Med Administration Flashcards

1
Q

Off Label Use

A
  • Off the label is when drugs have FDA approval but are being used for a specific age, group, or purpose in which they do not have FDA approval for
    • Ex. Aspirin for prophylaxis of heart attack
  • This practice is legal as the FDA cannot by law regulate how is drug is medically used
  • Virtually all inhaled beta agonists and corticosteroid formulations have FDA approval for 12 year and older.
    • These will be prescribed when a suitable alternative does not exist
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2
Q

Why do we use off label uses for Pediatric populations so much

A

Pediatric patient are the most common group for which off label use medications are prescribed

Due to the fact that it is so hard to get studies approved for pediatric patients

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3
Q

What factors will affect depoistion in in children

A

Smaller tracheal diameter

Shorter trachea

Higher RR

Lower MV

Lower deadspace

Lower inspiratory flow rate

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4
Q

DEPOSITION OF MEDICATION IN CHILDREN

A

A smaller fraction of the dose of aerosol medication will reach the lower airways

Decreased aerosol drug deposition to lungs due to smaller diameter of NN and pediatric lower airways.

Lower deposition may provide a comparable safety and efficacy profile to adults.

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5
Q

What is the acutal dose that is though to be given to neonates, ped, and adulst

A

~1% in Neonates and Infants

2.5% in young children

10-15% in adults

Even though smaller %, small patients may receive a higher drug/kg than adults

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6
Q

Aerolsolized Therapy

When less than 6 months old

A

The child will have a small Vt which will affect TCT and inspiratory flow

Decreased time in the airways= decreased aerosol deposition

This means they will inhale a lower % of emitted aerosol dose

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7
Q

What is an anatomical saftey feature in children airway

A

Age and size have a self limiting effect on lung dose

Produces a natural titration of dose

Aerosol doses to neonates and children and thought to be self limiting

This is due to differences between pediatric and adult airways

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8
Q

Dosing for Infants and NN

A

Generally dosing with inhaled aerosols for neonatal and pediatric patients is not based on body size and blood level

Rather it will be based on a target effect strategy with avoidance of toxicity

We give the same dose (5 puff) of Ventolin to kids that are one as we do for kids that are 3

The 3 year old will still get more medication as their airway is bigger, they have a smaller RR, etc.

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9
Q

DEPOSITION FACTORS

Patient

A

Breathing Pattern

Inspiratory Flow Rate

Tidal Volume

Cry and distress-This will seriously effect efficiency of aerosol administration

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10
Q

DEPOSITION FACTORS

Device

A

Chamber Volume

Design of inspiratory and expiratory valves if present

Amount of deadspace in mouthpiece

Electrostatic charge on plastic devices

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11
Q

Higher RR

A

Higher RR will affect sedimentation

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12
Q

Faster Inspiratory Flow Rate

A

The faster they breath in the more intertia of impactation

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13
Q

Breathing Pattern in Young Children

A

Slow, fast, holding their breath (use a spacer), crying

Look at the value on the spacer as it will open as they breath or you can look at their chest and count 5 breaths

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14
Q

Spacers

A
  • The more expensive spacers will be antistatic, but when people take it home they tend to scrub it clean which can scrub off the antistatic coating
  • Kid spacer is smaller than adult spacers
  • What makes spacers effective
    • Slow down breathing
  • Children that are 2-3 is when you can start using a mouthpiece instead of a mask
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15
Q

Aerosol vs. MDI, MDI with Spacer vs. DPI

A

All are equally effective when used properly for delivering short acting B agonists

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16
Q

Nebs and MDI + Spacer

A

Nebs and MDI + Spacer are most useful in young children because they only require tidal breathing

Holds true even in acute asthma attacks

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17
Q

When the Child is 4 Years or Less

A

SVN with mask or mouthpiece if able

MDI plus Valved holding device (VHD)

For 3 years or older: mouthpiece preferable to mask if tolerated

For smaller children a smaller volume VHD is preferable, less time to empty chamber=higher delivery

