respiration medications

Question 1

Oxygen Therapy

Answer 1

Up to 24% of all patients and 89% of COPD
patients are given oxygen therapy during a
hospital admission
• Long Term Oxygen Therapy (LTOT) (controlled
oxygen) has demonstrated a survival benefit in
COPD patients with hypoxia when used at least
15 hrs a day

Question 2

Oxygen Therapy indications for use

Answer 2

• Treatment or prevention of HYPOXIA
• Cyanide poisoning and carbon monoxide
poisoning

Question 3

Patients with COPD and those at risk of
hypercapnia
TSANZ Guidelines

Answer 3

• Controlled oxygen therapy to
maintain saturations 88%-92%
• Actively titrate oxygen therapy up
and down to achieve saturations 88%
- 92%

Question 4

TSANZ Guidelines Most other patients

Answer 4

• Controlled oxygen therapy to
maintain saturations 92%-96%
• Actively titrate oxygen therapy up
and down to achieve saturations
92%-96%

Question 5

Oxygen therapy: hypoxaemia

Answer 5

• In most patients aim for SpO2 >90% to avoid
hypoxia and end organ damage
Severe hypoxaemia may lead to brain damage and
death
• Sudden hypoxaemia is more dangerous than
gradual onset hypoxaemia

Question 6

Patients with conditions like COPD may tolerate

Answer 6

lower oxygen levels than ‘healthy’ patients

Question 7

Systematic review by Chu et al, 2018 found that liberal oxygen administration resulted in
INCREASED mortality

Answer 7

• 21% in-hospital mortality
• 14% 30 day mortality
• 10% mortality at longest follow up

Question 8

Risks of
oxygen
therapy and
hyperoxaemia
COPD and at risk patients and
risk of hypercapnia

Answer 8

• Worsening of V/Q matching
• Small reduction in
ventilation may contribute to
rise in CO2 (hypercapnia)
• Haldane effect
• Absorption Atelectasis
• Higher density of oxygen
compared with air
• Rebreathing (when a
facemask used)

Question 9

Other groups
Risks of
oxygen
therapy and
hyperoxaemia

Answer 9

• Worsening of V/Q
matching
• Absorption atelectasis
• Coronary and cerebral
vasoconstriction
• Reduced cardiac output
• Damage from oxygen free
radicals
• Increased systemic
vascular resistance

Question 10

Bronchodilators

Answer 10

Short acting B2 agonists (SABA)
Long acting B2 agonists (LABA)
Antimuscarinic agents

Question 11

Short acting B2 agonists (SABA)

Answer 11

• Relax bronchial
smooth muscle and
dilate bronchi
(increasing airflow).
• Inhibit the release of
mediators from mast
cells
• Work within 5-15
minutes
• Duration of action is
3-6 hours

Question 12

Long acting B2 agonists (LABA)

Answer 12

• Relax bronchial
smooth muscle and
dilate bronchi and
inhibit the release of
mediators from mast
cells
• Work within 10-30
minutes
• Duration of action is
approx. 12 hrs

Question 13

Antimuscarinic agents

Answer 13

• Causes
bronchodilation by
blocking vagal control
of bronchial smooth
muscle tone in
response to irritants
• Reduce excess mucus
in airways
• Works in 3-5 minutes
• Duration of action 4-6
hours