AEROSOL BRONCHODILATOR THERAPY

1. AEROSOL BRONCHODILATOR THERAPY

2. Aerosol Is a suspension of solid or liquid particles in gas Are used to deliver bland water solutions to the respiratory tract or to administer drugs to lungs, throat or nose Aim to is to deliver therapeutic dose of the selected agent to the desired site of action with minimal side effects and greater efficacy and safety

3. Characteristics of aerosol Aerosol output Particle size Particle deposition Aging

4. Characteristics of aerosol (i) aerosol output It indicates the weight or mass of the aerosol particle produced by the nebuliser per min This can be measured by collecting the aerosol that leaves the nebuliser on filters and measuring either the weight or the quantity of the drug

5. (ii) particle size(Ranges from 0.5 � 3.0 micrometer) Depends on substance being nebulised, the nebuliser chosen, the method used to deliver the aerosol and environmental condition surrounding the particle Only way to determine the particle size is by laboratory measurementtwo common laboratory methods cascade impaction laser diffraction Cascade impaction: The particle size is measured in terms of mass median aerosol diameter(MMAD) Laser Diffraction: It is measured in terms of volume median diameter(VMD) This two terms gives particle size in terms of micrometers

6. Characteristics continued (iii) particle deposition aerosol particles are deposited when they leave the suspension in gas There are two forms of aerosol deposition Inhaled dose: only a portion of aerosol inhaled Respirable dose: a smaller fraction of fine particles deposited in the lungs The mass of drug deposition is of two types * inhaled mass: the inhaled amount of drug * respirable mass: the propotion of the drug of proper size to reach the lower respiratory tract

7. Factors affecting penetration and deposition Inertial impaction Gravimetric sedimentation Diffusion

8. Inertial impaction It occurs when suspended particles in motion colloid with and are deposited on a surface This occurs in particle size larger than 5 micrometer Larger particles have greater inertia which keeps them moving in straight line . When they pass through the airway they cannot make directional changes, so it easily deposits

9. Gravimetric sedimentation This occurs when particle settles out of suspension and or deposited due to gravity The greater the mass the faster it settles This occurs in particles ranging from 1 to 5 micrometers Breath holding after the inhalation of the aerosol increases the residence time of the particle in the lung and increases the sedimentation

10. Brownian diffusion It is a primary mechanism through which deposition of particles less than 3 micrometers occurs Since these particles are 0.5micrometers in size they have greater retention in lungs

11. Aging Particles constantly grow shrink, collapse and fall out of suspension The process by which an aerosol suspension changes over time is called aging Aging is inversely proportional to the size of the particle, so smaller particles grow or shrink faster than the larger particles

12. Aerosol therapy A therapeutic administration of a drug in the form of an aerosol Indications Administer medication Bronchospasm Inflammation Mucosal edema Copious secretion For mobilization of secretion Home regimen Physicians order Need to obtain sputum

13. Hazards of aerosol therapy Infection Airway reactivity Pulmonary and systemic effects Drug reconcentration

14. Aerosol drug delivery systems MDI�s with and without spacer Nebuliser Nebuliser It is a device used to converting a liquid drug into a fine mist which can then be inhaled easily Two types: Jet Nebuliser Ultrasonic Nebuliser

15. Jet Nebuliser It is powered by high pressure air or oxygen provided by a portable compressor, compressed gas cylinder or 50psi valve outlet Principle: If a stream of gas is passed through a small hole it creates a lower pressure as it emerges from a hole

16. Small Volume Nebuliser Definition: Nebuliser commonly used in hospital and home for drug administration have small medication reservoirs(<10ml) Factors affecting SVN performance: Nebuliser design Gas pressure Density

17. Nebuliser Design Baffles Fill volume Residual volume Nebuliser position

18. Gas Source(wall, cylinder, compressor) Pressure Flow through nebuliser Gas density The lower the density of the carrier gas the less aerosol impaction occurs and better the deposition in the lungs

19. Large volume Nebuliser Used to deliver aerosolized drug to the lung Can be used for continuous nebulization Has an more than 240ml reservoir producing aerosol of MMAD 2.2 � 3.5micro meters Actual output and particle size vary with pressure and flow at which nebuliser operates If pt. On CBT drug toxicity should be monitored since it causes drug reconcentration

20. Ultrasonic Nebuliser It is a type in which an electric crystal is used to produce an aerosol The crystal transducer converts an electrical signal into high frequency vibration(1.2- 2.4MHz These vibration enters the liquid above the transducer and disrupts the surface and create oscillation waves If the frequency increases the amplitude is strong is enough and the oscillation waves form a geyser of droplets that break as fine aerosol particles This is capable of producing higher aerosol output(0.2-0.5ml/min) The particle size is inversely proportional to frequency of vibration

21. Types of USNs Large volume USN: Used mainly for bland aerosol therapy and sputum induction Uses air blowers to carry the mist to the patient Small Volume USN: Medication is directly placed on the top of the transducer which is connected by cable to a power source and the patients inspiratory flow draws the aerosol from the nebuliser into the lung

