Bronchial asthma

By: Nur Izzatul Ashikin HarunModerator: Dr Nik Azman Nik Adib

Outline

• Definition• Diagnosis• Management and prevention1 Develop patient-doctor relationship2 Identify and reduce exposure to risk factor3 Assess, treat and monitor asthma4 Management of exacerbation • Management of life threatening asthma

Introduction • Asthma is a serious public health problem throughout the

world• When uncontrolled, asthma can place several limits on daily

life and is sometimes fatal• Early diagnosis of asthma and implementation of appropriate

therapy significantly reduce the socioeconomic burden of asthma and enhance patients’ quality of life

Updated 2012

Objective• To increase awareness on asthma among health professionals,

public health authorities, and the genaral public• To improve prevention and management of asthma through a

concerted worldwide effort

GINA

•Offers a framework to achieve and maintain asthma control for most patient that can be adapted to local health care systems and resources

Definition

• Chronic inflammatory disorder of the airways associated with airway hyperreposive that leads to widespread but variable airflow obstruction that is often reversible either spontaneously or with treatment.

• causes recurrent episodes of wheezing, breathlessness, chest tightness and cough, particularly at night and in the early morning.

DiagnosisHISTORY

Wheezing - high-pitched whistling sounds when breathing out (A normal chest examination does not exclude asthma).

History of any of the following:• cough, worse particularly at night/early morning• recurrent wheeze• recurrent difficulty in breathing • recurrent chest tightness

Note: Eczema, hay fever, or a family history of asthma or atopic diseases is often associated with asthma.

Precipitating factor:

Symptoms occurs or worsen in presence of: Exercise• respiratory tract infection• animals • smoke (tobacco, wood)• pollen • changes in temperature• aerosol chemicals • drugs (aspirin, beta blockers) dust mites (in mattress, pillows, upholstered furniture,

carpets)• strong emotional expression (laughing or crying hard)

• Symptoms respond to anti-asthmatic therapy• Patient’s cold ‘go to the chest’ or take more than 10 days to

clear up

Lung Function Test1. Spirometry

- For confirmation of diagnosis- Measure the severity of air flow limitation and its reversibility- Increase in FEV1 of ≥12% and ≥ 200ml after administration of a

bronchodilator indicates reversible airflow limitation consistent with asthma

2. PEF- For diagnosis and monitoring- PEF measurement ideally compared to the patient’s own

previous best measurement- An improvement of 60L/min, or ≥20% of the pre-

bronchodilator PEF after inhalation of a bronchodilator- Diurnal variation in PEF more than 20% (with twice daily

readings, more than 10%)

Pefr chart

Other test:• Measurement of airway responsiveness to metacholamine

and histamine• Indirect challenge test i.e. inhaled mannitol• Exercise challenge test• Skin test

Management and prevention

4 components to achieve and maintain control:

1.Develop patient-doctor relationship2.Identify and reduce exposure to risk factor3.Assess, treat and monitor asthma4.Management of exacerbation

1. Develop patient-doctor relationship

• Development of partnership between patient and health care team• Avoid exposure to risk factor• Take medication correctly • Understand different between controller/reliever• Monitor symptoms, if relevant PEF• Recognize symptoms that asthma is worsening and take action• Seek medical advice as appropriate

2. Identify and reduce exposure to risk factor• Domestic mites – mattress encasing• Furred animal – remove from house• Outdoor allergen – close door and window• Indoor air pollutant – avoid passive and active smoking• Occupational exposure• Food allergy• Avoid drugs – aspirin, NSAIDs, B blocker • Obesity – weight reduction

3. Assess, treat and monitor asthma

• Asthma is controlled when:• Patient can prevent most attack• Avoid troublesome symptoms day and night• Keep physically active

• Good control is important reduce risk of exacerbation

Difficult to treat• Patient who do not reach an acceptable level of control at

step 4• Symptoms not control in spite of reliever + ≥2 controllers• Consider:

• Diagnosis, Compliance, Smoking, Comorbidities• Focus on achieving the best level of control

4. Management of asthma exacerbation

• Exacerbation?• Episodes of progressive increase in SOB, cough, wheezing, chest

tightness• Characterized by reduced in expiratory airflow, as measured by FEV1

and PEF

High risk for asthma-related death• History of near-fatal requiring intubation / mechanical

ventilation• Had history of emergency visit or hospitalization for

asthma in the past year• Not currently using inhaled corticosteroid• Currently using / have recently stopped using oral

glucocorticosteroid• Over-dependent on rapid-acting inhaled beta2-

agonist, esp those who use >1 canister monthly• History of psychiatric disease / psychosocial problem• History of non-compliance to asthma medication

TREATMENT OF EXACERBATION

MANAGEMENT IN COMMUNITY SETTING MANAGEMENT IN ACUTE CARE

Bronchodilator Oral glucocorticosteroid- Administration of rapid acting inhaled

B2 agonist - Mild attack - 2-4puffs every 3-4hr- Moderate attack – 6-10puffs every 1-

