The notion that acid-base and potassium homeostasis are linked is well known. Students of laboratory medicine will learn that in general acidemia (reduced blood pH) is associated with increased plasma potassium concentration (hyperkalemia), whilst alkalemia (increased blood pH) is associated with reduced plasma...

Reduced plasma calcium (hypocalcemia) is a common feature of critical illness. A recent clinical study sought to document the course of hypocalcemia during the early days of critical illness, its significance for mortality, and the efficacy of calcium supplementation. The study population comprised 1038 patients...

Normal cellular metabolism and function require that blood pH be maintained within narrow limits, 7.35-7.45. Even mild excursion outside this range has deleterious effect, and pH of less than 6.8 or greater than 7.8 is considered – according to medical and physiology texts – incompatible with life. Such a view is...

Diagnosis of myocardial infarction in the absence of characteristic electrocardiographic (ECG) changes depends on measurement of circulating cardiac troponin (cTn); either cardiac troponin I (cTnI) or cardiac troponin T (cTnT).  By definition myocardial infarction is associated with increased serum cTnI and cTnT;...

According to the nurse authors of this valuable review article, nurses working in intensive care units often have difficulty understanding the intricacies of acid-base balance as well as interpreting the results of blood gas analysis relating to the critically ill patients in their care. To address this issue and...

Patients with chronic obstruction pulmonary disease (COPD) may need long-term oxygen therapy, monitored with blood gas analysis (pO₂(a) and sO₂(a)). It is important that when adjustments are made to this therapy (either increase or decrease in fraction inspired oxygen, FIO₂) there should be delay until a new steady...

When monitoring the plasma/serum sodium concentration of sick newborn babies in neonatal intensive care units, it may be preferable to use direct ion-specific electrode (ISE) methodology incorporated in point-of-care analyzers (including blood gas analyzers), rather than the indirect ISE methodology commonly employed...

Hemolysis causes clinically significant bias in four of twelve parameters generated during blood gas analysis. That is the headline finding of a recently published study that is, according to the authors, the first ever to investigate the effect of hemolysis on blood gas analytes. Venous blood was sampled from nine...

By measurement of partial pressure of oxygen (pO₂) and oxygen saturation (sO₂), arterial blood gas analysis provides the gold standard method for assessment of blood oxygenation and the means for monitoring supplemental oxygen therapy. More frequent use of arterial blood gases for this purpose will be required if the...

Anemia is a common feature of critical illness and roughly a third of all patients being cared for in intensive care units are given red-cell transfusion. Although such transfusions are unequivocally lifesaving for some patients, e.g. the exsanguinating trauma victim, the benefit is less clear-cut for others.  There...