Responding to Patients in the Persistent Vegetative State
According to the MSTF, patients in PVS show no evidence of awareness or thinking, and do not communicate. None of their actions appear purposeful, learned or voluntary. However, the brain stem often functions normally in PVS, allowing a much greater range of activities than seen in related syndromes. Most patients in PVS continue to breathe on their own, circulate blood normally, have periods of waking and sleeping, may move their limbs, smile, shed tears and respond to external stimuli. Some may grunt, groan or scream.
Most patients in PVS cannot chew or swallow food, though some can. Thus arises the ethical dilemma. Some means of artificially administering food and fluids is usually required. Most often a liquid diet is given via a gastrostomy tube which is inserted directly into the stomach. Insertion of this tube requires surgery, but is a relatively low-risk procedure with almost guaranteed effectiveness. "Indeed, feeding tubes may be unique among all medical technologies in that they almost exceptionlessly deliver on their claims."
A patient's prognosis must be considered when choosing medical therapies. According to the MSTF, there is no effective treatment available to reverse PVS. The chances of spontaneous recovery depend on the cause of PVS and the age of the patient. There is currently no hope for recovery from degenerative diseases (like Alzeimher's) or developmental abnormalities (like anencephaly). However, when PVS in adults was caused by a traumatic injury (e.g. traffic accident), one year later, 33% had died, 15% remained in PVS and 52% recovered consciousness. Of those who recovered consciousness, 54% had severe disability, 33% had moderate disability and 13% had a good recovery. Among children in PVS dues to traumatic injuries, 62% recovered, 18% of those with a good recovery. When PVS resulted from a nontraumatic injury (e.g. cardiorespiratory arrest), only 15% of adults recovered consciousness, with severe disability being more common. Recovery among children was similar.
These statistics show that a significant number of people recover from PVS within a year after injury. However, the chances of recovery are much lower after longer periods in PVS. Therefore, the MSTF concluded that PVS should be considered permanent 12 months after a traumatic injury, or three months after a nontraumatic injury. However, a few cases of dramatic recovery after extended periods are well documented. One patient recovered after three years in PVS, to the point of being alert and well-oriented.
For those who remain in PVS, the average life-expectancy is two to five years. It is unusual for someone to survive more than 10 years, although two patients have survived for 37 and 41 years. However, the MSTF report did not take into account how different types of care affected patients' survival. In fact, there have been no formal studies on how the level of care impacts PVS patients' life expectancy. More aggressive and more caring treatment would probably lengthen survival times.
There are some related conditions which must, where possible, be clearly differentiated from PVS. In whole-brain death all brain function has ceased. There are no sleep-wake cycles, and no spontaneous respiration. Today, brain death is synonymous with death. Hence, statements like "She is brain dead. Why do they not let her die?" are misleading and reflect a misunderstanding of the terminology. In spite of efforts to change the definition of death, currently someone in PVS is neither dead nor brain dead.
The locked-in syndrome has some similarities to PVS since the person is almost completely paralyzed. However, locked-in patients can often move their eyes purposefully, showing they are conscious and aware of their environment. They can communicate with those around them. Tragically, they are otherwise unable to move.
The MSTF also distinguished patients in coma from those in PVS. Within two to four weeks, a patient in a coma usually either recovers consciousness, enters PVS, or dies. PVS differs because a patient in a coma does not have sleep-wake cycles, respiration is usually depressed and the duration of coma is much shorter. However, others treat coma and PVS as examples of the same kind of clinical entity because of their prominent similarities, namely apparent lack of consciousness and unarousability by ordinary means.