This document discusses humidification and nebulization in respiratory therapy. It defines humidification as artificially conditioning gas used for patient respiration. The two main humidification methods are active, using heat/water, and passive, recycling heat/humidity from exhalation. Inadequate humidification can cause various clinical issues. Nebulization delivers drugs to the lungs through an aerosol. Different nebulizer types are described including jet, ultrasonic and mesh varieties. Ideal particle sizes for deposition in different lung regions are noted.

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

13. 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.

14. Hydrophobic
 Hydrophobic membrane with
small pores
 Membrane is pleated to
increase the surface area
 provides moderately good
inspired humidity
 May be impaired by high
ambient temperatures
 Efficient bacterial and viral
filters
 Prevent the HCV from
passing
 Allow the passage of water
vapor but not liquid water at
usual ventilatory pressure
 Associated 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.
 Composite 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

15. 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

16. 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

17. 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

18. 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

19. 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.

20. NEBULIZATION

21.  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.

22. 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.

23. 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)

24. 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.

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

26. 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

27. 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”.

28.  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

29. 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.

30. 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.

31. 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.

32.  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

33. 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.

34.  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.

35. 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.

36. 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.

37. 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.

38.  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.

39. 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.