Adding measurement of serum lactate improves performance of the National Early Warning Score 2 (NEWS2) in predicting outcomes in critically-ill patients. This improvement was previously reported with the original NEWS.
Patient selection: critically-ill or deteriorating patient
Parameters:
(1) National Early Warning Score 2 (NEWS2) total score, from 0 to 20
(2) serum lactate in mmol/L
NEW2-L score =
= (NEWS2 total score) + (serum lactate)
Interpretation:
• minimum score: near 0
• maximum score: near 30 (dependent on lactate concentration)
• The risk of mortality increases as the NEWS2-L score increases.
• Durantez-Fernandez et al found the best cut-off for NEWS2 was 6.5, for lactate was 3.3, and the NEWS2-L was 11.7
• Martin-Rodriguez et al classified risk levels as: high risk if total score >= 7; medium risk if total score 5 or 6; low-to-medium risk if either NEWS2 or lactate >= 3; else low risk.
Performance:
• For community-acquired pneumonia the area under the ROC curve for inpatient mortality was 0.73.
• For patients in the Emergency Department the area under the ROC curve for 2-day mortality was 0.92.
