Acute Asthma Exacerbation Management in the ED by qga16183

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									Acute Asthma Exacerbation:
  Management in the ED
      Patrick PLAISANCE, M.D., PhD.
             Associate Professor
   Department of Anesthesia, MGH, MUHC.
          NIH Definition
   Chronic inflammatory changes in the bronchial
    submucosa


   Increased responsiveness of the airways


   Reversible expiratory airway obstruction
Ventilatory and Hemodynamic
        Consequences
     Ventilatory :
          dynamic resistances
          residual volume
         Atelectases
         V/P mismatching
         Airways dynamic collapse
     Hemodynamic :
         Paradoxical pulse > 18 mmHg
       Triggering Factors
• Infection:
  – Bacterial sinusitis
  – Tracheo-bronchial infection
  – Viral infection of the airways


• Medications:
  – Beta blockers (collyrium), aspirine, NSAI, antibiotics


• Others:
  –   Gastro-oesophageal reflux
  –   Psycho-sociological factors
  –   Stress
  –   Exercise
  –   Stop of chronic treatment
       Bad Prognosis Factors

• Previous severe exacerbations

• Hospitalization within the last year

• Psycho-sociological factors

• Previous intubations

• Stop of corticosteroid treatment

• Low patient’s compliance
  Importance of
an Early Treatment
Inhalation versus IV Infusion
   in Mild Exacerbations
Inhalation versus IV Infusion
  in Severe Exacerbations
Efficacy of the Inhaled Route



                      - nebulizer
                      - gas flow
                      - driving gas
Advantages of the Inhaled Route

 •   Direct respiratory tropism
 •   Short onset of action
 •   Low doses
 •   Less side-effects
 •   Simultaneous O2 delivery
 •   Humidification of the airways
 Intermittent versus Continuous
          Nebulization
• Small benefit from continuous nebulization
  – Gibbs et al. Acad Emerg Med, 2000
• Beneficial effect on severe exacerbations
• No increased side-effects
  – Moler et al. Am J Respir Crit Care Med, 1995
• Reduction of staff time
  – Fink et al. Respir Care 2000
Guidelines on Nebulizer Therapy
       (British Thoracic Society, Thorax 1997)



• Driving gas (SpO2 > 90%):
  – Air + simultaneous O2 (nasal prong)
  – O2
• Fill volume of 4 mL (if residual volume > 1 mL)
• Flow rate 6-8 L/min
• Nebulization time < 10 min
      Meter-Dose Inhalers
     with Holding Chambers
• As effective as nebulizers (Cates et al.
  Cochrane Database Syst Rev, 2000)
  – Similar hospital admission rate
  – Similar improvement in PEFR and FEV1
  – Children:
     •  HR more important
     •  duration of the treatment in the ED
• Progressive administration of the medication
• Interesting for children < 3 years
    2+ Mechanism of Action

•  muco-ciliary clearence

•  vascular permeability

• Inhibition of transmitter release from mast
  cells
                 2 Agonists

• Selective (Terbutaline, Salbutamol)
  –   First line therapy
  –   Short onset of action (2-5 min)
  –   Long duration of action (3-6 h)
  –   Different routes of administration

• Non selective (epinephrine)
  – Vasoconstricting agent
  – Short duration of action
  – Side effects
          Anticholinergics
        Mechanism of Action
• Ach competitive inhibitors

• muscarinic receptors antagonists

• Bronchodilators

• Inhibitors of the bronchoconstriction induced by
  irritant agents
Anticholinergics + 2 Agonists
           Children
• Schuh S et al. Pediatr 1995:
  – N = 120
  – 5-17 y.o.
  –  FEV1,  PEFR,  hospitalization stay:
     • Salbutamol < salbutamol + 1 ipratropium <
       Salbutamol + 3 ipratropium
     • More interesting in severe exacerbations
     Anticholinergics + 2 +
     Meta-analyses Children

• Plotnick LH et al. Cochrane Database Syst Rev
  2000
   – N = 836 children
   – Spirometric improvement
   –  Hospital admission rates
Anticholinergics + 2 Agonists
    Meta-analyses Adults
• Rodrigo et al. Am J Med 1999
  – n = 1483
  – Randomized studies, double-blind, controlled
  – Results:
     • Pulmonary function improvement
     •  Hospital admission