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18
Q

When the Child is more than 4 Years

A
  • MDI with VHD
    • MDI should not be used without a VHD
    • VHD also reduces oral-pharyngeal deposition
  • We can recommend a DPI when the child is four
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19
Q

SLEEPING KIDS

A

~70% of children will wake up when aerosol is given during sleep

When they wake up they will become distressed and cry

Try to distract and comfort them

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20
Q

Age and Dose Regulating Effects

A

Age will have a dose regulating effect on the amount of aerosol drug reaching the lungs

Less drug will reach the lung in younger subjects, but more studies are needed

It is important to monitor the patient for adverse systemic effects

Choose appropriate device for the patient based on ability

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21
Q

DPI vs. MDI

A

DPI is more effective than MDI without a spacer. If their MDI does have a spacer then it is about equivilantto the effectiveness of DPI

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22
Q

Humidity

A

Water that exists in the form of individual molecules in the vaporous or gaseous state.

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23
Q

Aerosol

A

a suspension of particles (solid or liquid) present in gas (air):

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24
Q

Clinical Use of Aerosols

A

Humidify dry inspired gas, using water aerosol

Sputum induction & to improve mobilization and clearance of respiratory secretions using bland aerosols

Deliver aerosolized drugs (bronchodilators, anti-inflammatories and antibiotics) to respiratory tract

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25
Q

Medication delivery with Croup

A

With croup we will give something that settles in the upper airway as opposed to something that is avaliabelin the lower airway

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26
Q

Ultrasonic Nebulizer vs Small Volume Nebulizer

A
  • SVN do not have a high quality control where as USN will have a higher quality control
  • To get rid of residual volume in a SVN you need to top it up
    • Deadvolume= residual volume
  • There will be no residual volume with a USN
  • USN is fading away and we are using a ultrasonic mesh instead
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27
Q

Hand Bulb Atomizers

A

Do not use baffle

Aerosol suspension designed for upper airway deposition.

nasal spray pumps (steroids) rhinitis,

high MMAD and GSD

Will give us big particles and the high the particle the high it will settle

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28
Q

Hand Bulb Atomizer Used for

A

Upper airway inflammation

Rhinitis

Local anesthesia

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29
Q

Particle Size and Predicted Lung Deposition

Upper Airway

A

Particle 5-10 micron range tend to deposit in UA and early airway generations

Ex. Medicine for Croup

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30
Q

Particle Size and Predicted Lung Deposition

Nose

A

100% deposition of particle sizes >10 microns

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31
Q

Particle Size and Predicted Lung Deposition

Mouth

A

100% deposition of particle sizes >15 microns

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32
Q

Particle Size and Predicted Lung Deposition

Lower Airway

A

Particles 1-5 micron range able to reach LRT and lung periphery

This range also called ‘respirable fraction’

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33
Q

Measures of Central Tendency

A

lMedical aerosols contain particles of many different sizes.

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34
Q

2 Common Ways of Measuring Central Tendency

A
  • The average particle size is expressed in terms of a measure of central tendency.
    • Mass Median Aerodynamic Diameter (MMAD)*
  • Variability of particle sizes in an aerosol.
    • Geometric Standard Deviation (GSD)
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35
Q

Mass Median Aerodynamic Diameter (MMAD)

A

Describes average particle diameter (µm).

50% of the particles are smaller & have less mass.

50% of the particles are larger & have greater mass.

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36
Q

Geometric Standard Deviation (GSD) “The Spread”

A
  • The greater the GSD, the wider the range of particle sizes produced by a device.
    • GSD < 1.22, aerosol considered monodispersed = single particle size
    • GSD > 1.22, aerosol considered heterodispersed= range of particle sizes
      • Most aerosols used in respiratory care
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37
Q

Aerosol output

A

Weight or mass of aerosol particles produced by nebulizer (usually per minute)

Does not indicate amount of drug reaching lungs as majority of particles leaving neb never reach lungs

Only 10-50% of administered dose actually reaches LRT, depending on device used & technique

