Download - Asthma in the acute care setting
A M A N Y A B O U Z E I D M D , F R C P , F C C S
P R O F . O F P U L M O N O L O G Y
C A I R O U N I V E R S I T Y
Asthma in the acute care setting
Objectives
Definition of acute asthma.
Clinical assessment.
Level of severity.
Treatment of acute severe asthma.
Definition of asthma exacerbation
Asthmatic exacerbations are defined as episodes of
increased breathlessness, cough, wheezing, chest
tightness or some combination of these symptoms.
Exacerbations may have a progressive or abrupt
onset and are always related to decreases in
expiratory (and in severe cases also in inspiratory)
airflows that should be quantified objectively by lung
function measurements(PEF;FEV1).GINA 2013.
Epidemiology
Annual worldwide deaths from asthma have been
estimated at 250,000 people.
Fatalities appear to have been decreasing worldwide
over the past 15 years, even in the face of an
increasing prevalence of the disease
Drugs 2009; 69 (17): 2363-2391
Clinical features Clinical features can identify some patients with severe asthma,e.g. severe breathlessness, tachypnea, tachycardia, silent chest,cyanosis, accessory muscle use, altered consciousness orcollapse.None of these singly or together is specific. Their absence does notexclude a severe attack.
Initial assessment – the role of symptoms,
signs and measurements
British Guideline on the Management of Asthma revised Jan 2012
Clinical features Clinical features can identify some patients with severe asthma,e.g. severe breathlessness, tachypnea, tachycardia, silent chest,cyanosis, accessory muscle use, altered consciousness orcollapse.None of these singly or together is specific. Their absence does notexclude a severe attack.
PEF or FEV1 Measurements of airway calibre improve recognition of severity and guide hospital or at home management decisions. PEF is more convenient and cheaper than FEV1. PEF as % previous best value or % predicted most useful
Initial assessment – the role of symptoms,
signs and measurements
British Guideline on the Management of Asthma revised Jan 2012
Clinical features Clinical features can identify some patients with severe asthma,e.g. severe breathlessness, tachypnea, tachycardia, silent chest,cyanosis, accessory muscle use, altered consciousness orcollapse.None of these singly or together is specific. Their absence does notexclude a severe attack.
PEF or FEV1 Measurements of airway calibre improve recognition of severity and guide hospital or at home management decisions. PEF is more convenient and cheaper than FEV1. PEF as % previous best value or % predicted most useful
Pulse Oximetry Necessary to determine adequacy of oxygen therapy and need for arterial blood gas measurement. Aim of oxygen therapy is to maintain SpO2 92%
Initial assessment – the role of symptoms,
signs and measurements
British Guideline on the Management of Asthma revised Jan 2012
Clinical features Clinical features can identify some patients with severe asthma,e.g. severe breathlessness, tachypnea, tachycardia, silent chest,cyanosis, accessory muscle use, altered consciousness orcollapse.None of these singly or together is specific. Their absence does notexclude a severe attack.
PEF or FEV1 Measurements of airway calibre improve recognition of severity and guide hospital or at home management decisions. PEF is more convenient and cheaper than FEV1. PEF as % previous best value or % predicted most useful
Pulse oximetry Necessary to determine adequacy of oxygen therapy and need for arterial blood gas measurement. Aim of oxygen therapy is to maintain SpO2 92%
Blood gases (ABG)
Necessary for patients with SpO2 <92% or other features of life threatening asthma
Initial assessment – the role of symptoms,
signs and measurements
British Guideline on the Management of Asthma revised Jan 2012
Clinical features Clinical features can identify some patients with severe asthma,e.g. severe breathlessness, tachypnea, tachycardia, silent chest,cyanosis, accessory muscle use, altered consciousness orcollapse.None of these singly or together is specific. Their absence does notexclude a severe attack.
PEF or FEV1 Measurements of airway calibre improve recognition of severity and guide hospital or at home management decisions. PEF is more convenient and cheaper than FEV1. PEF as % previous best value or % predicted most useful
Pulse oximetry Necessary to determine adequacy of oxygen therapy and need for arterial blood gas measurement. Aim of oxygen therapy is to maintain SpO2 92%
Blood gases (ABG)
Necessary for patients with SpO2 <92% or other features of life threatening asthma
Chest X-ray Not routinely recommended in patients in the absence of:• suspected pneumomediastinum or
pneumothorax• suspected consolidation• life threatening asthma
• failure to respond to treatment satisfactorily
• requirement for ventilation
Initial assessment – the role of symptoms,
signs and measurements
British Guideline on the Management of Asthma revised Jan 2012
Clinical features Clinical features can identify some patients with severe asthma,e.g. severe breathlessness, tachypnea, tachycardia, silent chest,cyanosis, accessory muscle use, altered consciousness orcollapse.None of these singly or together is specific. Their absence does notexclude a severe attack.
