S92
`
`Thorax 1997;52(Suppl 2):S92–S101
`
`Selecting and using nebuliser equipment
`
`A H Kendrick, E C Smith, R S E Wilson
`
`Aim of nebuliser therapy
`The aim of nebuliser therapy is to deliver a
`therapeutic dose of the desired drug in the form
`of an aerosol of respirable particles within
`a
`fairly
`short period of
`time, usually
`5–15 minutes. To achieve this, nebuliser sys-
`tems should be expected to provide a drug
`output with about 50% of the particles below
`5.0 lm mass median diameter. It is important
`to obtain an acceptable range of aerosol particle
`sizes because of the way in which these are
`deposited in the tracheobronchial tree.1–5
`
`when determining the fill volume required to
`deliver a drug to a patient.9
`Fill volume: the volume of drug solution initially
`put into the nebuliser chamber. It must exceed
`the residual volume by a suYcient amount to
`provide therapeutic benefit to the patient.9 It is
`suggested that it should be at least twice the
`residual volume. It is important to be aware
`of the desirable fill volume when prescribing
`nebuliser drugs in prepackaged ampoules.
`The definitions of aerosol output, respirable
`particles, mass median diameter (MMD), mass
`median aerodynamic diameter
`(MMAD),
`respirable output, and respirable fraction are
`given in the paper by O’Callaghan and Barry
`on page S35.
`
`Practical definitions
`Jet nebuliser: a nebulising chamber where an
`aerosol is generated from a flow of gas from an
`electrical compressor or from a compressed gas
`supply (air or oxygen). The gas passes through Factors aVecting nebuliser performance
`a very small hole (the jet or Venturi) resulting
`The general term “nebuliser” usually implies
`the combination of the nebuliser chamber and
`in liquid being sucked up through the small
`hole from the chamber base and atomised.
`the compressor. Jet nebulisers usually have a
`constant output, but to prevent wastage new
`The resultant large particles then impact upon
`baZes to generate small respirable particles.6
`breath-enhanced nebulisers are available where
`Ultrasonic nebuliser: an electrically driven sys-
`the output is enhanced in the inhalation phase.
`Ultrasonic nebulisers are eVective but are less
`tem whereby a rapidly vibrating piezoelectric
`robust and more expensive than jet nebuliser
`crystal vibrates the drug solution and produces
`aerosol particles of a respirable size.6
`systems and are generally not used for regular
`Flow rate through the nebuliser: the flow rate
`domiciliary therapy.
`of gas, whether from a compressed source or
`The major use of nebuliser systems is to
`deliver bronchodilator
`therapy. The
`spe-
`from a compressor, that actually drives the
`nebuliser chamber. It is not the same as the
`cification of the nebuliser chamber for ad-
`flow rate from the compressor which will often ministering bronchodilators is diVerent from
`be considerably higher.7 It is obtained by pro-
`that required to deliver other drugs such as
`antibiotics or pentamidine.
`ducing a pressure-flow rate curve for the nebu-
`liser. Recordings of circuit pressure are made
`The output of a nebuliser is determined by
`a combination of factors which must be taken
`from zero flow (maximum pressure) to max-
`imum flow (minimum pressure) using a rota-
`into account, and will depend on (1) the design
`of the nebuliser chamber,6 (2) the flow of the
`meter, a compressor unit (or flow generator),
`and pressure measuring device. By substituting
`driving gas and the performance characteristics
`of the compressor,7 10 11 (3) the volume of solution
`the nebuliser chamber for the rotameter the
`pressure in the circuit can be obtained with a
`(fill volume) of the drug at the start of nebu-
`lisation,9 12 (4) the time taken to nebulise the
`constant flow rate from the flow generator.
`solution of drug,7 9 (5) the viscosity, surface ten-
`From the pressure-flow curve the flow rate at
`the nebuliser can be obtained.7
`sion, and concentration of the drug solution,13
`(6) the residual volume,9 and (7) tapping of the
`Volume output from the nebuliser: the volume of
`solution leaving the nebuliser chamber. Whilst
`nebuliser chamber during nebulisation.
