We had an exam today on endocrine, urinary tract, and renal disorders. And I did very badly. It seems like no matter how much I study, there are details that I completely miss. And I don't just mean forget, I mean completely miss as in looked, didn't register, don't remember even seeing that before. We had a question on ABG's and DKA coma, which you were supposed to associate with metabolic acidosis, which seems like a no-brainer as long as you already know that's the answer. Here are the answers I was trying to choose between...
pH 7.1, pCO2 16, HCO3 [low]
pH 7.2, pCO2 46, HCO3 [high]
But what if diabetic ketoacidosis is a special case of pH imbalance--the pathophysiology is unique after all? (And why would you ask an ABG question if it's just supposed to get you to regurgitate a standard metabolic acidosis profile?) I was thinking... metabolic acidosis is related to failure of the kidneys to buffer adequately... so in a DKA patient the kidneys are working correctly... resulting in a higher circulating bicarb than in metabolic acidosis... possibly resulting in a different ABG profile... Plus... I don't really know how the diagnostic ABG test works and since acids and bases exist in dynamic equilibrium and not in a static state, it's possible that higher circulating bicarb is reflected in the ABG...
Well, obviously one problem is that I didn't really understand the underlying concept of metabolic acidosis, thinking it was related to an inadequacy of kidney function rather than an inadequacy of the kidney's function, you see. That's not entirely my fault as this was the message I took away from Nur362, in which I got the ABG questions right on the exams. But it does point to the problem that I'm not really learning physiology in nursing school. In order to keep myself from getting mixed up, I have to dig deeper than we are going.
Anyhow, the problem that really grates on me is that I reviewed the notes after the test and, sure enough, right there under the diabetic ketoacidosis heading it says metabolic acidosis. I had gone over these notes maybe five times last night, and I don't even remember seeing these words on the paper. They're so meaningless in that context that my eye glossed right over them. This happens to me all the time, and I don't know how to prevent it without, as I said above, taking every word in the notes and systematically reviewing it more thoroughly. I just don't have time for that.
And then there's The Big Number Issue. At work, I can't remember doctors' pager numbers even though I've been working as a ward clerk for 3 years--they just don't have meaning to me, and they don't stick. If I could have remembered the reference values for the ABGs, I probably could have figured out the correct answer. But I didn't remember the pCO2 value, and I assumed, of the two answers I was trying to choose between, that one represented a high value and one a low value. If you know your ABGs, you know that they actually represent a low-high value and high-high value. But what if the low-high value really was low? That would represent decreased ventilation, and wouldn't a patient in a coma have reduced respiratory status?
Well, it sounded good at the time. Wikipedia says that Kussmaul first defined Kussmaul breathing as a "sign of coma and imminent death," but the article on diabetic coma says "In the early to middle stages of ketoacidosis, patients are typically flushed and breathing rapidly and deeply, but visible dehydration, pallor from diminished perfusion, shallower breathing, and rapid heart rate are often present when coma is reached." So, depending on which article is right I was either wrong and wrong or wrong and right...
This whole nursing school situation is very frustrating. Since returning to school to do nursing, I had maintained a 4.0 average, including a 4.0 in the A&P crash summer course, which I took while working full time (40 hours per week). And it looks right now like I will be repeating at least Nur360 maternity and maybe this whole semester if I'm not kicked out of the program. This is really crappy.
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