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Asthma

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Asthma

  1. 1. -- Dr. Hardik Vora PG OMFS MRADC
  2. 2. Tracheobronchial tree
  3. 3. Respiratory unit
  4. 4. Neural control of respiration
  5. 5. Obstructive vs Restrictive disorders Obstructive Restrictive Limitation of airflow usually resulting from an increase in resistance caused by partial or complete obstruction at any level Reduced expansion of lung parenchyma accompanied by decreased total lung capacity. COPD – Emphysema, chronic bronchitis; bronchiectasis, asthma ARDS, Interstitial lung disease, such as idiopathic pulmonary fibrosis,Sarcoidosis, Scoliosis Neuromuscular disease – muscular dystrophy
  6. 6. Bronchial Asthma Definition:  Chronic inflammatory disease of airways that is characterized by increased responsiveness of lower airways to multiple stimuli; episodic, and with reversible obstruction; may range in severity from mild without limitation of patient’s activity to severe and life-threatening.  Severe obstruction persisting for days or weeks is known as status asthmaticus. (--Harrison’s Manual of Medicine-16thEd.)
  7. 7. Prevalence  Asthma affects 300 million persons worldwide and accounts for 1 of every 250 deaths worldwide  Prevalence in India – 3% *Global Burden of Asthma Report, GINA May 2004
  8. 8. Prevalence *Global Burden of Asthma Report, GINA May 2004
  9. 9. Etiology  Multifactorial and heterogeneous disease  Exact cause not completely understood  Four categories based on pathophysiology:  Extrinsic (allergic or atopic),  Intrinsic (idiosyncratic, non-allergic, or non-atopic),  Drug-induced,  Occupational asthma
  10. 10. Triggers
  11. 11. Pathogenesis
  12. 12. Clinical Features  Dyspnea, coughing and expiratory wheezing  May be worse at night and patients typically awake in the early morning hours  Onset usually is sudden, with peak symptoms occurring within 10 to 15 minutes.  Tenacious mucus that is difficult to expectorate  Prodromal symptoms may precede an attack  with itching under the chin,  discomfort between the scapulae, or  inexplicable fear
  13. 13. Classification of severity
  14. 14. Diagnosis  Compatible clinical history plus either/or:  FEV1 ≥ 15% (and 200 ml) increase following administration of a bronchodilator/trial of corticosteroids  > 20% diurnal variation on ≥ 3 days in a week for 2 weeks on PEF diary  FEV1 ≥ 15% decrease after 6 mins of exercise
  15. 15. Other investigations  Bronchial provocation tests with the suspected agent  Skin prick tests  Sputum Eosinophilia  Exhaled nitric oxide levels  Radiological examination – Generally unhelpful. May point to alternative diagnoses.  HRCT scan may be useful to detect bronchiectasis
  16. 16. *National Asthma Education and Prevention Program Guidelines for the Diagnosis and Management of Asthma: 2007 Report
  17. 17. Management Aims of Asthma Therapy Minimal (ideally no) chronic symptoms, including nocturnal Minimal (infrequent) exacerbations No emergency visits Minimal (ideally no) use of a required β2-agonist No limitations on activities, including exercise Peak expiratory flow circadian variation <20% (Near) normal PEF Minimal (or no) adverse effects from medicine
  18. 18. Pharmacotherapy Drugs Bronchodilators β2 sympathomimetics Salbutamol Terbutaline Bambuterol Salmeterol Formoterol Ephedrine Methylxanthines Theophylline Aminophylline Doxophylline Anticholinergics Ipratropium bromide Tiotropium bromide Leukotriene antagonists Montelukast Zafirlukast Mast cell stabilizers Sodium cromoglycate Ketotifen Corticosteroids Systemic Hydrocortisone Prednisolone Inhalational Beclomethasone dipropionate Budesonide Fluticasone propionate Ciclesonide Flunisolide Anti-IgE antibody Omalizumab
  19. 19. β2 sympathomimetics Effects of β2 -Adrenergic Agonists on Airways Relaxation of airway smooth muscle (proximal and distal airways) Inhibition of mast cell mediator release Inhibition of plasma exudation and airway edema Increased mucociliary clearance Increased mucus secretion Decreased cough No effect on chronic inflammation
  20. 20. Theophylline
  21. 21. Corticosteroids *Barnes PJ, Adcock IM. How Do Corticosteroids Work in Asthma?. Ann Intern Med. 2003;139:359-370.
