MANAGEMENT OF ASTHMA ACUTE ATTACK(Status Asthmaticus)Dadang Hudaya SomasetiaPediatric Emergency/Pediatric ICUHasan Sadikin General HospitalDept of Child Health - Faculty of MedicinePadjadjaran University Bandung

DefinitionAsthma: Diffuse pulmonary disease characterized by hyper-reactivity of trachea and bronchi, causing generalized narrowing of the airway in response to certain nonspecific stimuli.Status asthmaticus: Life threatening form of asthma characterized by unresponsiveness to the usual adrenergic drugs, resulting in respiratory failure.

Asthma Acute AttackAffects 10% of childrenCauses 25% of school absenteeismHospitalization rate has tripledDeath rate has increased in last 15 yearsAccounts for 5% of PICU admissions

STATUS ASTHMATICUS:Asthma attack refractory to initial therapyAsthma

Asthma Acute AttackBronchial Muscle SpasmMucosal EdemaThick Mucus SecretionEtiology/Pathology for Asthma

Asthma Acute AttackWheezingTachypneaRetractionsNasal flaringUse of accessory musclesCoughAnxietyDehydrationTachycardiaLate bradypneaClinical Findings for Asthma

Asthma Acute AttackOxygenBeta2-agonist bronchodilatorConsider steroidsMedicationsConsider mechanical ventilationInterventions for Asthma

PULMONARY SCORE for ASTHMA ACUTE ATTACKIf no wheezing due to minimal air exchange, score 3 Score < 3 = mild, 4-6 = moderate, > 6 = severe

SCORERespiratory Rate < 6 yr > 6 yrWheezeAccessory muscle use (Sternocleidomastoideus) 0< 30 < 20NoneNo apparent activity 131-45 21-35Terminal expirationheard with stethoscopeQuestionable increase 246-60 36-50Entire expiration heard by stethoscopeIncrease apparent 3> 60 > 50inspiration and expiration without stethoscopeMaximal activity

Indicators of Severe AsthmaAnxious & diaphoretic appearance, upright positionBreathlessness at rest and inability to speak in full sentencesPaCO2 normal or increasedPEFR < 150 L/min or 120) and tachypnea (RR>30)Expert Panel Report 2: Guidelines for the diagnosis and management of asthma. National Institute of Health- National Heart, Lung and Blood Institute 1997; NIH publication number 97-4051

Approach to Severe AsthmaReverse bronchoconstrictionTreat airway inflammationCorrect hypoxemiaConsider differential diagnosisMonitor for complicationsPneumothoraxHypotension

Mild Exacerbation (Schuch et al. J pediatr 1995;126:639-45)2 Agonist 2 Agonist + ipratropium bromide

Severe Exacerbation (KNAA Updated 2002)2 Agonist + ipratropium bromideInsufficient response systemic corticosteroid To reduced oral systemic corticosteroid in frequent episodic high doses budesonide inhalation (2mg every 8 hours)Acta paediatr 1999;88:841-3

Asthma Acute AttackUnderestimating severity of symptomsLack of dynamic observationUnderuse of beta-agonists and steroidsInstituting mechanical ventilation after arrest, not beforeAsthma: Common Failures of Management

In the management of a severe asthma exacerbationHow should beta-agonists be administered?Do anti-cholinergics have a role?Does aminophylline have a role?Does magnesium have a role?Should heliox be used?Does ketamine have a role?Should non-invasive ventilation be used?What should the ventilator settings be if the patient is intubated?

If the patient is unable to tolerate inhaled b-agonists SC b-agonists are an alternative to inhaled b-agonists

A randomized trial compared SC epinephrine 0.3-0.5 mg with SC terbutaline 0.25-0.5 mgPatients 18-64 years old Similar increases in PEFR and FEV at 5 and 15 minutesNo difference in heart rate or blood pressureContinuous ECG revealed no dysrhythmiasSpiteri: Subcutaneous adrenaline versus terbutaline in the treatment of acute severe asthma. Thorax 1988; 43:19-23

Should IV b2-agonist therapy be used?

Meta-analysis evaluated 9 RCTs comparing IV b2-agonists in addition to, or instead of, inhaled b2-agonists in severe asthma in adultsNo significant differences were found in multiple outcome measures between the two groups If the patient can tolerate inhaled b-agonists, there is no evidence to support the use of IV b2-agonistsTravers et al. The Cochrane Library, Issue 3, 2003.Small trial found a benefit of IV b-agonists in childrenBrowne et al. Lancet 1997; 349: 301-305.

