Arterial Blood Gases

Question 1

Respiratory Acidosis

Answer 1

Defined as a PH of less than 7.35 with a PaC02 of greater than 6KPa
Caused by an increase of C02 which combines with water to produce carbonic acid , thus lowering the Ph of the blood.

Respiratory acidosis can be caused by Hypoventilation. This is because there is more carbon dioxide which combines with water to produce carbonic acid thus making the blood more acidic.

Question 2

Respiratory Alkalosis

Answer 2

Defined as pH greater than 7.45 with a PaC02 of less than 4.7 Kpa. Any condition that causes hyperventilation can result in respiratory alkalosis. Hyperventilation removes carbon dioxide at a faster than normal rate. This results in decreased hydrogen ions.

Question 3

Metabolic Acidosis

Answer 3

Metabolic acidosis is defined as a PH of less than 7.35 with a bicarbonate level of less than 22mmol. Metabolic acidosis is caused by either a deficit of bicarbonate in the bloodstream or an excess of acid ( other than that of an increase of carbonic acid as a result of increased C02) 
Causes 
*lactic acid 
*ketoacidosis 
*chronic renal failure 
Chronic Diarrhoea (bicarbonate loss)

Question 4

Metabolic alkalosis

Answer 4

Metabolic alkalosis is defined as a greater than 7.45 with a bicarbonate level of greater than 26 mmol. Either an excess of bicarbonate or a loss of acid within the body can cause metabolic alkalosis
Causes:
Excess base occurs from ingestion of antacids , excess use of bicarbonate or use of lactate in dialysis.
Loss of acids can occur secondary to protracted vomiting.