  22. 22. Leukotriene antagonists
  23. 23. Omalizumab A recombinant humanized monoclonal antibody that recognizes IgE Forms complexes with circulating free IgE Prevents the binding of IgE to the high- and low-affinity receptors on cell membranes Impedes the recognition of the allergen by the effector cells Inhibits their allergen-induced activation
  24. 24. Classification of asthma control
  25. 25. Bronchial Thermoplasty
  26. 26. Acute Severe Asthma/ Status asthmaticus  Coughing, wheezing, shortness of breath, and chest wall recession (indrawing in the flesh between the ribs and sternum)  Inability to complete a sentence in one breath,  Use of accessory muscles,  Respiratory rate >30/min,  Pulse >120/min  Presence of pulsus paradoxus  severe asthma; PEFR < 60% of the predicted or best.  Silent chest type asthma.
  27. 27. Acute Severe Asthma/ Status asthmaticus  Silent chest  Cyanosis  Feeble respiratory effort  Bradycardia  Hypotension and PEFR <30% of the predicted or best.  Patient may be exhausted, confused and lapses into coma.  ABG  normal or high PaCO2 (more than 45 mm Hg), severe hypoxia (PaO2 <60 mm Hg) and a low pH.
  28. 28. Acute Severe Asthma/ Status asthmaticus  40% to 60% oxygen is administered. Achieve sPO2 >95%  Salbutamol 5 mg or terbutaline 10 mg via oxygen driven nebulizer – 2- 4 puffs every 20 min for first hour  Mild exacerbation – 2-4 puffs every 3-4 hours  Moderate exacerbation – 6-10 puffs every 1-2 hrs  Ipratropium 0.5 mg may also be added to the salbutamol nebuliser solution and repeated every 6 hours.  Prednisolone tablet 0.5-1 mg/kg(30 to 60 mg) or hydrocortisone hemisuccinate 200 mg through intravenous route – to reverse inflammation and speed recovery  If unresponsive, 2 gm Magnesium sulphate iv
  29. 29. Acute Severe Asthma/ Status asthmaticus  If any patient does not respond to treatment, Suspect pneumonitis or pneumothorax. Chest radiograph is useful. Patient should be closely monitored with PEFR every 15 to 30 minutes after starting the treatment, and Pulse oximetry to maintain oxygen saturation above 90%. Oxygen saturation < 90%, an arterial blood gas analysis should be done and repeated every 2 hours.  Assisted mechanical ventilation may be required
  30. 30. Therapies not recommended*  Sedatives (strictly avoid)  Mucolytic drugs – may worsen cough  Chest physiotherapy – may increase patient discomfort  Hydration with large volumes of fluids for adults and older children  Antibiotics  Epinephrine – indicated for acute treatment of anaphylaxis and angioedema not asthma attacks *GINA Pocket Guide for Asthma management and Prevention; 2012
  31. 31. Updating patients health history at every visit about these following factors will help identify the risk of an acute exacerbation:  Frequency of asthmatic attacks  Precipitating agents  Types of pharmacotherapy used  Length of time since an emergency visit owing to acute asthma Before Treatment
  32. 32.  Dental treatment can invoke a significant decrease in pulmonary function among asthmatic patients.  As a general rule, elective dentistry should be performed only on asthmatic patients who are asymptomatic or whose symptoms are well-controlled.  The symptomatic person should not be treated, and the presence of asthmatic symptoms such as coughing and wheezing necessitate reappointment. Before Treatment
  33. 33. During Treatment The most likely times for an acute exacerbation are:  During and immediately after local anesthetic administration.  With stimulating procedures such as extraction, surgery, pulp extirpation.
