Lab 2: Isohydria, acid-base balance, blood gas analysis

Question 1

what forms the vital buffer system?

Answer 1

the kidneys and the lungs

Question 2

describe the buffering capacity of the lungs?

Answer 2

the lungs can retain or secrete CO2 to regulate the blood PH accurately
CO2 combines with water in the blood to form carbonic acid
thus reducing PH

Question 3

describe the buffering capacity of the kidneys?

Answer 3

the kidneys can excrete or retain H+, and also effectively regenerate HCO3- via complex tubular mechanisms

Question 4

causes of metabolic acidosis?

Answer 4

• HCO3- loss: diarrhoea, ileus, kidney tubular disturbance
• increased acid intake: fruits, silage
• increased lactic acid production
• VFA overproduction
• high ketone concentration (ketoacidosis)
• hyperkalaemia

Question 5

effects of metabolic acidosis?

Answer 5

• kussmaul type breathing - hyperventilation
• hyperkalaema: decreased cardiac activity
• hypercalcaemia
• vomiting, depression

Question 6

causes of metabolic alkalosis?

Answer 6

• increased alkaline intake
  - overdose of bicarbonates
  - feeding of rotten food
• increased ruminal alkaline production
• liver failure
• increased acid loss
  - vomiting
  - gastric dilation volvulus syndrome
  - displaced abomasum
• muscle weakness - hypokalaemia
• hypocalcaemia
• ammonia toxicity

Question 7

causes of respiratory acidosis?

Answer 7

• upper airway obstruction
• pleural cavity disease, pleural effusion, pneumothorax
• pulmonary disease
• neuromuscular depression of respiratory muscles
• muscle weakness

Question 8

effects of respiratory acidosis?

Answer 8

• dypnoea
• cyanosis
• suffocation
• muscle weakness
• tiredness

Question 9

causes of respiratory alkalosis?

Answer 9

increased loss of CO2: hyperventilation

 - excitement 
 - fever 
 - interstitial lung disease 
 - epileptiform seizures

Question 10

Effects of respiratory alkalosis?

Answer 10

• hyperoxia, increased pCO2:O2 ratio may lead to apnea

- increased elimination of HCO3- from the kidneys

Question 11

what blood parameter indicates hypoventilation?

Answer 11

pCO2 = >40mmHg

Question 12

causes of hypoventilation?

Answer 12

• upper airway obstruction
• pleural effusion
• neuromuscular disease
• overcompensation of metabolic alkalosis

Question 13

what blood parameter indicated hyperventilation?

Answer 13

pCO2 = < 35mmHg

Question 14

causes of hyperventilation?

Answer 14

• forced ventilation during anaesthesia
• seizures
• excitation / shock
• compensation of severe metabolic acidosis, kussmaul type breathing