paediatric acute severe asthma

paediatric life threatening asthma

evidence consensusexperience

opinion “what I do”Julie McEniery

paediatric acute severe asthmapaediatric life threatening asthma

evidence

success

useful vs harmful

life threatening

asthma

oxygen provide to all children with severe acute asthma

even those with normal oxygenation pulse oximetry useful but does not predict course

level 111-2

Boychuk, R.B., Yamamoto L.G., DeMesa C.J., & Kiyabu, K.M. (2006) Correlation of initial emergency department pulse oximetry values in asthma severity classes (steps) with the risk of hospitalization. American Journal of Emergency Medicine, 24(1), 48–52.

Keahey, L., Bulloch, B., Becker, A.B., Pollack, C.V., Clark, S., & Camargo, C.A. (2002). Initial oxygen saturation as a predictor of admission in children presenting to the emergency department with acute asthma. Annals of Emergency Medicine, 40 (3), 300–7.

oxygen occasionally refractory hypoxia

VQ mismatch ? collapse/consolidation LRTI peak insp flow entrains air around mask maybe salbutamol effect – discuss later variable distress usually severe

give more oxygen! continuous nebs 8 L/m – add O2 tubing from

separate flowmeter high flow nasal cannulae 2 L/kg/min FiO2 1.0 high concentration mask, given salbutamol iv

instead mask PEEP – hand held, NIV

salbutamol inhaled level 1 efficacy mdi 10 puffs as effective as neb

but not better level 11 efficacy

2-agonists enhance action glucocorticoids nebuliser therapy should be wall oxygen driven

Cates CJ, Crilly JA, Rowe BH. Holding chambers (spacers) versus nebulisersfor beta-agonist treatment of acute asthma. Cochrane Database Syst Rev2006; 2:CD000052.

Deerjanwong, J., Manuyakorn, W., Prapphal, N., Harnruthakorn, C., Sritippayawan, S., & Samransamruajkit, R. (2005). Randomised controlled trial of salbutamol aerosol therapy via metered dose inhaler-spacer versus jet nebulizer in young children with wheezing. Pediatric Pulmonology, 39, 466-72..

Delgado, A., Chou, K. J., Silver, E.J., & Crain, E.F. (2003). Nebulizers vs metered-dose inhalers with spacers for bronchodilator therapy to treat wheezing in children aged 2 to 24 months in a pediatric emergency department. Archives of Pediatric & Adolescent Medicine,157, 76-80.

salbutamol inhaled **mdi use interrupts oxygen be aware of adverse effects with frequent or

continuous nebs (not only seen with infusion) don’t depend on continuous nebs

ipratropium bromide level 1 efficacy for initial management 3 doses inhibits cGMP mediated bronchoconstriction not absorbed into blood, minimal adverse effects consider repeating 4-6 hourly

why not, little harm?

Plotnick, L.H., & Ducharme, F.M. (2000). Combined inhaled anticholinergics and beta2-agonists for initial treatment of acute asthma in children. Cochrane Database of Systematic Reviews, 3, Art. No.: 000060..

Rodrigo, G.J., & Castro-Rodrigues, J.A. (2005). Anticholinergics in the treatment of children and adults with acute asthma: A systematic review with meta-analysis. Thorax, 60 (9), 740-6.

systemic glucocorticoids level 1 & 11 efficacy

Edmonds, M.L., Camargo, C.A., Pollack, C.V., & Rowe, B.H. (2003). Early use of inhaled corticosteroids in the emergency department treatment of acute asthma. Cochrane Database of Systematic Reviews, 3, Art. No.: CD002308.

Rowe, B.H., Edmonds, M.L., Spooner, C.H., Diner, B., & Camargo, C.A. (2004). Corticosteroid therapy for acute asthma. Respiratory Medicine, 98 (4), 275–84.

glucocorticoids in acute severe asthma

Barnes PJ & Aldock IM. (2003) How Do Corticosteroids Work in Asthma? Ann Intern Med, 139;359-370.

this takes hours and hours and hours and hours

systemic glucocorticoids level 1 & 11 efficacy iv early if not improving methylprednisolone iv 2mg/kg initially then

1mg/kg q6h first day hydrocortisone 8-10mg/kg initially then

4-5mg/kg q6h first day hypersensitivity to methylprednisolone sodium

succinate reported the other therapies just fill in time for corticosteroids

to kick in

Edmonds, M.L., Camargo, C.A., Pollack, C.V., & Rowe, B.H. (2003). Early use of inhaled corticosteroids in the emergency department treatment of acute asthma. Cochrane Database of Systematic Reviews, 3, Art. No.: CD002308.

