Determining predictors of underlying etiology and clinical deterioration in patients with physiologic instability in the emergency department

Abstract

Shock is a critical state defined by inadequate oxygen delivery to tissues. It is well known in the critical care community that early diagnosis and treatment of shock are crucial to improving patient outcomes. However, in many cases, when a state of circulatory shock has been reached, irreversible damage already occurred. In the present study, we broadened our patient cohort from those with shock to those with physiologic instability with the intent of finding predictive factors that allow us to recognize when a patient is at risk for deterioration or when it is already occurring. These patients included patients with pre-shock, shock, and other forms of dysfunction. The purpose of this study was to determine the predictors of underlying etiology of physiologic instability as well as the likelihood of clinical deterioration in these various states, using elements from the physical exam, history, laboratory values, and vital sign measurements. This study was a prospective observational study of patients, from November 15, 2012 to March 1, 2013, found to have physiologic instability in the emergency department at an urban, academic tertiary-care hospital with 55,000 annual visits. Physiologic instability was defined as any one of the following abnormalities: heart rate (HR) > 130, respiratory rate (RR>24), shock index (SI) > 1, systolic blood pressure (SBP) < 90 mm/hg, and Lactate > 4.0 mmol/L, for a time period of more than five minutes. We identified 540 patients, 74.8% of which were included. Data describing epidemiology, and elements from the patient history and physical exam were abstracted from physician charts and the final etiology of physiologic instability, defined as septic, cardiogenic, hypovolemic, hemorrhagic, or other, was adjudicated by a physician. Blood samples from a subset of our patient group were collected from the hospital hematology laboratory and sent to the Wyss Institute to be analyzed using a novel bacterial detection assay. All of the covariates that data was collected for were analyzed to determine their diagnostic and prognostic value. [TRUNCATED]