Asthma in Emergency room

ผศ.นพ.วั�ชรา บุ�ญสวั�สดิ์�� พบุ. Ph.Dภาควั�ชาอายุ�รศาสตร� คณะแพทยุ�ศาสตร�มหาวั�ทยุาลั�ยุขอนแก่!น

Contents

• epidemiology

• pathophysiology of asthma

• management of asthma at ER

• prevention of asthma exacerbation

Asthma morbidity in the past year

14.8

21.723.6

0

5

10

15

20

25

admit ER visit loss work

Boonsawat et al.Survey of asthma control in Thailand 2001

Admission and ER visit due to asthma in the past year according to severity classification

45.2

17.1 18.4

9.1

35.7

28.424.5

17.3

0

20

40

60

severe moderate mild intermittent

SEVERITY

% admission

ER visit

Asthma admission in Thailand (excluding Bangkok)

6667976202 79769

90606

0

20000

40000

60000

80000

100000

2538 2539 2540 2543

Health Information Division, Bureau of Health Policy and Planing

ER visit at Srinagarind hospital(Teaching hospital)

49 53 50 62 84 87 122 108165 178

162 180 176 162 124175

226178

234254

0

100

200

300

400

500

1985 1986 1987 1988 1989 1990 1991 1992 1998 2001

adult

child

ER visit at Nampong hospital (district hospital)

10791370

0

500

1000

1500

2543 2544

Mechanism of airway obstruction in severe asthma

Airway obstruction

HyperinflationUneven ventilation

Work of breathing

Wasted ventilationV/Q mismatching

VO2 ,VCO2

Hypoxemia, hypercapnia

Respiratory acidosisMetabolic acidosis

Management of asthma at ER

Step1. Diagnosis

Step 2. Assess the severity

Step 3. Treatment

Step 4. Assess the response

Asthma ?

Upper airway obstruction ?

Congestive heart failure ?

COPD exacerbate ?

Step1. Diagnosis

Step 2. Assess the severity

Assess the severity

• History– near fatal asthma requiring mechanical

ventilation

– long duration of current attack

– deterioration despite oral steroids

Assess the severity

• Physical examination– inability to lie supine

– impaired sensorium

– inability to speak

– use of accessory muscle

– RR >30

– PR >120

Assess the severity

• Lab– PEFR < 100L/M. FEV1 < 700 cc

– ABG

– CXR

Predicitive Index

• Fischl’s index– PR > 120

– RR > 30

– Pulsus paradox >= 18

– PEFR < 120

– Dyspnea

– accessory-muscle use

– Wheezing

-19813057839N Engl J Med ; :

Step 3. Treatment

• goal of treatment:

– correction of hypoxemia

– rapid reversal of airflow obstruction with minimum side effect

Treatment

• Oxygen

• Bronchodilators

• Corticosteroids

Rapid –acting inhaled 2-agonists

• Nebulization

• MDI with spacer

Classes of 2-agonists

fast onset, short duration fast onset, long duration

slow onset, short duration slow onset, long duration

inhaled terbutalineinhaled salbutamol

inhaled formoterol

oral terbutalineoral salbutamoloral formoterol

inhaled salmeteroloral bambuterol

MAINTENANCE

RESCUE MEDICATIONSpeed of

onset

Duration of action

fast

slow

longshort

Nebulized versus intravenous albuterol in hypercapnic acute asthma

• 47 patients admitted with severe asthma• PEF<150 L/m and PaCO2 > 40• nebulize 5 mgx2 vs IV 0.5 mg salbutamol in 1hr• 86% of nebulize gr had been treat successfully (vs 48 %

in IV gr)• increase PEF, decrease PaCO2 greater in neulize gr

• nebulize route has a greater efficacy and fewer side effect than intravenous route

Salmeron S.Am J Respir Crit Care Med 1994;149:1466-70

• Nebulization

• MDI with spacer

Ipratropium bromide

The effect of adding Ipratropium bromide to salbutamol in the treatment of acute asthma

