As a blood marker of tissue hypoxia, lactate is routinely measured to assess and monitor critically ill patients. Hypoperfusion and resulting tissue hypoxia with evolving lactic acidosis is a common feature of many conditions that render patients critically ill. Tissue hypoxia is by no means the only cause of lactic...

Plasma calcium is maintained within normal limits by the integrated action of three hormones: parathyroid hormone (PTH); the vitamin D-derived renal hormone, calcitriol; and the thyroid hormone, calcitonin.  Hypocalcemia (reduced blood calcium), which is defined as corrected total plasma calcium <2.20 mmol/L and...

Reduced blood glucose (hypoglycemia) is common during the hours and days following birth. This so-called neonatal hypoglycemia may be transitory and asymptomatic but can result in a range of acute symptoms. If sufficiently prolonged, the condition is associated with risk of irreversible neurological (brain) damage....

Discussion of acid-base physiology usually focuses mainly on the role of lungs and kidneys, and it is a disease that affects the function of these two organs that are usually invoked when considering, in general terms, acid-base disorders. As the authors of this review article make clear, the liver also plays an...

In health plasma potassium concentration is maintained within the approximate reference range of 3.5-5.3 mmol/L in part by the action of the adrenal hormone aldosterone on renal tubule cells. Hypokalemia (reduced blood potassium), defined as plasma potassium <3.5 mmol/L, is one of the most common electrolyte...

The gold standard sample for blood gas analysis is arterial blood. Compared with collection of venous or capillary blood, collection of arterial blood by arterial puncture is a painful procedure that can induce feelings of anxiety. The notion that this pain and anxiety could be a source of preanalytical error in blood ...

The physiological stress response to critical illness and trauma determines that transiently raised blood glucose (hyperglycemia) is common among those admitted to intensive care, irrespective of their diabetes status. Much research has been directed at establishing whether or not intensive insulin therapy aimed at...

Procalcitonin (PCT) is a peptide (116 amino acids) precursor of the calcium-regulating thyroid hormone, calcitonin. Serum/plasma levels are very low (<0.1 ng/mL) or even undetectable in healthy individuals. However, in response to cytokine release during systemic inflammation, PCT synthesis increases in extra-thyroidal ...

Measurement of serum lactate is increasingly being used in the assessment of emergency department (ED) patients. The prognostic significance of raised lactate (hyperlactatemia) at ED admission is the subject of a recent study conducted at the ED of a secondary and tertiary referral teaching hospital located in the...

Acute kidney injury (AKI) is defined as an abrupt decrease in kidney function evidenced by recent (within 48 hours) increase in serum creatinine concentration equal to or greater than 26.5 µmol/L (0.3 mg/dL). It can be a complication of many conditions that warrant hospital admission so it is common; up to 20 % of...