Rowe, B.H., Edmonds, M.L., Spooner, C.H., Diner, B., & Camargo, C.A. (2004). Corticosteroid therapy for acute asthma. Respiratory Medicine, 98 (4), 275–84.

magnesium sulphate level 1 efficacy mechanism not clearly defined - includes smooth

muscle relaxation, inhibition mast cell degranulation, inhibition acetylcholine

salbutamol causes fall in ser Mg MgSO4 25-100mg/kg (max 2g) iv infusion over 20min monitor for hypotension, toxicity rare preference use before iv salbutamol

Cheuk, D.K., Chau, T.C., & Lee, S.L. (2005). A meta-analysis on intravenous magnesium sulphate for treating acute asthma. Archives of Disease in Childhood, 90 (1), 74–7.

Rowe, B.H., Bretzlaff, J.A., Bourdon, C., Bota, G.W., & Camargo, C.A. (2000). Intravenous magnesium sulfate treatment for acute asthma in the emergency department: A systematic review of the literature. Annals of Emergency Medicine, 36 (3), 181–90.

salbutamol intravenous level 11 – ongoing debate load 15mcg/kg less controversial than continuing

infusion continuous infusion dose range 1-10 mcg/kg/min increased recognition adverse effects

Bohn D. Metabolic acidosis in severe asthma: Is it the disease or is it the doctor? Pediatr Crit Care Med 2007;8(6):582.

Tobin A. Intravenous Salbutamol : Too Much of a Good Thing ? Critical Care and Resuscitation 2005;7:119-27.

salbutamol adverse effects glucose & insulin ↑ BSL

liver muscle ß2 glycogenolysis, hyperinsulinaemia potassium ↓ K+

Na/K-ATPase intracellular shift lactate ↑ lactic acidosis

anaerobic glycolysis in muscle, increased vent demand

salbutamol adverse effects glucose & insulin ↑ BSL

liver muscle ß2 glycogenolysis, hyperinsulinaemia potassium ↓ K+

Na/K-ATPase intracellular shift lactate ↑ lactic acidosis

anaerobic glycolysis in muscle, increased vent demand cardiovascular ↓ BP ↑ HR

vasodilation skeletal muscle beds + reflex tachycardia, vasodilation pulmonary bed uncouples VQ matchtachycardia cardiac ß1, direct inotrope, prolongs QTc interval, cardiac ß2 exacerbated by low K+ low Mg

increases minute ventilation (does not x BBB) metabolic rate ↑ oxygen consumption ↑ CO2 production tolerance (reduced ß receptor sensitivity)

salbutamol intravenous level 11 – ongoing debate load 15mcg/kg less controversial than continuing

infusion continuous infusion dose range 1-10 mcg/kg/min increased recognition adverse effects measure ABG / VBG and lactate, taper dose if lactic

acidosis present

Bohn D. Metabolic acidosis in severe asthma: Is it the disease or is it the doctor? Pediatr Crit Care Med 2007;8(6):582.

Tobin A. Intravenous Salbutamol : Too Much of a Good Thing ? Critical Care and Resuscitation 2005;7:119-27.

