Acute Severe Asthma

Question 1

what is the definition of asthma

Answer 1

a chronic inflammatory disorder characterized by increased airway responsiveness to multiple stimuli leading to lower airway obstruction

Question 2

categorization of multiple stimuli

Answer 2

acute
sub-acute
chronic

Question 3

symptoms of asthma

Answer 3

wheezing
breathlessness
chest pain
chest tightness
coughing

Question 4

asthma severity

Answer 4

can be mild chronic (managed as outpatient) or
acute severe form (presents to the emergency center)

Question 5

asthma exacerbations/ acute asthma. asthma attacks

Answer 5

progressive (usually) or abrupt worsening in asthma symptoms, with increased use of bronchodilators (rescue medication) with progressively decreasing response and/or decrease in pulmonary function as measured by PEF or spirometry

Question 6

status asthmaticus

Answer 6

asthma exacerbation that is severe and continuous and life threatening. they can present with life threatening or near fatal asthma

Question 7

features of acute asthma

Answer 7

narrowing of the airways

Question 8

the pathophysiology of asthma

Answer 8

• airway narrowing
• smooth muscle constriction
  *hypersecretion of mucus
  *mucus plugging of small airways
  *oedema of the airway wall with infiltration with inflammatory cells (e.g. neutrophils and eosinophils)
  *disruption of the airway epithelium

Question 9

cardinal presenting symptoms and signs of severe asthma

Answer 9

wheezing
breathlessness/ SOB- even at rest
difficulty in talking
coughing
chest tightness or pain
fast breathing
use of accessory muscles to breath and might show suprasternal retraction
patient doesn’t want to lie down and appears agitated. he/she might want to sit forward in a hunched forward position

Question 10

signs of asthma

Answer 10

fast heart rate
low O2 saturation
pulses paradoxes

Question 11

silent chest

Answer 11

if the attack is very severe, wheezing might be absent. it is immediately life threatening asthma. it occurs either through muscle fatigue setting in and producing very poor respiratory effort or through bronchoconstriction being so severe that no air is entering the chest

Question 12

if muscle fatigue is so
severe in asthma

Answer 12

no pulses paradox might be appreciated, as the negative intrathoracic pressure that is the cause of the pulses paradoxes cannot be generated

Question 13

differential diagnosis

Answer 13

*foreign body obstruction
*heart failure
*anaphylaxis
*COPD
*pulmonary embolism
*inhalation injuries
*pneumothorax
*allergic bronchopulmonary aspergillosis
*bronchiectasis

Question 14

non- drug treatment of asthma

Answer 14

A- airway: protect airway
B- breathing: ensure adequate breathing and ventilation
C- circulation: check adequacy of circulation and perfusion
D- disability: check mental state and glucose

Question 15

which measurement should be made before treatment

Answer 15

A baseline PEF measurement

Question 16

first line treatment of asthma

Answer 16

oxygen
inhaled B2 agonists
systemic corticosteroids

Question 17

second line treatment of asthma

Answer 17

inhaled iprotropium bromide

Question 18

third line treatment of asthma

Answer 18

intravenous magnesium sulphate (MgSO4)

Question 19

fourth line treatment of asthma

Answer 19

intramuscular adrenaline
intravenous salbutamol
intravenous aminophylline
adjunctive therapy

Question 20

What percentage of oxygen are you going to deliver to a patient with asthma

Answer 20

not more that 40% O2

Question 21

when you deliver more that 40% of oxygen to patient with asthma what should this tell you

Answer 21

there is an underlying lung pathology

Question 22

when you titrate 02 what percentage of 02 saturation ae you aiming for

Answer 22

92%

Question 23

how to you measure oxygen saturation

Answer 23

pulse oximetry

Question 24

how are nebulizers bronchodilators delivered

Answer 24

by oxygen driven nebulizers

Question 25

flow rate of oxygen driven nebulizers

Answer 25

6L/ min (due to high respiratory rate)

Question 26

short acting inhaled B2 agonists examples

Answer 26

salbutamaol
fenoterol

Question 27

mechanism of inhaled Bb2 agonists

Answer 27

They are potent bronchodilators after binding to the β2-adrenoceptors on bronchial smooth muscle.
They may be repeated as frequently as necessary depending on the patient’s response: clinical improvement and improvement in peak flow to >60% predicted or >60% of previous best.

Question 28

how do administer inhaled B2 agonists

Answer 28

oxygen driver neublizer (preferred)
or via MDI if a nebulizer is not available

Question 29

goal of using the SABA

Answer 29

PEF returns to >60%

Question 30

dosages of SABA

Answer 30

Salbutamol 5mg or Fenoterol 1mg nebulized every 20 minutes until satisfactory response achieved

or Salbutamol 10 – 20 puffs (100mcg/puff) MDI via spacer every 20 minutes (take several deep breaths after every 2 puffs.

