Question 1. Discuss homeostasis and physiological significance of buffer systems. Describe how acid-base balance, including bicarbonate, hydrogen, carbon dioxide and oxygen are maintained in the body. What disease states could cause disturbances to hydrogen ion homeostasis?(800 words)

Question 2. What is the principle of analysis and limitations of the bicarbonate assay on the Roche Cobas analytics?

Question 3. Describe how a sample should be collected for blood gas analysis and how it must be handled prior to analysis.

Question 4. Discuss the principles and limitations of electrodes in a blood gas analyser. What other analytes can be obtained from the primary results on a gas analyser.

Question 5. Define the following:
• metabolic acidosis
• metabolic alkalosis
• respiratory acidosis
• respiratory alkalosis

Question 6.What is the anion gap? (100 words) with diagram

Question 7. Compensation is the body's attempt to correct an acid-base imbalance. What is: (200 words)
a) renal compensation
b) respiratory compensation

Question 8. What is a mixed acid-base disturbance? Explain the acid-base disorders which may exist in:(300 words)

• cardiac arrest
• salicylate overdose
• hyperventilation with naso-gastric suction
• chronic obstructive airways disease and thiazide diuretic treatment

Question 9. Define the term "Base Excess

Question 10. Calculate the anion gap from the following set of results and comment on the findings:

Na 134mmol/L (132-144)
K 5.9mmol/L (3.5-5.0)
Cl 94mmol/L (95-108)
Bic 14mmol/L (24-29)
Urea 5.3mmol/L (2.7-7.5)

Question 11. A73yr old man is found unconscious and cyanose:

The blood gas results have come back as follows:

pH 6.9 (7.35-7.45)
pCO2 10.5kPa (4.7-6.0)
p02 5.1kPa (12-14.6)
HCO3 16mmol/L (24-29)

Is there an acid base disorder present? Is there any compensation? What are the possible causes?

Question 12. Match the blood gas results shown below with the following hydrogen ion disorders.
a) Chronic, compensated respiratory acidosis
b) Metabolic acidosis
c) Acute respiratory acidosis
d) Respiratory alkalosis
e) Metabolic alkalosis

Question 13. What is normally the only cause of an increased PO2? (100 words)