ABSTRACT
Both pulse oximetry and arterial blood gas (ABG) measurement provide important information in the assessment of patients with respiratory disease. Pulse oximetry is a simple, non-invasive measure of arterial oxygen saturation (SpO2), but does have limitations regarding the amount of information it provides. In contrast, an ABG measurement provides much more information concerning the patient’s physiological status, such as their respiratory and metabolic function, in addition to other parameters such as electrolytes and haemoglobin measurements. However, obtaining an ABG sample can be
a painful procedure for the patient, owing to either cannulation of an artery to insert an arterial line, or by the ‘arterial stab’ method (Crawford, 2004). Capillary blood gases may provide an easier and less painful alternative to sampling arterial blood and this method is now used by a number of respiratory services (Zavorsky et al., 2006). Whether arterial or capillary blood is used in the sample, it is vital that healthcare staff have the knowledge and skills to interpret the results.
