Amnon Sonnenberg1. 1. Portland VA Medical Center and Oregon Health & Science University, Portland, OR 97239, USA.
Abstract
BACKGROUND: Multiple procedures and devices are used in a complex interplay to diagnose and treat GI bleeding. OBJECTIVE: To model how a large variety of diagnostic and therapeutic components interact in the successful management of GI bleeding. DESIGN: The analysis uses the concept of reliability block diagrams from probability theory to model management outcome. Separate components of the management process are arranged in a serial or parallel fashion. If the outcome depends on the function of each component individually, such components are modeled to be arranged in series. If components complement each other and can mutually compensate for each of their failures, such components are arranged in a parallel fashion. SETTING: General endoscopy practice. PATIENTS: Patients with GI bleeding of unknown etiology. INTERVENTIONS: All available endoscopic and radiographic means to diagnose and treat GI bleeding. MAIN OUTCOME MEASUREMENTS: Process reliability in achieving hemostasis. RESULTS: Serial arrangements tend to reduce process reliability, whereas parallel arrangements increase it. Whenever possible, serial components should be bridged and complemented by additional alternative (parallel) routes of operation. Parallel components with low individual reliability can still contribute to overall process reliability as long as they function independently of other pre-existing alternatives. LIMITATIONS: Probability of success associated with individual components is partly unknown. CONCLUSIONS: Modeling management of GI bleeding by a reliability block diagram provides a useful tool in assessing the impact of individual endoscopic techniques and administrative structures on the overall outcome.
BACKGROUND: Multiple procedures and devices are used in a complex interplay to diagnose and treat GI bleeding. OBJECTIVE: To model how a large variety of diagnostic and therapeutic components interact in the successful management of GI bleeding. DESIGN: The analysis uses the concept of reliability block diagrams from probability theory to model management outcome. Separate components of the management process are arranged in a serial or parallel fashion. If the outcome depends on the function of each component individually, such components are modeled to be arranged in series. If components complement each other and can mutually compensate for each of their failures, such components are arranged in a parallel fashion. SETTING: General endoscopy practice. PATIENTS: Patients with GI bleeding of unknown etiology. INTERVENTIONS: All available endoscopic and radiographic means to diagnose and treat GI bleeding. MAIN OUTCOME MEASUREMENTS: Process reliability in achieving hemostasis. RESULTS: Serial arrangements tend to reduce process reliability, whereas parallel arrangements increase it. Whenever possible, serial components should be bridged and complemented by additional alternative (parallel) routes of operation. Parallel components with low individual reliability can still contribute to overall process reliability as long as they function independently of other pre-existing alternatives. LIMITATIONS: Probability of success associated with individual components is partly unknown. CONCLUSIONS: Modeling management of GI bleeding by a reliability block diagram provides a useful tool in assessing the impact of individual endoscopic techniques and administrative structures on the overall outcome.