`useful as a general guide to nebuliser per-
`The volume output and particle size of water,
`formance, it does not give precise information
`saline,
`salbutamol,
`terbutaline, and ipra-
`about the actual drug output.2
`tropium bromide are similar.14 For more vis-
`Drug output
`from the nebuliser: the actual
`cous solutions the volume output is much
`slower (fig 1).13 15 The output of steroids may
`amount of drug that is released during nebu-
`lisation. Because of a variety of factors, in-
`be similar to salbutamol although the drug is
`cluding evaporation, a precise measure of drug
`a suspension. However, the volume output
`output (as opposed to volume output) must be
`from a nebuliser is not directly related to the
`assessed using marker techniques.8
`drug output,8 and the drug output and its
`availability are diVerent between broncho-
`Residual volume: the volume of solution left
`in a nebuliser chamber once nebulisation has
`dilators, antibiotics, and steroids. Measuring
`ceased and all of the aerosol particles have been
`volume output is simple and provides a guide
`generated and have left the nebuliser chamber.
`to the performance of nebuliser/compressor
`combinations.7 16
`It is an important volume to take into account
`
`Respiratory
`Department,
`Bristol Royal
`Infirmary,
`Bristol BS2 8HW, UK
`A H Kendrick
`
`Department of
`Medicine,
`c/o Respiratory
`Department,
`Bristol Royal
`Infirmary,
`Bristol BS2 8HW, UK
`E C Smith
`
`Department of
`Respiratory Medicine,
`Royal Shrewsbury
`Hospitals NHS Trust,
`Shrewsbury SY3 8XQ,
`UK
`R S E Wilson
`
`Correspondence to:
`Dr A H Kendrick.
`
`IPR2021-00406
`United Therapeutics EX2076
`
`

`

`Selecting and using nebuliser equipment
`
`S93
`
`ticular types of nebuliser or combinations of
`nebuliser and compressor will be required. The
`final choice of equipment should be made by
`the staV of the local unit and not by supplies
`departments acting in isolation.
`Specific information will be required to assist
`the choice. For the nebuliser this should include
`data on the flow rate at the nebuliser, residual
`volume, maximum fill volume, the volume (or
`drug) output at five and 10 minutes, the MMD
`(or MMAD), and the percentage of particles
`under 5 lm. For the compressor the size,
`weight, noise levels, and ease of use are im-
`portant considerations for patients and their
`families. Any clinical data that the supplier can
`provide on the clinical use of the system should
`also be obtained.
`
`Antibiotic solution
`Salbutamol
`Ipratropium bromide
`Saline or water
`
`10
`20
`30
`Nebulisation time (min)
`
`40
`
`5
`
`1234
`
`0
`
`0
`
`Volume (ml)
`
`Figure 1 The output of water/saline, salbutamol,
`ipratropium bromide, and an antibiotic solution. Those
`solutions with a specific gravity of 1 have similar rates of
`output. The slightly more viscous antibiotic solution has a
`slightly slower rate of output. Data from reference 14.
`
`Selecting nebulisers and compressors
`The choice of nebuliser and compressor de-
`pends on various factors including cost, ease Nebuliser/compressor combinations
`of use and of maintenance, and overall per-
`The performance of a given nebuliser chamber
`is closely linked to the flow of the driving gas
`formance. There are many nebuliser chambers
`and compressors available. Choice should be
`and, hence, the performance of the compressor
`chosen to drive the nebuliser chamber.7 It is
`based on assessment of the systems and com-
`ments from other users. It is not advisable
`therefore important
`to use a combination
`of nebuliser chamber and compressor that
`simply to pick a nebuliser chamber and a com-
`pressor at random. As will be discussed below,
`delivers an acceptable volume output of drug,
`the matching of a nebuliser and compressor with an acceptable range of respirable particles,
`is important to achieve optimal performance.
`over an acceptable period of
`time to the
`patient.7 12 16–23
`Furthermore, under certain circumstances par-
`
`Table 1 Examples of combinations of compressors and nebuliser chambers supplied for bronchodilator therapy. The
`compressors have been divided into high, medium, and low flow rates and have been used with the nebuliser chambers
`indicated
`
`Flow rate
`
`Compressor
`
`Nebuliser chambers sold
`with compressor unit
`
`Multivolt?