0

-100

100

200

SF Lanes. Chest 1988;114:365-372

CA NZ US TOTAL

IB+S better

S better

Total 55 (2-107)N=977

Chang in mean FEV1 at 45 min

risk of hospitalization

CA NZ US TOTALIB+S S IB+S S IB+S SIB+S S

Patients 171 171 171 167 192 192 534 530

hospitalized 16 23 35 42 24 28 75 93

risk ratio 0.70 0.81 0.86 0.8095%CI (0.38-1.27) 0.53-1.21 (0.52-1.42) (0.61-1.06)

Effect of nebulized ipratropium on the hospitalization rates of children with asthma

36.5

10.7

52.6

27.4

10.1

37.5

0

10

20

30

40

50

60

All patients moderateasthma

severe asthma

pat

ien

t h

osp

ital

ized

(%)

control

ipratropium

Qureshi et al.NEJM1988;339:1030-5

First-line therapy for adult patients with acute asthma receiving a multiple-dose protocol of ipratropium bromide

plus albutterol in the emergency department

• 180 patients, FEV1<50%• albuterol MDI vs. albuterol and IB

• subjects who received IB had an overall 20.5% greater improvement in PEFR

• reduce the risk of hospital admission 49% (39% vs 20%) RR=0.51(95%CI 0.31-0.83)

• Five patients (95% CI 3-17) would need to be treated with IB to prevent a single admission

Rodrigo et al. Am J Respir Crit Care Med 2000;161:1862-8

A Meta-analysis of the effect of Ipratropium bromide in adult with acute asthma

• 10 studies including 1483 adults with acute asthma

• improve lung function

• reduction in rate of hospital admission

Rodrigo et al. Am J Med1999; 107:363-370

Should inhaled anticholinergics should be added to b2 agonist for treating acute childhood and adolescent

asthma? A systematic review

• reduce the risk of hospitalization by 30% (RR 0.72 95%CI 0.53-0.99)

• Eleven children would need to be treated to avoid one admission

• improve lung function• no increase side effect

Plotnick LH.BMJ1998;317:971-977

Addition of Ipratropium bromide to b2-agonist

• improve lung function

• reduce hospitalization

• no additional side effects

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• Magnesium

• Helium Oxygen therapy (Heliox )

• general anesthesia

• Montelukast

Step 4. Assess the response

• Dyspnea

• PE– PR, RR, Accessory muscle use,

• PEFR

Predicitive Index

• PEFR at 30 min after treatment<40% predicted

• Change in PEFR at 30 min after treatment<60 L/Min

Poor Response

-1998 114 10161021Chest ; :

Acute Severe Asthma

B2-agonist (Neb or MDI) q 15-30 min + Corticosteroid

ImproveB2-agonist q 1-2h

PEFR > 70 % Discharge

Not improveadd anticholinergic

Admit

Acute Severe Asthma

B2-agonist q 20 min + Corticosteroid

ImproveB2-agonist q 1-2h

PEFR > 70 % Discharge

Not improveadd anticholinergic

Admit

PEF>50% PEF<50%

B2-agonist +IB q 20 min + Corticosteroid

NIH.NAEPP 1997

Prevent future relapses

•

Airway inflammation

Airway Hyperresponsiveness

Stimuli

Symptoms

Remodelling

Facilitated referral to asthma spectialist reduces relapses in asthma emergency room visits

• 50 % reduction in asthma ER relapses

• greater use of inhaled corticosteroids

-19918711608J Allergy Clin Immunol ; :

Results of a program to reduce admissions for adult asthma

104 asthmatic required multiple hospitalization

Intensive outpatient treatment• inhaled corticosteroid• peak flowmonitor• management plan

Threefold reduction in readmission Mayo PH.Ann Internal Med 1990;112:864-871

conclusions

• asthma exacerbation is common in ER

• bronchospasm mucosal edema inflammation is the cause of obstruction

• coticosteroid,2 agonist, anticholinergic is first line drugs

• asthma in ER indicate poor asthma control