Prevalence and clinical significance of point of care elevated lactate at emergency admission in older patients: a prospective study

Objective Patients who are over 65 years old represent up to 24% of emergency department (ED) admissions. They are at increased risk of under-triage due to impaired physiological responses. The primary objective of this study was to assess the prevalence of elevated lactate by point of care testing (POCT) in this population. The secondary objective was to assess the additional value of lactate level in predicting an early poor outcome, as compared to and combined with common clinical scores and triage scales. Methods This monocentric prospective study recruited ED patients who were over 65 years old between July 19th 2019 and June 17th 2020. Patients consulting for seizures or needing immediate assessment were excluded. POCT lactates were considered elevated if >= 2.5 mmol/L. A poor outcome was defined based on certain complications or therapeutic decisions. Results In total, 602 patients were included; 163 (27.1%) had elevated lactate and 44 (7.3%) had a poor outcome. There was no association between poor outcome and lactate level. Modified Early Warning Score (MEWS) was significantly associated with poor outcome, alongside National Early Warning Score (NEWS). Logistic regression also associated lactate level combined with MEWS and poor outcome. Conclusion The prevalence of elevated lactate was 27.1%. Lactate level alone or combined with different triage scales or clinical scores such as MEWS, NEWS and qSOFA was not associated with prediction of a poor outcome. MEWS alone performed best in predicting poor outcome. The usefulness of POCT lactate measurement at triage is questionable in the population of 65 and above.