A comparison of non-invasive versus invasive methods of haemoglobin estimation in patients undergoing intracranial surgery

Abstract

Background: Until recently, invasive monitoring techniques were the only ones available for the estimation of haemoglobin (Hb) in the blood. However, following the introduction of a new non-invasive monitor, Hb concentration could be non-invasively and continuously monitored. It allows immediate and ongoing Hb changes to be displayed during surgery, which may aid in the rapid detection of clinically significant blood loss. To test the accuracy of this non-invasive monitor, we compared Hb levels obtained using standard invasive techniques (laboratory and arterial blood gas machine analysis) with those derived from a non-invasive monitor.