PEF or FEV1 Measurements of airway calibre improve recognition of severity and guide hospital or at home management decisions. PEF is more convenient and cheaper than FEV1. PEF as % previous best value or % predicted most useful
Pulse oximetry Necessary to determine adequacy of oxygen therapy and need for arterial blood gas measurement. Aim of oxygen therapy is to maintain SpO2 92%
Blood gases (ABG) Necessary for patients with SpO2 <92% or other features of life threatening asthma
Chest X-ray Not routinely recommended in patients in the absence of:
• suspected pneumomediastinum or pneumothorax
• suspected consolidation• life threatening asthma
• failure to respond to treatment satisfactorily
• requirement for ventilation
Systolic paradox Abandoned as an indicator of the severity of an attack
Initial assessment – the role of symptoms,
signs and measurements
British Guideline on the Management of Asthma revised Jan 2012
Levels of severity of
acute asthma exacerbations
Near fatal asthma Raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures
British Guideline on the Management of Asthma revised Jan 2012
Levels of severity of
acute asthma exacerbations
Near fatal asthma Raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures
Life threatening asthma
Any one of the following in a patient with severe asthma:
• PEF <33% best orpredicted
• SpO2 <92%• PaO2 <8 kPa• normal PaCO2 (4.6-6.0 kPa)
• silent chest• cyanosis• feeble respiratory
effort• bradycardia
• dysrhythmia• hypotension• exhaustion• confusion• coma
British Guideline on the Management of Asthma revised Jan 2012
Levels of severity of
acute asthma exacerbations
Near fatal asthma Raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures
Life threatening asthma
Any one of the following in a patient with severe asthma:
• PEF <33% best orpredicted
• SpO2 <92%• PaO2 <8 kPa• normal PaCO2 (4.6-6.0 kPa)
• silent chest• cyanosis• feeble respiratory
effort• bradycardia
• dysrhythmia• hypotension• exhaustion• confusion• coma
Acute severe asthma
Any one of:
• PEF 33-50% best or predicted• respiratory rate 25/min• heart rate 110/min
• inability to complete sentences in one breath
British Guideline on the Management of Asthma revised Jan 2012
Levels of severity of
acute asthma exacerbations
Near fatal asthma Raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures
Life threatening asthma
Any one of the following in a patient with severe asthma:
• PEF <33% best or predicted
• SpO2 <92%• PaO2 <8 kPa• normal PaCO2 (4.6-60 kPa)
• silent chest• cyanosis• feeble respiratory
effort• bradycardia
• dysrhythmia• hypotension• exhaustion• confusion• coma
Acute severe asthma
Any one of:
• PEF 33-50% best or predicted• respiratory rate 25/min• heart rate 110/min
• inability to complete sentences in one breath
Moderate asthma exacerbation
• Increasing symptoms• PEF >50-75% best or predicted
• No features of acute severe asthma
British Guideline on the Management of Asthma revised Jan 2012
Levels of severity of
acute asthma exacerbations
Near fatal asthma Raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures
Life threatening asthma
Any one of the following in a patient with severe asthma:
• PEF <33% best or predicted
• SpO2 <92%• PaO2 <8 kPa• normal PaCO2 (4.6-6.0 kPa)
• silent chest• cyanosis• feeble respiratory
effort• bradycardia
• dysrhythmia• hypotension• exhaustion• confusion• coma
Acute severe asthma
Any one of:
• PEF 33-50% best or predicted• respiratory rate 25/min• heart rate 110/min
• inability to complete sentences in one breath
Moderate asthma exacerbation
• Increasing symptoms• PEF >50-75% best or predicted
• No features of acute severe asthma
Brittle asthma • Type 1: wide PEF variability (>40% diurnal variation for >50% ofthe time over a period >150 days) despite intense therapy
• Type 2: sudden severe attacks on a background of apparentlywell-controlled asthma
British Guideline on the Management of Asthma revised Jan 2012
Patients at risk of developing
near fatal or fatal asthma
Severe asthma Adverse behavioural or
psychosocial features
and
Recognised by combination of:
British Guideline on the Management of Asthma revised Jan 2012
Patients at risk of developing
near fatal or fatal asthma
and Adverse behavioural or
psychosocial features
Severe asthma
recognised by one or more of:
• previous near fatal asthma (previous ventilation or respiratory acidosis)
• previous asthma admission
• requiring 3 classes of asthma medication
• heavy use of ß2 agonist
• repeated attendances at A&E for asthma care
• brittle asthma
Recognised by combination of:
British Guideline on the Management of Asthma revised Jan 2012
Patients at risk of developing
near fatal or fatal asthma
Severe asthma Adverse behavioural or psychosocial features
recognised by one or more of:• non-compliance with treatment or monitoring• failure to attend appointments• self-discharge from hospital• psychosis, depression, other psychiatric illness or deliberate
self-harm• current or recent major tranquilliser use• denial• alcohol or drug abuse• obesity• learning difficulties• employment problems• income problems• social isolation• childhood abuse• severe domestic, marital or legal stress
and
Recognised by combination of:
British Guideline on the Management of Asthma revised Jan 2012
Lessons learnt from
studies of asthma deaths
Many deaths from asthma are preventable – 88-92% of
attacks requiring
hospitalisation develop over 6 hours
Factors include:
• inadequate objective monitoring
•failure to refer earlier for specialist advice
• inadequate treatment with steroids
British Guideline on the Management of Asthma revised Jan 2012
British Guideline on the Management of Asthma revised Jan 2012
British Guideline on the Management of Asthma revised Jan 2012
British Guideline on the Management of Asthma revised Jan 2012
If the patient did not respond
NIPPV should be considered in ICU and it is unlikely
it would replace intubation in this unstable patients
British Guideline on the Management of Asthma revised Jan 2012
Oxygen
Many patients with acute severe asthma are
hypoxaemic.