theophylline Level 1 mechanism complex

phosphodiesterase inhibition (smooth muscle relaxant) requires high plasma concentration

also effective at low concentration anti-inflammatory action via HDAC (switches genes off), potentiate steroid effect

also stimulate endogenous catecholamine, central respiratory stimulant, augment diaphragm contractility etc

role when salbutamol ineffective or side effects marked

Mitra A et al. 2005 Intravenous aminophylline for accute severe asthma in children over two years receiving inhaled bronchodilators. Cochtrane Database of Systematic Reviews

iv fluids maybe dry severe asthma impairs cardiac filling / function may benefit from bolus 10ml/kg 0.9%normal

saline use isotonic fluids, watch glucose, avoid

overhydration I use 2/3 maintenance

non-invasive positive pressure ventilation nippv limited data challenging in paediatrics unloads fatigued muscles, reduces dynamic

hyperinflation, reduces dead space ventilation

Ram, F.S., Wellington, S., Rowe, B.H, & Wedzicha, J.A. (2005). Non-invasive positive pressure ventilation for treatment of respiratory failure due to severe acute exacerbations of asthma. Cochrane Database of Systematic Reviews, 1, Art. No.: CD004360.

Thill PJ, McGuire JK, Baden HP, et al. Noninvasive positive-pressure ventilation in children with lower airway obstruction. Pediatr Crit Care 2004; 5:337–342.

Carroll CL, Schramm CM. Noninvasive positive pressure ventilation for the treatment of status asthmaticus in children. Ann Allergy Asthma Immunol 2006; 96:454–459.

Beers SL, Abramo TJ, Bracken A, Wiebe RA. Bilevel positive airway pressure in the treatment of status asthmaticus in pediatrics. Am J Emerg Med 2007; 25:6–9.

Teague WG. Noninvasive ventilation in the pediatric intensive care unit forchildren with acute respiratory failure. Pediatr Pulmonol 2003; 35:418–426.

non-invasive positive pressure ventilation nippv high flow nasal cannulae 2 L/kg/min FiO2 1.0 and wean in desperation..

CPAP via hand held anaesthesia T-piece and face mask

ventilator eg Respironics V60 exhausted child doesn’t usually

need sedation only needed for a few hours

slow responder phenotype / genotype emerging data obesity polymorphisms of ß2 receptor

(homozygosity for glycine instead of arginine at amino acid position 16 assoc with improved response to ß2 agonist Rx)

Carroll CL, Stoltz P, Raykov N, et al. Childhood overweight increases hospital admission rates for asthma. Pediatrics 2007; 120:734–740.

Carroll CL, Bhandari A, Zucker AR, Schramm CM. Childhood obesity increases duration of therapy during severe asthma exacerbations. Pediatr Crit Care 2006; 7:527–531.

Carroll CL, Schramm CM, Zucker AR. Slow responders to IV b2-adrenergic receptor agonist therapy: defining a novel phenotype in pediatric asthma. Pediatr Pulmonol 2008; 43:627–633.

Carroll CL, Stoltz P, Schramm CM, Zucker AR. b2-adrenergic receptor polymorphisms affect response to treatment in near fatal asthma exacerbations in children. Chest 2008. doi: 10.1378/chest.08-2041.

maybe it isn’t asthma? not. . .bronchiolitis <1 year, family has URTI grey zone older infant younger toddler grey zone older infant younger toddler maybe asthma >2 year, repeated events, sounds

wheezy, responds to asthma treatment

infection respiratory distress due to metabolic acidosis and

hyperventilation foreign body

“he’s starting to look tired”“she’s starting to look tired”“eveyone’s tired – it’s past bedtime”

tired or decompensating?

decompensation catecholamine xs

pale, tachycardic, anxious

working hard blood gas may help

moribund unconscious brief phase CO2 usually high

“getting tired”

summary oxygen salbutamol nebuliser with oxygen corticosteroids systemic oral or iv decent dose ipratropium nebuliser with oxygen magnesium sulphate iv load safe and helpful salbutamol iv initial load useful salbutamol infusion be aware of plateau of effect,

lactic acidosis, hyperglycaemia aminophylline may be used in life threatening

asthma non invasive bilevel ventilatory support don’t treat the wheeze, treat the physiology

acknowledgements RCH PICU “acute severe asthma guidelines”

recently revised by Tavey Dorofaeff

RCH Emergency Department“initial management and triage of acute severe asthma”

QH Children’s Health Services draft document“children and infants with asthma – acute management”author Greater Brisbane metropolitan procedures and work instructions working group

the children’s hospital at westmead“acute asthma: management, education and dischan\rge practice guideline”