`
`High flow rate
`(>6.0 l/min)
`
`MicroMist
`AFP Classic
`MicroMist
`AFP Aquillon
`MicroMist
`AFP Ultima
`MicroMist
`AFP Tourer
`Flaem Nuova Type 3
`Flaem Nuova Combineb
`Flaem Nuova Micelfluss Pro Flaem Nuova Type 2
`Medic-Aid CR50
`Medic-Aid Sidestream
`Medic-Aid CR60*
`Medic-Air Ventstream
`Medic-Air Freeway
`Gast*†
`Inspiron*
`Medix M Flo
`Medix AC2000*
`Medix World Traveller
`Medix Econoneb
`Medix Minor*†
`Medix Turboneb
`Porta-Neb
`
`MiniNeb, Incenti-Neb
`Medix A11
`Medix A11
`Medix A11
`Medix A11
`Cirrus
`Cirrus
`Medic-Aid Sidestream
`Medic-Aid Ventstream
`Medic-Aid Sidestream
`Perma Neb
`
`Medium flow rate
`(4.0–6.0 l/min)
`
`Low flow rate
`(<4.0 l/min)
`
`Porta-Neb Multi
`SunMist Plus
`
`Aeroneb HP†
`Atomolette†
`Flaem Nuova M70
`NebuPump†
`Novair II
`Pari InhalierBoy†
`Pari TurboBoy
`Pari JuniorBoy
`Pulmo-Aide†
`SunMist
`DeVilbiss Traveller
`
`Aeroneb Standard†
`Pari WalkBoy
`Aeroneb HP†
`
`Cirrus
`Own
`Flaem Nuova Type 2
`Acorn
`Cirrus
`Own
`Pari LC Plus, LC Plus Junior
`Pari LC Plus, LC Plus Junior
`Own
`Perma Neb
`Perma Neb
`
`Own, Cirrus
`Pari LC Plus,
`Own
`
`No
`No
`Rechargeable battery
`Yes
`Yes
`Yes
`No
`No
`Yes
`?
`No
`No
`No
`Yes
`No
`No
`No
`No
`
`Yes
`No
`
`No
`No
`No
`No
`No
`No
`No
`No
`No
`No
`Yes
`
`No
`Yes
`No
`
`Others
`
`Yes
`Wright
`Aerolyser CF1B†
`Yes
`Respi-Neb
`Aerolyser CF1R†
`Yes
`Respi-Neb
`Aerolyser 216†
`Yes
`Flaem Nuova Type 3
`Flaem Nuova Travelneb
`Yes
`Hudson MK II
`Henley HCU-1†
`* Wilson and Steventon have tested these compressors with 19 nebuliser chambers: Acorn, Aerflo, Cirrus, DeVilbiss, Econoneb,
`Hudson II, Jet set, MicroCirrus, MicroNeb III, MiniNeb, Sandoz, Suremist, Turret Turbo, Unicorn, Unimist, Unineb, Upmist
`and Wee Neb. With these compressors they all achieved flow rates at the nebuliser of >6.0 l/min.
`† These devices may not be currently available but are included since they may still be in use.
`
`

`

`S94
`
`Kendrick, Smith, Wilson
`
`Table 2 Details of nebuliser chambers. For each chamber the residual volume, maximum fill volume, the percentage of
`particles under 5 lm, and the mass median diameter (MMD) is given. The percentage of solution nebulised at five and
`10 minutes is also given as a guide to nebuliser output. Data from various sources.
`
`Nebuliser
`chamber
`
`Acorn
`A11
`Aeroflo
`Aeroneb
`Aeromist
`Aiolos
`Atomolette
`Ava Neb 1780
`Cirrus
`Cloud Chamber
`DeVilbiss 646
`Econoneb
`Flaem Nuovo Type 2
`Flaem Nuovo Type 3
`Hudson Neb MKII
`Hudson UD I
`Hudson UD II
`Incenti-Neb
`Jet set
`MicroCirrus†
`MicroMist
`MicroNeb
`MiniNeb
`Pari Boy
`Pari LC Plus
`Pari LC Plus Junior
`Perma Neb
`Raindrop
`Respi-Neb
`Respirgard II†
`Sandoz
`Medic-Aid Sidestream
`System 22 Mizer
`Turret Turbo
`Unicorn 1035
`Unineb
`Upmist
`Venticaire
`Medic-Aid Ventstream
`Wee Neb
`Wright
`
`Residual
`volume
`
`Maximum
`fill volume (ml)
`
`% nebulised
`
`5 minutes
`
`10 minutes
`
`% particles
`under 5 lm
`
`MMD
`(lm)
`
`1.76
`1.1
`?
`?
`?
`?
`?
`?
`0.9
`?
`2.1
`?
`0.5
`0.5
`?
`2.3
`1.4
`?
`?
`1.2
`?
`0.9
`2.3
`2.0
`1.0
`0.9
`1.2
`?
`?
`1.3
`?
`0.7
`2.0
`?
`?
`?
`?
`?
`1.0
`?
`?
`
`15
`?
`?
`?
`?
`?
`?
`?
