 In acute critical care settings, the diagnosis of adHF is based on the history and clinical signs, sometimes aided by echocardiography, chest radiography and blood markers such as B-type Natriuretic Peptide BNP. The value of BNP over clinical assessment in patients presenting with dyspnoea has been questioned and there is a need for other tools to improve diagnosis. Commencement, dosing, and withdrawal of vasopressors, vasodilators, and inotropes is still largely based on clinical assessment, sometimes assisted by measurement of surrogates of inotropy such as ejection fraction EF or aortic ejection velocity, despite the well-known shortcomings of these indices in critical care. This is particularly so in complex surgical patients where vascular tone and fluid loading status are highly variable and changing. 