Time to clinical stability in patients hospitalized with community-acquired pneumonia: implications for practice guidelines

It may be possible to shorten the hospital stay of patients with pneumonia without compromising their health. Researchers used measurements of heart rate, breathing, blood pressure, blood oxygen levels and body temperature to determine when 686 pneumonia patients became stable enough to be discharged from the hospital. The median time to stability ranged from 3 to 7 days depending on the definition of stability. Most of the patients remained in the hospital 3 to 4 days after they stabilized, indicating that their hospital stay could have been shortened.
Context.--Many groups have developed guidelines to shorten hospital length of stay in pneumonia in order to decrease costs, but the length of time until a patient hospitalized with pneumonia becomes clinically stable has not been established. Objective.--To describe the time to resolution of abnormalities in vital signs, ability to eat, and mental status in patients with community-acquired pneumonia and assess clinical outcomes after achieving stability. Design.--Prospective, multicenter, observational cohort study. Setting.--Three university and 1 community teaching hospital in Boston, Mass, Pittsburgh, Pa, and Halifax, Nova Scotia. Patients.--Six hundred eighty-six adults hospitalized with community-acquired pneumonia. Main Outcome Measures.--Time to resolution of vital signs, ability to eat, mental status, hospital length of stay, and admission to an intensive care, coronary care, or telemetry unit. Results.--The median time to stability was 2 days for heart rate ([is less than or equal to] 100 beats/min) and systolic blood pressure ([is greater than or equal to] 90 mm Hg), and 3 days for respiratory rate (524 breaths/min), oxygen saturation ([is greater than or equal to] 90%), and temperature ([is less than or equal to] 37.2 [degrees] C [99 [degrees] F]). The median time to overall clinical stability was 3 days for the most lenient definition of stability and 7 days for the most conservative definition. Patients with more severe cases of pneumonia at presentation took longer to reach stability. Once stability was achieved, clinical deterioration requiring intensive care, coronary care, or telemetry monitoring occurred in 1% of cases or fewer. Between 65% to 86% of patients stayed in the hospital more than 1 day after reaching stability, and fewer than 29% to 46% were converted to oral antibiotics within 1 day of stability, depending on the definition of stability. Conclusions.--Our estimates of time to stability in pneumonia and explicit criteria for defining stability can provide an evidence-based estimate of optimal length of stay, and outline a clinically sensible approach to improving the efficiency of inpatient management. JAMA. 1998;279:1452-1457