Introduction: According to experts, vegetative state (VS) patients are unable to perceive pain.
Background: Still, a large portion of nurses believe that VS patients can perceive pain and are uncomfortable when pain is not treated.
Aim: To identify the criteria used in clinical practice and in research to detect the presence or the absence of conscious perception of pain in VS patients.
Procedure: An integrative review exploring MEDLINE, CINAHL and Cochrane's data bank was conducted.
Results: A total of 4 clinical articles and 7 empirical studies were included. According to them, patients in VS may exhibit reflexes (ex : closing fists) when exposed to an external stimulation such as a painful stimuli or a verbal command. However, no voluntary reaction such as localisation of the painful stimuli should be observed in VS patients otherwise the diagnosis should be questioned. When exposed to an external stimulation, use of functional neuroimaging techniques (fMRI or PET scan) in VS patients can be used to detect brain activation in the primary cortical areas, the associative cortical areas, and also in the connections between the two. Those techniques may allow the identification of objective signs of consciousness that were not detected at the bedside.
Discussion: Assessment of behavioural reactions is complex and greatly subjective in VS patients. The role of the associative areas in the process of pain perception is still poorly understood.
Conclusion: Because of this incomplete picture of pain perception in VS patients, many experts recommend the prophylactic treatment on pain in this population.