Acid base disorders

Question 1

_ is the most important way of preventing H+ accumulation in the body

Answer 1

exhaling CO2 via the lungs

Question 2

what is PH

Answer 2

the negative logarithm to base 10 of H+ activity expressed in concentration

ph = -log10 [H+]. OR log 1/[H+]

Question 3

reference interval of arterial blood ph

Answer 3

7.35 -7.45

Question 4

what is pKa

Answer 4

this is the negative logarithm of the ionization constant of a WEAK acid

Question 5

the stronger the acid

Answer 5

the lower the pka

Question 6

the higher the pka

Answer 6

the stronger the conjugate base

Question 7

what is a buffer

Answer 7

compound that resists a change in ph when a strong acid or base is added to the system

Question 8

when do buffers work best at resisting ph change

Answer 8

in the interval of one ph unit of its pka when ratio of acid : base is (1:10/10:1)

Question 9

pka of bicarbonate buffer

Answer 9

6.1 (makes it a poor buffer)

Question 10

most important buffer

Answer 10

bicarbonate buffer (most abundant)

Question 11

what is compensation

Answer 11

when the body’s innate mechanisms are able to maintain/attempt to maintain homoeostasis in the face of acid-base disturbance

Question 12

henderson/hasselbach equation

Answer 12

ph = pka + log (base)/(acid) = 20/1

Question 13

reference interval for anion gap is

Answer 13

6-22mmol/l

Question 14

normal gap metabolic acidosis is also called

Answer 14

hyperchloraemic metabolic acidosis

Question 15

what causes chloride responsive metabolic alkalosis

Answer 15

volume depletion (contraction alkalosis)

Question 16

characteristics of chloride responsive metabolic alkalosis

Answer 16

1) renal retention of HCO3
2) urinary Cl- = <10mmol/l
3) increased exchange of sodium for potassium & H+

Question 17

chloride resistant metabolic alkalosis is associated with _

Answer 17

presence of an underlying disease
e.g Cohn’s, Cushing’s or Bartter’s syndrome

Question 18

characteristics of chlorine resistant metabolic alkalosis

Answer 18

1) urine chlorine > 20mmol/l
2) excessive loss of K+, H+ & Cl-
3) increased reabsorption of Na+ & HCO3-

Question 19

metabolic acidosis can coexist with alkalosis in

Answer 19

DKA + CCF on diuretics

Question 20

metabolic acidosis & resp. alkalosis can exist in

Answer 20

salicylate (aspirin) overdose

Question 21

metabolic alkalosis & resp acidosis exists in

Answer 21

COAD + diuretics

Question 22

metabolic acidosis & alkalosis + resp. alkalosis can occur in

Answer 22

vomiting, sepsis + dehydration

Question 23

metabolic acidosis & alkalosis + resp. alkalosis can occur in

Answer 23

vomiting, sepsis + dehydration

Question 24

plastic containers not recommended for sample collection because

Answer 24

• they are not air tight

*blood must be collected anaerobically & transported in ice sludge

Question 25

HCO3 - reference interval

Answer 25

18-31mmol/l

Question 26

(H+) & PCO2 reference interval

Answer 26

35-45 (mmol/l. // mmHg)

Question 27

pO2 reference interval

Answer 27

83-108mmHg