`10
`10
`3
`25
`7.0
`8.0
`?
`17
`10
`20
`?
`10
`10
`13
`38
`9
`8
`8
`9
`?
`?
`9
`?
`12
`15
`20
`10
`?
`?
`?
`10
`?
`20
`
`30
`30
`?
`19
`?
`?
`33
`32
`40
`?
`26
`?
`?
`?
`50
`?
`25
`?
`?
`?
`?
`28
`41
`50
`50
`55
`39
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`
`38
`38
`?
`38
`?
`?
`36
`48
`46
`?
`44
`?
`?
`?
`57
`?
`33
`?
`?
`?
`?
`59
`51
`64
`50
`55
`75
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`?
`
`79
`58
`?
`30
`?
`?
`28
`58
`80
`42
`70
`40
`?
`?
`82
`82
`79
`54
`?
`90
`76
`78
`79
`64
`60
`54
`70
`?
`?
`?
`?
`83
`73
`73
`68
`?
`?
`?
`86
`?
`83
`
`3.69
`4.42
`?
`7.50
`?
`?
`7.60
`4.30
`3.50
`?
`2.20
`?
`1.32/2.36*
`1.07/4.64*
`2.60
`4.80
`3.29
`?
`?
`1.20
`2.10
`3.63
`3.54
`4.16
`3.80
`4.60
`2.50
`?
`?
`1.88
`?
`3.18
`4.65
`?
`?
`?
`?
`?
`3.17
`?
`?
`
`The data in this table have been compiled from various sources and provide a guide only. Whilst the residual and maximum fill
`volumes are accurate, the percentage of solution nebulised at 5 and 10 minutes is the best figure obtainable. This has been
`obtained for a fill volume of 2–2.5 ml and is generally taken from data obtained with its retail compressor. The % of particles
`under 5 lm is taken from various sources. Where a ? appears there are no data currently available from any known source.
`* Depends on configuration of nebuliser chamber (Type 2) and on type of compressor unit. Data are for diaphragm/rotary piston
`compressors.
`† Data with pentamidine.
`
`poor performance system has resulted in either
`a reduction in the quality of life or increase in
`hospital admissions. Part of the reason for this
`is probably that the doses of bronchodilator
`drugs being administered are large and that
`even ineYcient systems deliver enough drug to
`ensure maximal bronchodilatation.
`
`AeroNeb
`Aquillon
`
`1
`10
`Particle size (m m)
`
`100
`
`100
`90
`80
`70
`60
`50
`40
`30
`20
`10
`0
`0.1
`
`Percentage of particles
`
`Figure 2 Two examples of particle distribution showing
`the cumulative percentage of particles within diVerent
`particle sizes for a high flow rate combination (Aquillon
`compressor with Neb MK II; flow rate 7 l/min) and a low
`flow rate combination (AeroNeb Standard compressor with
`Cirrus; flow rate 3 l/min). The fill volume in both cases
`was 2.5 ml of sterile water. For the Aquillon the percentage
`of particles less than 5 lm was 83%, while for the
`AeroNeb Standard it was 35%. Based on data from
`reference 7.
`
`bronchodilator therapy
`We have divided some currently available nebu-
`liser/compressor combinations into three bands
`based on the flow rate at the nebuliser (table
`1). High flow rate combinations produce more
`than 50% of the particle size output less than
`5 lm diameter and have an MMD of less than
`5 lm.7 16 19–21 The lower flow rate combinations
`have less than 40% of their particle size output
`below 5 lm diameter and an MMD of more
`than 9 lm. The performance of some of the
`nebuliser chambers is given in table 2. Particle
`size distributions may diVer with diVerent com-
`binations of nebuliser and compressor (fig 2).
`Breath assisted nebulisers such as the Vent-
`stream and Pari LC have been shown to have
`improved performance.23
`An important point about nebulising broncho-
`dilator drugs is whether or not there is a need
`for a specific combination or combinations.
`Whilst there are criteria for attaining an optimal
`performance, this may not matter in practice
`since subjective benefit and objective broncho-
`dilatation are the most
`important
`factors.