Question 31

use of corticosteroids

Answer 31

recommended for the routine treatment of acute asthma

Question 32

mechanism of Glucocorticosteroids

Answer 32

They are used for their anti-inflammatory properties (causing a decrease in the inflammatory component of airway obstruction) and have been shown to prevent relapse

Question 33

when do you administer glucocorticosteroids

Answer 33

As the onset of action of this medication is only hours after administration it is imperative that the first dose should be given orally or intravenously immediately as treatment is started and continued for 7 – 14 days

Question 34

which form of corticosteroids if preferred

Answer 34

Oral forms are as effective as IV administration and is preferred if feasible.

Question 35

examples of corticosteroids given

Answer 35

oral prednisone
IV hydrocortisone

Question 36

inhaled ipotropium bromide

Answer 36

anticholinergic agent that acts as bronchodilator via the vagal pathway (inhibition of muscarinic receptors).

Its bronchodilator effect in asthma is inferior to inhaled β2-agonists, and it provides no benefit in mild to moderate acute asthma.

The combination of this drug with an inhaled β2-agonists, however, has better bronchodilator capacity compared to either drug alone and has been shown to decrease hospital admissions in severe acute asthma attacks.

Ipratropium bromide may be administered every 20 minutes via a nebuliser at a dose of 0.5 mg or via an MDI (20 μg/puff, up to 20 puffs).

It is usually reserved for those cases where there is incomplete or refractory response to inhaled β2-agonists.

Question 37

intravenous magnesium sulphate

Answer 37

It’s mechanism of action is not fully elucidated, but thought to work by inhibiting smooth-muscle contraction, decreasing histamine release from mast cells, and inhibiting acetylcholine release

It has been shown to decrease hospital admission rates in severe acute asthma in patients with FEV1 <25% and those in which other bronchodilators failed.

Question 38

intramuscular adrenaline

Answer 38

Adrenaline has been replaced by the β2-agonists and is rarely indicated for acute asthma attacks.

It may, however, be used if patients condition is dire and up to 3rd line options have been exhausted.

Dose is 0.3 – 0.5mg adrenaline given IMI, up to 3 times.

Caution is advised in the elderly and in underlying cardiac disease.

Question 39

intravenous salbutamol

Answer 39

Very low evidence for its use.

Loading dose of 15 mcg/kg (max 0.25 mg) in 200ml 0.9% Saline IVI over 10 min, maintained at 3-20 mcg/min

Serum potassium and lactate should be monitored, and administration best done in ICU setting due to high risk of arrhythmias.

Question 40

intravenous aminophyline

Answer 40

Intravenous aminophylline (water soluble form of theophylline) is thought to act by phosphodiesterase inhibition and non-selective adenosine receptor antagonism.

It has a very narrow therapeutic range, and toxicity is common (cardiac arrhythmias, nausea and vomiting, convulsions, hypotension and coma)

Because of its high-risk side effect profile, compared to the low level of evidence with regards to its benefits, its use is only justifiable in the most severe forms of asthma and it should only be used in an ICU setting.

Question 41

adjunctive therapy

Answer 41

Antibiotics: Only to be given if definite evidence of infection such as fever, purulent sputum and clinical and/or radiological signs of pneumonia.

Intravenous fluids: Given based on the clinical setting, considering maintenance and replacement requirements.

Question 42

treatment with no evidence and/or should be avoided

Answer 42

*Leukotriene modifiers: No role in acute asthma.
*Antihistamines: No role in acute asthma.
*Mucolytics: Contraindicated, may worsen cough and bronchospasm
*Sedatives: Should be avoided because of their respiratory depressant effect.
*Physiotherapy: May provoke bronchospasm and worsen the attack.

Question 43

ongoing monitoring

Answer 43

Measurements of pulse rate, respiratory rate and blood pressure must be made at regular intervals.

Monitor pulse oximetry continuously and deliver O2 therapy if saturation below 92%

Peak expiratory flow rate (PEF) at 15-30 minute intervals. This is the best way to monitor response to therapy.

Question 44

bedside investigation

Answer 44

Perform an ABG if any life-threatening measure are present. Repeat measurement within one hour of starting treatment if
-Initial PaO2<8kPa
-Initial PaCO2 is normal or raised (more than or equal to 6kPa
-Deteriorating or not improving within 4-6 hours

Monitor blood glucose concentration.

Question 45

laboratory

Answer 45

Monitor serum potassium concentrations – salbutamol causes hypokalaemia.

Monitor serum aminophylline levels if on aminophylline infusion.

Question 46

radiography

Answer 46

A chest radiograph is not routine but should be done if a complication or other disease (e.g. tuberculosis, lung cancer) is suspected or if there is poor response to treatment, but its acquisition must not compromise ongoing monitoring and treatment.

Question 47

discharge plan

Answer 47

Provide a 7 - 14-day course of oral corticosteroid (20 - 40 mg daily of prednisone or equivalent). No tapering required if used for this duration.