One of the disturbing trends I have been observing in physiology is the tendency to move away from many of the gold standard, invasive measurements classically described in the scientific literature to non-invasive measures which may or may not accurately reflect the parameter of interest.
One of these non-invasive measurements (which is not used in any of the manuscripts on my desk) that has become the bane of my existence is to use the saturation of hemoglobin in arterial blood (SPO2) as a surrogate for the partial pressure of arterial blood (PO2). SPO2 is measured with a device called a pulse oximeter.
Figure 1: A fingertip pulse oximeter. This device indicates that this individuals arterial hemoglobin is 98 percent saturated and his heart rate is 73 beats/min. Read more »
*This blog post was originally published at On Becoming a Domestic and Laboratory Goddess*