Management of acute asthma

concised managent of acute asthma

1. MANAGEMENT OF ACUTE ASTHMA Speaker :GNANDAS BARMAN Guide : Dr. A. K. BALA

2. DEFINITION OF ASTHMA Asthma is a heterogeneous disease usually characterised by chronic airway inflammation. It is defined by history of respiratory symptoms such as wheeze , shortness of breath , chest tightness and cough that may vary over the time and in intensity together with variable expiratory airflow limitation.{GINA2015 }

3. Definition Non Communicable chronic lung disease characterised by the following: Airway inflammation Airway obstruction mainly due to Muscle Spasm associated with mucosal edema and stagnation of Mucus Airway hyper reactivity to Aerobiologicals and irritants Narrowing of the airways is usually reversible , but in some patients with chronic asthma, there may be an element of irreversible airflow obstruction.

4. Pathogenesis of asthma attacks

5. PATHOPHYSIOLOGY

6. Approximately 80% of all asthmatic patients report disease onset prior to 6 yr of age. However, of all young children who experience recurrent wheezing , only a minority go on to have persistent asthma in later childhood . Allergy in young children is the major risk factor for childhood asthma.

7. Types of childhood asthma Two main types of childhood asthma: 1.Recurrent wheezing in early childhood; primarily triggered by common viral infections of respiratory tract. 2.Chronic asthma associated with allergy that persists into later childhood and adulthood.

8. Types of Asthma Transient Early Wheezing Persistent Atopy -Associated Asthma Non atopic Wheezing Asthma with Declining Lung Function Late onset Asthma in Females associated with Obesity and Early Onset Puberty. Occupational type Asthma in Children.

9. WHAT IS AN EXACERBATION Exacerbation represents an acute or sub acute worsening in symptoms and lung function from patients usual status; Or in some cases initial presentation of asthma. FLURE UP is a better terminology.

10. A flare up or exacerbation of asthma in children less than 5 yr is defined as an acute or sub acute deterioration of symptoms control that sufficient to cause distress or risk to health; Need to visit health care provider or required systemic steroids.

11. Severe airflow obstruction Incomplete exhalation Increased lung volume Increased elastic recoil pressure Increased expiratory flow Expanded small airways Decreased expiratory resistance Compensated: Hyperinflation, normocapnia Decreased expiratory resistance Decompensated : Severe hyperinflation, hypercapnia Worsening airflow obstruction Pathophysiology

12. Cardiopulmonary interactions Negative intrapleural pressure Pulmonary edema Pulsus paradoxus Hyperinflation Hypotension Altered hemodynamics : Pathophysiology

13. Metabolism V/Q mismatch Hypoxia Dehydration Lactate Ketones Metabolic acidosis Increased work of breathing : Pathophysiology

14. RISK ASSESSMENT ON ADMISSION FOCUSED HISTORY Onset of current exacerbation Frequency and severity of daytime and night time symptoms and activity limitation Frequency of rescue bronchodilator use Current medications and allergies Potential triggers History of systemic steroid courses, emergency department visits, hospitalization, intubation, or life-threatening episodes

15. CLINICAL ASSESSMENT Physical examination findings : Vital signs, Breathlessness, Air movement, Use of accessory muscles, Retractions, Anxiety level, alteration in mental status Pulse oximetry Lung function (defer in patients with moderate to severe distress or history of labile disease)

16. Patients at high risk of asthma-related death Previous severe exacerbation (e.g., intubation or ICU admission for asthma) Two or more hospitalizations or >3 ED visits in the past year Use of >2 canisters of SABA per month Current or recently stoppage of oral corticosteroids. Difficulty perceiving airway obstruction or the severity of worsening asthma. Low socioeconomic status or inner-city residence Illicit drug use Major psychosocial problems or psychiatric disease Co morbidities, such as cardiovascular disease or other chronic lung disease Known food allergy in a asthma patient

17. TREATMENT GOALS Correction of significant hypoxemia Rapid reversal of airflow obstruction. This is best achieved by: Repetitive or continuous administration of a SABA or Early administration of systemic corticosteroids to patients who have moderate or severe exacerbations or to patients who fail to respond promptly and completely to SABA treatment Reduction of the likelihood of relapse of the exacerbation or future recurrence of severe airflow obstruction by intensifying therapy

