The association between vital signs and mortality in a retrospective cohort study of an unselected emergency department population

Abstract

BackgroundVital signs are widely used in emergency departments. Previous studies on the association between vital signs and mortality in emergency departments have been restricted to selected patient populations. We aimed to study the association of vital signs and age with 1-day mortality in patients visiting the emergency department.MethodsThis retrospective cohort included patients visiting the emergency department for adults at Södersjukhuset, Sweden from 4/1/2012 to 4/30/2013. Exclusion criteria were: age < 18 years, deceased upon arrival, chief complaint circulatory or respiratory arrest, key data missing and patients who were directed to a certain fast track for conditions demanding little resources. Vital sign data was collected through the Rapid Emergency Triage and Treatment System – Adult (RETTS-A). Descriptive analyses and logistic regression models were used. The main outcome measure was 1-day mortality.ResultsThe 1-day mortality rate was 0.3 %. 96,512 patients met the study criteria. After adjustments of differences in the other vital signs, comorbidities, gender and age the following vital signs were independently associated with 1-day mortality: oxygen saturation, systolic blood pressure, temperature, level of consciousness, respiratory rate, pulse rate and age. The highest odds ratios was observed when comparing unresponsive to alert patients (OR 31.0, CI 16.9 to 56.8), patients ≥ 80 years to <50 years (OR 35.9, CI 10.7 to 120.2) and patients with respiratory rates <8/min to 8–25/min (OR 18.1, CI 2.1 to 155.5).DiscussionMost of the vital signs used in the ED are significantly associated with one-day mortality. The more the vital signs deviate from the normal range, the larger are the odds of mortality. We did not find a suitable way to adjust for the inherent influence the triage system and medical treatment has had on mortality.ConclusionsMost deviations of vital signs are associated with 1-day mortality. The same triage level is not associated with the same odds for death with respect to the individual vital sign. Patients that were unresponsive or had low respiratory rates or old age had the highest odds of 1-day mortality.

Facilitators and constrainers of civilian–military collaboration: the Swedish perspectives

“…Prehospital triage aims at quickness and simplicity (using a simple method to quickly transfer the patient), while hospital triage aims at clinical justice and efficiency (to ensure that the patient receives the appropriate level and quality of care, using resources effectively) [2,38,39]. Such complexity in obtaining a safe and correct diagnosis using technological devices seems to be contradictive in a mass casualty situation, where a simple and quick method is preferred to save lives [2,40]. Triage should also exhibit a continuity, i.e., to be compatible in all levels of decision-making to alleviate the flow of the patients into the system in a local, regional or national perspective.…”

The association between length of stay in the emergency department and short term mortality

“…The effects of long ED-LOS and ED crowding on non-favourable outcome have been well studied [1,2] however very sparsely in the Swedish settings [27,29,30]. Changes in the vital signs, directing the patient to high triage priority, are in RETTS-A closely related to 1-day mortality [31]. Therefore, is anticipated that patients with very urgent symptoms and deranged vital parameters have a high mortality [32], in the present study reflected by a high mortality in patients with triage priority 1.…”

“…The accuracy of comorbidity scores can be questioned and data suggest that comorbidity scores only provide a modest improvement on age adjustment [54]. Age has also been a powerful predictor of short term mortality in the ED [31,55]. Underlying diagnoses and comorbidities are not used in RETTS-A and should therefore have less impact on ED-LOS compared to patients chief complaint or triage level assumed to be of more relevance to the clinical milieu at the ED than comorbidity.…”

The association between length of stay in the emergency department and short term mortality

“…The effects of prolonged ED-LOS and ED crowding on non-favourable outcome have been well studied 7 [1,2] however very sparsely in the Swedish settings [24,25]. Changes in the vital signs, directing the patient to high triage priority, are in RETTS-A closely related to 1-day mortality [26] and it is anticipated that patients with very urgent symptoms and deranged vital parameters have a high mortality [27], in this study reflected by a high mortality in patients with triage priority 1. In contrast to previous findings that prolonged ED-LOS is harmful for patients with high medical urgency (high triage priority), as for example observed in patients with non-ST-segment-elevation myocardial infarction [28] or in patients with sepsis [29] we were not able to find an increased mortality in patients triage with triage priority 1 and prolonged ED-LOS.…”