***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Colonoscopy may be associated with discomfort when performed without sedation . A study was conducted to determine whether instillation of water into the colon at the beginning of the procedure reduces intubation time as well as patient discomfort and pain . METHODS  Colonoscopy was performed in 259 patients by 3 endoscopists-in-training with limited experience . Patients were r and omly allocated to 2 groups . In one , a technique was used in which 500 to 1000 mL of water is instilled into the colon by enema at the beginning of the procedure ( instillation group , n = 130 ) . In the other , patients underwent a conventional colonoscopy ( control group , n = 129 ) . Intubation time was measured and compared between the groups , and subjective discomfort experienced by the patients was measured upon completion of the examination . RESULTS Success rates for insertion to the cecum were similar , ( 95.4 % , instillation group ; 96.1 % , control group ) . Detection rates for any colorectal diseases were not different between the groups ( 30.0 % vs. 32.6 % ) . Mean time to cecal intubation was 10.5 minutes in the instillation group and 16.2 minutes in the control group ( p < 0.0001 ) . The proportion of patients who complained of abdominal pain during the procedure was 17.1 % in the instillation group and 33.3 % in the control group ( p < 0.001 ) . CONCLUSIONS When used by endoscopists-in-training , the water-instillation colonoscopy technique was associated with less discomfort and faster cecal intubation with no decrease in the rate of detection of colorectal diseases Objective . The volume of colonoscopies performed is increasing and differences in colonoscopy practice over time and between centres have been reported . Examination of current practice is important for benchmarking quality . The objective of this study was to examine variations in  colonoscopy practice in endoscopy centres internationally . Material and methods . This observational study prospect ively included consecutive patients referred for colonoscopy from 21 centres in 11 countries . Patient , procedure and centre characteristics were collected through question naires . Descriptive statistics were performed and the variation between centres while controlling for case-mix was examined . Results . A total of 6004 patients were included in the study . Most colonoscopies ( 93 % ; range between centres 70–100 % ) were performed for diagnostic purpose s. The proportion of main indications for colonoscopy  showed wide variations between centres , the two most common indications , surveillance and haematochezia , ranging between 7–24 % and 5–38 % , respectively . High- quality cleansing occurred in 74 % ( range 51–94 % ) of patients , and 30 % ( range 0–100 % ) of patients received deep sedation . Three-quarters ( range 0–100 % ) of the patients were monitored during colonoscopy  , and one-quarter ( range 14–35 % ) underwent polypectomy . Colonoscopy  was complete in 89 % ( range 69–98 % ) of patients and the median total duration was 20 min ( range of centre medians 15–30 min ) . The variation between centres was not reduced when case-mix was controlled for . Conclusions . This study documented wide variations in colonoscopy practice between centres . Controlling for case-mix did not remove these variations , indicating that centre and procedure characteristics play a role . Centres generally were within the existing guidelines , although there is still some work to be done to ensure that all centres attain the goal of providing high- quality colonoscopy BACKGROUND Pilot studies using a novel water method to perform screening colonoscopy allowed patients to complete colonoscopy without sedation medications and also significantly increased the cecal intubation success rate . OBJECTIVE To perform a r and omized , controlled trial comparing air insufflation ( conventional method ) and water infusion in lieu of air insufflation ( study method ) colonoscopy in minimally se date d patients . HYPOTHESIS Compared with the conventional method , patients examined by the study method had lower pain scores and required less medication but had a similar cecal intubation rate and willingness to undergo colonoscopy in the future . SETTING Outpatient colonoscopy in a single Veterans Affairs hospital . METHODS After informed consent and st and ard bowel preparation , patients received premedications administered as 0.5-increments of fentanyl ( 25 microg ) and 0.5-increments of Versed ( midazolam ) ( 1 mg ) plus 50 mg of diphenhydramine . The conventional and the study methods for colonoscopy were implemented as previously described . Additional pain medications were administered at the patients ' request . MAIN OUTCOME MEASUREMENTS Increments of medications , pain scores , cecal intubation , and willingness to repeat colonoscopy . RESULTS Increments of medications used before reaching the cecum ( 1.6 + /- 0.2 vs 2.4 + /- 0.2 , P < .0027 ) , total increments used ( 1.8 + /- 0.2 vs 2.5 + /- 0.2 , P < .014 ) , and the maximum pain scores ( 1.3 + /- 0.3 vs 4.1 + /- 0.6 , P < .0002 ) were significantly lower with the water method .  