Acid Base Disturbance

Question 1

responses to changes in plasma H+

Answer 1

instantaneous
rapid
slow

Question 2

instantaneous response to changes in plasma H+

Answer 2

buffering by plasma buffers
phosphate and proteins and deoxygenation of haemoglobin with erythrocytes
HbO2 + H+ -> HbH+ + O2

Question 3

rapid response to changes in plasma H+

Answer 3

ventilation of CO2 by lungs

Question 4

slow response of changes in plasma H+

Answer 4

elimination of non volatile acids by kidneys - excretion of H+, regeneration of HCO3-

Question 5

carbon dioxide - bicarbonate buffer system

Answer 5

co2 + h2o <-> h2co3 <-> h+ + hco3- <-> h+ - co3 2-

Question 6

what levels of h+ are life threatening

Answer 6

<20 nmol/L or >120 nmol/L

Question 7

types of acid base disturbance

Answer 7

acidaemia - respiratory or metabolic
alkalaemia - respiratory or metabolic

Question 8

resp acidaemia

Answer 8

increased H+
increased PaCO2

Question 9

metabolic acidaemia

Answer 9

increased H+
decreased HCO3-

Question 10

resp alkalaemia

Answer 10

decreased H+
decreased PaCO2

Question 11

metabolic alkalaemia

Answer 11

decreased H+
increased HCO3-

Question 12

compensation of resp acidaemia

Answer 12

metabolic compensation
increased HCO3-

Question 13

compensation of metabolic acidaemia

Answer 13

resp compensation
decreased PaCO2

Question 14

compensation of resp alkalaemia

Answer 14

metabolic compensation
decreased HCO3-

Question 15

compensation of metabolic alkalaemia

Answer 15

resp compensation
increased PaCO2

Question 16

compensation of acid base disturbances

Answer 16

compensatory response changes parameter that was not affected by primary disturbance
change is always in same direction as in the parameter affected by primary disturbance, as to restore co2/hco3- ratio
resp compensation occurs quickly, metabolic much slower

Question 17

normal range of h+

Answer 17

36-44nmol/L

Question 18

normal range paco2

Answer 18

4.8-6 kPa

Question 19

normal hco3-

Answer 19

21-27.5 mmol/L

Question 20

what happens when plasma H+ falls

Answer 20

free Ca2+ also falls
- H+ dissociates from the side chains of plasma proteins
- proteins now have greater charge, so bind more Ca2+
- total plasma Ca2+ unchanged but since more Ca2+ is protein bound, free Ca2+ concentration falls

Question 21

thoracic crushing