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Anesthesia assistance in outpatient colonoscopy and risk of aspiration pneumonia, bowel perforation, and splenic injury


Background and Aims —The increase in use of anesthesia assistance (AA) to achieve deep sedation with propofol during colonoscopy has significantly increased colonoscopy costs without evidence for increased quality and with possible harm. We investigated the effects of AA on colonoscopy complications, specifically bowel perforation, aspiration pneumonia, and splenic injury.

Methods — In a population-based cohort study using administrative databases, we studied adults in Ontario, Canada undergoing outpatient colonoscopy from 2005 through 2012. Patient, endoscopist, institution, and procedure factors were derived. The primary outcome was bowel perforation, defined using a validated algorithm. Secondary outcomes were splenic injury and aspiration pneumonia. Using a matched propensity score approach, we matched persons who had colonoscopy with AA (1:1) to those who did not. We used logistic regression models under a generalized estimating equations approach to explore the relationship between AA and outcomes.

Results — We analyzed data from 3,059,045 outpatient colonoscopies; 862,817 of these included AA. After propensity matching, a cohort of 793,073 patients who had AA and 793,073 without AA was retained for analysis (51%, female; 78% were age 50 years or older). Use of AA did not significantly increase risk of perforation (odds ratio [OR], 0.99; 95% CI, 0.84 – 1.16) or splenic injury (OR, 1.09; 95% CI, 0.62 – 1.90]. Use of AA was associated with an increased risk of aspiration pneumonia (OR, 1.63; 95% CI, 1.11 – 2.37).

Conclusions — In a population-based cohort study, AA for outpatient colonoscopy was associated with a significantly increased risk of aspiration pneumonia but not bowel perforation or splenic injury. Endoscopists should warn patients, especially those with respiratory compromise, of this risk.



Bielawska B, Hookey LC, Sutradhar R, Whitehead M, Xu J, Paszat LF, Rabeneck L, Tinmouth J. Gastroenterology. 2018; 254(1):77-85.e3. Epub 2017 Aug 30.

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