Coma (Medical condition)
A coma is a serious medical condition characterized by severely diminished brain activity. It has nothing to do with sleep. A person in a coma is unconscious and will not respond to voices, other sounds, or any sort of activity going on around them. He or she is still alive, but his or her brain is functioning at its lowest stage of alertness. Comas can be caused by different things, including:
- a severe injury to the head that damages the brain
- infections involving the brain
- brain damage caused by oxygen deprivation
- an overdose (taking too much) of medicine or other drugs
- a stroke
When one of these events occurs, it can disrupt brain functioning, sometimes leading to a coma.
It is important to note that a coma is different from a vegetative state. Whereas coma patients do not experience sleep-wake cycles or exhibit any signs of arousal, patients in a vegetative state will experience periods of arousal. These may or may not mimic a normal sleep-wake cycle. Patients in a vegetative state may engage in involuntary movements and have near-normal reflexes but they exhibit no voluntary response to external stimuli.
Care of coma victims
A person in a coma usually needs to be cared for in the intensive care unit (ICU) of the hospital. Intensive care units provide extra care and attention from doctors, nurses, and other hospital staff. They make sure the person gets fluids, nutrients, and any medicines he or she needs to keep his or her body as healthy as possible. These are sometimes given through an intravenous tube inserted into a vein or through a feeding tube that brings fluids and nutrients directly to the stomach. Sometimes a comatose person is unable to breathe on his own and needs the help of a ventilator, a machine that pumps air into the lungs either through a tracheotomy tube or an intubation tube.
The hospital staff also tries to prevent bedsores in someone who is comatose. Bedsores are pressure sores on the body that come from inadequate blood supply caused by prolonged applied pressure in affected areas (e.g. when lying down for long periods of time).
Sometimes doctors find it necessary to deliberately cause a coma in a patient. The practice of using a medically induced coma to put the brain in hibernation so it can recuperate has been used for over a quarter of a century. In the first several days after an injury, there can be swelling and other reactions that are part of the body's repair mechanism. But in the brain, those processes can be damaging, so when swelling is likely, doctors can decide to induce a coma by using sedatives to put the brain to sleep. The patient's brain activity is closely monitored, and the level of drugs adjusted accordingly, to ensure the brain stays in a restive state until the critical window has passed. The technique carries risks, though, so it is not used unless the likelihood of secondary injury due to swelling is significant enough to warrant the procedure.