23 - Respiratory Acidosis and Alkalosis Flashcards
Normal arterial blood gas
HCO3-
PaCO2
PaO2
o HCO3- = 24
o PaCO2 = 40
o PaO2 = 95
Normal alveolar gas
PaCO2
PaO2
o PaCO2 = 36
o PaO2 = 105
Causes of respiratory acidosis
*Build up of co2 due to alveolar hyotension
Hypoventilation
COPD, Asthma
Severe obesity - restricts how much lungs can expand
Levels in resp acidosis
High paCO2, and slightly raised HCO3
Signs and symp of resp acidosis
As CO2 diffuses across BBB
o Headache, Drowsiness, weakness and fatigue, Lethargy, Anxiety, Sleepiness, Memory loss
• Signs
o Slowed breathing, Gait disturbances, Tachycardia, Tremor, Drop in b.p.
Treatment of resp acidosis
- Underlying lung disease
- Bronchodilator drugs
- Stop smoking
- Noninvasive positive-pressure ventilation (sometimes called CPAP or BiPAP)
- mechanical ventilation
- Oxygen
Difference between acute and chronic resp acidosis
Acute - paco2 >47
Chronic - Paco2>47 but normal blood ph
due to renal compensation (increase bicarb >30)
When do you get chronic resp acidosis compensation
Obesity
COPD
why respiratory alkalosis
Hyperventilation
Low co2
Chronic resp alkalosis
Low potassium in blood
hypokalaemia as retaining na
decreased excretion of H+ –> another cation K+ takes place
SS of resp alkalosis
Hyperventilation
HYperactivity = tingling, numbness, tremor
(if chronic - asymptomatic)
Cause of resp alkalosis
Stroke, anxiety, sepsis, cirrhosis
Compensation in resp alkalois
Kidney excretes HCO3- so it lowers
Respiratory failure T1
Hypoxic (PaO2 <60mmHg) with normal or low PCO2
ventilation perfusion mismatch
What causes ventilation perfusion mismatch in t1 resp failure
Co2 diffuses out much faster than O2 can diffuse in
Co2 can be maintained at normal with reduced ventilation
(restricts O2 but notco2)
