colonoscopy insertion
TABLE 1. Characteristics of the patients and the colonoscopies Characteristics* Age (years), mean (SD) Female, no. (%) BMI (kg/m2), mean (SD)
SP (n [ 175)
LHP (n [ 172)
51.5 (14.3)
52.8 (14.6)
.39
78 (44.6)
82 (47.7)
.56
22.9 (3.1)
23.3 (3.0)
.25
15
24
Indications for colonoscopy Screening
.28
Surveillance
31
28
Diagnosis
129
120
64 (36.6)
58 (33.7)
Previous colonoscopy, no. (%)
P value
.59
Risk factors for difficult insertion, no. (%) BMI >28 kg/m2
9 (5.2)
10 (5.9)
.78
BMI <18.5 kg/m2
11 (6.4)
13 (7.7)
.64
History of non-laparoscopic abdominal surgery, no. (%)
23 (13.1)
26 (15.1)
.60
9 (5.1)
10 (5.8)
.78
28 (16.1)
28 (16.3)
.96
History of laparoscopic abdominal surgery, no. (%) History of pelvic surgery, no. (%) Colonic diverticulum, no. (%)
3 (1.7)
4 (2.3)
.98
History of previously incomplete colonoscopy, no. (%)
3 (1.7)
3 (1.7)
1
Bai (>3000)
82
69
Yang (1000-3000)
84
85
Endoscopist experience
Fang (<1000) BBPS score, mean (SD) BBPS score 6, no. (%) Withdrawal time (seconds), mean (SD)
.22
10
18
6.0 (0.98)
6.0 (0.90)
.64
137 (81.1)
131 (80.4)
.87
369.7 (74.0)
369.6 (76.4)
.99
Polyp detection, no. (%)
64 (37.0)
68 (41.7)
.38
Adenoma detection, no. (%)
40 (23.1)
34 (21.0)
.64
SP, Supine position; LHP, left lateral horizontal position; SD, standard deviation; BMI, body mass index; BBPS, Boston bowel preparation scale. *All factors were analyzed by intention to treat except for BBPS, withdrawal time, polyp detection, and adenoma detection, which were analyzed per protocol.
difficulty score was also lower in the SP group (3.1 [SD, 1.2] versus 3.7 [SD, 1.5], P < .001; Table 2). There was a lower frequency of position change and abdominal compression in the SP group (12 [7.1%] versus 62 [38.0%], P < .001, and 66 [39.1%] versus 85 [45.5%], P Z .02; Table 2). In addition, the patients’ acceptance of unsedated colonoscopy was 88.2% in the SP group versus 73.0% in the LHP group (P < .001, Table 2). No adverse events were observed in both groups.
Multiple linear regression and multivariate logistic regression Being female was identified as a risk factor for longer CIT, whereas SP and endoscopists with more experience were protective factors for decreasing CIT (P < .001, P Z .02, and P Z .001, respectively; Table 3). Females tended to have more severe pain than males, but the SP could ease the pain (P Z .001 and P < .001, respectively; Table 4). Females, LHP, and colonic diverticulum were found to be associated with a lower rate of acceptance for unsedated colonoscopy, whereas patients with the www.giejournal.org
indication of surveillance reported a higher rate of acceptance (P Z .01, P < .001, P Z .01, and P Z .01, respectively; Table 5). SP was the only modifiable factor to reduce CIT and pain score, as well as improve acceptance of unsedated colonoscopy.
DISCUSSION For the first time, the study has demonstrated that changing the starting position of unsedated patients to SP could significantly reduce CIT, ease the pain of insertion, and improve patients’ acceptance of unsedated colonoscopy. Colonoscopy is traditionally started and ended (if no position changes occur) in the left lateral position but there is little evidence supporting its value in improving the performance. Recently, changing position has been demonstrated to improve mucosal visibility and adenoma detection rate during withdrawal,30-33 and has also been found to facilitate insertion.23-25 As a simple and convenient procedure, changing position can be easily realized for almost all patients undergoing unsedated colonoscopy. Therefore, it is vital to Volume
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TABLE 2. Comparison of efficiency of colonoscopy insertion between SP and LHP SP (n [ 169)
Factors* CIR, no. (%) CIT (seconds), median (IQR)
LHP (n [ 163)
P value
169 (96.6)
163 (94.8)
.41
275.0 (234.0-328.5)
316.0 (261.0-370.0)
<.001
BBPS score 6
270.0 (230.5-323.0)
313.5 (262.5-350.5)
<.001
BBPS score <6
300.0 (246.5-351.5)
344.5 (267.0-462.0)
.22
64.5 (52.0-86.3)
74 (62.0-92.0)
.001
DIT (seconds), median (IQR) Patients’ pain score, mean (SD)
3.3 (1.6)
3.9 (1.7)
.002
Patients’ acceptance of unsedated colonoscopy, no. (%)
149 (88.2)
119 (73.0)
<.001
Difficulty score, mean (SD)
3.1 (1.2)
3.7 (1.5)
<.001
Position change, no. (%)
12 (7.1)
62 (38.0)
<.001
Abdominal compression, no. (%)
66 (39.1)
85 (45.5)
.02
SP, supine position; LHP, left lateral horizontal position; CIR, cecal intubation rate; CIT, cecal intubation time; IQR, interquartile range; BBPS, Boston bowel preparation scale; DIT, descending colon intubation time; SD, standard deviation. *All factors were analyzed per protocol.
1050
1050
SP LHP
SP LHP
850
Cecal intubation time (S)
Cecal intubation time (S)
850
650
450
650
450
250
250
50
50 Male
> 3000
Female
Sex
1000 - 3000
< 500
Endoscopist experience
Figure 3. Cecal intubation time for the supine position (SP) and the left horizontal position (LHP) according to sex. *P < .001.
