D-dimers are protein products of cross-linked fibrin degradation that are present in the blood of most healthy individuals in only negligible amounts (of the order 100-200 ng/mL). As objective evidence of increased fibrinolysis, elevated blood concentration of D-dimer is by extension evidence of intravascular...

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...

Increased plasma sodium concentration (hypernatremia) acquired after admission to intensive care increases the risk that critically ill patients will not survive their illness. That is the headline finding of a recently published study of ~200,000 critically patients cared for in 344 intensive care units across the US ...

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;...

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...

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...

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...

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...

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...

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...