InvestigationS

Muhammad Redzwan 081303583

FEV1 Forced Expiratory Value in 1 second.

Using spirometry

Volume of air that can forcibly be blown out in one second, after full inspiration.

Average values for FEV1 in healthy people depend mainly on sex and age.

Asthma: FEV1 ≥ 15% increase following administration of

bronchodilator/trial of CSOR

FEV1 ≥ 15% decrease after 6 minutes of exercise

PEFR Peak Expiratory Flow Rate.

Measured with a small hand held device call Peak Flow Meter.

PEF is a person's maximum speed of expiration.

Patients need to record PEF after rising in the morning and before retiring in the evening.

Asthma: >20% diurnal variation on ≥ 3 days in a week for 2 weeks

Challenge Test Sometimes patients with symptoms are suggestive of

asthma have a normal lung function.

Challenge test is done to these type of patient

Administration of sequentially increasing of concentration of either histamine, mannitol or methacholine. Adenosine challenge test is more specific

Expressed as dose of either substance needed to produce 20% decrease in the FEV1

Exercise challenge also can be done

Measurement of Allergic Status Skin prick tests can demonstrate atopy

Measurement of total and allergen-specific IgE

Full blood picture may show peripheral blood eosinophilia

Other Ix CXR is usually normal.

May shows hyperinflation of lungs fields

Lobar collapse if mucus occludes large bronchus

Flitting infiltrates if allergic bronchopulmonaryaspergillosis

Assessment of eosinophilic airway inflammation.

Sputum differential eusinophil count greater than 2% OR exhaled breath Nitric Oxide concentration

Not specific

and

Arterial Blood Gas (ABG) Important to assess severity of asthma attack

Life-threatening Features

PEF < 33% predicted (< 100 L/min)

SpO2 < 92% or PaO2 < 8 kPa

Normal or raised PaCO2 (Normal: 6 kPa)

Near fatal Asthma

Raised PaCO2 and/or requiring mechanical ventilation

Tadaaa.. Nothing here~