Anti-hypertensive therapy and risk factors associated with hypotension during colonoscopy under conscious sedation

Pre-operative use of select anti-hypertensive therapy has been associated with peri-operative hypotension in the surgical setting. Our aim was to determine the effect of anti-hypertensive medications on blood pressure (BP) and procedural outcomes in gastrointestinal endoscopy.

Our study was a prospective, cross-sectional survey of outpatients undergoing colonoscopy with conscious sedation. We enrolled patients with hypertension that took anti-hypertensive medications within 24 hours of the procedure and patients without hypertension that were not on BP-lowering agents. We recorded mean BP prior to, during, and after the procedure.

626 patients (338 males; mean age 56.0 +/- 10.4 years) were enrolled, and 158 patients were on anti-hypertensive therapy. There were 57 patients who developed hypotension, defined as systolic BP <90 mmHg and/or diastolic BP <60 mmHg, during the colonoscopy. Taking a BP medication, regardless of class, was not associated with an increased risk of procedural hypotension (all p >0.05). Age, body mass index, gender, duration, fentanyl dose, midazolam dose, and co-morbidities (asthma, chronic obstructive pulmonary disease, congestive heart failure, coronary artery disease) were also not associated (all p >0.05). Instead, a lower pre-procedure systolic BP (OR=0.97, 95% CI=0.95-0.99; p=0.004) and diastolic BP (OR=0.95, 95% CI=0.92-0.97; p<0.001) were identified as the only risk factors.

Patients should continue their anti-hypertensive therapy leading up to endoscopy. A lower pre-procedure BP is the main risk factor for procedural hypotension in patients undergoing colonoscopy with conscious sedation. Future studies should explore other factors, such as bowel preparation, that can affect pre-procedure BP.