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.
This is a painful and invasive procedure and there needs to be a good reason for collecting this information. Patients who have their arterial blood sampled while they are awake describe the sensation as akin to having a needle stuck directly into their bone. Unfortunately, because one of the circumstances in which this information is important is while a patient is under an anesthetic, so the poor patient has to have the needle inserted while they are still awake.
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 main types of sleep apnea, obstructive and neurological. Obstructive sleep apnea (OSA) is the more common of the two and is also the easiest to treat. Therapies include surgery, continuous positive airway pressure (CPAP) or prescribing a device that the patient puts in their mouth when they go to bed that helps them to keep their airway open.
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.
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.
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.
This is a painful and invasive procedure and there needs to be a good reason for collecting this information. Patients who have their arterial blood sampled while they are awake describe the sensation as akin to having a needle stuck directly into their bone. Unfortunately, because one of the circumstances in which this information is important is while a patient is under an anesthetic, so the poor patient has to have the needle inserted while they are still awake.
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 main types of sleep apnea, obstructive and neurological. Obstructive sleep apnea (OSA) is the more common of the two and is also the easiest to treat. Therapies include surgery, continuous positive airway pressure (CPAP) or prescribing a device that the patient puts in their mouth when they go to bed that helps them to keep their airway open.
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.
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.
0 comments:
Enregistrer un commentaire