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38
Q

Deposition

A

Particles depositing out of suspension to remain in lung

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39
Q

Particle Size And Lung Distribution

A
  • Particle size is one of major factors affecting aerosol deposition in lung
  • Despite knowing its size, not possible to specify exactly where particle will deposit in lung
  • Particle deposition is function of several mechanisms:
    • Breathing pattern
    • Inspiratory flow rate
  • Thus site of penetration can be predicted but not confirmed
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40
Q

Particles > 10 microns

A

Tx nasopharyngeal or oropharyngeal regions

e.g. nasal spray for rhinitis

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41
Q

Particles 5- 10 microns

A

Deposition to more central airways with significant deposition in oropharyngeal region

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42
Q

Particles 2- 5 microns

A

Deposition in LRT

More adrenergic receptors in bronchioles (compared to rest of airway) thus ­response with bronchodilators

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43
Q

Particles 0.8- 3 microns

A

Delivery of aerosol to lung parenchyma

Used for anti-infective drugs such as pentamidine where intra-alveolar deposition needed with minimum deposition in airways due to irritation

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44
Q

Mass Median Aerodynamic Diameter (MMAD)

A

Describes average particle diameter (µm).

50% of the particles are smaller & have less mass.

50% of the particles are larger & have greater mass.

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45
Q

Aerosol Output:

A

Aerosol output: Weight or mass of aerosol particles produced by nebulizer (usually per minute)

Does not indicate amount of drug reaching lungs as majority of particles leaving neb never reach lungs

Only 10-50% of administered dose actually reaches LRT, depending on device used & technique

Fast the flow the smaller the particales

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46
Q

Mechanisms of Deposition

A

Inertial impaction

Gravitational settling (sedimentation)

Diffusion

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47
Q

Recommended MMAD for Mouth

A

> 15 um

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48
Q

Recommended MMAD for Nose

A

10-15 um

May just say > 10 um

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49
Q

Recommended MMAD for Lower Airways

A

2-5 um

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50
Q

Medicated Aerosol Therapy

A

Delivery of aerosol particles to respiratory tract for therapeutic purposes

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51
Q

Desposition

A

Particles depositing out of supsension to remain in the lung

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52
Q

Particle Size And Lung Distribution

A
  • Particle size is one of major factors affecting aerosol deposition in lung
  • Despite knowing its size, not possible to specify exactly where particle will deposit in lung
  • Particle deposition is function of several mechanisms:
    • Breathing pattern
    • Inspiratory flow rate
  • Thus site of penetration can be predicted but not confirmed
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53
Q

Inertial Impaction

A

Function of particle size (mass) and velocity

Direct relationship with mass and velocity

Primary deposition mechanism for large, high mass particles (> 5 microns)

Bigger particles can’t change direction easily.

Occurs in first 10 airway generations

Inital impact of large particles whose masses tend to retain the motion in a straight line. Meaning as airway direction changes the particle are depsoitied on nearby walls. Smaller particles are carried around corners by the air flow and will fall out less readily

54
Q

Sedimentation (Gravitational Settling)

A
  • Function of particle size and time
  • Occurs when aerosol particles settle out of suspension due to gravity
  • Increased settling for larger particles with slower velocities
    • Increased mass will lead to increased settling
  • Primary mechanism for deposition of particles in 2- 5 µm range
  • Occurs mostly in central airways
  • As sedimentation ­ with time, an end- inspiratory breath hold maximizes sedimentation
    • e.g. a 10 sec breath-hold can ­ aerosol deposition by ~ 10%
55
Q

Diffusion- Brownian Movement

A

Primary mechanism for deposition of small particles < 3 microns

Mainly occurs in alveolar region where bulk gas flow ceases and aerosol particle inertia is low

Small, low mass aerosol particles are easily bounced around by collisions with carrier gas molecules

Random molecular collisions cause deposition of some particles on to surrounding surfaces

Particles < 1 micron are so stable that they may remain suspended or even exhaled

56
Q

Upper and Central Airways

A

5-10 um

57
Q

Aersol Aging

A

Aging: Process by which an aerosol suspension changes over time.