Figure 4. Cecal intubation time for the supine position (SP) and left horizontal position (LHP) according to the experience of the endoscopist. *P < .001.
explore the most suitable position for the most common endoscopic procedure.4 For insertion, prone, right, and left tilt-down starting positions have been introduced to reduce pain and CIT of sedated or unsedated colonoscopy.23-25 Although the position of the patient is usually changed from the left to the supine to deal with colon loops and facilitate a difficult insertion,26 no study has explored the value of the supine starting position, particularly for unsedated patients who are sensitive to pain. In this study, a 41-second reduction in the median CIT was demonstrated in the SP group versus the LHP group. On one hand, the absolute decrease in CIT was significantly less than that in the prone position (130 seconds) (only in obese patients),25 right position (213 seconds),24
and LTDP (60 seconds),23 but the baseline median CITs of these studies varied greatly (316-720 seconds), and the CIT in our study was the least (316 seconds). In addition, another RCT conducted in a general population demonstrated that there was no benefit to CIT or no comfort observed in the prone position.34 On the other hand, inconsistent with our findings, a previous RCT reported a longer CIT in an SP group versus an LHP group (10 minutes versus 9 minutes, P Z .013).35 However, as that study aimed to compare the rate of hypoxemic events in different positions for sedated colonoscopy, the results should be interpreted with caution: (1) colonoscopies with position changes, the proportion of which was higher in LHP (41.2% versus
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Supine position for colonoscopy insertion
SP LHP
5
Factors
4
Pain score
TABLE 3. Factors increasing time to reach the cecum as identified by multiple linear regression
3 2
3.97
3.56
4.27
Coefficient
Standard error
Significance (P)
Supine position
46.3
19.1
.02
Female
73.7
19.2
<.001
Endoscopist experience
49.1
15.2
.001
2.84
1 0 Female
Male
TABLE 4. Factors increasing the pain score of the patients as identified by multiple linear regression
Sex Factor Figure 5. Pain score for the supine position (SP) and left horizontal position (LHP) according to sex. *P Z .001.
18.0%, P < .001), were excluded for analysis; as a result, time spent in position change and colonoscopies with difficult insertion, where the SP benefited greatly, were excluded; (2) the frequency of apnea, which had to be dealt with by a series of rescue measures according to protocol, was much higher in the SP group than the LHP group (16.1% versus 1.8%, P < .001), and this distinction unavoidably prolonged the CIT in the SP group; (3) for the unsedated colonoscopies, the patients’ discomfort or pain was reflected in real time, which would significantly affect the CIT, whereas the other study35 was conducted with propofol sedation, which would markedly affect generalization in unsedated colonoscopy. Moreover, the reduction of CIT accompanied by a lower pain score, less insertion difficulty, and higher acceptance of unsedated colonoscopy was demonstrated in our study, which comprehensively demonstrated that the SP facilitated insertion in unsedated patients. Multiple linear regression and multifactor logistic regression identified SP as the only modifiable factor reducing CIT and pain and improving acceptance of unsedated colonoscopy. Therefore, the benefits of SP on CIT in our study are more convincing, particularly for unsedated patients.35 When analyzing these results, we performed an intention-to-treat analysis on the characteristics of the patients and endoscopist experience, and a per-protocol analysis on the characteristics of colonoscopy and outcomes in patients with successful cecal intubation, which was also adopted by previous reports to analyze CIT.24,25,34 Notably, the cecal intubation rate in the SP group was slightly higher despite no statistical significance, which also supported the benefits of SP in facilitating insertion. Although we observed no adverse events in both the SP and LHP groups, this might be due to the small sample size and extremely low adverse event rate. The proportions of position changes and abdominal pressure in our study were www.giejournal.org
Supine position Female
Coefficient
Standard error
Significance (P)
-0.92
0.17
<.001
0.54
0.17
.001
relatively higher than in the previous reports.24,25 Potentially, the convenience of performing these changes for unsedated patients may encourage colonoscopists to use them for a faster and more painless colonoscopy, as also seen in other studies.16,36 Notably, although times of loop reduction were not recorded due to the lack of imaging devices, a significant decrease in the frequency of position changes and abdominal pressure could reflect an easier insertion in SP. For patients with inadequate bowel preparation quality (BBPS score <6) and endoscopists with experience of over 3000 procedures, a reduction of 37 to 44 seconds was seen in the SP group, despite no statistical significance. However, endoscopists with experience of less than 500 procedures and female patients were found to merely show an insignificant marginal reduction. The effect of SP for the subgroups needs to be confirmed by studies with larger samples. The pain score in females remained high even in the SP group, indicating that more approaches are warranted to alleviate the discomfort of female patients. Our study has several limitations: (1) this was a 2-center RCT conducted on a unsedated Chinese population and the effect of SP might not be directly generalized to whites due to distinct differences in baseline CIT, prevalence of colonic diverticulosis, and BMI; (2) because unsedated patients and endoscopists in the study could not be masked for the position, investigator bias could not be excluded, although multilevel (including subjective and objective assessment from both patients and endoscopists) measures were established to comprehensively assess the effect of SP; (3) one possible critique of SP might be that it could be difficult to find the location of the anus and therefore LHP was needed first to seek the anus for some patients, although the position changes in these patients only took a few seconds and would not cause pain at the beginning of insertion Volume
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TABLE 5. Factors increasing acceptance of unsedated colonoscopy as identified by logistic regression
Factors Female (versus male) LHP (versus SP) Diverticulum (versus none)
Odds ratio (95% confidence interval)
Significance (P)
0.5 (0.2-0.8)
.01
0.3 (0.2-0.6)
˂.001
0.08 (0.01-0.5)
.01
4.
5.
6.
Indications Diagnosis
7.
Reference
Screening (versus diagnosis)
1.9 (0.7-5.2)
.19
Surveillance (versus diagnosis)
6.2 (1.6-24.3)
.01 8.
LHP, Left lateral horizontal position; SP, supine position.
9.
in contrast to during colonoscopy when difficult insertion occurred with significant pain and embarrassment. Our study also has several strengths to reach a convincing and generalizable conclusion. First, with a broad range of endoscopist experience, this is the first study illustrating the value of SP in facilitating colonoscopy insertion for unsedated patients. In addition, multilinear regression and multifactor logistic regression were performed to adjust for risk factors, demonstrating that SP was the only modifiable factor to reduce CIT and pain and increase acceptance of unsedated colonoscopy. Finally, the SP could be applied widely in colonoscopy practice without the need for more equipment, personnel, or expense. In conclusion, SP can significantly reduce CIT and pain of insertion and improve patients’ acceptance of unsedated colonoscopy. SP can be widely used for colonoscopy insertion in unsedated patients for its economy and convenience, although studies with larger samples are warranted to confirm our findings.
10.
11.
12.
13.
14.
