acid base regulation Flashcards
What does alkaleamia, acidosis, alkalosis and acideamia means?
Emias-mean the proton concentrations that are in the blood
Osis-means conditions which cause an increase/decrease in proton. Osis cause eamias
How do protons concentration correlate with pH?
The equation is pH=-log10([H+])
What is main chemical reaction that changes proton concentrations in the blood? How?
H2O+CO2H2CO3H+HCO3
As the concentration of one increases, it tips the scale the other way (eg more H2CO3 means more HCO3+H), as it aims to be in equilibrium at all times
What is the average proton concentration in the body?
pH is 7.4, which corresponds to 0.00000004 Eq/L
Where do body acids come from? In which quantity?
Respiratory acid (from breathing out CO2 and breathing in O2, and related stuff), and metabolic acid (all the rest, like stomach acid). Ration resp to meta is about 100:1
What is the Henderson hasselbach equation?
pH=pK+Log10[HCO3]/[CO2], with K being the dissociation constant
What do arterial blood gases usually measure? And what are they?
Proton conc/pH. pCO2, pO2, HCO3, and Base excess-which is an indication of how much H2CO3 is used/still availtable to balance out pH changes-assess metabolic changes (like kidney secretion). Exact definition is BE is the amound of escpected bicarbonate with the pH (ideally 0, but actually around -2/2)
PaCO2 assess respiratory content
What are the ranges used for PaO2?
> 10kPa is normal. 8-10 is mild hypoxaemia, 6-8 is moderate and <6kPa is severe hypoxaemia
What are the main compensatory mechanism for pH change?
Changes in ventilation is the rapid compensation CO2 elimination and therefore pH
Changes in HCO3- and H+ secretion is slow
Need alkalosis to compensate acidosis
How do you differentiate between respiratory and metabolism concentration?
Can get the idea from the CO2 level, see if lungs are trying to compensate. Only works before compensation
How does hypoventilation change for ABG?
Uncompensated hypoventilation means rise in CO2, therefore H2CO3 and in turn H+
Compensation happens with metabolism-use HCO3 to compensate and make equation go to H2CO3 more readily (So BE up). Retain and produce more
Eventually compensate, pCO2 high (caused it), BE up (compensate) pH down
How does hyperventilation change ABG?
resp Alkalosis This time low CO2, so lower H+ concentration-compensate by secreting HCO3 and producing less-pCO2 down and BE down
pH up, pCO2 down, BE down
How does diarhoea affect ABG?
Diarhoea causes metabolism acidosis, as excrete bile
Reduce H+ by ventilating more, reducing CO2. Also compensate secreting HCO3. So pCO2 down and BE down
pH down, pCO2 down and BE down
How dies vomiting affect ABG?
Case of metabolic alkalosis-lose acid from stomach-Ventilation goes down-increase CO2. Also reabsorbe HCO3. pCO2 up and BE up
pH up, pCO2 up and BE up
What are normal values for pH, pCO2, pO2, HCO3 and BE?
pH 7.35 to 7.45. pCO2 4.7 to 6.4. pO2 >10kPa, HCO3 22-26, BE -2/2