• Stoodley et al. Ann Emerg Med 1999
  – N = 1377
  – Slight clinical improvement
  – No side-effects
    Anticholinergics and 2+ in Adults

Groups    PEFR (L/min)  PEFR (L/min)  PEFR (L/min) Hospital
             T12h           T36h           T60h       stay (d)
_______________________________________________________
S + IB 12h    68             62             56          5,4*

S + IB 36h   81               73                 47    4,1

S + IB 60h   100              69                 42     4


* p < 0,01

                   Brophy C et al. Thorax 1998
                 Corticosteroids
•  hospital admission if administered within the 1st hour
• Equal benefit of orally and IV administration
   – Rowe et al. Cochrane Database Syst Rev, 2000
• Dose ranging from 30-400 mg methylprednisolone :
   – Manser et al. Cochrane Database Syst Rev, 2000
• Inhaled vs systemic corticosteroids: (Edmonds et al.
  Cochrane Database Syst Rev. 2003)
   –  PEFR and FEV1 as compared with placebo
   – as effective as systemic corticosteroids ?
   – Combination better than systemic route alone ?
            Methylxanthines

• No benefit from adding methylxanthines to 2+
• More adverse effects
  – Parameswaran et al. Cochrane Database Syst Rev 2000
                        MgSO4

• Inhalation:
  – Improvement in clinical score (Fischl),  PEFR,  PP
  – Nannini LJJr. Am J Med 2000
  – Mangat HS Eur Respir J 1998
     •  PEFR


• IV:
  – Boonyavorakul C. Respiratology 2000
     • Hospital admission = NS; score = NS
  – Rowe BH. Ann Emerg Med 2000
     •  admission rate in severe asthma exacerbations
           Helium Properties
• Inert gas, colourless, odourless

• Density lower than air and O2

• No diffusion through cellular membranes

• No chemical and physiological action

• Action due to its physical properties

    No bronchodilator and anti-inflammatory action
 Barach et al. Ann Int Med 1935




• The use of Helium in the Treatment of Asthma
  and Obstructive Lesions in the Larynx and
  Trachea
                  Studies
• Small trials or case reports with poor
  methodology

• Evaluation criteria varying from one study to
  another

• Different treatment duration
           Importance of Flow Rate
  . Continuous nebulization
  . P1 = 3,5 bars

Gas flow        Q = 8 L/min Q = 12.7 L/min      Q = 8 L/min
                   He/O2       He/ O2               O2
_____________________________________________________________
P2 (bars)           0.64        1.41               1.45

MMAD (mm)             5.36     3.18                3.60

Nebulized mass
after 10 ’ (g)        2.25     3.35                2,.85

Nebulized mass
after 15 ’ (g)        3.35     4.08                3.69

Nebulized mass
after 20 ’ (g)        3.83     4.46                4.06
                             PEFR
      L/min
                                                   *
350                                                330
                                       *
                                       290
300
                            *
                           250
250
                                 190         192
200
                     150                                   O2
150            120                                         He-O2
         100
100
                                                         *p < 0,01
 50

  0
              T0      T20         T40         T60
                                    O2        HeO2       p
Transfer to ICU (%)              62,89%       52%       ns
Mean duration of stay in ICU    4,1 ± 5,4   2,1± 2,6    ns
Patient still in ICU at Day 4       19          8      0,02
Intubation rate                  7,37%         1%      0,03
ASUR    Within the last 3 months
2001
                                                   38 %
                                                                          4 087 asthma exacerbations
                                 30 %
                 30%


                 25%                                                  23 %


                 20%


                 15%
                                                                                          8%

                 10%


                  5%


                  0%
                                no        General Practitioner   Pneumologist          Both
                            (n = 1237)         (n =1555)          (n = 962)          (n =333)

                       Patients having a peak flow at home : 16 % (n = 652)

   Salmeron et al. Asthma severity and adequacy of management in accident and emergency departments in France : a prospective
   study.
   The Lancet ; 2001 ; 358 : 629 – 35.
ASUR          Severity Upon Arrival
2001

          Fatal asthma
                                    26 %
         (PEFR < 30%)             (n = 975)                                           49 %              Severe exacerbation
                                                                                   (n = 1834)          (30 %  PEFR  50 %)




            Mild to moderate
             exacerbation                 25 %
                                        (n = 963)
              (PEFR > 50%)


