Diagnosis & management of status asthmaticus

for post graduates pediatrics

1. DIAGNOSIS & MANAGEMENT OF STATUS ASTHMATICUS DR I H KASHIF

2. BRONCHIAL ASTHMA Asthma is a chronic inflammatory disease characterized by airflow obstruction due to airway hyper-responsiveness resulting in recurrent episodes of wheezing, breathlessness, and coughing particularly at night or in early morning.

3. STATUS ASTHMATICUS Status Asthmaticus (Acute Severe Asthma) is a condition of progressively worsening bronchospasm and respiratory dysfunction which fails to respond to conventional therapy (inhaled beta2 agonists, oral or IV steroids and O2) and that which requires hospitalization .

4. ACUTE EXACERBATION OF ASTHMA An increase in symptom (cough, wheeze and/or breathlessness) is termed as Exacerbation of Asthma. Severity of exacerbation can be classified into mild/ moderate/ Severe

5. BECKER ASTHMA SCORE SCORE RESPIRATORY RATE WHEEZING I/E RATIO ACCESSORY MUSCLE USE <30/min None 1:1.5 None 1 30-40/min Terminal Expiration 1:2 1 site 2 41-50/min Entire Expiration 1:3 2 site 3 >50/min Inspiration & entire Expiration >1:3 3site or neck strap muscle Score >4 : Moderate Asthma exacerbation Score =>7 : Admit In PICU

6. MANAGEMENT OF ACUTE SEVERE ASTHMA Aims Of Management- Treat to break cycle of bronchoconstriction and impaired ventilation. Reduce inflammation in the airways with steroids Offer supportive ventilation as necessary Treat precipitating factors. 3 Cornerstones of Severe Asthma Treatment Administration Of O2 Beta Agonists Steroids

7. Management of severe exacerbation General Treatment- Children with severe asthma admitted in PICU Require IV access Continuos pulse oxymetry Cardiorespiratory monitoring Sedation should be strictly avoided (unless intubated )

8. FLUIDS - Correct shock if present. Maintain Euvolemia (NS/RL) Avoid overhydration as there is a risk of SIADH , pulmonary edema. Restrict fluid to 2/3 rd if Serum Na <138mEq/l Potassium infusiom may be required if Serum K < 3 mEq /l ANTIBIOTICS - Not routinely indicated (most cases are triggered by viral infection) Cover for Community Acquired Pneumonia if temp>101.5 degree F OXYGEN - by nasal cannulae (maintain SPO2 93-95 %) Beta agonist may worsen hypoxia by attenuating hypoxic pulmonary vasoconstriction , hence O2 should always be administered along with nebulisation .

9. steroids IV Hydrocortisone 10mg/kg stat f/b 5 mg/kg QID Switch to oral steroids ( prednisolone 1-2 mg/kg/day) when stable. Gastric acid suppression with H2 blockers/PPI Begin effect in 1-3 hrs , reach to maximal effect in 4-8 hrs Should be use early in all patients with acute severe asthma Oral steroids are as effective as IV (if not vomitting ) Inhaled steroids- No benefit in acute episode. Total duration- 7 days (can be indivisualised based on severity of attack)

10. HIGH DOSE BETA2 AGONISTS When tidal volumes are severely reduced, MDI and spacers are ineffective and nebulised beta agonists are indicated Administer continuous nebulised salbutamol at 0.15-0.5 mg/kg/hr OR 3 doses of back to back salbutamol ,each nebulised over 15-20 min with O2 and ECG monitoring. Add Ipratropium to each of the 3 nebulizations 1ml of 0.5% Salbutamol = 5mg Dose- <20 kg- 2.5 mg(0.5 ml) >20 kg- 5 mg (1ml) Reassess clinical condition every 20 min. If no improvement, consider subcutaneous or intraavenous beta agonist

11. Subcutaneous beta agonist Options are adrenaline and terbutaline Adrenaline has superior bronchodialtory property but may cause more tachycardia. Sc dose of terbutaline or adrenaline : 0.01mg/kg/dose (max 0.3mg), can be repeated every 15-20 min *3 doses Intravenous beta agonists To be use if severe airflow limitataion persists despite continuos nebulised salbutamol . Salbutamol – 5mcg/kg over 1 hr (loading) f/b 1 mcg/kg/hr through IP OR Terbutaline - 5-10 mcg/kg over 10 min f/b 2-10 mcg/kg/hr Ecg & serum K monitoring should be there

12. Total beta agonist dose in an hour (Inhaled +SC +IV)should not exceed 20mg/hr An increase in HR by>20bpm should prompt a decrease in the dose and re evaluation of the diagnosis ( bcz tachycardia in severe asthma is related to respiratory distress and with relief of obstruction, tachycardia should be dramatically resolved)

13. Ipratropium nebulisation Add 250mcg of ipratropium to sabutamol in same nebulizer every 20 min for 3 doses during initial treatment then every 4 hourly Although ipratropium is a long acting drug, it is synergistic with and and enhances the performance and efficiency of salbutamoland hence must be given at a higher frequency during initial treatment

14. Magnesium sulphate Mechanism: smooth muscle relaxation by inhibition of calcium uptake, resulting in decreased Ach and Histamine release. Side effects: Tachycardia/ bradycardia , hypotension, respiratory muscle weakness at higher serum levels Dose- 20-50 mg/kg over 20 min No evidence of benefit from repeat dose., however toxicity is a concern

15. Aminophylline Useful for patients who do not respond well to beta agonist Dose: 5-10mg/kg over 20 min(loading), 0.5-1mg/kg/hr Possible role in improving diaphragmatic contractility s/e- arrhythmias, hypotension, confusion, gi symptoms May break cycle of bronchospasm within 6 -12 hours after which it may be stopped.

16. 1.Oxygen to maintain saturation > 90-95% 2. Nebulisation with Salbutamol : 3 doses at 20 min interval Salbutamol respule (0.63 mg) OR Nebulisation solution: <20 kg= 0.5 ml + 3 ml NS >20kg= 1 ml + 3ml NS 3. Nebulisation with Ipratropium : ( combine with salbutamol 20 minutely, 3 doses) <1 yr= 0.5 ml >1yr=1 ml 4 Steroids : Hydrocortisone 10mg/kg stat f/b 5mg/kg QID switch to oral prednisolone once stable. 5. Treat Shock with 20ml/kg saline bolus. Hourly nebulisation with salbutamol 3-4 doses May increase neb. Interval to 2-4 hourly. Continue steroids. improved

17. If not Improved Adrenaline 0.1 ml/kg (1:10000) sc Q20 min – 3 times OR Terbutaline 0.005 to 0.01 ml/kg sc Q20 min – 3 times If not Improved Injection Magnesium Sulfate 50 mg/kg in 10 ml NS over 30 min

18. If not Improved Terbutaline Infusion 0.05- 0.1 mcg/kg/min infusion, Reduce dose if HR increases >20/min over baseline or ST changes occur. Continue nebulisation If not Improved Aminophylline infusion (reduce terbutaline infusion by 50%) May need to consider mechanical Ventilation

19. Mechanical ventilation Indication include- Cardiopulmonary arrest Severe hypoxia Rapid deteoration of mental status Settings -(to minimise dynamic hyperinflation & air trapping) Slow rate with prolonged expiratory phase Minimal end expiratory pressure Short inspiratory time For older children- Volume Control mode using VT of 5-6ml/kg, RR approximately half for age, I:E ratio 1:3,PEEP 2-3 cm of water In infants- Pressure control mode is used

20. Thank you