When doctors, nurses or paramedics need a quick estimate of a patient's oxygen levels, they use technology called CMS pulse oximeters. These little gadgets can be easily clipped onto a finger or an earlobe and indirectly measure oxygen levels by determining the percentage of hemoglobin, a respiratory pigment, that is saturated with the life-giving gas. Normal values in most people are 95 percent or more.
The physical principles of how a pulse oximeter works are beyond the scope of this article. It is based on the absorbance of light. By shining light of two different wavelengths into the skin, the instrument can calculate the light absorbance, and hence the concentration of O2 in blood that is circulating in the arteries.
While this is an excellent way of screening sick people from really sick people, a more accurate measurement is obtained by measuring oxygen directly from arterial blood. This is important in places like intensive care units or when a patient is under anesthesia having an operation.
Jamming a needle into an artery, which are by design very thick, is very painful for the patient. Because of this, it is not routinely done unless it is really necessary. The feeling of having a needle pierce into an artery has been compared to having a sharp implement poking directly into a bone.
Pulse oximeters are used a lot in research. Oxygen saturation is one of the parameters that is measured as part of sleeping studies that are investigating whether an individual suffers from sleep apnea, a condition where they stop breathing for brief periods during the night. This is a potentially fatal condition because it can lead to heart attack or stroke. At the very least, it makes people sleepy and unproductive the next morning.
There are two categories of sleep apnea, neurological and obstructive. Obstructive sleep apnea (OSA) is more common than neurological sleep apnea, but no less dangerous. Treatments may include a device that is prescribed by a dentist to keep the mouth partially open at night, continuous positive airway pressure (CPAP) or, in extreme cases, surgery to correct an anatomic deformity that makes the airway unable to open.
Central, or neurological sleep apnea, is less common and harder to treat than OSA. Instead of stopping the breathing process, the brain doesn't attempt it. There is often a serious condition underlying neurological OSA that affects the brain stem. This is the brain area that is responsible for breathing and heart rate. Neurological sleep apnea can happen by itself or in combination with OSA.
The biggest risk factors for sleep apnea are being overweight, male gender or being over the age of 40. However, sleep apnea can happen to anybody. Some small babies can stop breathing for as long as 20 seconds, which is very disturbing for already anxious new parents. If a baby is discovered to be at risk for this condition, the parents can obtain an alarm that will alert them if and when this happens. CMS pulse oximeters are also available for use at home.
The physical principles of how a pulse oximeter works are beyond the scope of this article. It is based on the absorbance of light. By shining light of two different wavelengths into the skin, the instrument can calculate the light absorbance, and hence the concentration of O2 in blood that is circulating in the arteries.
While this is an excellent way of screening sick people from really sick people, a more accurate measurement is obtained by measuring oxygen directly from arterial blood. This is important in places like intensive care units or when a patient is under anesthesia having an operation.
Jamming a needle into an artery, which are by design very thick, is very painful for the patient. Because of this, it is not routinely done unless it is really necessary. The feeling of having a needle pierce into an artery has been compared to having a sharp implement poking directly into a bone.
Pulse oximeters are used a lot in research. Oxygen saturation is one of the parameters that is measured as part of sleeping studies that are investigating whether an individual suffers from sleep apnea, a condition where they stop breathing for brief periods during the night. This is a potentially fatal condition because it can lead to heart attack or stroke. At the very least, it makes people sleepy and unproductive the next morning.
There are two categories of sleep apnea, neurological and obstructive. Obstructive sleep apnea (OSA) is more common than neurological sleep apnea, but no less dangerous. Treatments may include a device that is prescribed by a dentist to keep the mouth partially open at night, continuous positive airway pressure (CPAP) or, in extreme cases, surgery to correct an anatomic deformity that makes the airway unable to open.
Central, or neurological sleep apnea, is less common and harder to treat than OSA. Instead of stopping the breathing process, the brain doesn't attempt it. There is often a serious condition underlying neurological OSA that affects the brain stem. This is the brain area that is responsible for breathing and heart rate. Neurological sleep apnea can happen by itself or in combination with OSA.
The biggest risk factors for sleep apnea are being overweight, male gender or being over the age of 40. However, sleep apnea can happen to anybody. Some small babies can stop breathing for as long as 20 seconds, which is very disturbing for already anxious new parents. If a baby is discovered to be at risk for this condition, the parents can obtain an alarm that will alert them if and when this happens. CMS pulse oximeters are also available for use at home.
No comments:
Post a Comment