Humidification & nebulization

this ppt contains depth of knowledge about humidification & nebulization

1. HUMIDIFICATION

2. Humidification is a method to artificially condition the gas used in respiration of a patient as a therapeutically modality. Active method is by adding heat or water or both to the device or passive which is recycling heat and humidity which is exhaled by the patient.

3. INDICATIONS Primary Overcoming humidity deficit (upper airway bypass) To humidify dry medical gasses Secondary To manage hypothermia To treat bronchospasm (due to cold air)

4. Clinical signs and symptoms of inadequate humidification Dry and non-productive cough Atelectasis Increased airway resistance Increased work of breathing Increased incidence of infection Thick and dehydrated secretions Complaints of substernal pain and airway dryness

5. Physiology Heat and moisture exchange is a primary function of the upper respiratory tract, mainly the nose. The nasal mucosal lining is kept moist by secretions from mucous glands, goblet cells , transudation of fluid through cell walls, and condensation of exhaled humidity. As the inspired air enters the nose, it warms (convection ) and picks up water vapor from the moist mucosal lining (evaporation), cooling the mucosal surface.

6. Physiology cont Condensation occurs on the mucosal surfaces during exhalation, and water is reabsorbed by the mucus (rehydration). The mouth is less effective at heat and moisture exchange than the nose because of the low ratio of gas volume to moist and warm surface area and the less vascular squamous epithelium lining the oropharynx and hypopharynx .

7. Principles of humidifier function Temperature – As the temperature of a gas increases, its ability to hold water vapour (capacity) increases and vice versa. Surface area – There is more opportunity for evaporation to occur with greater surface area of contact between water and gas. Time of contact – There is greater opportunity for evaporation to occur, the longer a gas remains in contact with water. Thermal mass – The higher the mass of water or core element of a humidifier, the higher its capacity to transfer or hold heat.

8. Method of humidification

9. Methods Systemic hydration Heated water bath humidifier Heat & moisture exchange Large volume jet nebulizers Ultrasonic humidifier Bubble through humidification Passover humidifier

10. Heat and moisture exchange (HME ) Known as ‘Swedish nose’ Light weight disposal device Used with mechanical ventilator or breathing spontaneously Similar to nasopharynx It function without the additon of a water source or electricity . It collects and conserves the patient’s expired moisture and heat .

11. Considered to be passive humidifier Traps heat and humidity in expired gas Has been used to provide humidity for spontaneously and mechanically ventilated patients With a filter for bacteria and viruses it become Heat and Moisture Exchanging Filter (HMEF) Types of HMEs: simple condenser humidifiers Hydrophobic hygroscopic

12. Simple condenser humidifier Contains condenser element to trap heat and humidity of expired gas Retains about 50% of expired heat and humidity Maximum absolute humidity is 18 to 28 mg/L Hygroscopic heat exchanger Uses condenser element made of paper, wool, or foam Material includes a salt Maximum absolute humidity is 22 to 34 mg/L Active Heat Moisture Exchangers Add heat or humidity ( or both ) to inspired gas External heat and moisture is introduced into inspired gas Capable of providing 100 % relative humidity.

13. Hydrophobic H ydrophobic membrane with small pores Membrane is pleated to increase the surface area p rovides moderately good inspired humidity M ay be impaired by high ambient temperatures E fficient bacterial and viral filters P revent the HCV from passing A llow the passage of water vapor but not liquid water at usual ventilatory pressure A ssociated with small increases in resistance even when wet Hygroscopic Contain a wool/foam/paper like material coated with moisture-retaining chemicals Medium may be impregnated with a bactericide Composite hygroscopic HMEs – a hygroscopic layer plus a layer of thin, nonwoven fiber membrane that has been subjected to an electrical field to increase its polarity -- improves filtration efficiency and hydrophobicity . C omposite hygroscopic HMEs are more efficient than hydrophobic ones Lose their airborne filtration efficiency if they become wet; microorganisms held by the filter medium can be washed through the device Their resistance can increase greatly when wet

14. Type Hygroscopic Hydrophobic Heat and moisture exchanging efficiency Excellent Good Effect of increased tidal volume on heat and moisture exchange Slight decrease Significant decrease Filtration efficiency when dry Good Excellent Filtration efficiency when wet Poor Excellent Resistance when dry Low Low Resistance when wet Significantly increased Slightly increased Effect of nebulized medications Greatly increased resistance Little effect

15. Bubble through humidification Gas passes through tube to bottom of water reservoir Gas bubbles through reservoir Unheated bubbles through humidifier Provides humidity for oxygen therapy

16. Passover humidifier Direct gas over liquid or over surface saturated by liquid Types : Simple reservoir model Wick units Membrane devices Simple reservoir Gas flows over surface of volume of water Usually used as heated system to provide humidity to mechanically ventilated patients

17. Systemic hydration Increase the amount of fluid intake orally or intravenous To keep our body from dehydrated To avoid air way secretion become more tenacious

18. Hazards Inhalation of cold mist or water may cause bronchoconstriction in patients with hyper reactive airways. Water reservoirs – good culture medium for bacteria – increase risk of infection – regular disposal, disinfection or sterilization of all equipment is must.

19. NEBULIZATION

20. Nebulization is means of administering drugs by inhalation . Liquid Nebulisation is a common method of medical aerosol generation . A nebuliser is a device that converts liquid into aerosol droplets (fine mist) suitable for inhalation. Nebulisers use oxygen, compressed air or ultrasonic power to break up medication solutions and deliver a therapeutic dose of Aerosol particles directly to the lungs.

