Q and A: Strokes By JUDY SIEGEL-ITZKOVICH If a patient is able to breathe on his own, why is his respirator not removed immediately? Breathing spontaneously indicates that the part of the brain stem that controls autonomous breathing is functioning. But breathing must be steady, at the right depth and the right pace. Thus the respirator remains inside the patient's trachea until the doctors are sure that he can breathe properly by himself. Muscles in the chest, carbon dioxide receptors in blood vessels, hormones and other mechanisms are also involved in regulating proper breathing. There are advanced computerized respirators that react to the patient's spontaneous breathing and adjust themselves to it, gradually reducing their role when the patient is able to breathe on his own. How long after a patient is brought out of an induced coma is he no longer in danger? It is difficult to know in the early stages, as even when a patient regains partial or complete consciousness after a stroke, there could be infections, metabolic problems, clogs in blood vessels or functional failure in parts of the brain. And if a patient does not come out of a coma even though the anesthesia drugs are halted, what are the causes? The brain is a very complex organ, much more so than the heart, which is a mechanical pump. There could be a neurological problem; the reticular formation in the lower brain, which is responsible for consciousness, may be harmed. Normally, the brain receives data, processes it and "broadcasts" it. A patient may receive data but not be able to emit it. Personality, emotions and brain function are involved in a complicated balance. Does a neurosurgery patient who wakes up from an induced coma feel pain from the operation? There are no pain receptors in the brain, so one can't feel pain from inside this organ. There are pain receptors in the skull and in the blood vessels surrounding the brain. Thus one feels a headache because the blood vessels contract, and if a part of the skull has been drilled, there could be some pain. There may be pain, but the patient is not able to feel it because of brain damage, and he may feel pain but not able to express it because of cognitive difficulties. Painkillers can be given if the experts see signs of the patient suffering. Should the patient hear music or noise, and should he be moved to avoid bedsores? Years ago, stroke patients used to be kept in bed and in quiet surroundings so they would not be disturbed. Today, they are often exposed to music and other sounds they are known to like to stimulate their brain. As for bedsores, these can be a serious potential danger of infection, especially in a heavy patient. So immediately after being hospitalized, the comatose patient is kept on a special air mattress or other type to reduce the risk of bed sores, and his body positions are frequently changed.