Cecal intubation rate ( 100 % ) and willingness to undergo a repeat colonoscopy ( 96 % ) were similar . LIMITATIONS Single Veterans Affairs hospital , older male population . CONCLUSION Water infusion in lieu of air insufflation is superior to air insufflation during colonoscopy in the minimally se date d patients ( Clinical Trials.gov Identifier NCT00785889 ) BACKGROUND & AIMS Several studies have indicated that water infusion , instead of air insufflation , enhances cecal intubation in selected patients undergoing unse date d colonoscopy . We performed a prospect i ve , r and omized , controlled trial to investigate whether the water technique increases the proportion of patients that are able to complete unse date d colonoscopy . METHODS We analyzed data from 116 consecutive out patients who were willing to start colonoscopy without sedation ; 58 were each r and omly assigned to groups given water infusion or air insufflation during the insertion phase . Sedation and analgesia were administered on dem and . RESULTS Fewer patients requested sedation in the water group ( 8.6 % ) than in the air group ( 34.5 % ; P = .003 ) and their maximum pain scores were lower ( 2.8 ± 1.9 vs 4.2 ± 2.3 in the air group ; P = .011 ) . However , differences in percentages of patients who received complete , unse date d colonoscopy between the water group ( 74.1 % ) and air group ( 62.1 % ) did not reach statistical significance ( P = .23 ) ; the percentage of successful cecal intubations was lower in the water group ( 82.8 % ) than in the air group ( 96.5 % ; P = .03 ) because of poor visibility . Failed procedures in the water group were completed successfully after air insufflation . The cecal intubation time was shorter in the air group ( 6.2 ± 3.4 min ) than in the water group ( 8.1 ± 3.0 min ; P = .01 ) . CONCLUSIONS In patients willing to undergo unse date d colonoscopy  , water infusion improves patient tolerance for cecal intubation , compared with air insufflation . However , it does not increase the overall percentage of successful cecal intubations because suboptimal bowel preparation interferes with visibility BACKGROUND : The increasing dem and for colonoscopy has renewed the interest for unse date d procedures . Alternative techniques , such as carbon dioxide insufflation and warm-water infusion , have been advocated to improve patient tolerance for colonoscopy in comparison with air insufflation . OBJECTIVE : The aim of this study was to evaluate the benefits of carbon dioxide insufflation and warm-water irrigation over air insufflation in unse date d patients . DESIGN : This study was a r and omized , controlled trial . SETTING : This study was conducted at a nonacademic single center . PATIENTS : Consecutive out patients agreeing to start colonoscopy without premedication were included . INTERVENTIONS : Patients were assigned to either carbon dioxide insufflation , warm-water irrigation , or air insufflation colonoscopy insertion phase . Sedation/analgesia were administered on patient request if significant pain or discomfort occurred . MAIN OUTCOME MEASURES : The primary outcome measured was the percentage of patients requiring sedation/analgesia . Pain and tolerance scores were assessed at discharge by using a 100-mm visual analog scale . RESULTS : Three hundred forty-one subjects ( 115 in the carbon dioxide , 113 in the warm-water , and 113 in the air group ) were enrolled . Intention-to-treat analysis showed that the proportion of patients requesting sedation/analgesia during colonoscopy was 15.5 % in the carbon dioxide group , 13.2 % in the warm-water group , and 25.6 % in the air group ( p = 0.04 carbon dioxide vs air ; p = 0.03 warm water vs air ) . Median ( interquartile range ) scores for pain were 30 ( 10–50 ) , 28 ( 15–50 ) , and 46 ( 22–62 ) in the carbon dioxide , warm-water , and air groups ( carbon dioxide vs air , p < 0.01 ; warm water vs air , p < 0.01 ) ; corresponding figures for tolerance were 20 ( 5–30 ) , 19 ( 5–36 ) , and 28 ( 10–50 ) ( carbon dioxide vs air , p < 0.01 ; warm water vs air , p < 0.01 ) . LIMITATIONS : This