Homeostatic mechanisms ensure that in health the extracellular fluid (ECF) concentration of electrolytes, including calcium, is maintained within well-defined limits. Abnormality in ECF calcium concentration can have profound adverse effects.  The most common means of assessing calcium status is to measure total...

Accurate blood gas results depend on a homogeneous blood sample and the necessity for thorough mixing of samples is reflected in written standard operating procedures for blood gas analysis. The results of a recent study suggest, however, that manual mixing techniques routinely used may be inadequate in achieving a...

Modern blood gas analyzers often have incorporated technology that allows hemoglobin measurement on the same blood sample used to measure pH, pCO₂ and pO₂. Clinicians working in a UK neonatal intensive care department where such an instrument was routinely used for blood gases were keen to exploit the newly available...

Arterial blood is the standard sample for measurement of pH, pCO₂ and pO₂, but collection of arterial blood can be painful. Furthermore, it is a procedure associated with some risk to the patient and can therefore only be performed by trained, medically qualified staff.   Capillary blood collection by finger or...

Acid-base physiology and significance of blood gas results are topics that many students find daunting. Their difficulty is not aided by the non-standard abbreviations used to indicate partial pressure of a gas. The issue is highlighted in a recent letter to the journal Clinical Chemistry.  The authors cite the...

Measurement of plasma/serum sodium concentration is one of the most frequently requested blood tests in clinical practice. Although usually performed in the laboratory, the test is also available at the point of care using technology incorporated into blood gas and other point-of-care analyzers. In health, sodium...

Where do you go for help, when you are a parent of a child who stops breathing while it sleeps? If you live in the south of Sweden, you go to Halmstad County Hospital, where a team of specialists are ready to monitor your sleeping child by polysomnography (PSG). The neonatal intensive care unit (NICU) in Halmstad has ...

Hypoxia and hypoxemia describe states of oxygen deficiency: hypoxia is deficiency in oxygenation at tissue or cellular level whilst hypoxemia is a suboptimal normal partial pressure of oxygen. Hypoxia and hypoxemia are interrelated, as untreated hypoxemia will ultimately result in hypoxia.  It should also be noted...

Hemorrhage, due to a reduction in the coaguability of blood, is a common cause of morbidity and mortality among trauma victims and the critically ill in general. Reduced blood pH (acidosis) is also common in these patient groups. Previous studies have shown that acidosis is an independent risk factor for development...

Measurements of pH, pCO₂ and pO₂ of arterial blood during blood gas analysis are all made at normal body temperature, 37 °C. The sample is warmed to that temperature prior to analysis. Blood gas analyzers provide the option for these primary measurements to be automatically "corrected" to the patient’s actual body...