22. Nebulization Therapy Definition: It is a process of dispersing a liquid (medication) into microscopic particles and delivering into the lungs as the patient inhales through the nebuliser Purposes: To administer medication directly into the respiratory tract to induce sputum expectoration in case of sputum induction To reduce the difficulty in bringing out the secretions To increase VC

23. Prerequisites Optimal volume of solutions in nebuliser chamber(2-4ml) Oxygen or Air driven device which produces Flow rate of 4-6lts/min Advantages: High doses can be given. Tidal breathing is adequate for inhalation Aerosolized drugs which cannot be administered through MDI�s can be given through this Avoids reflux coughing Allows mixing of drugs

24. Disadvantages High doses may result in toxicity Requires continuous supply of electricity Expensive Requires regular maintenance Risk of transmission of Air borne infection where cleaning is not adequate

25. Equipment Nebuliser Nebuliser solution(Terbutaline 10mg/ml, Ipravent 250mcg/ml) Normal saline Oxygen source or air driven device Oxygen tube Face mask or mouth piece

26. Procedure Wash hands Arrange equipment needed Explain the use of nebuliser Warn about side effects Assemble nebuliser equipment Add prescribed medicine and diluent Hold the mouthpiece between lips with gentle pressure Ask the patient to take deep breathes and exhale passively Turn the nebuliser machine on and ensure sufficient mist is formed Turn off when the mist stops If a steroid is given gargle or rinse mouth

27. Practical points Saline should be used as diluents not distilled water(hypoosmolar solution can lead to reflex bronchospasm) Drug delivery is effective depending on the source(mouth piece or face mask) If mask is used it should be used as close to the face as possible since any gap reduces drug delivery significantly Check for adequate mist production

28. In absence of mist, check for Any leak Obstruction of flow(kinking of tube) Misalignment of the nebuliser inadequate solution Position of the nebuliser

29. Post procedure Vital signs to be checked before and after therapy Assess for side effects like coughing and cardiac dysarrythmias In case of sputum induction note the amount, colour, consistency of the expectorant

30. Cleaning After each Rx Disassemble the nebuliser completely Rinse tubing, medication cup,mouth piece and mask in warm water Shake off excess water and allow to air dry Avoid drying in dusty and smoky areas After each day Disassemble the nebuliser completely Submerge the tubing and medication cup mouthpiece and mask in mild liquid detergent in warm water Use small brush to remove any sediment that is accumulated Rinse parts thoroughly after washing Immerse all parts in cidex Remove and rinse under water Air dry all parts

31. Bronchodilators Two types Adrenergic bronchodilators Anticholinergic bronchodilators Bronchodilators delivered through MDI Nebulisers

32. Adrenergic bronchodilators Stimulates Alpha receptor stimulation which causes vasoconstriction and vasopressor effect Beta 1 receptor stimulation causes increases HR and myocardial contractility Beta 2 receptor stimulation relaxing bronchial smooth muscle, stimulating mucociliary activity

33. Sub groups Ultra short acting bronchodilator E.g.. Epinephrine(1:100%) 0.25-0.5ml through neb Shorter duration of action Used for reducing swelling and controlling bleeding Short acting non catecholamine agents Action is app. For 4-6hours so can be taken PRN or QID Terbutaline 2.5mg through neb Inj 1mg/ml Tab 2.5/5mg Salbutamol Neb 2.5/5mg, MDI 100mcg/puff 2puffs PRN DPI 200mcg/cap 1 cap PRN Tab 2/4mg

34. Long acting adrenergic bronchodilator Long acting adrenergic bronchodilator Onset of action is within 20min and peak effect is within 3 to 5 hours and overall duration of action is 12hours E.g.. Salmeterol MDI 25mcg/puff 2puff BD Formeterol MDI

35. Adverse effects of adrenergic bronchodilators Common side effects : Head ache, insomnia, nervousness, tremor, palpitations and tachycardia Specific side effects: Dizziness, Nausea, hypokalemia, loss of bronchoprotection, CFC induced bronchospasm, worsening ventilation perfusion ratio CFC induced bronchospasm is managed by replacing HFA propellants

36. Assessment of bronchodilator therapy General assessment: Monitoring Vital signs(RR, PR, Breath sounds) Correct technique Specific : Monitor PEFR ABG or SpO2 in acute state K and Blood glucose If on long term � monitor PFT Action plan for Asthma patients Patient Education Technique of aerosol delivery Cleaning of aerosol device

37. Anti cholinergic bronchodilators Acts by producing airway relaxation through blockage of cholinergic induced bronchoconstriction Indications: COPD(chronic bronchitis, emphysema), Severe asthma E.g.. Ipratropium bromide 250mcg/ml neb 0.5mg MDI 18mcg/puff 2puffs qid

38. Mode of action Acts on the acetyl choline at the muscarinic receptors on the airway smooth muscle Drugs: Ipratropium bromide MDI 18mcg/puff 2puffs QID SVN 0.5mg QID

39. Adverse effects Common: Cough and dry mouth Occasional(MDI): Nervousness, irritation, dizziness, headache, palpitation, rash SVN: Pharyngitis, dyspnea, flu like symptoms, bronchitis, URI, nausea, occasional bronchoconstriction, eye pain, urinary retention

40. Aerosol therapy

41. Asthma medication