Emergency Medicine

BREATHLESS PATIENT

General Medical Emergencies 65

Acute asthma

DIAGNOSIS

1 Ascertain the precipitating factors in the present attack, its duration,
additional treatment given particularly steroids and the response to treat-
ment.

2 Ask about regular medication such as inhalers, previous attacks, hospital
admissions and ventilation in an ICU.

3 Risk factors for a severe or fatal attack are:
(i) Previous ICU admission.
(ii) A recent acute attack within the last month, especially if the
patient required steroids.
(iii) ≥3 ED visits, or ≥2 hospitalizations in the previous 1 year.
(iv) Difficulty perceiving asthma severity, and or lack of a written
asthma management plan.
(v) Drug or alcohol abuse, mental illness, low socioeconomic status
and non-compliance ‘denial’.
(vi) Comorbidities such chronic lung disease, cardiovascular disease.

4 Assess the severity of the present attack rapidly before any nebulizer therapy
is given.
(i) Severe attack is indicated by any one of the following:
(a) inability to complete sentences in one breath
(b) respiratory rate of ≥25 breaths/min
(c) tachycardia of ≥120 beats/min
(d) peak expiratory flow (PEF) rate or forced expiratory volume
in 1 s (FEV 1 ) 33–50% or less of predicted or known best (see
Fig. 2.1).
(ii) Life-threatening attack is indicated by any one of the following:
(a) PEF under 33% of predicted or best
(b) silent chest, cyanosis or feeble respiratory effort
(c) bradycardia, dysrhythmia or hypotension
(d) exhaustion, confusion or coma
(e) oxygen saturation (SaO 2 ) <92%, PaO 2 <60 mmHg (below
8 kPa), normal PaCO 2 34–45 mmHg (4.6–6.0 kPa), or worse
a raised PaCO 2 (imminently fatal).

MANAGEMENT

1 Commence high-dose 40–60% oxygen via a face mask. Maintain the oxygen
saturation above 94%.

2 Give salbutamol 5 mg via an oxygen-driven nebulizer, diluted with 3 mL
normal saline.