effect of 5-aminolaevulenic acid on postoperative lactate levels in patients undergoing surgery for malignant brain tumours.

Introduction 5-aminolaevulinic acid (5-ALA) is a natural precursor of haemoglobin. Exogenously administered 5-ALA can lead to intracellular accumulation of fluorescent porphyrins in malignant tissues, such as glioblastoma. 5-ALA is increasingly used to improve tumour visualisation and enable more optimal resection of malignant gliomas. In vitro, 5-ALA can cause oxidative damage to rat liver mitochondria. In vivo, rats exposed to 5-ALA developed increased lactate levels; possibly because inhibition of oxidative metabolism [1]. Univariate data also suggested an effect of 5-ALA in neurosurgical patients [2]. Since lactate levels are widely used to monitor patients, we performed multivariate analysis on the impact of 5-ALA on lactate levels.