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Background: Colonoscopic screening for colorectal cancer is being implemented in an increasing number of countries. This might lead to a demand for colonoscopies that could outstrip supply., Objective: We wanted to investigate whether undergoing a colonoscopic examination for colorectal cancer would affect the utilization of later distal GI endoscopies for other indications than follow-up of the findings at the screening examination (usual-care endoscopies)., Design: Prospective case control study., Patients: In 1996, a screening group of 634 individuals, aged 63 to 72 years, randomly drawn from the official population registry, was invited to a "once only" colonoscopic screening examination for colorectal cancer. A total of 451 individuals (71%) attended. An age- and sex-matched control group of 634 individuals was enrolled from the same registry. Both groups belonged to the encatchment area of a single hospital., Main Outcome Measurements: Distal endoscopies performed in the 2 groups from January 1996 to November 2004 were registered by investigating medical records., Results: A total of 1268 individuals (52.4% women) were followed for 9 years. Sixty-three individuals (9.9%) in the screening group and 110 (17.4%) individuals in the control group (odds ratio 0.53, 95% confidence interval 0.38-0.73) had had a total of 85 and 169 usual-care distal endoscopies, respectively (P < .001)., Conclusions: Undergoing a colonoscopic examination for colorectal cancer seems to reduce the utilization of later usual-care endoscopic examinations. This finding could have an impact on the estimation of endoscopic resources needed for colorectal cancer screening.

Background and Study Aims: Several studies have shown that insufflation of carbon dioxide (CO2) instead of air during colonoscopy can reduce postprocedural pain. However, CO2 insufflation might also lead to CO2 retention in the human body. It was recently shown that this side effect does not occur in unsedated patients, but that sedation leads to impaired respiration. Sedated patients may therefore be more prone to CO2 retention. This randomized, double-blinded study was designed to investigate whether CO2 insufflation leads to CO2 retention in sedated patients., Patients and Methods: A total of 103 consecutive patients undergoing colonoscopy were randomly assigned to the use of either CO2 or air insufflation. End-tidal carbon dioxide (ETCO2), a noninvasive parameter for arterial P CO2, was recorded before the examination, twice during it, and 10 min after it. Midazolam or pethidine, or both, were used for sedation. The patient's pain during the examination and 1, 3, 6, and 24 h afterwards was registered using a questionnaire., Results: CO2 was used in 52 patients and air insufflation in 51. A total of 52 patients (51 %) received sedation. There were no differences in ETCO2 between the CO2 and air group. A slight increase in ETCO2 was observed in sedated patients, while there was no increase in unsedated patients. CO2 insufflation significantly reduced pain after the procedure at all time points., Conclusions: This study indicates that CO2 insufflation reduces pain and is safe to use in colonoscopy for sedated patients.

Background: During colonoscopy, air or carbon dioxide is insufflated to secure adequate visualization of the colon, and endoscopy trainees are reminded to use as little gas as possible to avoid patient discomfort. However, the volume of gas insufflated by endoscopists during colonoscopy is unknown. The aim of the present study was to measure volumes of carbon dioxide and air insufflated during colonoscopy., Methods: A total 249 consecutive patients participating in a colorectal cancer screening program were randomized to undergo colonoscopy with either carbon dioxide or air insufflation. Gas volumes insufflated during the procedure were measured with a mass-flowmeter. Four experienced endoscopists performed all of the examinations., Results: Gas volumes were successfully measured in 218 (87%) patients. A mean of 8.3 L of carbon dioxide (range 1.2-19.8 L) and 8.2 L of air (range 1.8-18 L) were insufflated (p = 0.9). Mean volumes insufflated per minute were estimated to be 0.26 L and 0.24 L, respectively, in the carbon dioxide and air groups (p = 0.5). Statistically significant differences in the volumes of gas insufflated per minute were observed among some of the endoscopists., Conclusions: The volumes of carbon dioxide and air used during colonoscopy can be estimated. Differences in volumes of gas used by experienced endoscopists were detected.

Background: To eliminate the risk of combustion during electrosurgical procedures and to reduce patient discomfort, carbon dioxide (CO2) insufflation has been recommended during colonoscopy. However, air insufflation is still the standard method, perhaps due to the lack of suitable equipment and shortage of randomised studies., Aims: This randomised controlled trial was conducted to assess patient tolerance and safety when using CO2 insufflation during colonoscopy., Patients: Over an eight month period a successive series of patients referred for a baseline colonoscopy due to findings in a flexible sigmoidoscopy screening trial were randomly assigned to the use of either air or CO2 insufflation during colonoscopy., Methods: End tidal CO2 (ETCO2), a non-invasive parameter of arterial pCO2, was registered before and repeatedly during and after the examination. The patient's experience of pain during and after the examination was registered using a visual analogue scale (VAS). Sedation was not used routinely., Results: CO2 insufflation was used in 121 patients (51%) and air in 119 patients (49%). The groups were similar in age, sex, and caecal intubation rate. No rise in ETCO2 was registered. There were statistically significant differences in VAS scores between the groups with less pain reported when using CO2., Conclusions: This randomised study of unsedated patients shows that CO2 insufflation is safe during colonoscopy with no rise in ETCO2 level. CO2 was found to be superior to air in terms of pain experienced after the examination.

