Asthma in Emergency room

1
Asthma in Emergency room
??.??.????? ?????????? ??. Ph.D ??????????????????
?????????????? ??????????????????
2
Contents

• epidemiology
• pathophysiology of asthma
• management of asthma at ER
• prevention of asthma exacerbation

3
Asthma morbidity in the past year
Boonsawat et al.Survey of asthma control in
Thailand 2001
4
Admission and ER visit due to asthma in the past
year according to severity classification
5
Asthma admission in Thailand (excluding Bangkok)
Health Information Division, Bureau of Health
Policy and Planing
6
ER visit at Srinagarind hospital(Teaching
hospital)
7
ER visit at Nampong hospital (district hospital)
8
Mechanism of airway obstruction in severe asthma
9
Airway obstruction
Uneven ventilation
Hyperinflation
Work of breathing
V/Q mismatching
Wasted ventilation
VO2 ,VCO2
Hypoxemia, hypercapnia
Respiratory acidosis Metabolic acidosis
10
Management of asthma at ER

• Step1. Diagnosis
• Step 2. Assess the severity
• Step 3. Treatment
• Step 4. Assess the response

11
Step1. Diagnosis
Upper airway obstruction ?
Asthma ?
COPD exacerbate ?
Congestive heart failure ?
12
Step 2. Assess the severity

13
Assess the severity

• History
• near fatal asthma requiring mechanical
  ventilation
• long duration of current attack
• deterioration despite oral steroids

14
Assess the severity

• Physical examination
• inability to lie supine
• impaired sensorium
• inability to speak
• use of accessory muscle
• RR gt30
• PR gt120

15
Assess the severity

• Lab
• PEFR lt 100L/M. FEV1 lt 700 cc
• ABG
• CXR

16
Predicitive Index

• Fischls index
• PR gt 120
• RR gt 30
• Pulsus paradox gt 18
• PEFR lt 120
• Dyspnea
• accessory-muscle use
• Wheezing

N Engl J Med 1981305783-9
17
Step 3. Treatment

• goal of treatment
• correction of hypoxemia
• rapid reversal of airflow obstruction with
  minimum side effect

18
Treatment

• Oxygen
• Bronchodilators
• Corticosteroids

19
Rapid acting inhaled b2-agonists

• Nebulization
• MDI with spacer

20
Classes of b2-agonists
Speed of onset
RESCUE MEDICATION
fast onset, short duration
fast onset, long duration
M AINTENANCE
fast
inhaled formoterol
inhaled terbutaline inhaled salbutamol
slow onset, short duration
slow onset, long duration
oral terbutaline oral salbutamol oral formoterol
slow
inhaled salmeterol oral bambuterol
Duration of action
long
short
21
Nebulized versus intravenous albuterol in
hypercapnic acute asthma

• 47 patients admitted with severe asthma
• PEFlt150 L/m and PaCO2 gt 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
19941491466-70
22

• Nebulization
• MDI with spacer

23
Ipratropium bromide
24
The effect of adding Ipratropium bromide to
salbutamol in the treatment of acute asthma
Chang in mean FEV1 at 45 min
200
Total 55 (2-107) N977
100
IBS better
0
S better
TOTAL
CA
NZ
US
-100
SF Lanes. Chest 1988114365-372
25
risk of hospitalization
CA NZ US TOTAL
IBS S
IBS S
IBS S
IBS 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
0.80 95CI (0.38-1.27)
0.53-1.21 (0.52-1.42)
(0.61-1.06)
26
Effect of nebulized ipratropium on the
hospitalization rates of children with asthma
Qureshi et al.NEJM19883391030-5
27
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, FEV1lt50
• 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) RR0.51(95CI 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
20001611862-8
28
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 107363-370
29
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 95CI 0.53-0.99)
• Eleven children would need to be treated to avoid
  one admission
• improve lung function
• no increase side effect

Plotnick LH.BMJ1998317971-977
30
Addition of Ipratropium bromide to b2-agonist

• improve lung function
• reduce hospitalization
• no additional side effects

31
????????????????????????????????????????

• Magnesium
• Helium Oxygen therapy (Heliox )
• general anesthesia
• Montelukast

32
Step 4. Assess the response

• Dyspnea
• PE
• PR, RR, Accessory muscle use,
• PEFR

33
Predicitive Index
Poor Response

• PEFR at 30 min after treatmentlt40 predicted
• Change in PEFR at 30 min after treatment lt60
  L/Min

Chest 1998 114 1016-1021
34
Acute Severe Asthma
B2-agonist (Neb or MDI) q 15-30 min
Corticosteroid
Improve B2-agonist q 1-2h
Not improve add anticholinergic
Admit
PEFR gt 70 Discharge
35
Acute Severe Asthma
PEFlt50
PEFgt50
B2-agonist q 20 min Corticosteroid
B2-agonist IB q 20 min Corticosteroid
Not improve add anticholinergic
Improve B2-agonist q 1-2h
Admit
PEFR gt 70 Discharge
NIH.NAEPP 1997
36
Prevent future relapses

37
Symptoms
Airway inflammation
Stimuli
Remodelling
Airway Hyperresponsiveness
38
Facilitated referral to asthma spectialist
reduces relapses in asthma emergency room visits

• 50 reduction in asthma ER relapses
• greater use of inhaled corticosteroids

J Allergy Clin Immunol 1991871160-8
39
Results of a program to reduce admissions for
adult asthma
104 asthmatic required multiple hospitalization

• Intensive outpatient treatment
• inhaled corticosteroid
• peak flow monitor
• management plan

Threefold reduction in readmission
Mayo PH.Ann Internal Med 1990112864-871
40
conclusions

• asthma exacerbation is common in ER
• bronchospasm mucosal edema inflammation is the
  cause of obstruction
• coticosteroid,b2 agonist, anticholinergic is
  first line drugs
• asthma in ER indicate poor asthma control