Association between prehospital lactate categories with short- and long-term mortality. A prospective, observational multicenter study.

Abstract

Lactate is an already recognized biomarker for short-term mortality in emergency medical services (EMS). However, how different levels of lactate associate to short-, mid-, and long-term outcome should be unveiled. To determine how different categories of hyperlactatemia associate to mortality. And to clinically characterize hyperlactatemia groups. Multicenter, prospective, observational study performed between January 2019 and February 2022, considering 48 basic life support units and five advanced life support units referring to four tertiary care hospitals (Spain). Patients were recruited from phone requests for emergency assistance in adults, evacuated to emergency departments. The primary outcome was in-hospital mortality from any cause within the first to the 365 day following EMS attendance. The main measures were demographical and biochemical variables, prehospital advanced life support techniques used, and patient condition categorized in 24 diseases. Univariate and Cox regression analysis. A total of 5,072 participants fulfilled inclusion criteria. Group#1 (non-hyperlactatemia) was composed of 2389 subjects (47.1%), group#2 (mild hyperlactatemia) of 1834 (36.1%), group#3 (hyperlactatemia) of 333 (6.6%), and finally group#4 (severe hyperlactatemia) of 516 (10.2%). The 1-day mortality was 0.2%, 1.1%, 9% and 22.3% in the four lactate groups, respectively. Long-term mortality (365-day) was 10.2%, 22.7%, 38.7% and 46.7% in the four lactate groups, respectively. Differences between patients' conditions of lactatemia groups was also found. Our results demonstrated that prehospital lactate categories were associate to short and long-term in a different manner. These results will allow EMS to establish different risk states according to the prehospital lactate categories.