Clinical Deterioration Among Emergency Department Boarders: From Hallway Monitoring to a Structured Rescue System

Abstract

Background: Emergency department (ED) boarding places admitted patients in an environment designed for rapid episodic assessment rather than longitudinal inpatient surveillance. The resulting mismatch in ownership, monitoring, medication delivery, fundamental nursing care, and rescue capability creates a clinically important interval of vulnerability. Objective: To critically synthesize recent PubMed-indexed evidence on deterioration among adult ED boarders and translate it into a practical rescue framework. Methods: A targeted narrative search of PubMed was conducted for English-language publications from 1 January 2020 through 11 July 2026. Direct evidence from boarded adult populations was prioritized; supporting evidence was retained only when it informed a specific rescue-system component. Evidence was interpreted according to directness, design, consistency, confounding risk, and applicability rather than pooled statistically. Findings: Recent large cohorts show that longer boarding is associated with early clinical deterioration, longer subsequent hospitalization, and mortality. In a five-hospital cohort of 173,168 floor-level adult boarders, early deterioration occurred in 3.6%, with risk increasing as boarding time lengthened. Recurrent hazards include diagnostic closure, ambiguous ownership, surveillance decay, delayed or omitted treatment, unmet frailty-related needs, and unsafe temporary care environments. Evidence is strongest for the existence of harm and weakest for prospectively tested integrated rescue bundles. Proposed framework: The BOARD framework comprises: Begin the boarding clock and dynamic risk stratification; One accountable clinical team; Acuity-matched observation and reassessment; Rescue triggers with immediate rapid-response access; and Delivery of essential inpatient care, dignity, and hospital-wide flow escalation. Conclusion: Boarding should be treated as an active clinical exposure rather than passive waiting. Hospitals should simultaneously reduce boarding and protect patients who remain in the ED through explicit ownership, risk-based monitoring, uninterrupted treatment, and reliable rescue. The BOARD framework is an evidence-informed implementation model that requires prospective multicenter validation.