There is a controversy regarding the use of blood lactate monitoring for risk assessment in critically ill patients, as there is some confusion as to what the appropriate reference interval is and whether clinicians should perform a single lactate measurement or serial lactate measurements as a screening method at admission to the hospital.

Also, it is not clear where the blood sample should be taken from, whether it should be drawin from arterial, peripheral venous, or capillary blood.

This review aims to investigate whether blood lactate levels are predictive for in-hospital mortality in patients in the acute setting, and to examine the concordance between arterial, peripheral venous, and capillary blood lactate levels in patients in the acute setting.

Kruse et al. performed a systematic search of databases, and they analysed 66 articles which were considered potentially relevant and evaluated in full text. Of these 66 articles, the authors ended up working with 33 articles.

After reviewing the literature, the authors concluded that blood lactate monitoring is useful for risk assessment in patients admitted acutely to hospital, and especially the trend, achieved by serial lactate sampling, is valuable in predicting in-hospital mortality.

The results show that all patients with a lactate at admission above 2.5 mM should be closely monitored for signs of deterioration, and patients with even lower lactate levels should be considered for serial lactate monitoring.

The correlation between lactate levels in arterial and venous blood was found to be acceptable, and as the risk and inconvenience for this procedure is minimal for the patient, venous sampling should be encouraged.

This article was written in English by Ole Kruse, Niels Grunnet and Charlotte Barfod, and published in Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine 2011, 19:74

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Blood lactate as a predictor for in-hospital mortality in patients admitted acutely to hospital: a systematic review