All patients with a severe asthma exacerbation should receive steroids60 125 mg IV methylprednisolone40-60 mg PO prednisone (2 mg/kg)

Should anticholinergics be used in addition to b-agonists? Multiple doses of inhaled ipratropium bromide in addition to b-agonists lead to a significant improvement in pulmonary function testsBenefits most pronounced in those with FEV1

Is there a role for IV aminophylline?Multiple theoretically beneficial effectsCochrane review included 15 trials and found no benefit over b-agonists alone in PFTs or admission rates, even in severe asthmaIncrease in adverse effects (palpitations, vomiting)Parameswaran et al. The Cochrane Library, Issue 3, 2003No studies compare outcome in patients with severe asthma who are unable to tolerate inhaled b-agonistsThere is no evidence supporting its use

Is there a role for IV magnesium?Smooth muscle relaxation (bronchodilation)2 gm of MgSO4 is safe and beneficial in patients with severe acute asthma exacerbations (FEV1

What is heliox?Helium/Oxygen mixtureLaminar flow reduces the resistance associated turbulent airflow in more proximal airwaysAllows greater oxygen delivery during inspiration Reduced work of breathing

Should heliox be used in severe asthma?Review found no improvement in PFTs regardless of heliox mixture or severity of disease

Heliox-driven nebulizers were associated with a non-significant improvement in PFTs at one hourRodrigo. Chest 2003; 123: 891-896.Rodrigo. The Cochrane Library. Issue 3, 2003

Does IV ketamine improve outcome?Ketamine is a bronchodilator, potentiates catecholamines44 consecutive patients with severe asthma attacks received IV ketamine (0.1 mg/kg bolus and 0.5 mg/kg/hour infusion) for 3 hoursKetamine was used in conjunction with other standard therapiesNo difference in PEFR or hospital admission

Howton. Randomized, double-blind, placebo-controlled trial of IV ketamine in acute asthma. Annals of Emergency Medicine. 27(2). 1996.

Does noninvasive ventilation improve outcome?BiPAP can reduce work of breathing, reduce bronchoconstriction and offset intrinsic PEEPSmall trial used BiPAP in 30 patients with severe asthma after one neb in the ED Excluded patients with hypotension, Osat < 90%, depressed mental status, need for emergent intubationBiPAP was interrupted for short periods to deliver nebulized albuterolSignificant improvement in PFTsSoroksky et al. A Pilot Prospective, RCT of BiPAP in Acute Asthma Attack. Chest 2003. 123: 1018-1025.

Asthma Acute AttackIntubation may worsen bronchospasmBP may fall with intubation due to hypovolemia and cardiopulmonary interactionsSevere hypoxia can occur despite optimal rapid sequence induction techniqueBag-mask or bag-ET ventilation will be difficult due to the airway pressure requiredPneumothorax risk increases after intubationAsthma: Intubation Issues

Asthma Acute AttackDeterioration in state of consciousness with inability to protect the airwayApnea or near apneaHypoxemia refractory to maximal FiO2Asthma: Relative Intubation Criteria

Who should be intubated?Decision should be based on clinical deterioration (altered mental status, respiratory fatigue)

Neither hypoxia nor hypercarbia are absolute indications for intubation

Do not wait until respiratory arrest!

Rapid Sequence Intubation in the AsthmaticOxygenatePremedicate Lidocaine Glycopyrollate or atropine Induction with ketamine Paralysis with succinylcholineIntubation with large ETT

Mechanical Ventilation in AsthmaVolume cycled ventilationFiO2 1.0Rate 8-10I:E 1:4 or 1:5VT5-7 cc/kgPEEP 0Maintain peak pressures < 45 cm H20, plateau pressure < 30 cm H20

If peak pressures remain > 45 mm HgEvaluate for pneumothoraxEnsure sedation & paralysisAllow hypercapnea (up to 80 mmHg)Consider pressure-controlled ventilation

Complications of Mechanical VentilationHypotensionBarotrauma

Asthma Acute AttackPost-arrest with or without intubationFailure to improve after intensive ED RxAir leak syndromeClinical dehydration or risk of dehydration

Asthma: Referral to a CRPCAltered LOC ExhaustionDeteriorating patientDrug toxicitySilent chest

Asthma Acute AttackUnderestimating severity of symptomsLack of dynamic observationUnderuse of beta-agonists and steroidsInstituting mechanical ventilation after arrest, not beforeAsthma: Common Failures of Management

CONCLUSIONSBeta-agonists are first line therapyAminophylline does not have a role in the management of acute asthmaAnticholinergics and magnesium may improve PFTs in severe asthma Consider using noninvasive ventilationIntubation is based on clinical status, not on numbers Ventilator management is based on permissive hypercapnea

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