15.
16.
17.
ACKNOWLEDGMENTS 18.
We thank Dr Qian Wei for analyzing the data and all the nurses who helped change the position of patients. Y.B. is supported by the National Key R&D Program of China (2017YFC1308800, 2018YFC1313103), the National Natural Science Foundation of China (grant nos. 81670473 and 81873546), and Three Engineering Training Funds in Shenzhen (no. SYLY201718). S.Z. is supported by the Outstanding Postgraduate Fund of Second Military Medical University.
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20.
21.
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23.
24.
blood testing: analysis of prevalence and incidence screening. BMJ 2010;341:c5531. Peery AF, Crockett SD, Murphy CC, et al. Burden and cost of gastrointestinal, liver, and pancreatic diseases in the United States: update 2018. Gastroenterology 2018;156:254-72.e11. Dougherty MK, Brenner AT, Crockett SD, et al. Evaluation of interventions intended to increase colorectal cancer screening rates in the United States: a systematic review and meta-analysis. JAMA Intern Med 2018;178:1645-58. Deng SX, Gao J, An W, et al. Colorectal cancer screening behavior and willingness: an outpatient survey in China. World J Gastroenterol 2011;17:3133-9. Ghevariya V, Duddempudi S, Ghevariya N, et al. Barriers to screening colonoscopy in an urban population: a study to help focus further efforts to attain full compliance. Int J Colorectal Dis 2013;28: 1497-503. Denberg TD, Melhado TV, Coombes JM, et al. Predictors of nonadherence to screening colonoscopy. J Gen Intern Med 2005;20:989-95. Kravochuck S, Gao R, Church J. Differences in colonoscopy technique impact quality. Surg Endosc 2014;28:1588-93. Bugajski M, Wieszczy P, Hoff G, et al. Modifiable factors associated with patient-reported pain during and after screening colonoscopy. Gut 2018;67:1958-64. Predmore Z, Nie X, Main R, et al. Anesthesia service use during outpatient gastroenterology procedures continued to increase from 2010 to 2013 and potentially discretionary spending remained high. Am J Gastroenterol 2017;112:297-302. Wernli KJ, Brenner AT, Rutter CM, et al. Risks associated with anesthesia services during colonoscopy. Gastroenterology 2016;150: 888-94; quiz e18. Adams MA, Prenovost KM, Dominitz JA, et al. predictors of use of monitored anesthesia care for outpatient gastrointestinal endoscopy in a capitated payment system. Gastroenterology 2017;153:1496-503.e1. Petrini JL, Egan JV, Hahn WV. Unsedated colonoscopy: patient characteristics and satisfaction in a community-based endoscopy unit. Gastrointest Endosc 2009;69:567-72. Bretthauer M, Kaminski MF, Loberg M, et al. Population-based colonoscopy screening for colorectal cancer: a randomized clinical trial. JAMA Intern Med 2016;176:894-902. Jia H, Pan Y, Guo X, et al. Water exchange method significantly improves adenoma detection rate: a multicenter, randomized controlled trial. Am J Gastroenterol 2017;112:568-76. Holme O, Hoie O, Matre J, et al. Magnetic endoscopic imaging versus standard colonoscopy in a routine colonoscopy setting: a randomized, controlled trial. Gastrointest Endosc 2011;73:1215-22. Pasternak A, Szura M, Solecki R, et al. Impact of responsive insertion technology (RIT) on reducing discomfort during colonoscopy: randomized clinical trial. Surg Endosc 2017;31:2247-54. Suzuki T, Matsushima M, Tsukune Y, et al. Double-balloon endoscopy versus magnet-imaging enhanced colonoscopy for difficult colonoscopies, a randomized study. Endoscopy 2012;44:38-42. Lee DW, Li AC, Ko CW, et al. Use of a variable-stiffness colonoscope decreases the dose of patient-controlled sedation during colonoscopy: a randomized comparison of 3 colonoscopes. Gastrointest Endosc 2007;65:424-9. Crockett SD, Cirri HO, Kelapure R, et al. Use of an abdominal compression device in colonoscopy: a randomized, sham-controlled trial. Clin Gastroenterol Hepatol 2016;14:850-7.e3. Wallace MB, Wang KK, Adler DG, et al. Recent advances in endoscopy. Gastroenterology 2017;153:364-81. Zhao SB, Yang X, Fang J, et al. Effect of left lateral tilt-down position on cecal intubation time: a 2-center, pragmatic, randomized controlled trial. Gastrointest Endosc 2018;87:852-61. Vergis N, McGrath AK, Stoddart CH, et al. Right Or Left in COLonoscopy (ROLCOL)? A randomized controlled trial of right- versus left-sided starting position in colonoscopy. Am J Gastroenterol 2015;110: 1576-81.
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Zhao et al 25. 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;58:782-7. 26. Weinstock LB. Body positions for colonoscopy: value of Trendelenburg. Gastrointest Endosc 2009;69:1409-10. 27. Fang J, Wang SL, Fu HY, et al. Impact of gum chewing on the quality of bowel preparation for colonoscopy: an endoscopist-blinded, randomized controlled trial. Gastrointest Endosc 2017;86:187-91. 28. Bai Y, Fang J, Zhao SB, et al. Impact of preprocedure simethicone on adenoma detection rate during colonoscopy: a multicenter, endoscopistblinded randomized controlled trial. Endoscopy 2018;50:128-36. 29. Cooper GS, Kou TD, Rex DK. Complications following colonoscopy with anesthesia assistance: a population-based analysis. JAMA Intern Med 2013;173:551-6. 30. Zhao SB, Wan H, Fu HY, et al. Quantitative assessment of the effect of position changes during colonoscopy withdrawal. J Dig Dis 2016;17: 357-65. 31. Lee SW, Chang JH, Ji JS, et al. Effect of dynamic position changes on adenoma detection during colonoscope withdrawal: a randomized controlled multicenter trial. Am J Gastroenterol 2016;111:63-9. 32. Zhao SB, Wan H, Li ZS, et al. Is dynamic position changes an effective way to improve the adenoma detection rate? Am J Gastroenterol 2016;111:1359-61. 33. East JE, Suzuki N, Arebi N, et al. Position changes improve visibility during colonoscope withdrawal: a randomized, blinded, crossover trial. Gastrointest Endosc 2007;65:263-9. 34. Vergis N, Scarborough AJ, Morris JA, et al. Prone or left for colonoscopy? A randomized controlled trial of prone versus left-sided starting position for colonoscopy. J Clin Gastroenterol 2018;52:e82-6. 35. Klare P, Huth R, Haller B, et al. Patient position and hypoxemia during propofol sedation for colonoscopy: a randomized trial. Endoscopy 2015;47:1159-66. 36. Cadoni S, Sanna S, Gallittu P, et al. A randomized, controlled trial comparing real-time insertion pain during colonoscopy confirmed
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Supine position for colonoscopy insertion water exchange to be superior to water immersion in enhancing patient comfort. Gastrointest Endosc 2015;81:557-66.
