The importance of pulse oximetry for anesthesia

: With the combination of a noninvasive saturation measurement and plethysmography, pulse oximetry has become an important monitoring method for peripheral perfusion and oxygen supply. Indications for pulse oximetry is practically every anaesthesia especially in geriatric patients and patients with one-lung-anaesthesia, obesity, asthma and emphysema. Pulse oximetry has proved its worth in the transport of emergency patients. Sources of error are a bad perfusion at the site of measurement (hypotension, hypothermia), dyshaemoglobinaemia (Met-carboxy-haemoglobin) and interference of colours (dark skin, intravenous colours, high light intensity). Accuracy of response of most currently available pulse oximeters lies between 2-3% (SD) with oxygen saturations between 80-100%. Deviations increase at lower oxygen saturations. Pulse oximetry will soon be regarded as minimal monitoring standard worldwide together with the ECG, blood pressure, pulse and respiratory monitoring.