Arterial blood gas analysis to monitor acute oxygen therapy

Perform arterial blood gas analysis in patients at risk of hypercapnia receiving oxygen therapy¹. Hypercapnia is not detected by pulse oximetry. If the oxygen flow rate is increased, repeat arterial blood gas analysis after 30 to 60 minutes. Also perform arterial blood gas analysis if the patient’s condition worsens.

Note: Arterial blood gas analysis is needed to quantify hypercapnia; hypercapnia is not detected by pulse oximetry.

Consider hypercapnia if a patient on acute oxygen therapy develops a reduced level of consciousness (eg drowsiness, confusion), or other signs of hypercapnia (eg bounding pulse, flushed skin). Perform arterial blood analysis in these patients.

In critically ill patients, serial arterial blood gas analysis may be indicated at routine intervals to monitor progress. If blood gas values for oxygen and carbon dioxide cannot be corrected with oxygen therapy, ventilatory support may be indicated.

For more information on arterial blood gas analysis, see here.

¹ Venous carbon dioxide values do not correlate directly with arterial carbon dioxide values; their use to exclude carbon dioxide retention is controversial. For more information, see Venous blood gas analysis.Return