Incidence of Complications in High-Risk Patients Undergoing Combined Esophagogastroduodenoscopy and Colonoscopy with Total Intravenous Anesthesia: A Prospective Cohort Study

Objective: To evaluate the incidence, characteristics, and risk factors of complications related to anesthesia complication in ASA Class III patients undergoing combined esophagogastroduodenoscopy (EGD) and colonoscopy under total intravenous anesthesia (TIVA). Materials and Methods: This prospective cohort study was conducted from April 1, 2024, to February 11, 2025. Data collected included baseline characteristics (age, sex, comorbidities, functional capacity, nutritional status, smoking, fasting and medications) and intraoperative/postoperative parameters (anesthetic technique, sedative dosing, IV fluids, complications, and 24-hour status). Descriptive statistics, univariate analysis, and binary logistic regression were applied. Results: Of 403 ASA Class III patients enrolled, 393 were analyzed after excluding 10 for inadequate bowel prep or early termination due to malignancy. A total of 207 patients (52.7%) experienced at least one complication. Common complications included transient hypotension (40.2%), desaturation (15.8%), and airway obstruction (15.5%). Less frequent events were bradycardia (4.1%), hypoxia (1.8%), hypertension (1.8%), tachycardia (0.3%) and respiratory depression (0.5%). Five independent risk factors were significantly associated with complications: preexisting cardiovascular disease - odds ratio (OR=1.678), respiratory disease (OR=1.877), functional capacity < 4 metabolic equivalents (METs), (OR=1.851), nutritional screening score ≥1 (OR =1.518), and single - dose bowel prep regimen (OR=1.614). Complications were more common in women, patients aged 65 years or older, and inpatients, although the difference in hospitalization and outpatient was not statistically significant. Patients with complications received lower total doses of propofol and fentanyl per weight per hour. Dexmedetomidine use was significantly associated with complications among inpatients (p = 0.015). The duration of the procedure was longer in patients with complications (p = 0.002). Conclusion: Anesthesia-related complications were frequent among ASA Class III patients who underwent combined EGD and colonoscopy under TIVA, particularly cardiovascular and respiratory events. Identification of five preprocedural risk factors supports the need for improved risk stratification and individualized sedation planning to optimize safety in this high-risk group.