[Arterial puncture or pulse oximetry?].

Arterial puncture is the general accepted standard method for monitoring oxygen therapy in critically ill patients, but this technique is painful for the patient, has the potential of complications, and does not provide immediate continuous data. Pulse oximetry is a non-invasive method used to measure arterial oxygen saturation with a clinically acceptable accuracy of +/- 2%. Despite some limitations, pulse oximetry is considered to be reliable in most cases in detecting hypoxaemia and monitoring oxygen therapy in stationary units. The pulse oximeter can reduce the number of arterial punctures, personnel's time consumption, and limit oxygen abuse. Furthermore the new transportable and hand-held pulse oximeters offer new possibilities for continuous 24 hour monitoring of oxygen saturation also out of hospitals. The pulse oximeter can optimize monitoring patients' oxygen saturation in the stationary units, however, arterial puncture will remain the most reliable method in the assessment of hypoxaemia and hypercapnia, especially in acute situations.