The severity of exacerbation is independent of : • age
                                                                           • gender
                                                                           • recent corticosteroid treatment per os
                                                                           • hospitalization within the last year
          Salmeron S, et al. Asthma severity and adequacy of management in accident and emergency departments in France : a
          prospective study.
          The Lancet ; 2001 ; 358 : 629 – 35.
ASUR     Treatment in the ED
2001
          • inhaled 2 agonists : 92 % (n = 3492)
          • inhaled anticholinergics : 49 % (n = 1841)
          • systemic corticosteroids : 60 % (n = 2251)
                    95 %
                   (n = 924) 93 %
                           (n = 1708) 89 %
          90 %                     (n = 860)

          80 %
                                                                           68 %
          70 %                                                            (n = 666)     61 %
                                                51 %                                  (n = 1117)
          60 %                                          50 %                                       49 %
                                               (n = 494) = 913) 45 %
                                                       (n                                      (n = 468)
          50 %                                                (n = 434)
                                                                                                                        Fatal asthma
          40 %

          30 %                                                                                                    Severe exacerbation

          20 %
                                                                                                                       Mild to moderate
          10 %                                                                                                          exacerbation
              0
                          Inhaled                      Inhaled                 Systemic
                        2 agonists              anticholinergiques          corticosteroids




   Salmeron S, et al. Asthma severity and adequacy of management in accident and emergency departments in France : a
   prospective study.
   The Lancet ; 2001 ; 358 : 629 – 35.
Pre-Determined Management Plan

• McFadden et al. Am J Med 1995
  – Length of stay in the ER
  – Admission rates
  – Re-admission
  – Cost savings
                Initial Monitoring
• Pulse oxymetry
• PEFR (best of three)
• Pulse, BP
• RR
• Clinical judgement:
   – Cyanosis
   – Use of accessory muscles
   – Stridor
   – diaphoresis
• Blood gasses
  Initial Treatment in Children

    Inhaled Treatment               Associated Treatment
 every 20’ within the 1st hour
. O2 6-8 L/min (SpO2  95%)        . Salbutamol or Terbutaline
. Salbutamol 0.5%: 0.03 mL/kg or     7-10 g/kg SC
Terbutaline 5 mg + IB 0.25 mg      . HSHC 5 mg/kg or methyl-
. Or 0.2-0.3 puffs/kg with MDI      prednisolone 2 mg/kg IVD
 + HC
     Initial Treatment in Adults
     Inhaled Treatment              Associated Treatment
every 20 min within the 1st hour
. O2 6-8 L/min (SpO2  90%)        . Salbutamol or Terbutaline
. Salbutamol 2.5 mg (or 7.5 mg      (0.5 mg) or epinephrine
continuously) + IB 0.5 mg           0.25 mg SC
. or 2-3 puffs with MDI + HC       . HSHC 200-400 mg or
. or epinephrine 2 mg + 3 mL NS     methyl-prednisolone 1 mg/kg
                                    IV
             Inhospital Treatment
                        Initial treatment


Improvement (PEFR: 50-70%)       No improvement (PEFR < 50%)

2+: 1/h for 1-3 h               2+ + IB: 3/h pdt 1-3 h
                                 2 IV

Good response        Incomplete Response    No improvement
response>1h          . Moderate signs       . Severe signs
Examination nl       . PEFR: 50-70%         . PEFR < 30%
PEFR > 70%                                  . PaCO2 > 45 mmHg
                                            . PaO2 < 60 mmHg
 Discharge
      PEFR > 70%                                     ICU
      Examination nl    Admission   No improvement
      12h with no tt                within 6-12h
                  Antibiotics
• Graham et al. Cochrane Database Syst Rev.
  2001
  – No benefit when comparing antibiotics to placebo


• Indications: GOLD-guideline (Pauwels et al.
  Respir Care 2001)
  – Worsening dyspnea and cough
  – Increased sputum volume and purulence
  – Infiltrates on the chest X-ray
                        NIV

• VS-PEP (Shivaran U et al. Resp 1987)
  –  residual volume
  –  respiratory work
  – Risks:
    • Overdistension of zones with low resistance
    • Pulmonary hyperinflation
                    Conclusion
• Importance of an early treatment

• Importance of nebulization

• Combination 2 agonists/Ipratropium Bromide

• Combination of different routes

• PEFR monitoring

• Interest of MgSO4 and Helium ?

								
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