Yes, an abbreviation. No, not short for non-profit organization in this case, though it sometimes is. It appeared in instructions from the Palo Alto Medical Foundation, about preparations for being ultrasounded yesterday:
“NPO (nothing to eat or drink) 6 hours prior to exam.
The left quotation mark was presumably supposed to be matched by a right one, after NPO or after the parenthesis. The real question is why the PAMF staff thought they should use NPO at all. From Wikipedia:
Nothing by mouth is a medical instruction meaning to withhold food and fluids from a person for various reasons. It is also known as nil per os (npo or NPO), a Latin phrase whose English translation is most literally, “nothing through the mouth”.
“Nothing to eat or drink” would have been an entirely adequate instruction — clear, precise, and brief — so what’s added by “NPO”? I’m afraid that someone on the staff thinks the medical abbreviations (intended as shorthand to medical staff, not to patients) are more scientific, more accurate, more correct, than instructions in ordinary English, especially if the abbreviations are derived from Latin (the language of science) — even though the Latin originals are nothing but everyday Latin.
Providing the abbreviation NBM (for not by mouth) in instructions to patients would have been silly: why should a patient ever care about the abbreviations medical staff use on the clinic floor? But providing the abbreviation NPO is doubly silly, since it’s opaque, unguessable.
Ah, but there’s magic — Science Magic, Medical Magic– in those abbreviations.
Actually, there’s a positive reason for avoiding most of the abbreviations, especially the Latin-derived ones: physicians’ notoriously imperfect handwriting. Coupled with the fact that the shorter the text, the less useful redundancy there is in it, and the more room there is for misreading. Consider the instructions for administering medications. One set of Latin-derived ones:
qd, q1d quaque die ‘every day’, i.e., once a day
od omne in die ‘all in a day’, i.e., once a day
bid, bd bis in die ‘twice a day’
tid ter in die ‘three times a day’
qid quater in die ‘four times a day’
These are all dangerously short, and qd/q1d and qid are dangerously close to one another. Better: 1 a day, 2 a day, 3 a day, 4 a day. Or something along those lines.