In health the partial pressure of oxygen (pO₂) in arterial blood is maintained between 10.6 and 13.3 kPa (80-100 mmHg). Hypoxemia (reduced arterial pO₂) is usually a signal of significant respiratory or cardiac disease and respiratory failure is defined as arterial blood pO₂ < 8 kPa ( So when arterial blood gas...

Two very different reviews of acid-base pathophysiology are recently published. The first, written by a nurse educator is a comprehensive overview and serves as an introduction to the topic. The approach is familiar and reflects standard physiology texts.  After a very brief synthesis of the significance of...

Reduction in platelet numbers (thrombocytopenia) is associated with reduced hemostatic response to blood-vessel injury and therefore increased risk of bleeding. In health, the concentration of platelets in peripheral blood is maintained within the range of 150-400 × 10³/mL. The risk of spontaneous life-threatening...

Umbilical cord blood gas analysis has for many years been recommended for assessment of newborn babies after high-risk delivery associated with possible hypoxic stress and consequent risk of permanent brain damage. More recently there has been an increasing trend towards its routine use after all deliveries.  With...

Critically ill patients often require frequent monitoring of blood gases and the arterial blood required for these analyses is most conveniently sampled via an indwelling arterial catheter; arterial catheterization also provides the means for continuous monitoring of blood pressure.  Of all the invasive procedures...

Lactate measurement is important for diagnostic and prognostic assessment of the critically ill. Traditionally, lactate has been measured on serum/plasma samples in the central laboratory, but modern blood gas and other point-of-care analyzers now provide the means for real-time monitoring of lactate on whole blood at ...

Chronic obstructive pulmonary disease (COPD), a common condition of the elderly affecting an estimated 10 % of those over the age of 60 years, is characterized by an accelerated long-term decline in lung function due to inflammation-induced lung damage. Arterial blood gases are routinely used to monitor patients with...

Reduced plasma sodium concentration (hyponatremia), the most common electrolyte abnormality in hospitalized patients, is the subject of a recently published review. Disordered secretion of the pituitary hormone vasopressin (alternative name, antidiuretic hormone ADH) is central to the pathogenesis of hyponatremia for...

As with any aspect of healthcare, laboratory testing is prone to errors that may have a negative impact on outcome for patients. The focus for laboratory management in this regard has not unnaturally been the analytical process with great emphasis placed on the value of internal and external quality control programs...

In health no more than 1-2 % of total hemoglobin is present as methemoglobin. This is a dysfunctional form of hemoglobin that is unable to bind and transport oxygen because the iron atom of the heme moiety is in the ferrous rather then the normal ferric state. Abnormal increase in methemoglobin, a condition called...