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.
It isn't obvious how a non-invasive instrument can measure with any degree of accuracy something down to the molecular level. Without getting too technical, oximetry works on the principle that different substances absorb light differently. Two different wavelengths of light are passed through the patient and the instrument is able to determine the absorbance, and therefore the concentration, of oxygen in pulsating arterial blood.
While this technology can reveal the oxygen saturation of a person's hemoglobin, it is at best an indirect means of finding out how much actual oxygen is circulating in the bloodstream. To measure this directly, it is necessary to sample the blood passing through the arteries in real time. This involves placing a needle into an artery.
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 basic forms of sleep apnea; neurological (or central) and obstructive sleep apnea (OSA). Of these, OSA is the more common and the easiest to treat. Some people need surgery to correct an anatomical abnormality, while others are easier to treat with continuous positive airway pressure (CPAP) or wearing an oral device, prescribed by an oral surgeon, while thy sleep.
The other form of sleep apnea, central, is less common and potentially more serious than OSA. This is because the center of the brain that regulates physiological processes like heart rate and breathing, malfunctions to the point where the body won't try to breathe. Either type of apnea may occur on its own or in conjunction with the other form.
Although anyone can have any type of sleep apnea, the major risk factors are male gender over the age of 40 and being overweight. Sleep apnea is particularly dangerous in infants, who can stop breathing for as long as twenty seconds. This is a very daunting prospect for new parents. Fortunately, there are apnea alarms available that will alert the parents when a baby stops breathing for a set number of seconds. It is also possible to obtain CMS pulse oximeters for home use.
It isn't obvious how a non-invasive instrument can measure with any degree of accuracy something down to the molecular level. Without getting too technical, oximetry works on the principle that different substances absorb light differently. Two different wavelengths of light are passed through the patient and the instrument is able to determine the absorbance, and therefore the concentration, of oxygen in pulsating arterial blood.
While this technology can reveal the oxygen saturation of a person's hemoglobin, it is at best an indirect means of finding out how much actual oxygen is circulating in the bloodstream. To measure this directly, it is necessary to sample the blood passing through the arteries in real time. This involves placing a needle into an artery.
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 basic forms of sleep apnea; neurological (or central) and obstructive sleep apnea (OSA). Of these, OSA is the more common and the easiest to treat. Some people need surgery to correct an anatomical abnormality, while others are easier to treat with continuous positive airway pressure (CPAP) or wearing an oral device, prescribed by an oral surgeon, while thy sleep.
The other form of sleep apnea, central, is less common and potentially more serious than OSA. This is because the center of the brain that regulates physiological processes like heart rate and breathing, malfunctions to the point where the body won't try to breathe. Either type of apnea may occur on its own or in conjunction with the other form.
Although anyone can have any type of sleep apnea, the major risk factors are male gender over the age of 40 and being overweight. Sleep apnea is particularly dangerous in infants, who can stop breathing for as long as twenty seconds. This is a very daunting prospect for new parents. Fortunately, there are apnea alarms available that will alert the parents when a baby stops breathing for a set number of seconds. It is also possible to obtain CMS pulse oximeters for home use.