Persistent Vegetative State

Definition

A PVS usually occurs within one month after an acute traumatic or non-traumatic brain injury and evolves from a coma to a state of sleep-wake cycles without awareness. Loss of ability to control bladder and bowel function is present.

Description

Individuals in a persistent vegetative state (PVS) have sustained injury resulting in a loss of higher brain functioning including thinking abilities but breathing and circulation are intact. Individuals in a PVS do not speak and cannot respond to commands. Individuals in a PVS do have variable reflexes but show no evidence of purposely responding to stimuli.

Demographics

About 10,000 to 25,000 adults and 10,000 children in the United States are diagnosed as being in a PVS.

Causes and symptoms

The most common cause of PVS is traumatic brain injury resulting in oxygen deprivation but any condition resulting in brain damage can result in a PVS. Some adults and children progress into a PVS as a result of degenerative and nervous systems disorders. Some infants are born with congenital deformities of the nervous system that result in a PVS.

The individual in a PVS shows no awareness of self or the environment and there are no purposeful responses to stimuli or commands. There is no language comprehension or expression. Some reflex activity is present. Sleep-wake cycles do occur but may not be rhythmic. Bladder and bowel incontinence is present.

Diagnosis

Diagnosis is usually made by the presence of characteristic findings obtained by observing the individual. Imaging studies by computerized axial tomography (C.A.T.) scan and magnetic resonance imaging (M.R.I.) may be used to rule out treatable conditions and confirm a diagnosis of PVS. PET Scans (Positron Emission Tomography) and SPECT scans (Single Photon Emission Computed Tomography) are more sophisticated types of nuclear imaging that use radioactive material to evaluate functioning of an organ. PET and SPECT scans may be done if there is doubt regarding a diagnosis of PVS.

Treatment

Once any acute conditions, if present, are treated the focus is on providing supportive care and preventing infection. Infection is the most common reason for death for someone in a PVS. Medical and nursing care is targeted at maintaining nutrition and preventing complications related to immobility e.g., pneumonia , urinary tract infections, bedsores, and blood clots .

QUESTIONS TO ASK YOUR DOCTOR

• What is a persistent vegetative state?
• How long will the condition last?
• What type of treatment is needed?
• What is the prognosis for recovery?

Nutrition/Dietetic concerns

During a PVS, the ability to chew and swallow in a normal way is lost because these actions are voluntary. Nutrition and hydration may be provided by artificial means either intravenously or through a feeding tube into the stomach.

Therapy

Supportive medical and nursing care must be provided. The individual in a PVS requires frequent repositioning and daily skin care, including bowel and bladder hygiene, to prevent bedsores. Antibiotics may be necessary to treat frequent infections e.g., pneumonia and bladder infections. A tracheostomy may be necessary to maintain adequate breathing. Feeding tube placement is usually necessary to maintain adequate nutrition and hydration. Physical therapy may be initiated to prevent the limbs from contracting.

Prognosis

Most individuals die within six months of the original brain injury and for most of the others, life expectancy is approximately two to five years after the injury. The chance of recovery from a PVS is generally higher if the brain injury is the result of a traumatic injury (like a blow to the head) than they are for non-traumatic injury (such as a stroke ). The chance of recovery decreases the longer the individual is in a PVS. Chance of recovery is not likely after one month for a non-traumatic injury and after 12 months if the damage is traumatic. Even if recovery occurs after these time periods, most individuals are severely disabled. The degree of recovery, if it occurs, varies and if recovery does occur, it is usually very gradual. Chance of recovery may be higher for younger individuals and children.

Caregiver concerns

Family members are often called upon to make decisions regarding the amount and level of treatment that will be administered or withheld for an individual in a PVS including medication, oxygen, dialysis, blood, and artificial nutrition and hydration. Family may also be involved in the decision on whether or not to implement a “Do Not Resuscitate” (DNR ) order if the patient has no advance directive.

June G. Borazjani R.N., M.S.N., C.P.H.Q.