What are the limitations of blood gas analysis and monitoring?

What will be an ideal response?

Arterial blood sampling is an invasive procedure requiring the puncture of an artery or placement of an arterial catheter. Inaccurate results can occur with introduction of air bubbles, dilution with excessive heparin, or with faulty handling of the sample itself. It is also important to keep in mind that blood gas values reflect an isolated measurement in time rather than a trend. They should be used to correlate and document trends established by noninvasive monitoring devices such as pulse oximetry. Finally, arterial blood gas measurements are generally a late indicator of respiratory failure and of limited use as an early warning sign.