Therapeutic aerosols are dynamic with particles constantly growing, shrinking, coalescing or falling out of suspension

58
Q

Aging of an aerosol depends on:

A

Ambient conditions

Composition of aerosol

Initial size of particles

Time in suspension

59
Q

Effect Of Temperature And Humidity

A
  • Aerosol particles change size as result of their hygroscopic tendency
  • Rate of particle growth is inversely proportional to their size
    • Smaller particles grow faster than larger particles
    • Small water based particles can also shrink when exposed to relatively dry gas
  • Aerosols are generated in relatively dry ambient conditions and then taken into airway where both temperature and humidity ­ (37°C and 100% relative humidity)
60
Q

Pattern Of Inhalation

A
  • Pattern of inhalation can influence aerosol drug delivery to lungs
  • It includes :
    • Lung volumes at beginning and end of inspiration
    • Inspiratory time and flow rates
    • Mouth vs nose breathing
    • Breath hold
  • Optimal pattern of inhalation varies with type of aerosol generating device
61
Q

Clinical Use of Aerosols

A

Humidify dry inspired gas, using water aerosol

Sputum induction & to improve mobilization and clearance of respiratory secretions using bland aerosols

Deliver aerosolized drugs (bronchodilators, anti-inflammatories and antibiotics) to respiratory tract

62
Q

Aerosol Generators Used Clinically Include:

A
  • Hand- bulb atomizers
  • Nebulizers
    • LVN
    • SVN
    • USN
    • SPAG
  • Inhalers
    • MDI
    • DPI
63
Q

Measures of Central Tendency

A
  • Medical aerosols contain particles of many different sizes.
  • Two common ways of quantifying
    • The average particle size is expressed in terms of a measure of central tendency.
      • Mass Median Aerodynamic Diameter (MMAD)*
    • Variability of particle sizes in an aerosol.
      • Geometric Standard Deviation (GSD)
  • Quantifying = Measuring=mathamatical value which helps us to compare things

GSD the range seen

64
Q

Disadvantages of Aerosol Drug Therapy

A

There are a number of variables that can affect dose of aerosol drug delivered to the airways

Difficulties in dose estimation and dose reproducibility

lack of technical information on aerosol producing devices

Inconsistency on devices use and on patient and health care provider comprehension

65
Q

Advantages of Aerosolized Medications

A

Onset is rapid as drug is delivered to the intended target area (respiratory tract)

Aerosol doses smaller than those for systemic treatment

Systemic side effects fewer and less severe than with oral or parenteral therapy. Parenteral: taken into the body in a way other than through the alimentary tract or digestive system (IV, IM)

Inhaled drug therapy painless and relatively convenient

66
Q

Effective Aerosol Therapy

A

Delivers adequate amount of drug to site of action

Minimal waste

Low cost

67
Q

Why do we care about particles sizes in aerosols?

A

We know size influences deposition. So if we want to target a specific part of the respiratory tract, we design an aerosol of appropriate size.

68
Q

Recommended MMAD for Parenchyma (alveolar Region)

A

0.8-3 um

69
Q

Hazards Of Aerosol Therapy

A
  • Primary hazard:
    • Adverse reaction to drug being administered
  • Other hazards include:
    • Infection
      • Aerosol generators can cause nosocomial infections by spreading bacteria by airborne route
    • Common sources of infection include:
      • Contaminated solutions (multiple drug dose vials)
      • Inadequate hand washing between patients
      • Contaminated respiratory equipment (homecare)
70
Q

The particle size of aerosolized drug released controlled by:

A
  • Vapor pressure of propellant blend
    • Increased vapor pressure will decrease particle size
  • Diameter of actuator opening
    • Decreased actuator opening Decreased particle size
71
Q

Types of Nebulizer

A

SVN

USN

SPAG

Operate on different physical principles to generate aerosol from solution

72
Q

Baffle

A

by which solution is shattered into suspension of liquid particles in carrier gas

