Respiratory Acidosis

Question 1

Respiratory acidosis >>> type of respiratory failure

Answer 1

Type 2 respiratory failure

Question 2

Why is type 2 respiratory failure associated with respiratory acidosis, rather than type 1?

Answer 2

• Respiratory failure has low pO₂
• Type 2 respiratory failure has low pO₂ + high pCO₂
• As respiratory acidosis has also high pCO₂ >>> when it also has low pO₂ (due to some specific causes) >>> it has type 2 respiratory failure

Question 3

Respiratory acidosis occurs mainly due to - ?

Answer 3

Hypoventilation

Question 4

Hypoventilation >>> ABG changes

Answer 4

• pCO₂ rises
• If respiration is severely depressed >>> also low pO₂ (> type 2 respiratory failure)

Question 5

Causes of respiratory acidosis

Answer 5

• COPD (can be with type II respiratory failure: low pO₂ + high pCO₂)
• Life-threatening or Near-fatal asthma (type II respiratory failure: low pO₂ + high pCO₂)
• Respiratory muscle disease
• Benzodiazepines
• Opiates

Question 6

Drug causes of respiratory acidosis

Answer 6

• Benzodiazepines
• Opiates

Question 7

ABG level in respiratory acidosis (uncompensated)

Answer 7

• pH >>> Low
• HCO₃ >>> Normal (High if its compensatory)
• pCO₂ >>> High

Question 8

ABG level in respiratory acidosis (partially compensated)

Answer 8

• pH >>> Low
• HCO₃ >>> High
• pCO₂ >>> High

Question 9

ABG level is respiratory acidosis (fully compensated)

Answer 9

• pH >>> Normal
• HCO₃ >>> High
• pCO₂ >>> High

Question 10

Respiratory acidosis is compensated by - ?

Answer 10

Renal system (by HCO₃; it goes high)

Question 11

ABG level in (respiratory acidosis + type 2 respiratory failure)

Answer 11

• pH: Low
• pCO₂: High
• HCO₃: Normal (in uncompensated); High (If compensatory)
• pO₂: Low

Question 12

Why is type 1 respiratory failure not usually seen in respiratory acidosis?

Answer 12

• Because respiratory acidosis has high pCO₂
• But type 1 respiratory failure has low/normal pCO₂

Question 13

Time to compensate respiratory acidosis

Answer 13

3-5days

Question 14

What is acute respiratory acidosis and chronic respiratory acidosis?

Answer 14

• Acute respiratory acidosis/alkalosis: NOT yet compensated by HCO₃ (normal level); it takes 3-5days to compensate (pastest)
• Chronic respiratory acidosis/alkalosis: 3-5days are passed → Compensated by HCO₃ (high to compensate acidosis, low to compensate alkalosis) (pastest)
• Same apples for metabolic acidosis/alkalosis (maybe)

Question 15

ABG level in different types of ‘acute severe asthma’

Answer 15

• Moderate: Normal pCO₂
• Severe: Normal pCO₂
• Life-threatening: Normal/high pCO₂
• Near fatal asthma: High pCO₂

Question 16

When does an asthma patient need intubation?

Answer 16

Respiratory acidosis + type 2 respiratory failure (when pH low, pCO₂ high, pO₂ low)

(it can be near fatal asthma or sometimes life-threatening asthma)

Question 17

In acute respiratory acidosis >>> 1kPa rise in CO₂ produces - ?

Answer 17

6nmol/L of H⁺ ion & 1mmol/L increase in HCO₃^-

Question 18

In chronic respiratory acidosis, 1kPa rise in CO₂ produces - ?

Answer 18

2.5nmol/L of H⁺ ion