Pulse oximetry Pulse oximeter measures The oxygen saturation of haemoglobin in arterial blood – which is a measure of the average amount of oxygen bound to each haemoglobin molecule. Average reading 97-100% Can be placed on finger or ear lobe The pulse rate – in beats per minute , averaged over 5-20 seconds

Indications Monitoring effectiveness of oxygen therapy Sedation or anesthesia Haemodynamic instability – AMI, CCf Respiratory illness Monitoring during administration of respiratory depressant drugs

Inaccurate readings May be caused by A reduction in peripheral pulsatile blood flow produced by peripheral vasoconstriction (hypovolaemia). Severe hypotension Cold shivering CCF Some cardiac arrhythmias PVD Nail varnish (may cause low readings) Bright fluorescent lighting