73
Q

Most Nebulizers Contain

A

lReservoir chamber

lBaffle or a similar mechanism

74
Q

Small Volume Nebulizer

A

Hand held nebulizer

<10 ml volume

Clinical use for over 100 years

Small reservoir, gas powered (pneumatic) aerosol generators

High pressure gas source (air or O2)

50 psi wall outlet

Air compressor

Compressed gas cylinder

75
Q

SVN Equipment Design

A
  • Utilize jet shearing princiaple for creating aerosol from drug solution
  • Powered by high pressure stream of gas directed through a restricted orficie
  • Gas strem leaving jet passes htrough the opening of capillary tube immersed in drug solution
  • Produces low lateral pressure at its outlet due to high jet veolocity
  • Draws liquid up capillary tube and into jet stream where it is sheared into droplets producing a heterodisperseaerosol
  • This aerosol is also directed against one or more well designed baffles which reduces MMAD & GSD to within a target range
  • Droplets that impact on baffle return to reservoir to be nebulized again
76
Q

How much to put into a SVN & where to set the flow meter?

A

Residual or ‘dead’ volume

Ideal filling volume

Length of Tx time

Continuous vs intermittent nebulization

Gas source & flow rate

Physical nature of solution to be nebulized

Temperature and Humidity

77
Q

Residual Dead Volume and Jet Nebulizers

A

Jet nebulizers do not aerosolize below minimum volume called ‘dead’ volume

Dead volume is amount of drug solution remaining in reservoir when device begins to ‘sputter’ and aerosolization ceases

~ 0.5 to 1.0 ml but varies with different devices (always read the device manufacturers specifications)

78
Q

Ideal Filling Volume

A

At any given flow rate an increase in volume will result in an increase in time of effective nebulization

A volume between 3-5 ml (or as per manufecters recommendations) of solutions is recommended

79
Q

Treatment Time

A

Increase volume will also decrease concentration of drug remaining in residual volume thus increase drug dose to patient

increase volume will lengethn treatment time- too long may affect patient compliance (convience)

80
Q

Intermittent Nebulization

A

Accomplished by patient controlled finger port that directs gas to neb on inspiration only

Wastes less aerosol but increases treatment time

Technique requires good hand- breath coordination

81
Q

Effect of Gas Source and Flow Rate

A
  • Gas pressure and flow rate affect to variables
    • Size of particle produced
    • output (affecting length of treatment time)
  • Increase flow rate or gas pressure
    • decreased particle size and shift MMAD lower
  • Increased flow rate or gas pressure
    • increased output thus shorten time of treatment
    • At a flow rate of 6 lpm, volume 3 ml, treatment will last 10 min
    • At a flow rate of 8 lpm, volume 5 ml, treatment will last 10 min
  • Thus adequate flow rate for SVN is 6-8 lpm depending on volume
82
Q

Gas Density

A

Affects both aerosol production and deposition

Decrease density of carrier gas (heliox)-> Decrease aerosol impaction and thus better deposition in lungs

With heliox, output is much less than with air or O2 requiring ­ in flow to produce comparable weight of aerosol per minute

Thus even though heliox­ increased amount of aerosol in lungs, it requires very high flows

83
Q

Temperature and Humidity

A

Affect particle size and conc. of drug remaining in neb

Evaporation of water ®¯temp. of aerosol below ambient ®solution viscosity thus ¯neb output

Loss of water by evaporation ®¯particle size and solute concentration

Aerosol particles entrained into warm saturated gas stream, can grow in size depending on solution’s tonicity

84
Q

When Aerosol Particles Enter the Respiratory Tract

A

Aerosol from isotonic solntend to maintain their size

Aerosol from hypertonic solntend to in size

Aerosol from hypotonic solntend to shrink & evaporate

85
Q

Type Of Solution

A

Viscosity and density of medication formulation effects both its output and particle size

Performance of SVN is tested for different drug solutions

Cannot be assumed to produce adequate particle sizes for all solutions

Bronchodilator solutions generally meet above described specifications, thus are usually administered with these devices

86
Q

However with certain solutions, volumes and flow rates suggested earlier may need to be modified such as:

