57 THE SIGNIFICANCE OF BLOOD LACTATE IN CRITICALLY ILL NEONATES

Abstract

We have, therefore, studied the prognostic value of serial ABL and acid-base changes in 65 consecutive ill, ventilated neonates with median (range) gestation 29 (23-40) weeks and birthweight 1330(550-4080) g, with indwelling arterial catheters. Lactate concentrations were measured in 40 ul of deproteinised blood by a specific enzymatic method. Hyperlactatemia was defined as ABL > 2.5 mmol/L. The overall mortality was 20% (13/65). Hyperlactatemia was strongly associated with mortality. While 6/48 babies with peak lactate concentrations (PLC) <2.5 mmol/L died, 3/12 babies with PLC 2.5-4.9 mmol/L and 4/5 babies with PLC >5 mmol/L died. None with persistent hyperlactatemia survived. The median (Q1-Q3) % reduction from PLC was significantly lower in non-survivors than in survivors { 3.6(0-16.4) vs 32.1(17.6-48); p=0.001 }. The acid-base changes were not related to outcome. ABL was also superior to CRIB scores in predicting mortality. ABL, therefore, appears to be a useful indicator of the outcome in critically ill neonates. Blood lactate levels that are rising, show little reduction or are > 5mmol/L carry a bad prognosis.