18. Evaluation of asthma exacerbation severity in emergency setting SYMPTOMS MILD MODERATE SEVERE IMMINENT RESP ARREST Breathles sness While walking Can lie down While at rest[infant-softer, shorter cry, difficult feeding] Prefers sitting While at rest[infant-stop feeding] Sits upright Talks in Sentences Phrases Words Alertness May be agitated Agitated Agitated Drowsy or confused

19. SIGNS MILD MODERATE SEVERE RESP . ARREST IMMINENT RESP RATE INCREASED INCREASED OFTEN >30 /min Use of accessory muscles Usually not common usually Paradoxical TA movement Wheeze Moderate ,often end exp Loud, throughout exp Loud , both isp and exp Absence Pulse rate <100[normal for age] 100-120 >120 bradycardia Pulsus paradoxus Absent <10 May present 10-25 Often present >25[adult] 20-40[children] Absence suggest resp. Muscle fatigue

20. FUNCTIONAL ASSESSMENT MILD MODERATE SEVERE IMMINENT ARREST PEAK EXPIRATORY FLOW[value predicted/personal best] >70% 40-69 % <40% <25% PaO2[Breathing air] Normal[test usually not necessary] >60 <60,possible cyanosis Pco2 <42[test usually not necessary] <42 >42,possible respiratory failure Sao2[breathing air] >95%[test usually not necessary] 90-95% <90%

21. Management of mild to moderate exacerbations [home based/Primary care] Early treatment by the patient and family member at home is the best strategy for managing asthma exacerbations . Provide to all patients a written asthma action plan that includes daily management and recognizing and handling worsening asthma, including self-adjustment of medications in response to acute symptoms or changes in PEF measures in the event of an exacerbation.

22. INITIAL TREATMENT : Inhaled SABA: up to thrice 20 minutes apart of 2–6 puffs by metered-dose inhaler (MDI) or nebulizer treatments. If possible Controlled O2 therapy [94-98%], O2 Should not be withheld if oxymetry not available Note: parents should seek medical attention if child is lethargic,acutely distressed,especially children <1yr

23. SPECIAL NOTE NOT RECOMMENDED: Drinking large volumes of liquids or breathing warm, moist air (e.g ., the mist from a hot shower ). Using over-the-counter products such as antihistamines or cold remedies. Although pursed-lip and other forms of controlled breathing may help to maintain calm during respiratory distress, these methods do not bring about improvement in lung function .

24. MANAGEMENT OF ACUTE SEVERE ASTHMA ATTACKS In emergency or PICU, secure AIRWAY BREATHING CIRCULATION Brief history and clinical examinations.

25. Status Asthamaticus Its a acute severe exacerbation of asthma that does not respond to conventional therapy Score Respiratory Rate Wheezing I/E Ratio Accessory Muscle Use <30 None 1 : 1.5 None 1 30 - 40 Terminal Expiration 1 : 2 1 Site 2 41 - 50 Entire Expiration 1 : 3 2 Sites 3 >50 Inspiration and Entire Expiration > 1 : 3 3 Sites or Neck Strap Muscle Uses Beckers Score < 4 : Mild 4-7 : Moderate > 7 : Severe

26. GENERAL MANAGEMENT OXYGEN: Administer supplemental oxygen (by nasal cannulae or mask, whichever is best tolerated) to maintain an SaO2[94-98%]. Monitor SaO2 until a clear response to bronchodilator therapy has occurred. Titrated by pulse oxymetry . NOTE-maintain saturation@94-98% associated with better physiological outcome than 100% high flow O2

27. I.V. FLUIDS Aggressive hydration is not recommended for older children and adults but may be indicated for some infants and young children. I nfants and young children may become dehydrated as a result of increased respiratory rate[ insensible loss ] and decreased oral intake or vomiting. Fluid replacement by isotonic fluids then maintenance NOTE- over hydration should be avoided . Serum electrolytes; specially potassium level should be checked