A
  • Pentamidine
  • Antibiotics that have different characteristics and viscosity
    • Gentamicin requires 10- 12 lpm to produce adequately small aerosol particles
87
Q

Advantages Of SVN

A

Less technique and device dependent

Minimal coordination

Effective with low insp flows and volumes which improve deposition

Useful in very young, very old, pts in severe distress, debilitated patients

No breath hold is required, although it can’t hurt

Patients in severe distress may have high inspiratory flows…we like the fact we can use a “hands free mask” & just continuously administer medication, eventually some medication reaches our intended target site

88
Q

Disadvanatges Of SVN

A

Treatment time can get long

Contamination

Wet cold spray with mask delivery

External power source-electrical power, or compressed gas

89
Q

Commonly Use Nebulizer Solutions

A
  • Salbutamol sulphate (Ventolin)
  • lpratropium bromide (Atrovent)
  • Combivent
  • Budesonide (Pulmicort)
90
Q

Salbutamol sulphate (Ventolin)

A
  • Reliever; bronchodilator; short acting beta agonist (SABA)
  • Single or Unit Dose Nebules
    • 2.5 mg in 2.5 ml
    • 5 mg in 2.5 ml
  • Multi-dose vial
    • 5 mg per ml
91
Q

lpratropium bromide

A

lpratropium bromide (Atrovent)

Reliever*; bronchodilator; short acting anticholinergic (SAAC)

  • Single dose or unit nebules
    • 125 mcg/ml
    • 250 mcg/ml
  • Multi-dose vial
    • 250 mcg/ml
92
Q

Combivent

A

Combines salbutamol sulphate with ipratropium bromide (ventolinwith atrovent)

Reliever; bronchodilator; SABA with SAAC

93
Q

SABA vs. SAAC

A

SABAs work to relieve bronchospasm in the small airways

SAACs work to prevent bronchospasm in the larger airways (bronchi)

94
Q

Budesonide

A

Budesonide (Pulmicort)

Controller; Anti- inflammatory; steroid

Single or Unit dose vials

  • 0.125 mg/ ml in 2 ml
  • 0.25 mg/ ml in 2 ml
  • 0.5 mg/ ml in 2 ml
95
Q

Geometric Standard Deviation (GSD) “The Spread”

A

The greater the GSD, the wider the range of particle sizes produced by a device.

GSD < 1.22, aerosol considered monodispersed = single particle size

GSD > 1.22, aerosol considered heterodispersed = range of particle sizes

Most aerosols used in respiratory care

96
Q

What will enhance particle deposition by inertial impaction

A

Turbulent Flow

Convoluted passages

Bifurcation of the airways

Inspirtory flows of > 30 lpm

97
Q

Ultrasonic Nebulizers (USN)

A
  • Electrically powered
  • Can deliver high output and high aerosol densities
  • Operate on piezoelectric principle
    • Uses piezoelectric crystal to create aerosol
  • Crystal transducer converts electrical signal into high frequency acoustic vibrations
  • Vibrations create oscillation waves
  • Oscillation waves form droplets which break free as fine aerosol particles
  • Not routinely used in hospitals for aerosolization of medications
98
Q

Advantages of USM

A

Small size

Rapid nebulization with shorter treatment time

smaller filling volume

portability (batteries)

As dead space is minimal we can use a small volume of solution and shorter treatment time-Can also be used for undilated bronchodilators

99
Q

Dsiadvantages of USM

A

Expensive

Fragility-Lack of durability

Infection control

100
Q

Small Particle Aerosol Generator (SPAG)

A

Large reservoir, pneumatically powered nebulizer

Can hold 300 ml of soln for long periods of nebulization

Operates on jet shearing principle with baffle, also has drying chamber to further reduce particle size to ~1.3 µm MMD

Solns in SPAG reservoir replaced 24 hours

Residual solution discarded before adding new solution

Nebulizer connected to hood or ventilator for administration to patient

101
Q

Small Particle Aerosol Generator (SPAG) and Ribavarin

A

Used for administering ribavirin (antiviral agent) in the treatment of RSV

There are other ways to treat RSV in infants that may be used.