21. Indications Delivery of bronchodilator drugs : On acute attack of asthma Nebulization is the most common means of delivery. Administration of antibiotics and anti antifungal agents : In some cases of resistant chest infections for eg.cystic fibrosis antibiotics may be prescribed to be inhaled directly into the lung. To aid expectoration : Inhalation of hypertonic saline has been found to increase clearance of bronchial secretions. Local analgesia : To relieve dyspnea in patients such as those suffering from alveolar carcinoma.

22. Contraindications In some cases, nebulization is restricted or avoided due to possible untoward results or rather decreased effectiveness such as: Patients with unstable and increased blood pressure Individuals with cardiac irritability (may result to dysrhythmias ) Persons with increased pulses Unconscious patients (inhalation may be done via mask but the therapeutic effect may be significantly low)

23. Ideal Nebulizer A minimum residual volume(< 0.5 ml) Aerosol delivered only during inhalation. No waste aerosol released to the environment. Small and portable. Aerosol delivered with a droplet size distribution suitable for pulmonary deposition. Rapid treatment time , quite and unobtrusive in use. Finally,perhaps also a means to monitor patient compliance.

24. Particle size Mass median aerodynamic diameter ≤ 1μm : Reach up to the alveoli, 0.5-5μm: Beyond the 10th generation of bronchi ( respirable particles), ≥ 5 μ m : oropharynx

25. Nebulizers Solution or suspensions can be nebulized by ultrasonics or an air jet and administered via a mouthpiece, ventilation mask or tracheostomy . Types of nebulizers : Jet nebulizer Ultrasonic wave nebulizer Vibrating mesh Nebulizers

26. Air jet Nebulizer In air jet nebulizer compessed air is forced through an orifice , an area of low pressure is formed where the air jet exists. A liquid may be withdrawn from a perpendicular nozzle (the Bernoulli effect) to mix with the air jet to form droplets. A baffle within the nebulizer is often used to facilitate the formation of the aerosol cloud. Carrier gas (oxygen) can be used to generate the “air jet”.

27. Jet nebulizers are the most commonly prescribed because they are easy to use and inexpensive. Disadvantages : Less portable than inhalers Delivery may take 5 to 10 mins or longer . Require power sources, maintanance , cleaning . Traditional jet nebulizers are often bulky and require an electrical source, which can be a problem intraveling . Noisy

28. Breath-Enhanced Jet Nebulizers Continuous gas flow to neb chamber combined with patients inspired air. Exhaled air does not mix with aerosol, amount of solution wasted is minimized.

29. ADVANTAGES High output ,short treatments. Higher dose than T-Neb or MDI is possible . Multiple one –way valve reduce waste . Dishwasher safe, may be boiled or autoclaved Cost effective for long -term DISADVANTAGES Cannot be used in ventilator circuits. Not cost effective for short term use. Not readily adaptable to tracheostomy masks.

30. Ultrasonic Nebulizer Ultrasound waves are formed in an ultrasonic nebulizer chamber by a ceramic piezoelectric crystal that vibrate when electrically excited. These set up high-energy waves in the solution , within the device chamber ,of a precise frequency that generates an aerosol cloud at the solution surface.

31. Ultrasonic nebulisers (i.e. aerosonic nebulisers ) are characterised by fast nebulisation of medicine particles into extra small size for enhanced absorption in the very depth of the respiratory system, helping to increase the effects of medication . Ultrasonic nebulisers are fast and discreet with reduced noise levels . They can be used at home and during travel as many modern ultrasonic nebulisers are not only mains powered, but also battery powered for convenience. Car adaptors are also used for nebulisation on the move or for recharging batteries. The only drawback is medication restrictions because heat is transferred to the medication

32. Vibrating Mesh Nebulizer In this technology a mesh/membrane with 1000-7000 laser drilled holes vibrates at the top of the liquid reservoir, and thereby pressures out a mist of very fine droplets through the holes . This technology is more efficient than having a vibrating piezoelectric element at the bottom of the liquid reservoir, and thereby shorter treatment times are also achieved .

33. The high nebulization capacity (>0.25 ml/min) device offers short inhalation time. The old problems found with the ultrasonic wave nebulizer , having too much liquid waste and undesired heating of the medical liquid, have also been solved by the new Vibrating Mesh nebulizers .

34. New Generation Nebulizer AERx Advantages of the AERx System Small hand-held devices Very short administration time(typically 1-2 breaths) Highly efficient, precise aerosol delivery Breath control to ensure reliable drug delivery to lung Simple to use.

35. Nebulizer Solution Formulations Nebulizers are designed primarily for use with aqueous solution or suspension. Drug suspension use primary particles in the range of 2-5 microns . Nebulizer solutions are usually formulated in water, although other cosolvent for eg . Glycerin, propylene glycol,and ethanol may be used. Nebulizer solution pH be greater than 5.0 to show that bronchoconstriction is a function of hydrogen ion concentration .

36. Method of Administration Nebulized aerosol is introduced to the patient by compressed air from a device known as positive pressure ventilator . A mouthpiece may be inserted in the mouth may be attached tightly to the face . A face tent fits more loosely around the patients mouth,allowing speech . A tracheostomy mask may be fitted to the patients tracheostomy tube directly and require T shaped adapter.

37. Face masks should be avoided or sealed very tightly when anticholinergic drugs are administered to patients with glaucoma . Face masks should ideally also be avoided for delivery of nebulized corticosteroids, to prevent contact with the surrounding facial skin and eyes.

38. Practical Issues Cleaning : Nebulizers should be cleaned daily in regular usage and after each use in intermittent use. The mask, mouthpiece and chamber should be disconnected, disassembled and washed in a warm detergent and water solution. The components should be left to dry overnight. Before reuse, the nebuliser should be run for a few seconds before adding medications. Maintenance : Disposable components such as the mouthpiece, mask, tubing and nebulizer chamber should be changed every three to four months. Compressors require annual servicing by manufacturer or local service provider .