Factors influencing challenging colonoscopies during anesthesiologist-assisted deep sedation

Increased demand for colon cancer screening procedures can significantly impact on routine colonoscopy management at dedicated facilities, prompting a review of the factors that can negatively affect workflow. Although potential adverse effects and impact on costs of deep sedation have been documented elsewhere, this study focuses on variables that can influence performance of colonoscopy in deep sedation and interfere with normal procedure scheduling in settings where the presence of an anesthesiologist is mandatory.

We performed a cross-sectional study of the activities of a colonoscopy screening unit, applying Bayesian Network (BN) analysis, designed to assess interdependencies among variables that can affect a process in complex, multidimensional systems. The study was performed at a teaching hospital where endoscopists and anesthesiologists of varying work experience operate on a rota basis. During a six-month period, we analyzed 1485 consecutive colonoscopies performed under deep propofol sedation, administered by an anesthesiologist via hand-controlled syringe. The BN was constructed with the variables: Gender, age, ASA status, bowel preparation, baseline blood pressure, endoscopist's experience, anesthesiologist's experience, presence of polypectomy, and the target node, "challenging procedure." This previously undefined category refers to any events disrupting the scheduled rota.

Two distinct networks were identified. One deals mainly with relationships among the variables, patients' demographic and clinical characteristics (procedures with polypectomy, ASA and baseline blood pressure). The other explains relationships among the variables, "challenging procedure," bowel preparation, and endoscopist's experience. The factors associated with the anesthesiologist's activity do not influence challenging colonoscopies.