Abbreviations: BBPS, Boston Bowel Preparation Scale; BMI, body mass index; CIT, cecal intubation time; CRC, colorectal cancer; DIT, descending colon intubation time; LHP, left lateral horizontal position; LTDP, left tilt-down position; RCT, randomized controlled trial; SD, standard deviation; SP, supine position; VAS, visual analog scale. DISCLOSURE: All authors disclosed no financial relationships relevant to this publication. *Drs Zhao, Yang, Meng, and Wang contributed equally to this article. Copyright ª 2019 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 https://doi.org/10.1016/j.gie.2019.01.009 Received November 6, 2018. Accepted January 4, 2019. Current affiliations: Department of Gastroenterology, Changhai Hospital, Second Military Medical University/Naval Medical University, Shanghai (1); Department of Gastroenterology, No. 905 Hospital of The Chinese PLA, Shanghai (2); Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan (3); Department of Gastroenterology, Ruijing Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (4). Reprint requests: Duowu Zou, MD, PhD, Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China, and Department of Gastroenterology, Ruijing Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; or Zhaoshen Li, MD, PhD, or Yu Bai, MD, PhD, Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China.
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SUPPLEMENTARY TABLE 1. Subgroups for cecal intubation time and pain score SP (n [ 169)
LHP (n [ 163)
P value
275.0 (234.0-328.5)
316.0 (261.0-370.0)
<.001
Male
248.5 (219.5-303.0)
306.0 (257.5-349.0)
<.001
Female
312.0 (268.0-388.0)
318.0 (268.0-379.0)
.43
CIT (seconds), median (IQR) Sex
Endoscopist Bai (>3000)
272.0 (220.0-377.2)
310.0 (240.0-475.0)
.14
Yang (1000-3000)
272.0 (238.0-302.0)
315.0 (276.0-340.00)
<.001
Fang (<1000)
540.0 (344.0-736.0)
565.0 (262.0-703.0)
.91
Patients’ pain score, mean (SD) Male
2.8 (1.4)
3.7 (1.4)
.001
Female
4.0 (1.7)
4.3 (1.6)
.26
SP, Supine position; LHP, left lateral horizontal position; CIT, cecal intubation time; IQR, interquartile range; SD, standard deviation.
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Impact of the supine position versus left horizontal position on colonoscopy insertion: a 2-center, randomized controlled trial Shengbing Zhao, MD,1,* Xia Yang, MD,1,2,* Qianqian Meng, MD,1,* Shuling Wang, MD,1,* Jun Fang, MD,3 Wei Qian, MD,1 Tian Xia, MD,1 Peng Pan, MD,1 Zhijie Wang, MD,1 Lun Gu, MD,1 Xin Chang, MD,1 Duowu Zou, MD, PhD,1,4 Zhaoshen Li, MD, PhD,1 Yu Bai, MD, PhD1 Shanghai; Wuhan, China
GRAPHICAL ABSTRACT
Background and Aims: Colonoscopy insertion is painful for some patients and is one of the main barriers to screening colonoscopy. Few studies have assessed the impact of the supine position (SP) on colonoscopy insertion, especially for unsedated patients. The aim of this randomized controlled trial was to clarify this issue. Methods: Unsedated patients were randomized to SP or left horizontal position (LHP) as the starting position of colonoscopy insertion. The primary outcome measure was cecal intubation time (CIT), and the secondary outcome measures were descending colon intubation time (DIT), pain score of patients, difficulty score according to the endoscopist, and patients’ acceptance of unsedated colonoscopy. Results: A total of 347 patients were randomized to the SP group (175) or the LHP group (172). The CIT in the SP group was significantly shorter than that in the LHP group (275.0 seconds [interquartile range (IQR), 234.0-328.5 seconds] versus 316.0 seconds [IQR, 261.0-370.0 seconds], P < .001). The DIT was also shorter in the SP group (64.5 seconds [IQR, 52.0-86.3 seconds] versus 74.0 seconds [IQR, 62.0-92.0 seconds], P Z .001). Compared with the LHP, the SP had a lower pain score (3.3 versus 3.9, P Z .002), a lower difficulty score (3.1 versus 3.7, P < .001), a lower frequency of position change (7.1% versus 38.0%, P < .001), and less need for abdominal compression (39.1% versus 45.5%, P Z .02). SP was the only modifiable and independent factor identified to reduce CIT and pain score and improve patients’ acceptance of unsedated colonoscopy. Conclusions: As an economical and convenient method, SP can reduce CIT, ease pain, and improve patients’ acceptance of unsedated colonoscopy. (Clinical trial registration number: NCT03289442.) (Gastrointest Endosc 2019;-:1-9.)
