Pain perception and the interruption of artificial nutrition and hydration (ANH) in unresponsive

Background: In this presentation, we will review the recent literature indicating that some patients with Disorders of Consciousness reveal a form of residual awareness and that they are capable of perceiving painful stimuli and exhibiting consistent responses to them. Empirical evidence suggests that, when tested with the appropriate tools, these patients can exhibit consistent reactions to emotionally salient stimuli.Objectives: Based on these findings, we propose that the voluntary withdrawal of ANH should be carefully reconsidered on medical and ethical grounding. For patients with severe pathologies (e.g., terminally ill), the hydration and starvation may have benefits (patients could be intolerant of enteral feeding because of abdominal distension, vomiting, diarrhoea, or fluid overload) and to refuse food and fluids and to have relief of distress through provision of medicine may be a right. However, most patients in VS/UWS are unlikely to be intolerant of nutrition and hydration that are considered basic compassionate care because they promote physical and emotional well-being. Withdrawal of ANH has biologic consequences including distress and pain. Neurophysiological and neuroimage studies are finding ways to assess awareness in VS/UWS patients. The identification of the ‘pain matrix’ along with the design of experimental tools capable of detecting consistent patterns of brain activation in response to noxious stimuli allowed us to integrate the original definitions of pain, which rested largely upon subjective experiences with objective measurements.