Persistent Vegetative State (PVS)

A vegetative state can be defined as "a clinical condition of unawareness of self and environment in which the patient breathes spontaneously, has a stable circulation, and shows cycles of eye closure and opening which may simulate sleep and waking" [Working Group of Royal College Physicians, "The Permanent Vegetative State," The Journal of the Royal College of Physicians 430 (1996): 119-21]. Since patients in such a state sometimes show behavior that could be interpreted as evidence of consciousness, the diagnosis is not always self-evident. Additionally, the condition of being in a vegetative state is similar to that of other conditions that involve the absence or partial absence of awareness of self and the environment, such as coma, locked-in syndrome and akinetic mutism. The Multi-Society Task Force on PVS (MSTF) has recommended the use of seven clinical criteria in making the diagnosis. It also has been suggested that these criteria be reviewed through neurologic examinations repeatedly. According to the MSTF and the American Neurological Association, the vegetative state has to have endured for at least one month in order for it to be considered persistent [The Multi-Society Task Force on PVS, "Medical Aspects of the Persistent Vegetative State," New England Journal of Medicine 330 (1994): 1572-79; ANA Committee on Ethical Affairs, "Persistent Vegetative State: Report of the American Neurological Association Committee on Ethical Affairs," Annals of Neurology 33 (1993): 386-90]. Some clinicians make a distinction between a persistent vegetative state and a permanent vegetative state based on the duration of the vegetative state, but there is little difference in the prognosis and the ethical considerations remain very similar, if not identical. [Gastone, CG, "Persistent Vegetative State: Clinical and Ethical Issues," Theoretical Medicine 18 (1997): 221-36.]

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