The Impact of Pre-Procedure Blood Pressure on Cardiopulmonary Events During Colonoscopy

Abstract

Purpose: The safety of endoscopic procedures is remarkable, especially when considering the co-morbidities patients often have prior to these exams. One understudied issue is the impact of pre-procedural blood pressure (BP) levels on outcomes. Current guidelines are based on expert opinion and suggest that a pre-procedure systolic BP (SBP) > 180 and/or diastolic BP (DBP) > 120 are unsafe. Our purpose was to determine the impact of pre-procedure BP levels and anti-hypertensive medications on procedural outcomes. Methods: Prospective, cross-sectional survey of outpatients undergoing colonoscopy for any indication. We restricted enrollment to procedures using conscious sedation. We recorded median BP prior to, during, and after the procedure,as well as sedative dosages. Additional procedural data included heart rate, oxygen saturation, and respiratory rate. Complications during recovery were identified. Results: We enrolled 643 patients - 346 (53.8%) females and mean age 55.6 ± 10.6 y. The majority of patients were black (58.9%). ASA grades were I (14 %), II (83.2 %), III (2.8%), and IV (0 %). Mean dose of fentanyl was 106.3 ± 32.1 μg and midazolam 5.6 ± 2.0 mg. There were 140 (21.8%) patients taking an antihypertensive medication. Median pre-procedure SBP and DBP were 134.0 and 79.0 mmHg. One 57y male patient developed bradycardia that responded to atropine. His pre-, intra-, and post-procedure BPs ranged from 100-140 over 70-90 mmHg. Otherwise, we found no correlation between pre-procedure SBP and intra-procedure or post-procedure O2 saturation, respiratory rate, or heart rate after controlling for age, gender, ASA class, sedative doses, and procedure duration. However, DBP correlated weakly with procedural (r=0.14; p=0.001) and post-procedural (r=0.09; p=0.02) heart rate. There were 10 patients who underwent colonoscopy despite a SBP > 180 mmHg (none were treated for pre-procedure HTN). There was no difference (all p > 0.05) in mean procedural and post-procedural HR, RR, and O2 saturation compared to those with better BP control. Median drop in SBP for these patients was 3 and 19 mmHg during and after the procedure. Median drop in DBP was 7 and 3 mmHg. No procedural cardiac or pulmonary events occurred in this group. Conclusion: In a large sample of outpatients undergoing colonoscopy, we found little evidence that pre-procedure BP elevation correlated with pulmonary or cardiac adverse events. For asymptomatic outpatients with an elevated SBP or DBP, we suggest proceeding with the endoscopic exam. SBP will drop ˜ 20 mmHg by the end of the procedure without treatment. For severe elevations (e.g. SBP > 200 mmHg), we suggest a low dose of hydralazine or labetolol to attain acceptable BP levels rather than cancellation.