p50 is a shorthand representation of hemoglobin-oxygen affinity. A lower p50 is protective in ambient hypoxemia, whereas increasing the p50 should be beneficial in hypoxia due to lung disease, anemia, and tissue ischemia. Despite encouraging theoretical and experimental data, it is not yet established that...

John Severinghaus, who recently turned 80, is one of the pioneers in the field of blood gas. To celebrate his birthday, bloodgas.org has asked him to look back on the first developments leading to the modern blood gas analyzers. The following article has also been published in Anesthesiology, The Journal of the...

"Six Sigma" is the latest trend in quality management and is being widely implemented in business and industry today. Six Sigma represents an evolution of Total Quality Management (TQM), providing a more quantitative framework for evaluating process performance and clearer goals for process improvement. The...

Electronic fetal monitoring (EFM) during labor has been performed for 40 years. However, the specificity in diagnosing asphyxia is still insufficient. The combination of EFM and fetal scalp-blood sampling was introduced shortly after the introduction of EFM.  Although this monitoring ensures a better sensitivity and...

The concept of “metrological traceability” is important when establishing comparable clinical decision limits for a measured analyte at different hospitals within one country and in different countries.  This can only be achieved if all instrument manufacturers establish the performance characteristics of their...

What quality is being controlled in laboratories today?  The definition of a quality requirement for each laboratory test is the starting point of quantitative quality management. Different types of requirements may be used as long as there are appropriate quality-planning models for translating those requirements...

The possibility of continuously monitoring arterial blood oxygen and carbon dioxide using heated surface electrodes on human skin was discovered in the early 1970s and made commercially available by 1976.  These devices were applied initially to premature infants in an effort to reduce the incidence of blindness due...

There are several diagnostic approaches to identify and quantify different types of vascular disease. However, these methods usually do not reflect the condition of the cutaneous circulation.  Because transcutaneous oxygen reveals the status of cutaneous circulation, it has been shown to be a powerful diagnostic tool ...