Red Book - Asthma

Question 1

Define asthma

Answer 1

Chronic inflammatory disorder of the small airways

Presents as breathlessnewss, wheeze and cough with diurnal variation

Variable reversible obstruction demonstrated

FEV1/FVC< 65%
FEV1< 70%
Or improved ratio by 12% after inhlalers

Question 2

Patholophysiology

Answer 2

Chronic airway inflammation

Smooth muscle hypertrophy

Leads to goblet cell hyperplasia

Increased airway reactivity, mucosal oedema and secretions +++

BRONCHOSPASM and MUCOUS PLUGGING —> scarring

Question 3

Define moderate acute

Answer 3

PEFR > 50-75% best/predicted
Increasing symptoms

No features of severe

Question 4

Define severe acute

Answer 4

1 of:

PEFT 33-50%
RR>25
HR > 110/min
Cant complete sentence

Question 5

Define life threatening

Answer 5

Any one Signs or Investigation in patient with severe

Signs 										Ix
Altered GCS							PEFR<33%
Exhaustian							SpO2<92%
Arrhytmia								PaO2<8kPa
Hypotension							Normal CO2
Cyanosis
Silent Chest
Poor Effort

Question 6

Define near fatal

Answer 6

Raised CO2 +/- requiring mechanical ventilation

Raised inflation pressures

Question 7

Management

Answer 7

ABCDE treating life threatening isses as found

Liaise with anaesthesia, resp

A - assess airway
B- 100% with Sats 94-98%
Perform ABG
CXR

Nebs - salbutamol 2.5-5mg
Ipratropium 250-500mcg nebs

Steroids - 40mg or 100mg hydrocortisone

Magnesium 8mmol over 20 minutes

Iv salbutamol
Aminophyline in life threatening

Question 8

Indications of I&V

Answer 8

Poor/worsening resp effort

Exhaustion

Persistant hypoxia

Drowy/confused

Resp arrest

Question 9

Drugs for intubation

Answer 9

Ketamine 1-2mg/kg induction

Avoid atracuiusm - istamine

Question 10

Circulatory considerations

Answer 10

Usually intravascular depletion
CO drops as rising intrathoraci pressure impedes venous return
Beware loss of sympathetic drive when induced

Therefore fluid resus

Monitor electrolytes and correct

Question 11

Ventilation in asthma

Answer 11

High airway resistance
Expiratroy flow restricted —> breath stacking/air trapping (dynamic hyperinflation)
(Barotrauma, and CVS depression)

Vent strategy

Low PEEP (80% of intrinsic PEEP in spont patients)
Measure intrinsice on expiratory hold and apply extrinsic accordingly

Prolong IE time 1:2 to 1:4

Hypovent: Slow RR 10-14
Low Tv 5-7mls/kg
Plataeua pressure < 30cm H20
Allow permissive hypercapnia so long as pH>7.2

Manual deceopression

Question 12

Adjunctive therapies

Answer 12

Ketamine 0 as infusion, causes bronchodilation

Sevoflurane/volatile

VV ECMO

Question 13

NIV in asthma

Answer 13

Inconclusive

Not establsihed evidence

Low threshold for tube is doing it

Question 14

Risk for near fatal asthma

Answer 14

Previous ICU admission/I&V

Oral steroid use

Increasing salbutamol use

Poor compliance

Age over 40

Question 15

Types of Brittle asthma

Answer 15

Type 1 - >40% diurnal variation for 50% of the time despite tx

Type 2 - Sudden severe attacks on a background of well controlled