Supplementary oxygen should be given urgently to
hypoxaemic patients, using a face mask, Venturi
mask or nasal cannulae with flow rates adjusted as
necessary to maintain SpO2 of 94-98%.
Hypercapnea indicates the development of near-fatal
asthma and the need for emergency
specialist/anaesthetic intervention.
British Guideline on the Management of Asthma revised Jan 2012
β2-Adrenergic Receptor Agonists
In most cases inhaled β2 agonists given in high doses
act quickly to relieve bronchospasm with few side
effects1
SABAs potentially induce additional responses that
may be of benefit in asthma, such as:2
1. Decreased vascular permeability
2. Increased mucociliary clearance
3. Inhibition of release of mast cell mediators.
4. Oxgen driven neubliser : continuoustly given.
1-British Guideline on the Management of Asthma revised Jan 2012
2- Drugs 2009; 69 (17): 2363-2391
Corticosteroids
Corticosteroids are recommended for most patients in
the emergency department, especially:
Those who do not respond completely to initial SABA
therapy,
Those whose exacerbation develops even though they were
already taking oral corticosteroids
Those with previous exacerbations requiring oral
corticosteroids
Drugs 2009; 69 (17): 2363-2391
Steroids reduce mortality, relapses, subsequent
hospital admission and requirement for β2 agonist
therapy.
The earlier they are given in the acute attack the
better the outcome.
It is not known if inhaled steroids provide further
benefit in addition to systemic steroids.
Inhaled steroids should however be started, or
continued as soon as possible to commence the
chronic asthma management plan
Corticosteroids
British Guideline on the Management of Asthma revised Jan 2012
Magnesium Sulfate
Studies report the safe use of nebulized magnesium
sulphate, in a dose of 135 mg-1152 mg, in
combination with β2 agonists, with a trend towards
benefit in hospital admission.
A single dose of IV magnesium sulphate is safe and
may improve lung function in patients with acute
severe asthma
British Guideline on the Management of Asthma revised Jan 2012
Anticholinergics
Combining nebulized ipratropium bromide with a
nebulized β2 agonist produces significantly greater
bronchodilation than a β2 agonist alone, leading to a
faster recovery and shorter duration of admission.
Anticholinergic treatment is not necessary and may
not be beneficial in milder exacerbations of asthma
or after stabilization
British Guideline on the Management of Asthma revised Jan 2012
Intravenous Aminophylline
In acute asthma, IV aminophylline is not likely to
result in any additional bronchodilation compared to
standard care with inhaled bronchodilators and
steroids.
Side effects such as arrhythmias and vomiting are
increased if IV aminophylline is used
British Guideline on the Management of Asthma revised Jan 2012
Leukotriene Receptor Antagonists
There is insufficient evidence at present to make a
recommendation about the use of leukotriene
receptor antagonists in the management of acute
asthma
British Guideline on the Management of Asthma revised Jan 2012
Antibiotics
When an infection precipitates an exacerbation of
asthma it is likely to be viral.
The role of bacterial infection has been
overestimated.
Routine prescription of antibiotics is not indicated for
acute asthma.
British Guideline on the Management of Asthma revised Jan 2012
Heliox
The use of heliox, (helium/oxygen mixture in a ratio
of 80:20 or 70:30), either as a driving gas for
nebulizers, as a breathing gas, or for artificial
ventilation in adults with acute asthma is not
supported on the basis of present evidence.
British Guideline on the Management of Asthma revised Jan 2012
Heliox
A systematic review of ten trials, including 544
patients with acute asthma, found no improvement in
pulmonary function or other outcomes in adults
treated with heliox, although the possibility of benefit
in patients with more severe obstruction exists.
British Guideline on the Management of Asthma revised Jan 2012
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