Respiratory Emergencies

Question 1

What’s the difference between lung failure vs muscle pump failure?

Answer 1

Pump = Muscles of respiration: either brain is not telling the muscles to breathe (central depression) or the muscles cannot breathe themselves (fatigue, mechanical defects)

Question 2

Causes of type 1 respiratory failure

Answer 2

Type 1 respiratory failure - causes:

(Decreased O2; normal/decreased CO2)

• PE
• Asthma
• COPD
• Pulmonary oedema
• Pneumonia

Question 3

Causes of type 2 respiratory failure

Answer 3

Type 2 respiratory failure - causes:

(Decreased O2 and increased CO2)

A. Central: head injury, sedatives, spinal cord, NMJ

B. Restrictive disease: airway obstruction

C. Obstructive disease: COPD, kyphoscoliosis

Question 4

Symptoms of respiratory failure (3)

Answer 4

A. Pleuritic chest pain: pneumonia, PE, pneumothorax, COPD (exacerbation -> tight chest), asthma

B. Fever (usually more infective but possible in malignancy): pneumonia, TB, malignancy

C. Tachypnoea: anxiety, acidosis, PE

Question 5

Signs possibly seen on assessment/examination of pt with dyspnoea / respiratory failure

Answer 5

A. Stridor: upper airways

B. Wheeze (small airway become tighter): asthma, COPD, allergy, heart failure, (‘cardiac wheeze’)*

C. Crackles: Pneumonia

D. Cough: Pneumonia, COPD, asthma

Question 6

What’s ‘cardiac wheeze’?

Answer 6

Cardiac wheeze/ cardiac asthma - it is not a type of asthma, it is a sound/ type of coughing or wheezing that occurs with left cardiac failure

Pathophysiology: heart failure -> fluid builds up in the lungs (pulmonary oedema) and around airways -> signs and symptoms (SOB, coughing and wheezing) that mimic asthma

It is important to make a distinction between true asthma and a heart failure -> as treatments are different

Question 7

Ix in respiratory failure

Answer 7

A. CXR: CXR diagnoses pneumonia

B. CT: we may see large PE on it

C. ECHO, US: to see what heart is doing

D. D-Dimer, Trop T, BNP: to see what’s going on in a background

E. PEFR: Peak flow (but we need to know the baseline before treatment and after-> to see if pt is improving and how)

Question 8

Treatment of exacerbation of asthma

Answer 8

-salbutamol (nebuliser) -> then depends how they

respond -> may need to give more nebuliser

-Ipratropium bromide * (nebuliser)-> opens up

medium and large airways in the lungs (used usually for Rx of Asthma or COPD symptoms)

• steroids

Other drugs that we can use:

• IV magnesium -> if. patient is getting worse
• IV salbutamol
• IV aminophylline (bronchodilator theophylline with ethylenediamine in 2:1 ratio; in IV form it

is used in acute exacerbation of symptoms of reversible airway obstruction in asthma, COPD,

emphysema and chronic bronchitis)

Question 9

Side effects of iprapropropium bromide

Answer 9

• common side effects: dry mouth, cough, inflammation, airways
• safe in pregnancy and breastfeeding

- less common side effects: urinary retention, worsening spasms of airways, severe allergic reaction

Question 10

MoA of Ipratropium bromide

Answer 10

Mode of action of Ipratropium bromide: muscarinic antagonist (type of anticholinergic) -> smooth muscles would relax

Question 11

Moderate asthma presentation

Answer 11

Question 12

Severe asthma presentation and management

Answer 12

Question 13

Life-threatening asthma presentation and management

Answer 13

Question 14

Near-fatal asthma presentation

Answer 14

Question 15

What’s ‘brittle asthma’?

Answer 15

Brittle asthma

• rare form of severe asthma
• characterised by wide variations in peak flow (PEF), in spite of heavy doses of steroids
• tend to have very serious, recurring and often life-threatening attacks

Question 16

Types (2) of Brittle asthma

Answer 16

Types of brittle asthma:

A. Type 1: persistent, daily chaotic variability in peak flow (usually greater than 40% diurnal

variation in PEF more than 50% of the time)

B. Type 2: sporadic, sudden falls in PEFR against a background of usually well-controlled

asthma with normal or near to normal lung function

Individuals with type 1 suffer chronic attacks in spite of ongoing medical Rx

Type 2 experience sudden, acute and severe attacks in a background of usually well controlled

asthma

Question 17

Treatment of brittle asthma

Answer 17

*In addition to solving the issues of treatment compliance*

• to maximise corticosteroids (inhaled or oral)
• Beta agonist (for type 1 of brittle asthma -> additional subcutaneous injections of beta2

agonist and inhalation of long acting beta-adrenoceptor agonist)

• Type 2: allergen avoidance + self management advice (as sudden attacks may occur, pts should

have MedicAlert bracelet and an epinephrine autoinjector)