The relationship between elevated prehospital point-of-care lactate measurements, intensive care unit admission, and mortality: A retrospective review of adult patients

Objective
To determine whether prehospital point-of-care lactate (pLA) is associated with mortality, admission, and duration of hospital stay.

Design
A retrospective clinical audit, where elevated lactate was defined as ≥2 mmol/L.

Setting
The ambulance service and primary referral hospital in the Australian Capital Territory from 1st July 2014 to 30th June 2015.

Participants
Adult patients (≥18 years) who had pLA measured and were transported to the primary referral hospital.

Main outcome measures
Mortality, admission, and duration of hospital stay.

Results
Two hundred fifty-three patients with a median pLA of 2.5 mmol/L (interquartile range [IQR]: 1.5–3.7) were analysed. Overall mortality was 8.3%; 68% were admitted to the hospital; 8.3% to the intensive care unit (ICU). pLA was non-significantly higher in those who died compared to survivors (3.5 [IQR: 2.75–5.85] vs 2.4 [1.5–3.6]; W = 1631.5; p = 0.053). pLA was higher for those admitted to the hospital (2.9 [1.9–3.9] vs 2.0 [1.4–3.1]; W = 5094.5, p = 0.001) and the ICU (3.2 [2.4–5.7] vs 2.4 [1.5–3.6]; W = 1578.5; p = 0.008). There was no relationship between pLA and duration of stay. Considered as a screening tool, at a cut-off of 2.5 mmol/L, pLA had a likelihood ratio+ of 1.61 for mortality and 1.44 for ICU admission; the odds ratio for mortality was 3.76 (95% confidence interval = 1.30, 13.89).

Conclusions
Elevated prehospital lactate was associated with significantly increased ICU and hospital admissions. There may be value in pLA as a screening tool.