LONDON (Reuters Health) – In patients with acute liver failure resulting from paracetamol (acetaminophen) poisoning, arterial blood lactate measurement identifies those who are likely to die and are therefore in need of urgent liver transplantation, UK researchers report in The Lancet for February 16.
Dr. Julia Wendon, from King's College Hospital, London, and associates first established levels of lactate associated with mortality in retrospective cohort of 103 patients with paracetamol-induced acute liver failure. They found that lactate levels were significantly higher in nonsurvivors than in survivors at 4 hours (8.5 vs 1.4 mmol/L) and at 12 hours after fluid resuscitation (5.5 vs 1.3 mmol/L).
The investigators then prospectively applied these criteria to a 107-patient validation sample. In predicting nonsurvival, a threshold value of 3.5 mmol/L for early lactate levels yielded a sensitivity of 67%, a specificity of 95%, a positive likelihood ratio of 13 and a negative likelihood ratio of 0.35. Using a threshold of 3.0 mmol/L for lactate measured after fluid resuscitation the corresponding values were 76%, 97%, 30 and 0.24, Dr. Wendon's team reports.
Compared with criteria used at King's College Hospital for identifying patients in need of emergency liver transplantation, early and late lactate measurements identified non-survivors sooner (p = 0.01).
Dr. Wendon and colleagues conclude that "on the basis of this analysis, we propose modification of the King's College Hospital criteria (panel) to include blood lactate concentrations measured early in the course of and after completion of volume resuscitation. We expect that this approach will further improve the speed and accuracy of selection of appropriate candidates for transplantation."