[QUOTE=Pullet]
Last week, I went in to my local student health center because the virus I had been working on the week prior finally had me hacking up bloody stuff. Before, it was more of the low-grade fever, feel like shit variety of virus.
The emergency care nurse stuck a pulse Oximeter on my finger, declared that I was at 98% saturation, and therefore did not have pneumonia and could go home.
Question 1: Exactly how accurate would a pulseox be at diagnosing pneumonia? By my thinking, I would have to have pretty severe pneumonia before I’m not saturating my hemoglobin significantly. But maybe there is some aspect of physiology that I’m forgetting.
Question 2: What does walking pneumonia feel like?
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Assuming the nurse was competent, what you got was a shorthand way of saying that you did not have an infectious condition serious enough to require extensive evaluation or inpatient treatment.
Making this inference based solely on a pulse oximeter reading is mostly reasonable but of course there is still a margin for error. While it is popular to divide respiratory infections into those which affect the larger airway tubes (“bronchitis” e.g., or “upper respiratory infections” e.g.) and those which affect the substance of the air-exchanging sacs themselves (“pneumonia” e.g., or “lower respiratory infections”), from a clinical standpoint there are other ways to divvy up respiratory infections which are more useful.
Froma purely practical standpoint the typical issues are whether or not there is a therapy which will help (antibiotics; bronchodilators…) and whether or not you are sick enough to warrant hospitalization for more intensive monitoring and care. Other considerations might include your potential for sudden deterioration, your underlying robustness of physiology and capacity to fight illness, and whether or not other conditions (pulmonary embolus, lung abscess, tuberculosis and its pals…) should be considered in addition to ordinary illnesses.
In general, a severe pneumonia of any etiology would lower a room-air pulse ox below 98%. On the other hand, a number of non-emergent conditions can lower the pulse ox quite a bit (associated bronchospasm, for instance). Low pulse ox’s get further workup; normal pulse ox’s are only one of many indicators that everything is OK. If other signs and symptoms are out of bounds, a normal pulse ox does not rule out serious respiratory or cardiovascular illness.
Although I have treated many inpatients and outpatients who have pneumonia, I have no idea what “walking pneumonia” is. I assume it’s some sort of term used (inconsistently) to describe patients who have a lower respiratory infection but who are less ill than some other group. It is not a clinically useful term.
As an aside, bloody sputum is not typically ascribed to viral respiratory illness.