(footnotes appear on last page of article)
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INTRODUCTION Colorectal cancer (CRC) is one of the most commonly diagnosed malignancies worldwide, with the third highest morbidity and the second highest mortality.1 CRC screening has significantly reduced the incidence and mortality of CRC, and colonoscopy is generally recognized as the criterion standard. It is the most performed endoscopic procedure for CRC screening and surveillance.2-4 However, the participation rate of CRC screening and public acceptance of colonoscopy have often been suboptimal, although several efforts have been made.4-6 On the one hand, pain arising from colonoscopy, particularly during insertion, is one of the most important factors precluding the public from participating in screening.7,8 On the other hand, colonoscopy insertion is technically challenging and time consuming for inexperienced colonoscopists with looping occurring frequently, especially in the sigmoid, which increases the severity of pain and the risk of adverse events.9 Although propofol sedation can help ease discomfort during colonoscopy10 and is performed discretionarily for two-thirds of colonoscopies in the United States, the widespread use of sedation has been long criticized for the high cost of medical resources, time, and personnel, as well as the high risk of sedation-related and procedure-related adverse events,11,12 with great efforts made to reduce the number of colonoscopies with unnecessary anesthesia.13,14 Ideally, a high-quality, safe, and painless colonoscopy with no or minimal sedation is considered the optimal colonoscopy. Currently, unsedated colonoscopy is increasingly accepted and routinely performed in Europe and China,15,16 and a wealth of techniques and equipment have been introduced to facilitate insertion, ease pain, and reduce time, mainly for unsedated colonoscopy. However, these new techniques and equipment, including imaging devices,17 responsive insertion technology,18 doubleballoon endoscopy,19 variable-stiffness colonoscope,20 abdominal compression device,21 and water-exchange colonoscopy,16 showed conflicting findings on cecal intubation time (CIT) and procedure-related pain, or depended on expensive equipment, all of which limit their wide application.22 In addition, individual endoscopists were reported to be the most important modifiable factor associated with the pain of colonoscopy, and therefore more efforts are warranted to improve insertion skills and reduce the variation among endoscopists.10 Notably, changing the starting position of patients was considered to be able to alleviate discomfort and reduce time of insertion, and we also reported that the left tilt-down position (LTDP)23 could reduce CIT and pain, and potentially improve patients’ acceptance of unsedated colonoscopy because LTDP straightens the sigmoid and redundant colon and facilitates the fecal residue and fluid flowing away from the view of endoscopists compared with the left lateral horizontal position (LHP).23-25 Rationally, the supine position (SP) can also alleviate the disadvantages of LHP and is often used for
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position changes during insertion.26 However, the value of SP as the starting position has not been fully illustrated, especially for unsedated patients. Therefore, we conducted a 2-center randomized controlled trial (RCT) to explore the effect of SP on colonoscopy insertion.
METHODS Overview We conducted the RCT between August 2017 and January 2018 in 2 digestive endoscopy centers, as introduced previously.23,27,28 The study protocol was approved by the ethics committees of both hospitals, and informed consent was acquired from all participants. The trial was registered at ClinicalTrials.gov (identifier, NCT03289442). Professors Z.S. Li, Y. Bai, D.W. Zou, and co-authors had full access to the study data, and the final manuscript was reviewed and approved by all authors.
Participants Consecutive adult outpatients with indications of CRC screening, surveillance, and diagnostic examinations for colonoscopy were invited to participate in the study by the 3 endoscopists (Y.B, X.Y., and J.F.). Patients younger than 18 years or older than 75 years, those who did not provide informed consent, pregnant women, and those with histories of colonic resection, severe cardiopulmonary and renal diseases, major psychiatric disorders, therapeutic colonoscopy, or any contraindications for colonoscopy were excluded.
Randomization Patients were randomized to SP or LHP with stratification according to the centers. The randomization list generated by the Center for Clinical Epidemiology and Evidence-Based Medicine (Second Military Medical University/Naval Medical University, Shanghai, China) was put into sealed opaque envelopes, which were opened at the start of the colonoscopy. The person generating the list did not participate in data acquisition and analysis.
Bowel preparation and intervention procedures All patients received the same split-dose bowel preparation with 3 L of polyethylene glycol (Wanhe Pharmaceutical Co, Ltd, China or Tianjin Beaufour Ipsen, Pharmaceutical Co, Ltd, China), as described previously.23,27,28 No hyoscine was used in the study. High-resolution colonoscopes (CF-Q290 or CF-Q260, Olympus) without endoscopic attachments, image devices, or water immersion/exchange were used, using carbon dioxide as the standard gas for insufflation. At the start of the colonoscopy, patients in the SP group were instructed to lie in a supine position to receive inspection (or first in a left position to seek the entrance for the colonoscope and immediately transfer
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Supine position for colonoscopy insertion
Figure 1. A, The supine position. B, The left lateral horizontal position.
to the supine position depending on the preference of the colonoscopist); patients in the LHP group were positioned in the left lateral horizontal position (Fig. 1). The colonoscopists were required not to take biopsy samples or resect polyps and insufflate the colon with as little gas as possible during insertion so that they could identify the direction of insertion to reduce pain and the risk of adverse events during insertion. The application of loop reduction, position change, and abdominal compression depended on the preferences of colonoscopists. The time to the descending colon and cecum was recorded. Insertion difficulty and pain were assessed by the endoscopists and patients as soon as the cecum was reached. No colonoscopist had previously performed colonoscopy with the supine starting position, and no trainees participated in the RCT.
scopists were unable to complete the insertion; (5) the need for position change and abdominal compression during insertion; and (6) rates of adverse events, including aspiration pneumonia, perforation, splenic injury/rupture, and death, which required hospitalization within 30 days of the colonoscopy.29
Sample size calculation A pilot study was conducted to find that SP could reduce CIT by 30 seconds; the mean CIT was 5.3 minutes with a standard deviation (SD) of 1.6 minutes. A sample size of 161 patients in each group was estimated to provide a power of 80% and a Z 0.05 to detect a 30-second difference in CIT between the SP and LHP groups.