  34. 34. During Treatment At each visit make sure:  Confirm that they have taken their most recent scheduled dose of medication  The patient’s own metered-dose inhaler bronchodilator should be on hand at each visit to minimize the risk of an attack  Patient’s appointment should be in the late morning or the late afternoon  If the asthmatic patient does not use a bronchodilator, make sure the emergency kit has both a bronchodilator and oxygen
  35. 35. During Treatment  Prophylactic dose of β2 agonist bronchodilator could prevent diminished lung function during dental treatment.  H1-blocking antihistamines– useful in blunting the bronchoconstrictor response with a pretreatment dose.  Promethazine and diphenhydramine have the benefit of being antiemetic and sedative as well as antihistaminic
  36. 36. During Treatment  Anxiety is a known asthma trigger thus the dental environment is a common site for an acute asthmatic attack. Therefore, it should be ascertained that the patient has taken his or her most recent scheduled dose of antiasthma medication before treatment  Substantive stress-management techniques should be used  Attempt to lessen fear of dental treatment by gentle handling and reassurance.
  37. 37. During Treatment  N2O in patients with mild-to-moderate asthma can prevent acute stress related symptoms. However, because of its potential for causing airway irritation, N2O is contraindicated for use in patients with severe asthma. It is advisable to obtain a medical consultation before administering N2O to such patients  Patients with severe persistent asthma and those who are prone to severe abrupt episodes of airway obstruction are best given dental treatment in the hospital
  38. 38. During Treatment Check for: i. Improper positioning of suction tips ii. Avoid prolonged supine positioning. iii. Bacteria-laden aerosols from plaque or carious lesions and ultrasonically nebulized water also can be asthma triggers in the dental setting. iv. Additionally, aeroallergens such as tooth-enamel dust and methyl methacrylate have been reported to trigger asthmatic attacks.
  39. 39.  Be aware that some patients may have an adverse reaction to nonsteroidal anti-inflammatory drugs.  Avoid use of erythromycin in patients taking theophylline.  Avoid use of phenobarbitals in patients taking theophylline.  Analgesic of choice for these patients is acetaminophen. After Treatment
  40. 40. Acute Asthmatic Attack on Dental Chair  Discontinue the dental procedure  Allow the patient to assume a comfortable position.  Calm the patient.  Begin basic life support A, B,C,Ds activity as needed.  Administer β2 agonists via inhaler or nebulizer.  Administer oxygen 6-10 liters via face mask, nasal hood or cannula.
  41. 41. Acute Asthmatic Attack on Dental Chair  If no improvement is observed and symptoms are worsening, administer epinephrine subcutaneously (1:1,000 solution, 0.01 mg/kg of body weight to a maximum dose of 0.3 mg).  Hydrocortisone sodium succinate 100-200 mg iv  Alert emergency medical services-109.  Maintain a good oxygen level until the patient stops wheezing and/or medical assistance arrives.  Escort patient to hospital as needed.
  42. 42. Drugs to be avoided, since they may precipitate an asthmatic attack  Aspirin (also increases serum zafirlukast levels) and other NSAIDs  Barbiturates (e.g. methohexitone)  Beta-blockers  Cyanoacrylates  Drugs causing histamine release directly  Mefenamic acid  Morphine and some other opioids  Pancuronium  Pentazocine  Suxamethonium  Tubocurarine
  43. 43. Little and Falace’s Dental Management of the Medically Compromised Patient, 8th Ed.
  44. 44.  During GA the most important consideration is to prevent reflex stimulation of airways by laryngoscopy and intubation.  Induction: Although Ketamine has the best bronchodilator property therefore, theoretically most preferred agent but due to its side effects not used practically.  Propofol is the most commonly employed agent (because of bronchodilator property).  Thiopentone can induce bronchoconstriction therefore should be avoided. General anesthetic considerations * Ajay Yadav. Short Textbook of Anesthesia 5th Ed.; 2012
  45. 45. Maintenance:  Oxygen, nitrous oxide and sevoflurane.  Sevoflurane is considered as agent of choice.  Halothane most bronchodilator  Sensitizes myocardium; increases the risk of arrhythmias in patients on β agonist and Aminophylline  Halothane should be avoided General anesthetic considerations * Ajay Yadav. Short Textbook of Anesthesia 5th Ed.; 2012
  46. 46. Relaxant:  As Benzylisoquinoline compounds by releasing histamine can produce bronchospasm  Vecuronium should be used.  Cis-atracurium does not release histamine so, can be safely used. General anesthetic considerations * Ajay Yadav. Short Textbook of Anesthesia 5th Ed.; 2012

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