'Liver function tests' on the intensive care unit: a prospective, observational study

To evaluate the prevalence, patterns and significance of deranged liver function tests (LFT) in critically ill patients.

A prospective, observational data collection of the LFT [bilirubin, alanine aminotransferase (ALT), alkaline phosphatase (AKP), gamma glutaryl transferase (gammaGT)] and critical care parameters in all admissions to the general intensive care unit (ICU) of our institution. Prevalence of abnormal LFT on the day of ITU admission is described and the relationship of abnormal LFT to clinical events and 30-day mortality analysed.

Of 263 first admissions without hepatobiliary disease, 61% demonstrated an abnormal LFT at the point of admission. The majority of abnormalities were less than twice the upper limit of normal. Episodes of ventilation, haemofiltration and hypotension during the first 48 h were associated with an abnormal ALT on day 3. The presence of an abnormal ALT [odds ratio 2.7 (1.2-6.0)], AKP [OR 2.8 (1.1-7.3)] or gammaGT [OR 3.9 (1.9-8.3)] was associated with an increased risk of death within 30 days of admission. When adjusted for APACHE II score, LFTs were not independent predictors of mortality.

Low-grade abnormalities of LFT are a significant entity in critically ill patients and show an association with mortality outcomes and clinical events on ICU. They are likely to represent part of a spectrum of liver injury associated with critical illness and should not be disregarded.