Acid Base balance

Question 1

what are the equations for pH?

Answer 1

1. pH= pKa + log10 ([base]/[acid])
2. pH= -log10[H+]
3. pH= log10 1/[H+]

Question 2

what is the definition for standard bicarbonate measured on ABG?

Answer 2

Calculation of bicarbonate concentration under standard conditions for example in plasma of fully oxygenated blood which has been equilibrated to a partial CO2 of 5.32 at 37 degrees

Question 3

what is ‘base excess’?

Answer 3

The calculated amount of strong acid (mmol/L) which would have been added to one litre of the patients blood to reach a pH or 7.4 at a pCO2 of 7.4 at 37 degrees in alkalosis

Question 4

what is ‘base deficit’?

Answer 4

The calculated amount of strong alkali (mmol/L) which would have been added to one litre of the patients blood to reach a pH of 7.4 at a pCO2 of 5.32 at 37 degrees

Question 5

what is osmolality?

Answer 5

An estimation of the osmolar concentration of plasma and is proportional to the number of particles per kg of solvent.

Question 6

what is the definition of osmolarity?

Answer 6

An estimation of the osmolar concentration of plasma and is proportional to the number of particles per L of solution

Question 7

what is the equation for calculated osmolality?

Answer 7

2 x [Na] + Urea + Glucose

Question 8

what is the osmolal gap?

Answer 8

Measured osmolality - calculated osmolality

Question 9

what is the normal range for osmolal gap?

Answer 9

less than 10mmol/L

Question 10

what is the equation for anion gap?

Answer 10

([Na] + [K+]) - ([HCO3-] +Cl-])

Question 11

what is the normal range for anion gaps?

Answer 11

10-18mmol/L

Question 12

what causes an anion gap?

Answer 12

un-measured anions such as albumin, phosphate, sulphate, lactate.

Question 13

what does an albumin of 40g/L normally contribute to a negative charge causing an anion gap?

Answer 13

10mmol/L

Question 14

if albumin levels reduce what happens to the anion gap?

Answer 14

it will also reduce

Question 15

how long does respiratory compensation take to occur?

Answer 15

It occurs very rapidly

Question 16

what is kussmaul breathing?

Answer 16

A type of respiratory compensation in response to acidosis. very deep breathing

Question 17

how long does metabolic compensation normally take to occur?

Answer 17

36-72 hours

Question 18

why does metabolic transcription take so much longer to occur?

Answer 18

It requires enzyme induction for increased genetic transcription or translation to occur.

Question 19

how is bicarbonate produced in the tubular cell?

Answer 19

water + carbon dioxide = hydrogen bicarbonate

hydrogen bicarbonate with carbonic anhydrase makes it break down to hydrogen and bicarbonate ions.

Question 20

how is the hydrogen from the breakdown of carbonic acid removed from the tubular cell?

Answer 20

It goes into a sodium hydrogen ATPase, this stops the potassium sodium ATPase pump meaning potassium will build up in the cell

Question 21

what normally happens to the potassium levels in acidosis?

Answer 21

increase due to removal of hydrogen from the tubular cell

HYPERKALAMIA