ABSTRACT
Accurate assessment of blood gases is fundamental to supportive care in critical care medicine. Traditionally, blood gases have been measured by invasive sampling, either through an indwelling arterial catheter or by arterial puncture, and analyzed in the laboratory by blood gas analyzers. This presents significant drawbacks, mainly because of the prolonged delay between sample acquisition and the availability of the laboratory results. In neonatal applications, for example, frequent blood sampling can cause significant blood loss, especially for very small infants, unless microblood samples are used for analysis. Furthermore, blood gas values are available only intermittently and therefore indicate the status of the patient only at the time the blood sample was drawn. The inevitable delay and lack of continuous information can lead to potential diagnostic errors, particularly in critically ill patients, in whom rapid and often life-threatening cardiopulmonary changes can occur during short periods of time. Continuous monitoring of blood gases, on the other hand, offers a major advantage since instantaneous changes in blood gas levels can be recognized and adequately corrected before irreversible tissue damage occurs. Furthermore, it provides trending information to assist in assessing the therapeutic response and predicting prognosis.