investigation was limited because it was a single-center study and the endoscopists were not blinded to r and omization . CONCLUSIONS : Carbon dioxide insufflation was associated with a decrease in the proportion of patients requesting on-dem and sedation , improved patient tolerance , and decreased colonoscopy-related pain in comparison with air insufflation . The findings regarding warm-water irrigation confirmed the previously reported advantages , so that warm-water irrigation and carbon dioxide insufflation could represent competitive strategies for colonoscopy in unse date d patients BACKGROUND AND STUDY AIMS Water immersion is an alternative colonoscopy technique that may reduce discomfort and facilitate insertion of the instrument . This was a prospect i ve study to compare the success of colonoscopy with minimal sedation using water immersion and conventional air insufflation . PATIENTS AND METHODS A total of 229 patients were r and omized to either  water immersion or the st and ard air insertion technique . The primary outcome was success of minimal sedation colonoscopy  , which was defined as reaching the cecum without additional sedation , exchange of the adult colonoscope or h and s-on assistance for trainees . Patient comfort and satisfaction were also assessed . RESULTS Successful minimal-sedation colonoscopy  was achieved in 51 % of the water immersion group compared with 28 % in the st and ard air group ( OR , 2.66 ; 95 % CI 1.48 - 4.79 ; P = 0.0004 ) . Attending physicians had 79 % success with water immersion compared with 47 % with air insufflation ( OR , 4.19 ; 95 % CI 1.5 - 12.17 ; P = 0.002 ) , whereas trainees had 34 % success with water compared with 16 % using air ( OR , 2.75 ; 95 % CI 1.15 - 6.86 ; P = 0.01 ) . Using the water method , endoscopists intubated the cecum faster and this was particularly notable for trainees ( 13.0 + /- 7.5 minutes with water vs. 20.5 + /- 13.9 minutes with air ; P = 0.0001 ) . Total procedure time was significantly shorter with water for both experienced and trainee endoscopists ( P < 0.05 ) . Patients reported less intraprocedural pain with water compared with air ( 4.1 + /- 2.7 vs. 5.3 + /- 2.7 ; P = 0.001 ) , with a similar level of satisfaction . There was no difference in the neoplasm detection rates between the groups . CONCLUSION Colonoscopy insertion using water immersion increases the success rate of minimal sedation colonoscopy .  Use of the technique leads to a decrease in discomfort , time to reach the cecum , and the amount of sedative and analgesic used , without compromising patient satisfaction OBJECTIVES : Completion rates , pain , and difficulties during the exam are still problems in colonoscopy . New methods of lubrication , rarely considered a matter of study , may help in this respect . Our aim was to compare an oil-assisted technique with a modified warm water method applied during colonoscopy . METHODS : A prospect i ve , r and omized , and controlled study was planned in which three groups of patients were su bmi tted to colonoscopy : a st and ard lubricating method ( water-soluble jelly : group A , 170 patients ) was adopted in a control group , whereas the st and ard method plus injection into the colon of corn seed oil  ( group B , 170 patients )  or warm water ( group C , 170 patients ) were employed in the other groups . The main variables evaluated were : the success rate for total intubation , the time required to reach the cecum and the time needed to examine the colon at withdrawal , and the level of pain and degree of difficulty associated with the examination 
    Output:
    
Qualitative analysis suggests that water infusion colonoscopy was not associated with a markedly increased rate of adverse events compared with the st and ard procedure .
Completeness of colonoscopy , that is cecal intubation rate , was not improved by water infusion compared with st and ard air insufflation colonoscopy .
However , adenoma detection , assessed with two different measures ( that is adenoma detection rate and number of detected adenomas per procedure ) , was slightly augmented by the water infusion colonoscopy .
Improved adenoma detection might be due to the cleansing effects of water infusions on the mucosa .
Detection of premalignant lesions during st and ard colonoscopy is suboptimal , and so improvements in adenoma detection by water infusion colonoscopy , although small , may help to reduce the risk of interval colorectal carcinoma .
The most obvious benefit of water infusion colonoscopy was reduction of procedure-related abdominal pain , which may enhance the acceptance of screening/surveillance colonoscopy