A growing body of evidence suggests that the potential exists to reduce morbidity and high mortality rates associated with major surgery in high-risk patients. Dopexamine is a dopamine analogue with agonist activity at β2-adrenoceptors and dopaminergic receptors that has been used to maintain tissue perfusion in critically ill and high-risk surgical patients with the aim of improving clinical outcomes. Postoperative complications occur more frequently in the presence of poor tissue microvascular flow and oxygenation, and dopexamine has been shown to improve these abnormalities. However, the effect of dopexamine on clinical outcomes is less clear, and the findings of randomized trials have proved inconsistent. These conflicting findings might be explained by dose-related differences in the hemodynamic and immunologic effects of dopexamine. The series of investigations that make up this thesis set out to explore the nature of any such dose-related effects and reveal potent anti-inflammatory effects of dopexamine in the absence of haemodynamic effects.