Ribavarin with a type of interferon is also used to treat Hep C

102
Q

Types of Inhalers

A

Metered Dose Inhalers (MDIs)

  • Puffers

Dry Powdered Inhalers (DPI)

  • Turbuhaler
  • Diskus
  • Handihaler
103
Q

Metered Dose Inhalers

A

Small pressurized canisters

Multiple doses of accurately metered drug

Many different drugs & come in different doses

3- 6 µm MMAD

Initial velocity and dispersion of aerosol ~ 80% of dose leaving actuator to impact and deposit in oropharynx

Pulmonary deposition ranges 10- 20%

104
Q

Technical Design of Metered Dose Inhalers

A
105
Q

Metered Valve Function

A

When inverted and placed in actuator, suspension will fill the metering valve chamber

When canister is depressed into actuator, drug- propellant mixture in metering valve is released under pressure

  • Liquid propellant is ejected from pressurized valve rapidly expanding and vaporizes (ambient pressure)
    • shatters liquid stream into an aerosol
  • Upon release, metering valve refills with drug- propellant mixture from canister ® ready for next discharge
  • Metering valve volume: 30 to 100 µL
    • ~60- 80 % by weight consists of propellant
    • ~ 1% active drug
107
Q

Metered Dose Inhaler-Propellant

A

Drug mixed/suspended in with propellant

Dispersing agents or surfactants added to prevent coalescence of drug particles

Propellants: Chloro-fluoro carbons (CFCs) have been replaced with hydrofluoro alkanes (HFAs)

Propellants maintain steady vapor pressure as canister used / exhausted

Pressure in canister is specific to medication formulation

108
Q

Factors Affecting MDI Performance

A
  • Increase or decrease of drug concentration in first discharge, or if standing unused
  • Drug suspension can separate from propellant when stored unused (creaming)
  • MDI canister needs to be shaken before first actuation & if not used for period of time
  • Rapid actuations can lead to turbulence and coalescence of particles
    • Actuations – at least 30 seconds apart
  • Loss of propellant from metering valve
    • Little or no drug discharged on actuation
    • Can be felt and heard by user
    • Usually takes days and weeks to occur
  • Regular use of MDI prevents this!
109
Q

Advantages of MDI

A

Portable and Compact

Efficient Drug Delivery

Shorter treatment time

110
Q

Disadvantages of MDI

A

Complex hand- breathing coordination required (if no holding chamber used)

Canister depletion difficult to determine accurately

Possible reactions to propellant

High oropharyngeal impaction and loss if holding chamber not used

Foreign body aspiration of coins and debris from mouth piece

Sensitive to extremem temps

111
Q

MDI Contents

A

The MDI is empty is on shaking

  • it seems light
  • There is no movement of particles
  • Recently there will be a counter which indicates 0 doses left

You can hold the canister next to your ear and shake it several times. If it has medicine, you’ll hear and feel the liquid contents swishing back and forth.

Another method is to keep track of the number of puffs you take in a notebook. You could also plan how long it will last based on the prescribed puffs per day: for example, using 2 puffs, 2 times a day. Calculate how many days this will last.

112
Q

Spacers and Holding Chambers

A

Simple extension devices that puts distance between MDI and patient’s mouth

MDI accessory devices designed to decreaseinitial velocity of particles released from MDI before reaching oropharynx

Decrease oropharyngeal deposition

Can reduce bad taste of meds and eliminate cold propellant effect

Allow for vaporization of propellants and decrease particle size by evaporation thus better deposition in LRT and lung

113
Q

Reservoir Device

A

Also known as extension device

is the global term for spacers and holding chamber

It will slow down and decrease the size of the particles

The longer the device the slower and smaller the particle will become

114
Q

Spacer

A

Simple extension device

Extend aerosol spray away from the mouth

115
Q

Holding Chamber

A

A spacer device with the addition of one way valves

Contain and hold aerosol until inspiration occurs

116
Q

Reservoir Designs

A

Size

Shape

Volume

Presence of a one way valve

Inspirtory flow indicators

117
Q

Advantage of Reservoir Devices

A

Decrease oropharyngeal drug loss

Sligt seperation of MDI actuation and inhalation

118
Q

Disadvantage of Reservoir Devices

A

Some brands are large and cumbersome

Assembly required

Possible source of bacterial contamination with inadequate cleaning

119
Q

Dry Powder Inhalers (DPI)