Statistical analysis Outcome measures The outcome measures were the same as described previously.23 The primary outcome was CIT, which was confirmed by identifying the characteristic anatomic landmarks of the triradiate fold, appendiceal orifice, and ileocecal valve. The secondary outcome measures were (1) descending colon intubation time (DIT), which was identified by the presence of the straight colonic lumen and affirmed by an independent observer; (2) patients’ pain score using a 10-cm visual analog scale (VAS), in which a score of 0 denoted no pain and a score of 10 denoted unbearable pain; (3) patients’ acceptance of unsedated or sedated colonoscopy for future colonoscopies; (4) difficulty score for colonoscopy insertion assessed by the endoscopist, as measured by VAS in which a score of 0 represented no technical challenge and a score of 10 represented an extreme technical challenge such that endowww.giejournal.org
The analyses were performed according to intention-totreat analysis (patient characteristics, endoscopist characteristics, and indications) and per-protocol analysis (withdrawal time, polyp/adenoma detection, insertion time, and pain/difficulty score). Continuous variables were expressed as mean with ranges (SD) or median with the interquartile range and were compared using the Student t test or the Mann-Whitney non-parametric test when appropriate. Categorical data were analyzed using the chi-squared test. P values <.05 were considered to be statistically significant, and all tests were 2-sided. Multiple linear regression and multivariate logistic regression were performed using the following variables: age, gender, body mass index (BMI) (18.5 kg/m2 < BMI < 28 kg/m2, BMI >28 kg/m2, or BMI <18.5 kg/m2), the presence or absence of previous abdominal surgery and pelvic surgery, previous colonoscopy, history of previously incomplete colonoscopy, colonic diverticulum, experience Volume
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Assessed for eligibility (n=420)
Enrollment (n=347)
Excluded (n = 73) 1. Declined consent (n = 30) 2. Age <18 or >75 years (n = 14) 3. Urgent/therapeutic colonoscopy (n = 3) 4. Colonic resection (n = 7) 5. Others (n = 19)
Randomization
Allocation
Allocated to supine position (N=175)
Allocated to left lateral horizontal position (N=172)
Analysis Per-protocol analysis (n=169)
Per-protocol analysis (n=163)
Excluded(n=6) Obstructive disease (n=4) Intolerant abdominal pain (n=2)
Excluded(n=9) Poor bowel preparation (n=3) Obstructive disease (n=4) Intolerant abdominal pain (n=2)
Figure 2. Flowchart of the enrollment process.
of endoscopist, indications, bowel preparation quality, and the starting position. The model was built using stepwise regression. All statistical analyses were performed using SPSS Statistics v22 (IBM, Chicago, Ill).
RESULTS Enrollment and baseline characteristics Overall, 420 consecutive patients referred to the 2 centers were invited to participate and 73 patients were excluded for refusal, not within the required age range, urgent/therapeutic colonoscopy, colonic resection, and other reasons. Finally, 347 patients were randomized to SP (175) and LHP (172); 15 (4.3%) colonoscopies failed to reach the cecum for obstructive diseases (8), intolerant pain (4), and poor bowel preparation (3) (Fig. 2). The baseline characteristics were well balanced in the 2 groups (Table 1).
Primary outcomes and subgroup analysis CIT in the SP group was significantly shorter than that in the LHP group (275.0 seconds [interquartile range (IQR), 234.0-328.5 seconds] versus 316.0 seconds [IQR, 4 GASTROINTESTINAL ENDOSCOPY Volume
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261.0-370.0 seconds], P < .001, Table 2). Patients with Boston Bowel Preparation Scale (BBPS) score 6 showed a significant reduction in CIT (270.0 seconds [IQR, 230.5323.0 seconds] versus 313.5 seconds [IQR, 262.5-350.5 seconds], P < .001), but those with BBPS score <6 did not reach a significant difference (P Z .22, Table 2). Only male patients and endoscopists who had performed 1000 to 3000 procedures showed a shorter CIT in the SP group (both P < .001, Figs. 3 and 4), but the difference for female patients and endoscopists with more or fewer procedures was not statistically significant (P Z .43, P Z .14, and P Z .91, respectively; Figs. 3 and 4).
Secondary outcomes Compared with the LHP group, a shorter DIT was also observed in the SP group (64.5 seconds [IQR, 52.0-86.3 seconds] versus 74.0 seconds [IQR, 62.0-92.0 seconds], P Z .001, Table 2). The pain score in the SP group was lower than that in the LHP group (3.3 [SD, 1.6] versus 3.9 [SD, 1.7], P Z .002; Table 2) and the decrease in pain score was significant for males but not for females (P Z .001 and P Z .26, respectively; Fig. 5). The www.giejournal.org
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Supine position for colonoscopy insertion
TABLE 1. Characteristics of the patients and the colonoscopies Characteristics* Age (years), mean (SD) Female, no. (%) BMI (kg/m2), mean (SD)
SP (n [ 175)
LHP (n [ 172)
51.5 (14.3)
52.8 (14.6)
.39
78 (44.6)
82 (47.7)
.56
22.9 (3.1)
23.3 (3.0)
.25
15
24
Indications for colonoscopy Screening
.28
Surveillance
31
28
Diagnosis
129
120
64 (36.6)
58 (33.7)
Previous colonoscopy, no. (%)
P value
.59
Risk factors for difficult insertion, no. (%) BMI >28 kg/m2
9 (5.2)
10 (5.9)
.78
BMI <18.5 kg/m2
11 (6.4)
13 (7.7)
.64
History of non-laparoscopic abdominal surgery, no. (%)
23 (13.1)
26 (15.1)
.60
9 (5.1)
10 (5.8)
.78
28 (16.1)
28 (16.3)
.96
History of laparoscopic abdominal surgery, no. (%) History of pelvic surgery, no. (%) Colonic diverticulum, no. (%)
3 (1.7)
4 (2.3)
.98
History of previously incomplete colonoscopy, no. (%)
3 (1.7)
3 (1.7)
1
Bai (>3000)
82
69
Yang (1000-3000)
84
85
Endoscopist experience
Fang (<1000) BBPS score, mean (SD) BBPS score 6, no. (%) Withdrawal time (seconds), mean (SD)
.22
10
18
6.0 (0.98)
6.0 (0.90)
.64
137 (81.1)
131 (80.4)
.87
369.7 (74.0)
369.6 (76.4)
.99
Polyp detection, no. (%)
64 (37.0)
68 (41.7)
.38
Adenoma detection, no. (%)
40 (23.1)
34 (21.0)
.64
SP, Supine position; LHP, left lateral horizontal position; SD, standard deviation; BMI, body mass index; BBPS, Boston bowel preparation scale. *All factors were analyzed by intention to treat except for BBPS, withdrawal time, polyp detection, and adenoma detection, which were analyzed per protocol.
difficulty score was also lower in the SP group (3.1 [SD, 1.2] versus 3.7 [SD, 1.5], P < .001; Table 2). There was a lower frequency of position change and abdominal compression in the SP group (12 [7.1%] versus 62 [38.0%], P < .001, and 66 [39.1%] versus 85 [45.5%], P Z .02; Table 2). In addition, the patients’ acceptance of unsedated colonoscopy was 88.2% in the SP group versus 73.0% in the LHP group (P < .001, Table 2). No adverse events were observed in both groups.
