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,...

Metabolic acidosis is the most common disturbance of acid-base balance among the critically ill of all ages, usually due to increased lactate production consequent on inadequate tissue perfusion and/or hypoxemia. The condition is characterized by primary reduction in bicarbonate and pH revealed during arterial blood...

All newborn babies have, by comparison with adults, a raised serum concentration of unconjugated (and therefore total) bilirubin, due principally to the transient increase in red cell destruction associated with the move from intrauterine support to physiological independence.  In close to half of all newborns the...

Over a third of patients admitted to intensive care develop hypernatremia (raised serum sodium concentration) or hyponatremia (reduced plasma sodium concentration) within a few days of admission. Both hypo- and hypernatremia acquired after admission prolong hospital stay and decrease chance of survival.  These are the ...

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 anticoagulant potassium ethylenediaminetetra-acetic acid (K+ EDTA) is present in sample tubes used to collect samples for full blood count (FBC) and some other tests. However, the anticoagulant has the effect of markedly increasing plasma potassium concentration and reducing plasma calcium, magnesium and zinc...

Blood gas analysis has been performed at the point of care for well over 20 years and is sufficiently established for clinicians to have no misgivings about using pH, pCO₂ and pO₂ results obtained at the point of care for direct patient management.  Modern blood gas analyzers now have the capacity to measure not only...

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...

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...

Fingerstick (capillary blood) samples are not suitable for glucose measurement in an intensive care setting and whole-blood glucose results obtained using a blood gas analyzer agree more closely with reference laboratory measurement than a dedicated point-of-care glucose meter. These are the two headline conclusions...