M Lougheed, M Borgaonkar, D Pace, C Marcoux, B Evans, D Boone, J McGrath. Memorial University, Faculty of Medicine, St. John’s, NL
Introduction: The objective of this study is to determine if annual colonoscopy volume of endoscopists is related to the risk of adverse events, patient comfort, and the amount of sedation used. There is some debate about whether these factors are related to the experience of the endoscopist.
Methods: A retrospective cohort study was performed on 3235 patients who underwent colonoscopy in the city of St. John's, NL between January and June 2012. Using the electronic medical record system, including the endoscopy procedure report, the nursing record of the endoscopy, and the pathology report, data on subjects were collected on adverse events, including cardiorespiratory compromise (hypoxia – saturation < 85%; hypotension – blood pressure < 90/50 or < 20% of baseline), perforation, bleeding (immediate or delayed 14 days), or death. Data were also collected on patient comfort during the procedure as noted by the endoscopy nurse and the total amount of Fentanyl and Versed used for sedation. SPSS was used for analysis. Endoscopists were divided into quintiles based on annual case volume (1st 0-149; 2nd 150-249; 3rd 250-301, 4th 302-530, 5th >530). Chi-squared tests were performed to see if there was a difference in adverse events and patient comfort (comfortable vs. uncomfortable). ANOVA was performed to compare the use of sedation between the quintiles.
Results: Mean age was 58.4 years with 55.8% of the group being female. A total of 13 surgeons and 8 gastroenterologists were studied. There was a linear reduction in the rate of hypoxia from the 2nd to 5th quintiles, from 16.1% to 3.6%, p<0.001 (1st quintile 10.2%). There was also a linear reduction in the rate of hypotension from the 2nd to 5th quintiles, from 29.0% to 9.9%, p<0.001 (1st quintile 11.8%). There was no signifcant difference found between quintiles in terms of reversal agents used, risk of immediate or delayed bleeding, perforation, or death within 30 days. There was a significant difference in the percentage of patients who reported discomfort between the 1st and 2nd quintiles (46.5% vs 32.2%, p<0.001), with the other quintiles the same as the second. There was a significant difference between the 4th and 5th quintiles in Fentanyl use (99.8 mcg vs 88.9 mcg, p<0.001, with the other quintiles the same as the fourth. There was also a significant difference between the 4th and 5th quintiles in Versed use (3.4 mg vs 2.8 mg, p<0.001), with the other quintiles the same as the fourth.
Conclusion: Higher annual colonoscopy volume is associated with less hypoxia and hypotension. It is also associated with less patient discomfort, and less sedation. This study did not show an effect of annual volume on use of a reversal agent, risk of bleeding, perforation, or death.