The integrity and function of all cells depend on an adequate supply of oxygen. Severe acute illness is frequently associated with inadequate tissue perfusion and/or reduced amount of oxygen in blood (hypoxemia) leading to tissue hypoxia.  If not reversed, tissue hypoxia can rapidly progress to multiorgan failure and ...

Arterial blood is the standard sample for blood gas analysis but arterial blood sampling is more painful and hazardous to the patient. Such is the relative convenience and safety of sampling venous blood that several studies have sought to investigate the validity of its use as a substitute for arterial blood.  The...

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...

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...

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...

The principal function of the protein hemoglobin contained in red blood cells is transport of oxygen in inspired air from lungs to tissue cells. Although normally present in only trace amounts, there are three species of hemoglobin that cannot transport oxygen. The three species, collectively called the dyshemoglobins ...