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ACUTE SEVERE ASTHMA

Asso Prof Deepak Doshi FACEM, FCEM(UK), MPH, MRCS Ed(A&E), MRCS(Surgery), DCH, MS, MBBS

Director Medical Services Southwest Hospitals and Health Services, Roma.

Dr Deepak DoshiFACEM, FCEM(UK), DCH, MRCS A&E (Ed),

MRCS (Glasgow), MS, MBBS

Case

 10 year old boy

 SOB x 16 hours, worse in last 4 hours despite 2 hourly salbutamol puffs at home

 Came by ambulance

 Unable to speak full sentences

 Increased efforts of resp

 HR 160, RR 60, Sats 88% on 6 L, Temp 36.6

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What the next question?

Step wise management

 O2 to 100% rebreather

 Salbutamol neb - back to back

 Atrovent - three times

 Hydrocortisone 4mg/kg

 call for help

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Further steps

 Magnesium - Routes

 Salbutamol infusion

 BiPAP, high flow

 Intubate

 Aminophylline infusion

AIMS

 Magnesium

 Aminophylline

 High flow and NIV

 Ventilation strategies

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Mg – The wonder molecule!

  Reversal of bronchospasm and decrease airway inflammation

  Decreases uptake of calcium by bronchial smooth muscle

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Cochrane

 Reduces hospitalisation in MODERATE and severe asthma

 NO significant side effects

Authors' conclusionsIV MgSO4 may reduce the need for hospital admission in children presenting to the ED with moderate to severe exacerbations of asthma

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Practical maths  2.47 g in 5 ml vial

 10 mmol in 5 ml vial = 1ml equals 2 mmol

 0.2 mmol/kg

 10 year child : 28 kg weight = 5.6 mmol = 2.8 ml in 100 ml N saline over 20 min

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Cochrane on Inhaled Mg

 Limited studies

 No side effects

 Observed tingling sensation around mouth

 500 mg in 2.5 ml normal saline given as nebulised

 Repeat x 3

individual study results from three trials suggest possible improved pulmonary function in those with severe asthma exacerbations (FEV1 less than 50% predicted).

USA

  NAEPP: National Asthma Education and Prevention Program (2012)

-  IV Mg in children -  Neb Mg -  Heliox (Evidence B) -  Aminophylline – NOT recommended

(Evidence A)

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GINA - GENEVA

  GINA: Global Initiative for Asthma

-  IV Mg - children who fail to respond and FEV1 <60% after 1 hr of care

-  Neb Mg : (Evidence A) -  Aminophylline in ICU settings

Practical maths

 50 mg/kg or 0.2 mmol/kg

  1ml = 500 mg

 10 kg child = 1 ml solution = 500 mg = 2 mmol

 20 kg child = 2 ml solution

 30 kg child = 3 ml solution

Magnesium sulfate concentrated : Ampoule contains 2.465 g/5 mL (49.3%) of magnesium sulfate (or 493 mg/mL).1

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Aminophylline

  Mitra AD et al 2009 Cochrane review

  7 trials - 380 participants -  FEV1 improved upto 24 hours -  Length of hospital stay and mechanical

ventilation rates - same -  Amino- 3 fold increased risk of vomiting

Adverse effects

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Aminophylline led to a three-fold increase in the risk of vomiting. There was no significant difference between treatment groups with regard to hypokalaemia, headaches, tremor, seizures, arrhythmias and deaths.

High Flow Oxygen

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 Treatment of severe respiratory failure during status asthmaticus in children and adolescents using high flow oxygen and sodium bicarbonate.

 Mansmann HC Jr. Abboud EM. McGeady SJ.

 Annals of Allergy, Asthma, & Immunology. 78(1):69-73, 1997 Jan.

 [Journal Article]

 Case series : 6 patients – 9 episodes

 Hypercarbia is well tolerated in children

 High flow oxygen may prevent mechanical ventilation in some patients

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NIV

NIV

 Murase , Tomii K, Chin K et al. The use of non-invasive ventilation for life threatening asthma: Changes in the need for intubation. Respirology. 15(4):714-20

 May 2010

 Retrospective 1999 to 2003 (48 pts) and

 Then 2003 to 2008 (54 pts/57 events)

 Rate of ETI dec from 18% to 3.5%

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 Respir Care. 2010 May;55(5):536-43.

 A prospective randomized controlled trial on the efficacy of noninvasive ventilation in severe acute asthma.

 Gupta D, Nath A, Agarwal R, Behera D.

 Source

 Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Sector 12, Chandigarh 160012, India.

 53 patients

 Improved FEV1

 Decreased need for bronchodilators

 Decreased ICU/Hospital stay

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Ventilation strategies

 Auto PEEP - Reduce rate - Reduce tidal volume - Shorten the inspiratory time

 Hyperinflation - Accept hypercapnia (permissive hypercapnia)

 Breath stacking - Measure the end expiration volume (in some

machines)

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 Avoid: Mophine and Atracurium (Histamine release)

 Use : Ketamine - Propofol - Vec , Sux- Halothane and other gases

 Caution: Aminophylline

 Practical - Respiratory rate 10/min (or 25% less than

calculated for age) - Tidal volume 5-7 ml/kg - Oxygen 60% - PEEP 0-1 - Reverse/equalise I:E ratio

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 Hypercapnia is preferred over hyperinflation

Sudden deterioration

 Tension pneumothorax

 Breath stacking

 Hypovolemia

 Medication - propofol

 use KETAMINE