28. CHILD WITH ACUTE ASTHMA EXACERBATION

29. INVESTIGATIONS Most of the patients who have an asthma exacerbation do not require any initial laboratory studies. If laboratory studies are ordered, they must not delay initiation of asthma treatment. CXR : is not recommended for routine assessment but should be obtained for patients suspected of a complicating cardiopulmonary process, as congestive heart failure, or any pneumothorax , pneumomediastinum , pneumonia, or lobar atelectasis;or cause of wheeze in doubt. ABG: measurement for evaluating (PCO2) in patients who have suspected hypoventilation, severe distress, or FEV1 or PEF ≤25 percent of predicted after initial treatment. ( Note :Respiratory drive is typically increased in asthma exacerbations, so a “normal” PCO2 of 40 mmHg indicates severe airflow obstruction and a heightened risk of respiratory failure.) CBC,ELECTROLYTES

30. BETA 2 AGONIST B2 agonist remain the mainstay of treatment. Salbutamol and terbutaline is preferred due to there B2 selectivity. They can be administered via inhaled, IV, SC or orally . Rapid action {<5 min} and duration 4-6 hrs. No added benefit of using levo than racemic salbutamol . Continuous nebulisation is superior than intermittent doses. The use of nebulized magnesium sulfate in combination with SABAs may result in further improvements in pulmonary function

31. I.V. B2 AGONIST NOT ROUTINELY USED Considered in patients unresponsive to nebulisation or Whom nebulisation is not feasible. Terbutaline is the agent of choice for IV and SC route. Adverse reactions : mostly CVS, including tachycardia, increase QTc interval, hypertension, diastolic hypotension CNS- hyperactivity, tremors. Hyperglycemia and hypokalemia are common .

32. Anticholinergic drugs Anticholinergics are now a standard of care in treatment of acute asthma in children in combination with SABA. Most commonly used is Ipratropium bromide by inhaled route, every 20 mins for 3 doses. Subsequently every 4-6 hrs. Fewer side effect due to poor systemic absorption. Dry mouth, bitter taste, flushing , tachycardia are common.

33. CORTICOSTEROIDS These are included as first line therapy in management of acute asthma. Oral corticosteroids have same efficacy as parenteral but not feasible in critically ill childrens . Commonly used [IV] hydrocortisone , methylprednisolone and dexamethasone . Because of cost hydrocortisone is preferred. Started to work within 1-3h,maximum effect in 4-8h. With short term high dose steroids side effects are less as hyperglycaemia, hyper tension or acute psychosis. Aerosolized steroids have limited role in acute asthma.

34. SPECIAL MEDICATIONS

35. Adrenaline Intramuscular adrenaline is indicated in addition to standard therapy in asthma associated with anaphylaxis or angioedema . Not recommended in other form of exacerbations .

36. MAGNESIUM SULFATE Not recommended as a routine for exacerbations. Commonly used when fail to respond with initial treatment or having persistent hypoxemia. Serum magnesium should be monitored if facility available. Common side effects include hypotension, CNS depression, muscle weakness or flushing Severe CARDIORESPIRATORY complication in high serum levels[>10-12 mg/dl]

37. METHYLXANTHINES Infrequently use due to less effectiveness than B2 agonist and severe side effects. May be helpful in critically ill children who are not responsive to standard treatment. Serum theophylline level should preferably be measured after 1-2h of bolus if facility avaialble . Toxicity includes nausea, vomiting, tachycardia, agitation. Severe life threatening complications are- CARDIAC ARRYTHMIAS,SEIZURES AND DEATH

38. ANTIBIOTICS Antibiotics are not generally recommended for the treatment of acute asthma exacerbations except as needed for co morbid conditions. Viral infections frequently contribute to exacerbations of asthma. The use of antibiotics is generally reserved for patients who have fever, purulent sputum or evidence of pneumonia. In exacerbations STEROIDS should be aggressively used than antibiotics.