2hr

- Oral prednisolone (0.5-1mg/kg) to treat exacerbation

MANAGEMENT IN COMMUNITY SETTNG

- Oxygen therapy- Aim SPO2 >95%- SPO2<92% good predictor of the need for hospital admission- ABG: paO2<60mmHg with normal/increased PaCO2 (>45mmHg)

indicates respiratory failure

MANAGEMENT IN ACUTE CARE

• Rapid acting inhaled B2 agonist• Administer at regular intervals by MDI or spacer device• Intermittent vs continuous neb no significant difference in

bronchodilator effect / hospital admission• Reasonable aproach initial use of continuous therapy,

followed by intermittent on demand therapy

Additional bronchodilator• Ipratropium bromide

• Anti-cholinergic• Combination of nebulized B2 agonist with anti-cholinergic may

produce better bronchodilation than either drug alone • Theophylline

• Minimal role because the effectiveness and relative safety of rapid acting B2 agonist

• Associated with severe and potentially fatal side effect (in patient with long term therapy with theophylline)

Systemic glucocorticosteroid• Speeds resolution of exacerbation• Should be utilized in all cases, esp:

• Initial rapid acting inhaled B2 agonist therapy fails to achieve lasting improvement

• The exacerbation develops even though the patient was already taking oral glucocorticosteroid

• Previous exacerbations required oral glucocorticosteroid • Oral vs iv equally effective• Course: 7days vs 14days • No need to taper down as long as pt on inhaled corticosteroid

• Inhaled corticosteroid• Effective therapy for exacerbation• Combination of high dose inhaled glucocorticosteroid and

salbutamol in acute asthma provide greater bronchodilation than salbutamol alone

• Effective for prevent relapse • Discharge with prednisolone and inhaled budesonide lower

rate of relapse

• Magnesium sulphate• IV MgSO4 2g infusion over 20min• Reduce hosp admission rates in certain patient

Life threatening asthma

• Initial mx• Rapid ABC assessment

• Oxygen therapy• Correct hypoxemia with high concentrations of inspired oxygen• Aim spo2> 92%

Nebulized B2 agonist• Short acting B2 agonist should be given repeatedly in 5mg

doses or by continuous neb or 10mg/hr driven by oxygen• Administration should continue until there is significant

clinical response or serious side effects

Nebulized ipratropium bromide• Added to nebulized B2 agonist (500mcg 4hly)• Produce significant greater bronchodilator than B2 agonist

alone

Steroids • Systemic steroids in adequate doses should as early as

possible (tables/intravenous) as it may improve survival• Inhaled/nebulized steroids do not provide additional

additional benefit

Iv MgSO4• Is a smooth muscle relaxant, producing bronchodilator• Single dose 1.2-2g over 20min shown to be safe and effective

in acute severe asthma• Rapid administration may a/w hypotension

Iv bronchodilator• Should be considered in ventilated pt and those with life

threatening asthma• Iv salbutamol 5-20mcg/min or terbutaline 0.05mcg/min

should be titrated to response• Lactic acidosis will develop on 70% of patients after 2-4hr

therapy• In extremis, salbutamol 100mcg can be given iv bolus or via

ETT

Epinephrine• Should be considered in pt not responding adequately to

measure outlined above• Route:

• s/c 0.3-0.4ml 1:1000 every 20min for 3 doses• Neb 2-4ml of 1% solution hly• Iv 0.2-1mg bolus 1-10mcg/min

Who should be intubated & when & how should mechanical ventilation be initiated?

• Bed side assessment based on assessment of risk and benefits

• Absolute indications:• Coma• Respiratory collapse / cardiac arrest• Severe refractory hypoxemia

• Relative indications• not response to initial mx• Fatigue• Somnolence• Cardiovascular compromise• Development of pneumothorax

Intubation • Place large ETT (≥7.5 for female, ≥8 for male)

• To facilitate suctioning of mucus plugs and reduce airway resistance

• Bags slowly to reduce auto-peep• Sedation and often paralysis is necessary during and after

intubation

Mechanical ventilation• Aim

• Achieve adequate oxygenation• Avoid lung hyperinflation• Buy time for medical mx to work

Recommended initial settings

• RR 10-14/min• Vt 6-8mls/kg• Minute ventilation 8-10L/min• PEEP 0cm/H20• Inspiratory flow 100Ls• I:E ≥1:3• FiO2 1.0

• Keep Pplat <30cm H2O• Keep PEEPi <12 cm H2O• Allow permissive hypercarbia

Sedation• Ketamine• Propofol• Fentanyl• Midazolam

Neuromuscular blockade- Rocuronium / pancuronium

Extubation• Once airway resistance starts to fall & PaO2 normalizes,

paralytic agents and sedatives should be withheld in anticipation of extubation

References • GINA• Management of life threatening asthma in adults

• David Stanley MRCP FRCA• William Tunniciffe FRCP

• Bedside icu handbook