A

Unit doses of drug in powder form

Breath actuated and dispense drug during inspirtion

Flow from user creates an aerosol micro fine solid particles of drug as it is inhaled through the mouth piece

Are as effective as MDIs for deposition and drug response

120
Q

Common DPI Designs

A

Diskus

Turbuhaler

HandiHaler

121
Q

Diskus

A

Pre loaded doses

Each dose contained in a foil blister which is advanced and opened as the inhaler is used

122
Q

Turbuhaler

A

Powder preparation reloaded in the device-Opened by rotating grip or thumb wheel

High number of doses (60-200)

May have a counter incorporated which will give a warning when there are ~ 20 doses left

Effective flow rate ~40 lpm (30-60 lpm)

Desiccating agent present

123
Q

HandiHaler

A

Contains a single dose powder preparation of drug in gelatin capsule

Capsule inserted into the device and punctured to release powder prior to inhalation

Carrier subsatnce (glucose or lactose) improves flow properties of powder suitable volume to unit dose

124
Q

Advanatges of DPI

A

Small and portable

Short preparation and administration time

less hand- breathing coordination

No propellants (thus environmentally friendly)

No ‘cold freon effect’ causing bronchoconstriction or inhibiting full inspiration

Count of remaining drug doses relatively easy

No extension device needed

125
Q

Disadvantages of DPI

A

Patients not as aware of dose inhaled thus may distrust delivery

Possible reaction to glucose or lactose carrier substance

High inspiratory flow rates needed

Most of carrier impacts in oropharynx & can cause irritation

126
Q

Important Points to Remeber in Regards to DPI

A

High Inspirtory Flows are the most critical factor in DPIs-Inspirtory flow of >30-60 lpm are needed

Should not be used with patient that are unable to generate a high inspiratory flow (small children, acute bronchospasm, etc)

Exhalation into the device may result in a loss of drug

High humididty can affect DPI drug avalibility-Hygroscopic partical will clump together when exposed to high humididty thus increasing particle size

127
Q

Factors Associated With Reduced Aerosol Drug Deposition In The LungCriteria For Choosing An Aerosol Delivery Device

A

Mechanical ventilation

Artificial airways

Reduced airway size (infants and children)

Severe airway obstruction

Poor patient compliance and Technique

Limitation of specific delivery device

128
Q

Criteria For Choosing An Aerosol Delivery Device

A
  • Avalibility of drug formula
  • Desires site of deposition
  • Patient
    • age
    • Acuity of problem
    • Alertness
    • Ability to follow instruction
    • Preference
129
Q

When to Use a Small Volume Neb

A
  • Emergency
    • Unable to follow instruction/disoriented
    • Tachypneic (>25 bpm)
      • Unstable respirtory pattern
    • Poor inspirtory capcity
    • Incapability of breath hold
  • Patient preference/home use
  • Formulation of drug
130
Q

When to Use of MDI

A

Able to follow instruction and demonstrate correct use

Adequate inspirtory capcity

Capable of breath hold

stable respirtory pattern

drug is avalible in MDI form

131
Q

When to Use a Reservoir Device

A

With all MDI aerosol

Especially in patient that have poor hand breathing coordination

Enhanced MDI use and reduced oropharyngeal losss

132
Q

When to Use a DPI

A

Drug available in DPI form

Poor MDI coordination

Sensitive to propellants

Capable of generating high inspiratory flow rates (> 30-60 lpm) depending on drug

Need accurate dose count monitoring

Strive for consistency with devices.

133
Q

What Happends when we add Normal Saline into a SVN

A

Adding diluent (normal saline) does not alter amount (dose) of drug present in neb;

Conc. of solution is less but not amount of drug