39. SEDATION Sedation is not generally recommended. Anxiolytic and hypnotic drugs are contraindicated in severely ill asthma patients because of their respiratory depressant effect. INDICATED in children who are excessively anxious[ not hypoxemic or hypercarbic ] or intubated patients . Mechanically ventilated children require sedation and sometimes , muscle relaxant to prevent Tachypnea , Asynchrony and sudden cough induced Barotraumas .

40. KETAMINE - is sedation of choice It provide sedation and bronchodilation with minimum respiratory depression. It can lead excessive bronchial secretions Continuous or intermittent dose of benzodiazepine can be used FENTANYL is the opiates of choice as less histamine release and bronchospasm VECURONIUM –commonly used muscle relaxant.

41. VENTILATORY SUPPORT

42. MECHANICAL VENTILATION Indications are- Altered sensorium or coma. Increasing or decreasing pulsus paradoxus . Rapid deterioration of mental status. Cardiopulmonary arrest Severe lactic acidosis[sp in infants] Refractory hypoxemia. Intubation and mechanical ventilation should be considered in a child who responds poorly to initial therapy or rise of PCO2

43. Rapid sequence intubation is preferred along with premedication with atropine, sedatives and muscle relaxant . Cuffed tube with largest diameter of appropriate age should be used. Typically slow ventilator rate with prolonged expiration, low PEEP. Extubation should be attempted as soon as possible.

44. “Permissive hypercapnia ” or “controlled hypoventilation” is the recommended ventilator strategy . Permissive hypercapnia provides adequate oxygenation and ventilation while minimizing high airway pressures and barotrauma It involves administration of as high a fraction of inspired oxygen as is necessary to maintain adequate arterial oxygenation , acceptance of hypercapnia [ upto 90 mmHg],with acceptable pH ≥7.2

45. COMPLICATIONS OF INVASIVE VENTILATION Most frequent complications in these children are- HYPOTENSION[should be anticipated during intubation] Pneumothorax /subcutaneous emphysema Cardiac arrest. If hypotension or hypoxemia not corrected by fluids and alteration of setting,then tension pneumothorax must be considered .

46. NON INVASIVE VENTILATION NIV can be tried before invasive ventilation. No strong recommendation regarding use of NIV in severe asthma. Should not be tried in agitated patient and not be sedated in order to receive NIV

47. NOT RECOMMENDED Chest physical therapy is not recommended : For most exacerbations, chest physiotherapy is not beneficial and is unnecessarily stressful for the breathless asthma patient. Because mucus plugging is a major contributing cause of fatal asthma. Avoid mucolytic agents ( e.g., acetylcysteine , potassium iodide) because they may worsen cough or airflow obstruction.

48. OTHERS HELIOX Heliox  is a breathing gas composed of a mixture of helium (He) and oxygen(O2). Heliox has been used medically since the 1930s . It was the mainstay of treatment in acute asthma before the advent of   bronchodilators. Mixture of 21% O 2  (the same as air) and 79% He, although other combinations are available (70/30 and 60/40). INDICATIONS-children who not responding to conventional therapy or who receiving high pressure MV ,HELIOX may be good adjunct therapy

49. Bronchoscopy , bronchial lavage Marked mucus plugging may render bronchodilating and anti-inflammatory therapy ineffective “ Plastic bronchitis ” has been described in asthmatic children Combined bronchoscopy / lavage can be used in desperately ill asthmatic children

50. DISCHARGE AND FOLLOW UP AFTER EXACERBATION ORAL MEDICATIONS : OCS - Prednisolone [1-2mg/kg/day] or equivalent steroid for 3-5 days. INHALED MEDICATIONS: SABA- 2-6 puffs 4-6 hrly as needed. ICS- start inhaled corticosteroids if not started previously at lowest possible dosing for one month. Patients who started it previously should steps up for 2-4 weeks.

51. PEAK FLOW METER - in selected patients[>5yrs] To monitor the A.M-P.M variations FOLLOW UPS- To primary clinician or asthma clinic within 7 days of discharge. Follow up should be for at least 1-2 months after the attack.

52. ACTION PLAN[before or at discharge]

53. REFERENCES – Nelson’s textbook of pediatrics . AIIMS PICU guideline GINA updates 2015 EPR 3; 2007 INTERNET.

54. THANK YOU