NEAR-FATAL HEAT-STROKE DURING THE 1995 HEAT-WAVE IN CHICAGO

Background: In July 1995, Chicago sustained a heat wave that resulted in more than 600 excess deaths, 3300 excess emergency department visit s, and a substantial number of intensive care unit admissions for near -fatal heat stroke. Objective: To describe the clinical features of pa tients admitted to an intensive care unit with near-fatal classic heat stroke. Patients were followed for 1 year to assess delayed functiona l outcome and mortality. Design: Observational study. Setting: Intensi ve care units in the Chicago area. Patients: 58 patients admitted to t he hospital from 12 July to 20 July 1995 who met the case definition o f classic heat stroke. Measurements: The data collection tool was desi gned to compile demographic and survival data and to permit analysis o f organ system function by abstracting data on physical examination fi ndings, electrocardiography and echocardiography results, fluid resusc itation, radiography results, and laboratory findings. Data on functio nal status at discharge and at 1 year were collected by using a modifi ed Stanford Health Assessment Questionnaire. Results: Patients experie nced multiorgan dysfunction with neurologic impairment (100%), moderat e to severe renal insufficiency (53%), disseminated intravascular coag ulation (45%), and the acute respiratory distress syndrome (10%); Fift y-seven percent of patients had evidence of infection on admission. In -hospital mortality was 21%. Most survivors recovered near-normal rena l, hematologic, and respiratory status, but disability persisted, resu lting in moderate to severe functional-impairment in 33% of patients a t hospital discharge. At 1 year, no patient had improved functional st atus, and an additional 28% of patients had died. Conclusions: Near-fa tal classic heat stroke is associated with multiorgan dysfunction. A h igh percentage of patients had infection at presentation. A high morta lity rate was observed during acute hospitalization and at 1 year, in addition, substantial functional impairment at discharge persisted 1 y ear. The degree of functional disability correlated highly with surviv al at 1 year.