Identification of the adult septic patient in the prehospital and emergency department setting

Abstract

Sepsis is one of the most urgent conditions encountered within emergency care but is often difficult to recognize due to its non-specific presentations. One third of the patients lack the classic sign of infection; i.e. fever, and it is often not obvious that the patient suffers from an underlying infection, which is a prerequisite for sepsis. Identification of sepsis within emergency care is today mainly based on clinical judgment, which is known to have a low sensitivity. Timely identification and treatment influence patient outcome. We believe that screening tools may increase the identification of septic patients, which may in turn improve outcome. The problem is that current screening tools designed for emergency care are based on vital signs despite one third of the patients with severe infections present with normal vital signs. The general aim of the current thesis was to study the presentation of adult septic patients within emergency care and to find a way to improve identification of the septic patient. The thesis builds upon four studies.

Study I was a retrospective cross-sectional study of 353 septic Emergency Medical Services (EMS) patients. Two previously unvalidated screening tools were compared to clinical judgment by EMS with respect to sepsis identification. The Robson screening tool (including temperature, heart rate, respiratory rate, altered mental status, plasma glucose, and a history suggestive of a new infection) surpassed both BAS 90-30-90 (refers to the vital signs systolic blood pressure, respiratory rate and oxygen saturation) and clinical judgment with respect to sensitivity for identification of septic patients in the ambulance. Study II was a retrospective cross-sectional study where time to treatment and mortality among 61 septic Emergency Department (ED) patients with ED chief complaint decreased general condition (DGC) was compared with that of 516 septic patients with other ED chief complaints. Furthermore, the sensitivity and specificity of the Robson screening tool was compared with that of clinical judgment by the ED physician among 122 patients presenting to the ED with chief complaint DGC, of which 61 were discharged with ICD-code sepsis. Septic patients with non-specific presentations, here exemplified as the chief complaint DGC, had a longer time to treatment and a higher mortality. A larger proportion of these patients was identified as septic if the Robson screening tool was applied. Clinical judgment was more specific than the Robson screening tool. In Study III the presentation of septic patients within the prehospital setting was explored and keywords relating to symptom presentation were identified. A mixed-methods analysis was conducted, starting with a content analysis of 80 EMS records from septic patients, followed by quantification of the identified keywords, among 359 septic EMS patients admitted the following year. Keywords related to patients´ symptom presentation recurred, so that a pattern was discernible, and some symptoms were particularly frequent. Furthermore, certain keywords were associated with a high mortality. Study IV was a prospective cohort study of 878 EMS patients. Symptoms, vital signs and POC variables were associated with outcome sepsis/ infection/ no infection. Variables with the strongest association to sepsis among the 551 patients with suspected infection were used to create a screening tool; the Predict Sepsis screening tool. The predictive accuracy of the Predict Sepsis screening tool exceeded that of prior proposed prehospital screening tools.

Conclusions: In general, our findings indicate a low sensitivity of emergency care providers´ clinical judgment and support the use of a screening tool, with respect to sepsis identification within emergency care. However, neither earlier proposed tools nor the Predict Sepsis screening tool identifies all septic patients, and addition of novel variables such as symptoms in the screening process were not as important as we had expected. Nevertheless, this approach may be of greater benefit if tested among unselected emergency care patients, i.e. not only among those with a suspected infection, to identify septic patients with non-specific presentations. Sepsis identification remains a challenge within emergency care, mainly due to the diversity of its presentations. Increased education would most likely increase sepsis identification. However, an enhanced understanding of the underlying pathophysiology to explain the diversity in sepsis presentation is of major concern to improve identification. Future identification and management of sepsis may require consideration of delineated sub-populations of septic patients.