Studies in the early 2000s suggested that the introduction of flow or cardiac output monitoring could improve outcome in major surgery, especially in high-risk patients. This led the National Institute of Health and Care Excellence (NICE) in the UK to issue guidance in 2011 recommending the use of the Deltex Cardio Q Doppler flow monitor in these patients both to improve outcome and also reduce costs. This advice was subsequently extended to include all “flow monitors” in 2012. However, recent systematic reviews and major randomized controlled trials have failed to confirm the benefits of adding “flow” to conventional monitoring in the perioperative period. This paper examines physiological and methodological reasons behind this failure and introduces an alternative management strategy in high risk patients which incorporates cardiac output monitoring alongside the additional monitoring of cortical suppression and cerebral and tissue oxygenation.
Key words: multi-modal monitoring, cardiac output monitoring, depth of anaesthesia monitoring, cerebral oxygenation,venodilation