Respiratory Acidosis & Alkalosis

Question 1

respiratory acidosis

Answer 1

*a decrease in pH levels of the blood caused by inadequate ventilation and subsequent retention of carbon dioxide
*results in:
-low pH
-high PaCO2 ( > 40 mmHg)
-high bicarbonate (compensation)

Question 2

volatile acid

Answer 2

*CO2
*an acid that can be made gaseous and can therefore be excreted via ventilation in the lungs

Question 3

causes of impaired ventilation → respiratory acidosis

Answer 3

impaired ventilation = slow and/or weak breathing
1. decreased respiratory drive: opioids, sedatives, trauma, alcohol, cardiac arrest, obesity hypoventilation syndrome, central sleep apnea
2. decreased respiratory muscle function: myasthenia gravis, ALS, diaphragm paralysis, Guillane-Barre syndrome
3. decreased ventilation due to obstruction: OSA, foreign body aspiration

Question 4

causes of impaired gas exchange → respiratory acidosis

Answer 4

impaired gas exchange = lungs are disease, preventing CO2 from moving across alveolar membrane
1. pneumonia, pulmonary edema (filling of alveolar spaces with exudates)
2. emphysema (decreased alveolar surface area available for gas exchange)
3. COPD and asthma exacerbations (airway obstruction traps CO2 within the lungs)

Question 5

respiratory alkalosis

Answer 5

*an increase in pH levels of the blood due to alveolar hyperventilation and reduction of arterial levels of carbon dioxide
*results in:
-high pH
-low PaCO2
-low bicarb (compensation)

Question 6

causes of hypoxemic hyperventilation → respiratory alkalosis

Answer 6

hypoxemic hyperventilation = low PO2 (hypoxemia) causes reflex hyperventilation
1. high altitude (inspired oxygen pressure falls due to low atmospheric pressure)
2. cardiopulmonary diseases (CHF, pneumonia, ARDS) cause reduced oxygen diffusion across the alveolar membrane, leading to low PaO2 and low oxygen delivery to tissues

Question 7

causes of non-hypoxemic hyperventilation → respiratory alkalosis

Answer 7

nonhypoxemic hyperventilation = hyperventilation triggered by something other than hypoxemia (e.g. pain, CNS stimuli, systemic illness)
1. CNS stimulation: panic attacks, stress pain, fear, panic disorder
2. increased metabolic demand (hyperthyroidism, sepsis, nonpulmonary infections)
3. increased progestins (pregnancy)
4. altered serum biochemistry/hormoes
5. ASPIRIN OVERDOSE: causes an isolated respiratory alkalosis in early stages, then a mixed respiratory alkalosis-metabolic acidosis

Question 8

acid-base abnormality of aspirin (salicylate) overdose

Answer 8

causes an isolated respiratory alkalosis in early stages, then a mixed respiratory alkalosis-metabolic acidosis