Wednesday, January 26, 2011

Sleep apnea and micro-arousals

Sleep apnea is divided into obstructive sleep apnea and central sleep apnea. Obstructive is caused by blockage of the airway and central apnea, which is less common, is caused when the brain doesn’t send signals to the muscles to breathe. As with most things there are different levels of severity of sleep apnea. With obstructive sleep apnea the range of severity can be determined by a sleep study that counts the number of apnea, or cessation of breathing, that occurs if the number isn’t high, and then your sleep apnea might be cured by an oral device or by just losing weight. It should also be noted that not all awakening are the same there are apneas and there are micro-arousals.

What is a micro-arousal?

According to micro arousals are “a sudden transient cortical activation during sleep, but does not necessarily result in a behavioral awakening. The origin of an arousal is usually "cortical" but it can also be generated in response to sensory perturbations, such as respiratory interruption (apnea or snoring), alteration of heart rate or blood pressure, noise, or movement disorders The criterion for pathology in terms of number of arousals has not yet been determined, but a reasonable cut-off point, used in "normal" sleepers, is approximately 10 to 12 arousals per hour.”

So it isn’t uncommon to have micro arousals but when they develop into apneas then it is a concern.

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  1. One of the most important parts of the heart is the pacemaker. When the natural (or original) pacemaker starts functioning with a lesser efficiency compared to the recommended one, the use of artificial pacemakers is suggested. Surgery is needed to implant an artificial pacemaker inside the body.

    The artificial pacemaker (or simply ‘pacemaker’) is a device which functions on electrical impulses which are delivered by electrodes in contact with the heart muscles, thus helping in the regulation of the heart’s beating.

    So, the most important function of the pacemaker is maintaining the heart rate within specified safe limits. This is required when the natural pacemaker is not functioning with sufficient speed. It may also be needed in case there is some kind of a block (obstruction) in the electrical conducting system of the patient’s heart.

    Artificial pacemakers come in the following types --- Rate-responsive pacemaker, Single chamber pacemaker and Dual (or double) chamber pacemaker.

    Some pacemakers are implantable. These are required for permanent pacing of the heart. Surgical operation is carried out for doing this and pacing electrodes are placed in the heart’s chambers. This type of pacemaker has in-built electronic circuitry, which detects the change in the pace of heart and adjusts it automatically to bring it within the recommended limit. This function is done by an important part of the pacemaker called as the pacemaker generator.

    For getting best results from the artificial pacemaker, it is suggested that the battery of the pacemaker be replaced at regular intervals of time. It is extremely important to check the pacemaker regularly from a practicing physician.

    The use of a pacemaker has helped a lot of people so far. The best part of it is that it does change the person’s lifestyle to much of an extent. Only the use of devices or gadgets generating magnetic fields is not allowed.

  2. thanks for the great explanation of pacemakers