

She was given nasogastric feeding and a ventilator to help her breathe. She was prone to unpredictable, violent thrashing of her limbs. She lost weight and eventually weighed less than 80 pounds (36 kg). Over the next few months, she remained in the hospital and her condition gradually deteriorated. Her EEG showed only abnormal slow-wave activity. Her eyes were "disconjugate" (they no longer moved in the same direction together).

Her brain was damaged to the extent that she entered a persistent vegetative state. No precise cause of her respiratory failure has been given. Quinlan had suffered irreversible brain damage after she had experienced an extended period of respiratory failure, lasting no more than 15–20 minutes. Quinlan weighed 115 pounds (52 kg) when admitted to the hospital. She remained there for nine days in an unresponsive condition before she was transferred to Saint Clare's Hospital, a larger facility in Denville. Quinlan was admitted in a coma to Newton Memorial Hospital in Newton, New Jersey. Eventually, some color returned to her pallid skin, but she did not regain consciousness. An ambulance was called, and mouth-to-mouth resuscitation was attempted. When friends checked on her about 15 minutes later, they found that she was not breathing. Shortly afterwards, she felt faint and was quickly taken home and put to bed. At the party, she reportedly drank several gin and tonics and took Valium. She had eaten almost nothing for two days. On April 15, 1975, a few days after moving into her new house, Quinlan attended a friend's birthday party at a local bar, then known as Falconer's Lackawanna Inn, on Lake Lackawanna in Byram. Around the same time, she went on a radical diet, reportedly to fit into a dress that she had bought.

In April 1975, shortly after she turned 21, Quinlan left her parents' home and moved with two roommates into a house a few miles away in Byram Township, New Jersey. Quinlan was a singer, and her parents remember her as a tomboy. After graduation, she worked at the Mykroy Ceramics Corporation in Ledgewood, New Jersey, from 1972 to 1974, and worked several jobs over the next year. Quinlan attended Morris Catholic High School in Denville, New Jersey. Julia and Joseph also had daughter Mary Ellen in 1956 and son John in 1957. A few weeks later, she was adopted by Joseph and Julia Quinlan, devout Roman Catholics who lived in the Landing section of Roxbury Township, New Jersey. Quinlan was born on March 29, 1954, in Scranton, Pennsylvania, to a young woman of Irish American ancestry. A significant outcome of her case was the development of formal ethics committees in hospitals, nursing homes and hospices. Her case has affected the practice of medicine and law around the world. Quinlan's case continues to raise important questions in moral theology, bioethics, euthanasia, legal guardianship and civil rights. After doctors, under threat from prosecutors, refused the request of her parents, Joseph and Julia Quinlan, to disconnect Quinlan's ventilator, which the parents believed constituted extraordinary means of prolonging her life, her parents filed suit to disconnect Quinlan from her ventilator. When she was 21, Quinlan became unconscious after she consumed Valium along with alcohol while on a crash diet and lapsed into a coma, followed by a persistent vegetative state. Karen Ann Quinlan (Ma– June 11, 1985) was an American woman who became an important figure in the history of the right to die controversy in the United States.
