human choroinic gonadotropin

Nursing Lecture on Fluid and Electrolytes

Written by kimmel52 on November 8, 2008 – 5:23 am

Wednesday continuing on fluids and e-lytes
Respiratory Acidosis
Respiratory Alkalosis
Metabolic Acidosis
Metabolic Alkalosis

I. Respiratory Acidosis

A. Signs and symptoms
a. Acidosis signifies that H+ ions are prevalent and multiplying.
b. There are several reasons that H+ ions are present. Let us look at the bicarbonate ion, H2Co3. The bicarbonate ion is a very good buffer. It allows enzymatic reactions to take place without drastically altering the pH of the blood. Our blood must remain at a pH of between 7.35-7.45

2. Let’s take a look at what constitutes respiratory acidosis given a few scenarios
A. pH = 7.2
PCO2 = 25
HCO3- = 15

Here are the normals

pH = 7.35-7.45
pCO2 = 35-45 mm/hg
HCO3 – = 20-30 mmol/L

Now here’s how we do this
1. First look at the pH. Notice that it is 7.2 which is in the acidic range for the blood.
2. Now look at the pCO2, it is in the abnormal range. It is below the normal range. This means that the less pressure in the respiratory system the less CO2 present and more O2. But as the pressure decreases beyond the normal range we have a alkaline situation. This doesn’t match our pH. Could it be that the respiratory system is trying to compensate for the acidic situation occurring? Yes.
3. Now look at the bicarb- ion, it is in the abnormal range below the base normal of 20 mmol/dl. What does this mean? Well, it means that as the bicarbonate ion decreases the H+ proton increases.
4. Now let’s see what we have. What two values agree with each other? The answer to that would be the Acidic pH and the Acidic bicarbonate ion. Since they are both acidic, the term of the system is metabolic acidosis, and the respiratory system is trying to compensate.
5. So the system is partially compensated.
Let’s take a look at what happens in a system that is under Respiratory Alkalosis

pH [The body is in a state of alkalosis]

7.50 The body is
[trying to get back to normal]

7.47
[back to normal]

7.45

pCO2 [below normal]
alkaline

30mm hg [below normal]
alkaline

30mm hg [below normal]
alkaline

30mm hg

HCO3-
[normal range]

20 mmols/L
[below normal] becoming acidic

18 mmols/L
[farther below normal]more acidic

16 mmols/L
What’s
happening Respiratory Alkalosis
uncompensated Respiratory Alkalosis

Partially compensated We are still in respiratory alkalosis, however, the kidneys have Fully compensated by bringing the pH back to normal by releasing more H+ ions
The less CO2 in the respiratory system, the more alkaline it becomes. Or in other words the more HCO3- that is generated.

1. pH = 7.17

pCO2 = 98 mm hg

HCO3- = 38 mmols/L

Let’s see what’s happening here. First of all the pH is below normal which means that it is in the Acidic range.
Next, we look at the pressure in the lungs. We see that the pressure is very high. We know that as the pressure of CO2 increases, that it means that CO2 is multiplying in the lungs and creating a higher pressure. The more CO2 that we have, the more H2CO3 [carbonic acid] that is going to be made. Look at the bicarb ion. This is also elevated. However, if the bicarb ion[HCO3-] is elevated, this means that more base is being made. More base is being made in response to the acidic state of the body. So what is happening, is that the body is in Respiratory Acidosis, and the kidneys are trying to hang on to the bicarb ion to counter act the acid environment.


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