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 really is fascinating that a simple instrument can take a measurement down to the molecular level without being stuck underneath the skin. This isn't the place to go into the smoke and mirrors physics, but it is something to do with absorbing light. Somehow, the machine to which the oximeter is attached can calculate the concentration of oxygen circulating in a patient's arterial blood.
While this is a decent method of measuring oxygen saturation, it gives no information about the actual level of oxygen in the blood. More accurate measurements of blood oxygen levels may be obtained by measuring arterial blood flow. The best method of doing this is by sticking a needle directly into an accessible artery.
They need a good reason to measure arterial oxygen levels because placing the needle into an artery is very painful to the patient. This is fine if the person is unconscious, as if they were under an anesthetic or unconscious. If they are awake and aware, it feels like someone is plunging a needle directly into bone.
A pulse oximeter may also be used for research purposes, for example, during sleeping studies. These investigations are performed when a patient is suspected to have a condition called sleep apnea. People with this type of disorder are unable to breathe, sometimes for dangerously long periods, while they are sleeping. This can result in stroke, heart attack or even death. At best, it can leave people foggy headed and tired the next day.
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 kind of sleep apnea, neurological or central sleep apnea, is rarer and more serious than OSA. Rather than being unable to breathe, your brain doesn't bother to try. This is usually associated with a serious underlying condition affecting the brain stem, which is the part of the brain that controls breathing. Central sleep apnea may manifest itself alone or alongside OSA.
Anybody can be diagnosed with either form of sleep apnea. The principal risk factors are age over 40, obesity and being male. This is a particularly heart-breaking condition in young babies, who can sometimes stop breathing for periods as long as 20s. This is frightening for new parents. Fortunately, alarms are available that can sound an alert when the baby has an apnea episode. CMS pulse oximeters may also be purchased for use at home for both adult and child use.
It really is fascinating that a simple instrument can take a measurement down to the molecular level without being stuck underneath the skin. This isn't the place to go into the smoke and mirrors physics, but it is something to do with absorbing light. Somehow, the machine to which the oximeter is attached can calculate the concentration of oxygen circulating in a patient's arterial blood.
While this is a decent method of measuring oxygen saturation, it gives no information about the actual level of oxygen in the blood. More accurate measurements of blood oxygen levels may be obtained by measuring arterial blood flow. The best method of doing this is by sticking a needle directly into an accessible artery.
They need a good reason to measure arterial oxygen levels because placing the needle into an artery is very painful to the patient. This is fine if the person is unconscious, as if they were under an anesthetic or unconscious. If they are awake and aware, it feels like someone is plunging a needle directly into bone.
A pulse oximeter may also be used for research purposes, for example, during sleeping studies. These investigations are performed when a patient is suspected to have a condition called sleep apnea. People with this type of disorder are unable to breathe, sometimes for dangerously long periods, while they are sleeping. This can result in stroke, heart attack or even death. At best, it can leave people foggy headed and tired the next day.
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 kind of sleep apnea, neurological or central sleep apnea, is rarer and more serious than OSA. Rather than being unable to breathe, your brain doesn't bother to try. This is usually associated with a serious underlying condition affecting the brain stem, which is the part of the brain that controls breathing. Central sleep apnea may manifest itself alone or alongside OSA.
Anybody can be diagnosed with either form of sleep apnea. The principal risk factors are age over 40, obesity and being male. This is a particularly heart-breaking condition in young babies, who can sometimes stop breathing for periods as long as 20s. This is frightening for new parents. Fortunately, alarms are available that can sound an alert when the baby has an apnea episode. CMS pulse oximeters may also be purchased for use at home for both adult and child use.
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