Plüddeman et al1 write about the use of pulse oximetry. This seems to be one of the new trio of diseases — the other two being D-dimers for blood clots, and troponin for the detection of myocardial damage.
All three tests need to be used appropriately in their clinical situation. It seems from observation that the SpO2 can vary significantly over a fairly short period of time, and with an error of 2% this can make a big difference to the reliability of the reading. This becomes especially true of those with chronic obstructive pulmonary disease — when their normal saturations can be really quite low.
All three tests need to be used appropriately and co-related to the clinical picture. It is very tempting to use anything numerical as having greater power than softer signs of speech, use of accessory muscles, and primarily, clinical history. Ill advised use of these tests will inevitably lead to increasing hospital admission, maybe particularly in the out-of-hours care of patients.
In assessing a patient, there are often pivotal cues, symptoms, or signs that open up the diagnosis. I think we all develop a primacy of signs, those bits of information that we rely more heavily on in making clinical decisions. We can allow something with a number attached, especially with a guideline behind it, to become the primary sign. However, I believe good general practice involves weighing up history, examination, and other data. If our action is determined by one or two bits of information I think we will lose our touch as generalists.
Pulse oximeters are useful tools as part of our armamentarium. But if doctors continue to become more risk averse, and rely on gadgets rather than the whole clinical picture, iatrogenic disease will continue to increase.
- © British Journal of General Practice 2011
