The Systemic Inflammatory Response Syndrome (SIRS) in acutely hospitalised medical patients: a cohort study

Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine The Systemic Inflammatory Response Syndrome (SIRS) in acutely hospitalised medical patients: a cohort study Pl Comstedt 2 Merete Storgaard 1 Annmarie T Lassen 0 2 0 Institute of Clinical Research, University of Southern Denmark , Odense , Denmark 1 Department of Infectious Diseases, Arhus University Hospital , Skejby , Denmark 2 Department of Infectious Diseases, Odense University Hospital , Odense , Denmark Background: Sepsis is an infection which has evoked a systemic inflammatory response. Clinically, the Systemic Inflammatory Response Syndrome (SIRS) is identified by two or more symptoms including fever or hypothermia, tachycardia, tachypnoea and change in blood leucocyte count. The relationship between SIRS symptoms and morbidity and mortality in medical emergency ward patients is unknown. Methods: We conducted a prospective cohort study of the frequency of SIRS and its relationship to sepsis and death among acutely hospitalised medical patients. In 437 consecutive patients, SIRS status, blood pressure, infection and comorbidity on admission was registered together with 28day mortality. Results: A hundred and fifty-four patients (35%) had SIRS on admission, 211 patients (48%) had no SIRS, and 72 patients (16%) had insufficient data to evaluate their SIRS status. SIRS patients were 2.2 times more frequently infected, with 66/154 SIRS patients versus 41/211 non-SIRS patients: p < 0.001, relative risk (RR) 2.2 (95% confidence interval (CI) 1.6-3.1), and they had a 6.9 times higher 28-day mortality than non-SIRS patients with 15/154 SIRS patients versus 3/211 non-SIRS patients: p = 0.001, RR 6.9 (95% CI 2.0-23.3). Most of the deaths among patients with SIRS occurred among patients with malignant conditions. Septic shock developed in 4/154 (3%) of the patients with SIRS, whereas this occurred in only one of the 211 patients (0.5%) without SIRS on arrival: p = 0.08, RR 5.5 (95% CI 0.6-48.6). Conclusion: We found SIRS status on admission to be moderately associated with infection and strongly related to 28-day mortality. - Background Sepsis is a systemic inflammatory response to a confirmed or suspected infection. Clinically, the Systemic Inflammatory Response Syndrome (SIRS) is the occurrence of at least two of the following criteria: fever >38.0C or hypothermia <36.0C, tachycardia >90 beats/minute, tachypnea >20 breaths/minute, leucocytosis >12*109/l or leucopoenia <4*109/l [1,2]. The development from sepsis to septic shock represents a continuum with increasing mortality. The in-hospital/28day mortality in severe sepsis is 10%-40% and in septic shock it is 30%-60% [3-11]. Early treatment with antibiotic and fluid resuscitation has been found to be strongly related to increased survival, which makes severe sepsis a condition which is important to identify and treat as early as possible [2,12,13]. Although a few studies have evaluated the progress of SIRS among emergency ward patients with suspected infection, most studies of SIRS have focused on patients in intensive care units (ICUs) [8-11,14,15]. The occurrence and usefulness of registered SIRS status among all acute medical patients in an emergency ward is unknown. The aim of the present study was to describe the relevance of SIRS in predicting morbidity and mortality among patients in a medical emergency ward. Materials and methods Patient population All acutely hospitalised medical patients admitted to the medical emergency ward as well as medical patients admitted directly to ICU, Odense University Hospital in a six-week period (3 September to 14 October 2007) were included. Patients transferred from other wards or hospitals were excluded. If patients had more than one admission to the department during the inclusion period, they were included at the first admission and not at the following admissions. Odense University Hospital serves as a primary hospital for 185,000 people. The medical emergency ward admits adult patients (> age 15 years) with acute medical conditions, with the exception of patients with a suspected acute heart disease or verified diabetes, chronic gastroenterological, haematological or nephrological disease. There were no interventions related to the study, and all patients received standard care following the ward's guidelines. Data collection and categorisation of patients SIRS was defined as fulfilling at least two of the following four criteria: fever >38.0C or hypothermia <36.0C, tachycardia >90 beats/minute, tachypnea >20 breaths/ minute, leucocytosis >12*109/l or leucopoenia <4*109/l. The body temperature, heartbeat frequency and respiratory frequency of all patients were registered on arrival by the nurses. The data were collected a few minutes after the patient arrived in the ward. The nurses were aware of the study and were repeatedly reminded to obtain a full set of observations for all patients. Documentation of infection was based on the clinical evaluation within the first two days after arrival, including clinical examinations as well as radiological evaluation, and where infection was suspected by the clinical doctor or indicated by blood, urine and other cultures. Leucocyte count on arrival and information on previous hospitalisation were obtained from the electronic Patient Administrative System of Funen County, and comorbidity was defined as the main discharge diagnoses (if any) during the last six months. Follow up was performed on day 28 by recording the occurrence of documented infection, treatment in ICU, start of antibiotic treatment, development of sepsis, severe sepsis or septic shock, length of hospital stay, diagnosis on discharge, 28 day mortality and, if possible, the course of mortality. The follow-up registration was made by chart review by one of the authors (PC), with evaluation by a specialist in infectious diseases (MS or AL) if there were any doubts about interpretation or classification. SIRS status was evaluated in a separate setting, but parameters registered on patient arrival were not blinded in the chart review. Only infection, sepsis, severe sepsis and septic shock occurring within the first two days of the hospital stay were registered in order to exclude conditions acquired in the hospital. Infection was defined as identification of a relevant pathogen by microscopy/culture/polymerase chain reaction, positive serology, pneumonia verified by chest X-ray, infection documented with other imaging techniques, positive urine dip test combined with symptoms of urine tract infection, or as typical clinical symptoms such as erysipelas. Sepsis was defined as SIRS plus a documented infection Severe sepsis was defined as sepsis plus at least one of the following (without other comorbidity/therapeutic explanation): Glasgow coma scale 14; PaO2 9.75 kPa; oxygen saturation 92%, PaO2/FiO2 250;, pH 7.3; lactate 2.5 mmol/l; creatinine 177 mol/l; 100% increase of creatinine (...truncated)