Background: The administration of sedative drugs at colonoscopy has its drawbacks such as increases in the rate of complications and cost. Our aim was to study how individuals, drawn from a population registry and invited to undergo screening colonoscopy for colorectal polyps, experienced the procedure without conscious sedation., Methods: Four hundred fifty-one individuals underwent the screening examination (median age 67 years, range 63 to 72). The cecum was intubated in 369 (82%). Fourteen days after the examination, 429 of the attendees received a questionnaire designed to evaluate their tolerance of the procedure., Results: Four hundred nine participants (95%) replied.Twenty-one (5%) of these individuals found the examination very uncomfortable, 184 (45%) found it moderately uncomfortable, and 204 (50%) did not find it uncomfortable. A larger proportion of women than men, 110 (63%) versus 79 (41%), found the procedure very or moderately uncomfortable (p<0.001). Three hundred sixty-eight (90%) individuals stated that they would undergo repeat colonoscopy in 5 years., Conclusion: In this screening setting, routine use of conscious sedation did not seem to be necessary, as most participants found the examination to be only moderately uncomfortable or not at all uncomfortable. Colonoscopy without conscious sedation may, however, reduce the rate of intubation of the cecum and increase the risk of missing adenomas and cancers.

Background: Most cases of colorectal cancer originate from adenomas. Removing adenomas has been shown to reduce the incidence of colorectal cancer. The design of cost effective endoscopic screening programmes requires a knowledge of the distribution of adenomas in different age groups., Aim: To investigate the distribution of colorectal adenomas in older age groups in the normal population., Method: A total of 356 men and women selected randomly from the population register were offered a colonoscopic screening examination to detect and remove polyps., Results: In all, 241(68%) subjects, mean age 67.4 years (range 62-73), attended. The caecum was intubated in 193 (80%), and in this group 32 (38%) women and 51 (47%) men had adenomas. One hundred and ten (54%) of the adenomas and 11 (39%) of the "high risk adenomas" (adenomas larger than 10 mm in diameter, adenomas containing villous components, and adenomas with severe dysplasia) were found proximal to the sigmoid colon. In 36 (43%) of the subjects with adenomas, the adenomas were only found proximal to the sigmoid colon. Twenty two (11%) subjects had more than two adenomas. Of 203 adenomas discovered, 189 (93%) were less than 10 mm in diameter., Conclusion: More than half of the adenomas were localised proximal to the sigmoid colon, and, in nearly half of the adenoma bearing subjects examined, the adenoma was proximal to the descending colon. This indicates that a sigmoidoscopic screening examination in this age group would miss a substantial number of adenomas, but this may be acceptable as the vast majority of proximal adenomas do not progress to clinical cancer within the life expectancy of this age group.

Background: Most cases of colorectal cancer (CRC) develop from adenomas. Polypectomy is believed to reduce the incidence of CRC, but this effect has never been explored in prospective controlled studies. The aim of the present study was to evaluate the effect of polypectomy on colorectal cancer incidence in a population-based screening program., Methods: In 1983, 400 men and women aged 50-59 years were randomly drawn from the population registry of Telemark, Norway. They were offered a flexible sigmoidoscopy and, if polyps were found, a full colonoscopy with polypectomy and follow-up colonoscopies in 1985 and 1989. A control group of 399 individuals was drawn from the same registry. In 1996 both groups (age, 63-72 years) were invited to have a colonoscopic examination. Hospital files and the files of The Norwegian Cancer Registry were searched to register any cases of CRC in the period 1983-96., Results: At screening endoscopy 324 (81%) individuals attended in 1983 and 451 (71%) in 1996. From 1983 to 1996, altogether 10 individuals in the control group and 2 in the screening group were registered to have developed CRC (relative risk, 0.2; 95% confidence interval (CI), 0.03-0.95; P = 0.02). A higher overall mortality was observed in the screening group, with 55 (14%) deaths, compared with 35 (9%) in the control group (relative risk, 1.57; 95% CI, 1.03-2.4; P = 0.03)., Conclusion: Endoscopic screening examination with polypectomy and follow-up was shown to reduce the incidence of CRC in a Norwegian normal population. The possible effect of screening on overall mortality should be addressed in larger studies.