[Problems and limits in noninvasive oxygen monitoring]

Recently, professional anaesthesiologists organizations, have set up recommendations for intraoperative monitoring. These recommendations are based upon the assumption that anaesthesia-related deaths are largely preventable and that extensive monitoring will reduce mortality. Hypoxaemia appears to be an important pathophysiological mechanism, and this is why oxygen monitoring is given a high priority in safety standards in anaesthesia. However, no reduction in mortality has been definitively shown to follow the use of any monitoring device in randomized, controlled trials. Four techniques of oxygen monitoring are discussed and evaluated. Oxygen monitoring during inspiration can be recommended, although its implementation will probably prevent only a few anaesthesia-related deaths. Pulse oximetry is certainly highly recommended, but also has some deficiencies which are not sufficiently well known considering the popularity of this technique. Transcutaneous PO2 is considered mainly for historical reasons. Near infrared spectrometry is a new technique offering noninvasive and continuous monitoring of intracerebral oxygenation.