Respiratory acidosis and alkalosis are characterized by primary change in pCO₂ (increase in the case of acidosis and decrease in the case of alkalosis). Secondary physiological compensation, aimed at returning blood pH to normal, is evident in blood gas results as a change in bicarbonate concentration (increase in the ...

In health the partial pressure of oxygen (pO₂) in arterial blood is maintained between 10.6 and 13.3 kPa (80-100 mmHg). Hypoxemia (reduced arterial pO₂) is usually a signal of significant respiratory or cardiac disease and respiratory failure is defined as arterial blood pO₂ < 8 kPa ( So when arterial blood gas...

Critically ill patients often require frequent monitoring of blood gases and the arterial blood required for these analyses is most conveniently sampled via an indwelling arterial catheter; arterial catheterization also provides the means for continuous monitoring of blood pressure.  Of all the invasive procedures...

Chronic obstructive pulmonary disease (COPD), a common condition of the elderly affecting an estimated 10 % of those over the age of 60 years, is characterized by an accelerated long-term decline in lung function due to inflammation-induced lung damage. Arterial blood gases are routinely used to monitor patients with...

Umbilical cord blood gas analysis has for many years been recommended for assessment of newborn babies after high-risk delivery associated with possible hypoxic stress and consequent risk of permanent brain damage. More recently there has been an increasing trend towards its routine use after all deliveries.  With...

Reprinted from AMERICAN JOURNAL OF CRITICAL CARE, November 2006, Volume 15, No 6, 595-599 Hudson TL, Dukes SF, Reilly K. Use of local anesthesia for arterial puncture. Copyright with permission from American Journal of Critical Care BACKGROUND Except for intravenous therapy, arterial access is the most common...

Tartu University Hospital has improved the quality of blood gas testing in its clinical laboratory and critical care units by introducing an automatic system for blood gas analysis. Not only did the quality of processes in the preanalytical phase improve, but also the automatic calculation of pO₂(A-a), for APACHE...

In health no more than 1-2 % of total hemoglobin is present as methemoglobin. This is a dysfunctional form of hemoglobin that is unable to bind and transport oxygen because the iron atom of the heme moiety is in the ferrous rather then the normal ferric state. Abnormal increase in methemoglobin, a condition called...

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...

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 ...