Multiple linear regression and multivariate logistic regression Being female was identified as a risk factor for longer CIT, whereas SP and endoscopists with more experience were protective factors for decreasing CIT (P < .001, P Z .02, and P Z .001, respectively; Table 3). Females tended to have more severe pain than males, but the SP could ease the pain (P Z .001 and P < .001, respectively; Table 4). Females, LHP, and colonic diverticulum were found to be associated with a lower rate of acceptance for unsedated colonoscopy, whereas patients with the www.giejournal.org
indication of surveillance reported a higher rate of acceptance (P Z .01, P < .001, P Z .01, and P Z .01, respectively; Table 5). SP was the only modifiable factor to reduce CIT and pain score, as well as improve acceptance of unsedated colonoscopy.
DISCUSSION For the first time, the study has demonstrated that changing the starting position of unsedated patients to SP could significantly reduce CIT, ease the pain of insertion, and improve patients’ acceptance of unsedated colonoscopy. Colonoscopy is traditionally started and ended (if no position changes occur) in the left lateral position but there is little evidence supporting its value in improving the performance. Recently, changing position has been demonstrated to improve mucosal visibility and adenoma detection rate during withdrawal,30-33 and has also been found to facilitate insertion.23-25 As a simple and convenient procedure, changing position can be easily realized for almost all patients undergoing unsedated colonoscopy. Therefore, it is vital to Volume
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TABLE 2. Comparison of efficiency of colonoscopy insertion between SP and LHP SP (n [ 169)
Factors* CIR, no. (%) CIT (seconds), median (IQR)
LHP (n [ 163)
P value
169 (96.6)
163 (94.8)
.41
275.0 (234.0-328.5)
316.0 (261.0-370.0)
<.001
BBPS score 6
270.0 (230.5-323.0)
313.5 (262.5-350.5)
<.001
BBPS score <6
300.0 (246.5-351.5)
344.5 (267.0-462.0)
.22
64.5 (52.0-86.3)
74 (62.0-92.0)
.001
DIT (seconds), median (IQR) Patients’ pain score, mean (SD)
3.3 (1.6)
3.9 (1.7)
.002
Patients’ acceptance of unsedated colonoscopy, no. (%)
149 (88.2)
119 (73.0)
<.001
Difficulty score, mean (SD)
3.1 (1.2)
3.7 (1.5)
<.001
Position change, no. (%)
12 (7.1)
62 (38.0)
<.001
Abdominal compression, no. (%)
66 (39.1)
85 (45.5)
.02
SP, supine position; LHP, left lateral horizontal position; CIR, cecal intubation rate; CIT, cecal intubation time; IQR, interquartile range; BBPS, Boston bowel preparation scale; DIT, descending colon intubation time; SD, standard deviation. *All factors were analyzed per protocol.
1050
1050
SP LHP
SP LHP
850
Cecal intubation time (S)
Cecal intubation time (S)
850
650
450
650
450
250
250
50
50 Male
> 3000
Female
Sex
1000 - 3000
< 500
Endoscopist experience
Figure 3. Cecal intubation time for the supine position (SP) and the left horizontal position (LHP) according to sex. *P < .001.
Figure 4. Cecal intubation time for the supine position (SP) and left horizontal position (LHP) according to the experience of the endoscopist. *P < .001.
explore the most suitable position for the most common endoscopic procedure.4 For insertion, prone, right, and left tilt-down starting positions have been introduced to reduce pain and CIT of sedated or unsedated colonoscopy.23-25 Although the position of the patient is usually changed from the left to the supine to deal with colon loops and facilitate a difficult insertion,26 no study has explored the value of the supine starting position, particularly for unsedated patients who are sensitive to pain. In this study, a 41-second reduction in the median CIT was demonstrated in the SP group versus the LHP group. On one hand, the absolute decrease in CIT was significantly less than that in the prone position (130 seconds) (only in obese patients),25 right position (213 seconds),24
and LTDP (60 seconds),23 but the baseline median CITs of these studies varied greatly (316-720 seconds), and the CIT in our study was the least (316 seconds). In addition, another RCT conducted in a general population demonstrated that there was no benefit to CIT or no comfort observed in the prone position.34 On the other hand, inconsistent with our findings, a previous RCT reported a longer CIT in an SP group versus an LHP group (10 minutes versus 9 minutes, P Z .013).35 However, as that study aimed to compare the rate of hypoxemic events in different positions for sedated colonoscopy, the results should be interpreted with caution: (1) colonoscopies with position changes, the proportion of which was higher in LHP (41.2% versus
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SP LHP
5
Factors
4
Pain score
TABLE 3. Factors increasing time to reach the cecum as identified by multiple linear regression
3 2
3.97
3.56
4.27
Coefficient
Standard error
Significance (P)
Supine position
46.3
19.1
.02
Female
73.7
19.2
<.001
Endoscopist experience
49.1
15.2
.001
2.84
1 0 Female
Male
TABLE 4. Factors increasing the pain score of the patients as identified by multiple linear regression
Sex Factor Figure 5. Pain score for the supine position (SP) and left horizontal position (LHP) according to sex. *P Z .001.
