RISK-FACTORS ASSOCIATED WITH VASOVAGAL REACTIONS DURING COLONOSCOPY

To define the syndrome of vasovagal reactions that occur during colono scopy and to identify those risk factors associated with this developm ent, we prospectively evaluated patients undergoing colonoscopy with m onitored sedation. A total of 223 consecutive patients were evaluated during the 60-day study period. A vasovagal reaction was defined as th e occurrence of one or more of the following: diaphoresis, sustained b radycardia of less than 60 beats/min or a decrease in heart rate of 10 %, or hypotension (systolic blood pressure less than 90 mm Hg, diastol ic blood pressure less than 60 mm Hg, or a reduction in blood pressure of more than 10% below a baseline measurement before colonoscopy and after sedation). Thirty-seven (16.5%) of the 223 patients experienced a vasovagal reaction by our criteria. The remaining 186 patients did n ot; 100 of these patients were randomly selected by computer to form a control group. No statistically significant differences were observed between the vasovagal and control groups with regard to demographics, cardiopulmonary disease, cardiac medications, procedure success, the endoscopist, patient procedure tolerance, colon preparation, or proced ure difficulty. A significant difference was seen in the mean dose of midazolam used in the vasovagal group as compared with that used in th e control group (4.6 mg versus 3.9 mg, p < 0.04), and moderate to seve re diverticulosis was more commonly seen in the vasovagal group as com pared with the control group (43% versus 16%, p < 0.02). Thirteen (35% ) of the 37 patients who had a vasovagal reaction required medical int ervention (5.8% of the 223 patients). No interventions were required i n control patients. Vasovagal reactions during colonoscopy are commonl y detected if careful procedure monitoring is performed. However, the need for medical intervention during the vasovagal reaction is uncommo n, and in our patients, no significant post-procedural sequelae occurr ed.