Of all tests performed on patient blood samples, arterial blood gases (ABGs) are conceptually probably the most complex. An understanding of the clinical significance of the measured and derived parameters generated by blood gas machines depends on a basic knowledge of so many topics, including acid-base theory,...

Premature neonates frequently have inadequate respiratory function and require oxygen therapy during the weeks after birth. Since they are also exquisitely vulnerable to oxygen toxicity, careful monitoring of oxygen status is an essential component of neonatal intensive care.  Measuring % oxygen saturation by pulse...

Hemolysis, the breakdown of erythrocyte (red-cell) membranes, can occur in vivo as a result of disease, or more commonly in vitro when it is most usually a consequence of poor blood collection or sample handling technique.  Hemolysis is of significance for laboratory staff because it results in the release of...

As point-of-care applications of lab testing demand more rapid and clinically integrated order entry and results-reporting processes, it becomes paramount for the laboratory to investigate entire clinical processes. Direct observation and process mapping of these clinical applications – end to end - are "lean" tools...

The factors that influence critical care nursing staff when making the decision to sample blood for arterial blood gas analysis is the subject of a recent UK study. The authors of this study specifically sought to establish if there is an association between patient values for four parameters (FO₂(I) , pCO₂, pO₂ and % ...

The population-based reference interval is the most widely used tool for interpretation of individual patient laboratory test results. The clinical value of those results depend crucially on the reference intervals with which they are compared, and all efforts directed at ensuring analytically precise and accurate...

Premature, very-low-birth-weight babies have immature lungs and frequently require mechanical ventilation to ensure the gas (O₂, CO₂) exchange necessary for survival. Ventilation sufficiently aggressive to maintain partial pressure of carbon dioxide in blood (pCO₂) within normal limits can cause mechanical damage to...

Pulse oximetry provides a simple non-invasive method of monitoring the oxygenation status of patients by indirectly measuring the percentage of hemoglobin that is saturated with oxygen, i.e. % oxygen saturation (SpO₂). Pulse oximetry has important limitations, including inaccurate readings in patients with inherited...

Pleural effusion, defined as excess fluid in the pleural cavity, can complicate the course of a pathologically diverse range of common clinical conditions, including infectious and malignant disease of the lung, heart failure, cirrhosis, pancreatitis and rheumatoid arthritis. Microbiological, cytological and chemical...

Arterial oxygen saturation sO₂(a) is a parameter calculated during blood gas analysis that is useful for monitoring respiratory function. Pulse oximetry provides a safer and more convenient, non-invasive means of measuring oxygen saturation that is used in many clinical settings.  The value of pulse oximetry depends...