18.0%, P < .001), were excluded for analysis; as a result, time spent in position change and colonoscopies with difficult insertion, where the SP benefited greatly, were excluded; (2) the frequency of apnea, which had to be dealt with by a series of rescue measures according to protocol, was much higher in the SP group than the LHP group (16.1% versus 1.8%, P < .001), and this distinction unavoidably prolonged the CIT in the SP group; (3) for the unsedated colonoscopies, the patients’ discomfort or pain was reflected in real time, which would significantly affect the CIT, whereas the other study35 was conducted with propofol sedation, which would markedly affect generalization in unsedated colonoscopy. Moreover, the reduction of CIT accompanied by a lower pain score, less insertion difficulty, and higher acceptance of unsedated colonoscopy was demonstrated in our study, which comprehensively demonstrated that the SP facilitated insertion in unsedated patients. Multiple linear regression and multifactor logistic regression identified SP as the only modifiable factor reducing CIT and pain and improving acceptance of unsedated colonoscopy. Therefore, the benefits of SP on CIT in our study are more convincing, particularly for unsedated patients.35 When analyzing these results, we performed an intention-to-treat analysis on the characteristics of the patients and endoscopist experience, and a per-protocol analysis on the characteristics of colonoscopy and outcomes in patients with successful cecal intubation, which was also adopted by previous reports to analyze CIT.24,25,34 Notably, the cecal intubation rate in the SP group was slightly higher despite no statistical significance, which also supported the benefits of SP in facilitating insertion. Although we observed no adverse events in both the SP and LHP groups, this might be due to the small sample size and extremely low adverse event rate. The proportions of position changes and abdominal pressure in our study were www.giejournal.org
Supine position Female
Coefficient
Standard error
Significance (P)
-0.92
0.17
<.001
0.54
0.17
.001
relatively higher than in the previous reports.24,25 Potentially, the convenience of performing these changes for unsedated patients may encourage colonoscopists to use them for a faster and more painless colonoscopy, as also seen in other studies.16,36 Notably, although times of loop reduction were not recorded due to the lack of imaging devices, a significant decrease in the frequency of position changes and abdominal pressure could reflect an easier insertion in SP. For patients with inadequate bowel preparation quality (BBPS score <6) and endoscopists with experience of over 3000 procedures, a reduction of 37 to 44 seconds was seen in the SP group, despite no statistical significance. However, endoscopists with experience of less than 500 procedures and female patients were found to merely show an insignificant marginal reduction. The effect of SP for the subgroups needs to be confirmed by studies with larger samples. The pain score in females remained high even in the SP group, indicating that more approaches are warranted to alleviate the discomfort of female patients. Our study has several limitations: (1) this was a 2-center RCT conducted on a unsedated Chinese population and the effect of SP might not be directly generalized to whites due to distinct differences in baseline CIT, prevalence of colonic diverticulosis, and BMI; (2) because unsedated patients and endoscopists in the study could not be masked for the position, investigator bias could not be excluded, although multilevel (including subjective and objective assessment from both patients and endoscopists) measures were established to comprehensively assess the effect of SP; (3) one possible critique of SP might be that it could be difficult to find the location of the anus and therefore LHP was needed first to seek the anus for some patients, although the position changes in these patients only took a few seconds and would not cause pain at the beginning of insertion Volume
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TABLE 5. Factors increasing acceptance of unsedated colonoscopy as identified by logistic regression
Factors Female (versus male) LHP (versus SP) Diverticulum (versus none)
Odds ratio (95% confidence interval)
Significance (P)
0.5 (0.2-0.8)
.01
0.3 (0.2-0.6)
˂.001
0.08 (0.01-0.5)
.01
4.
5.
6.
Indications Diagnosis
7.
Reference
Screening (versus diagnosis)
1.9 (0.7-5.2)
.19
Surveillance (versus diagnosis)
6.2 (1.6-24.3)
.01 8.
LHP, Left lateral horizontal position; SP, supine position.
9.
in contrast to during colonoscopy when difficult insertion occurred with significant pain and embarrassment. Our study also has several strengths to reach a convincing and generalizable conclusion. First, with a broad range of endoscopist experience, this is the first study illustrating the value of SP in facilitating colonoscopy insertion for unsedated patients. In addition, multilinear regression and multifactor logistic regression were performed to adjust for risk factors, demonstrating that SP was the only modifiable factor to reduce CIT and pain and increase acceptance of unsedated colonoscopy. Finally, the SP could be applied widely in colonoscopy practice without the need for more equipment, personnel, or expense. In conclusion, SP can significantly reduce CIT and pain of insertion and improve patients’ acceptance of unsedated colonoscopy. SP can be widely used for colonoscopy insertion in unsedated patients for its economy and convenience, although studies with larger samples are warranted to confirm our findings.
10.
11.
12.
13.
14.
15.
16.
17.
ACKNOWLEDGMENTS 18.
We thank Dr Qian Wei for analyzing the data and all the nurses who helped change the position of patients. Y.B. is supported by the National Key R&D Program of China (2017YFC1308800, 2018YFC1313103), the National Natural Science Foundation of China (grant nos. 81670473 and 81873546), and Three Engineering Training Funds in Shenzhen (no. SYLY201718). S.Z. is supported by the Outstanding Postgraduate Fund of Second Military Medical University.
19.
20.
21.
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Abbreviations: BBPS, Boston Bowel Preparation Scale; BMI, body mass index; CIT, cecal intubation time; CRC, colorectal cancer; DIT, descending colon intubation time; LHP, left lateral horizontal position; LTDP, left tilt-down position; RCT, randomized controlled trial; SD, standard deviation; SP, supine position; VAS, visual analog scale. DISCLOSURE: All authors disclosed no financial relationships relevant to this publication. *Drs Zhao, Yang, Meng, and Wang contributed equally to this article. Copyright ª 2019 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 https://doi.org/10.1016/j.gie.2019.01.009 Received November 6, 2018. Accepted January 4, 2019. Current affiliations: Department of Gastroenterology, Changhai Hospital, Second Military Medical University/Naval Medical University, Shanghai (1); Department of Gastroenterology, No. 905 Hospital of The Chinese PLA, Shanghai (2); Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan (3); Department of Gastroenterology, Ruijing Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (4). Reprint requests: Duowu Zou, MD, PhD, Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China, and Department of Gastroenterology, Ruijing Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; or Zhaoshen Li, MD, PhD, or Yu Bai, MD, PhD, Department of Gastroenterology, Changhai Hospital, Second Military Medical University, Shanghai, China.
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SUPPLEMENTARY TABLE 1. Subgroups for cecal intubation time and pain score SP (n [ 169)
LHP (n [ 163)
P value
275.0 (234.0-328.5)
316.0 (261.0-370.0)
<.001
Male
248.5 (219.5-303.0)
306.0 (257.5-349.0)
<.001
Female
312.0 (268.0-388.0)
318.0 (268.0-379.0)
.43
CIT (seconds), median (IQR) Sex
Endoscopist Bai (>3000)
272.0 (220.0-377.2)
310.0 (240.0-475.0)
.14
Yang (1000-3000)
272.0 (238.0-302.0)
315.0 (276.0-340.00)
<.001
Fang (<1000)
540.0 (344.0-736.0)
565.0 (262.0-703.0)
.91
Patients’ pain score, mean (SD) Male
2.8 (1.4)
3.7 (1.4)
.001
Female
4.0 (1.7)
4.3 (1.6)
.26
SP, Supine position; LHP, left lateral horizontal position; CIT, cecal intubation time; IQR, interquartile range; SD, standard deviation.
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