`There are a number of nebuliser/compressor
`combinations currently available that do not
`achieve the standard criteria.7 However, these
`systems are still being used and there have been
`no reports to suggest that long term use of a
`
`

`

`Selecting and using nebuliser equipment
`
`S95
`
`2.5 ml
`4.0 ml
`
`0
`
`1
`
`2
`
`3
`
`4
`5
`6
`Time (min)
`
`7
`
`8
`
`9
`
`10
`
`5
`
`1234
`
`0
`
`Drug (mg)
`
`Table 3 Examples of nebuliser/compressor combinations for antibiotic therapy
`
`Compressor
`
`Nebuliser chamber
`
`Medic-Aid CR60
`Medic-Aid Porta-Neb
`Medic-Aid CR50
`AFP Tourer
`AFP Classic
`AFP Aquillon
`
`AFP Ultima }
`
`Pari TurboBoy
`Pari JuniorBoy
`
`Respirgard II
`Medic-Aid Ventstream
`Medic-Aid Sidestream, MicroCirrus, Raindrop, Hudson UD II
`
`Medic-Aid Ventstream, MicroMist,
`MicroNeb III, MicroCirrus, Medic-Aid Sidestream
`
`Pari LC Plus, Pari LC Plus Filter
`Pari LC Plus Junior, Pari LC Plus Filter
`
`Data from various sources and from other centres using antibiotic therapy. This list is not
`exhaustive and other devices may be suitable.
`
`antimicrobial agents
`It is preferable for high power nebuliser systems
`to be used with antibiotics.16 24–28 A powerful,
`continuously rated compressor should be used
`(table 3). Various nebuliser chambers have been
`shown to be acceptable, although in some cases
`nebulisation times were longer than is perhaps
`ideally required by the patient.29
`
`Figure 3 Comparison of rate of delivery of drug with a
`2.5 ml and a 4.0 ml fill volume. The 2.5 ml fill volume
`delivers the same amount of drug as the 4.0 ml fill volume
`but in approximately half the time. Data obtained using a
`Sidestream nebuliser under simulated tidal breathing using
`compressed air to drive the nebuliser. The residual volume
`is 0.5 ml. For a fill volume of 2.5 ml nebulisation time to
`“dryness” was six minutes which increased to 10 minutes
`using the 4 ml fill volume. The 70% increase in
`nebulisation time increased the drug output by only 12%.
`Data from reference 12. Reproduced from reference 9 with
`permission.
`
`mucolytics and saline
`Where mucolytics such as acetylcysteine are
`used, standard delivery systems, as shown in
`table 1, can be used. The high and medium
`flow rate systems appear to be adequate,30 31
`especially since there appears to be little diVer-
`ence in the rate of output of saline and of
`bronchodilators.14
`
`rhDNase
`Current recommendations are based on limited
`data.32–35 rhDNase should be nebulised using
`a jet nebuliser since ultrasonic nebulisers may
`inactivate it or have unacceptable aerosol char-
`acteristics. Recommended combinations are
`given in table 4.
`
`steroids
`These can be nebulised with medium or high
`power systems as shown in table 5.
`
`Volume-time output and fill volume
`Four criteria should be considered:
`(1) The minimum initial fill volume is de-
`termined by the size of the residual volume of
`the nebuliser chamber. The larger the residual
`volume, the greater the initial fill volume will
`need to be.9 17 22 The residual volume of the
`modern, small volume, nebuliser chambers is
`less than 1.0 ml (table 2) and for these a fill
`volume of 2.0–2.5 ml of drug solution is
`
`Table 4 Recommended nebuliser/compressor combinations
`for rhDNase therapy
`
`Compressor
`
`Pulmo-Aide
`
`Pari InhalierBoy
`Pari TurboBoy
`Aiolos
`Medic-Aid Porta-Neb
`Medic-Aid CR50
`Medic-Aid CR60
`AFP Aquillon
`
`Nebuliser chamber
`
`Hudson T Up-draft II
`Airlife Misty
`A11
`Pari LL, Pari LC
`Pari LC Plus
`Aiolos
`Medic-Aid Sidestream
`Medic-Aid Sidestream
`Medic-Aid Sidestream
`MicroMist
`
`Data from studies using Pulmozyme.
`
`enough. Increasing the fill volume with a small
`volume nebuliser (Sidestream) will deliver the
`same amount of drug but over a longer period
`of time (fig 3).12 Where the residual volume is
`greater than 1.0 ml, a larger initial fill volume
`is required. Since many nebuliser drugs are now
`available in prepackaged ampoules of 2.0 ml
`or 2.5 ml, it is important to ensure that the
`nebuliser chamber used by a patient either has
`a small residual volume or that the patient is
`instructed to dilute the contents of the ampoule
`with normal saline and to make up the initial
`fill volume to at least twice the size of the
`residual volume. Table 6 lists suitable com-
`binations of nebuliser chambers and drug am-
`poules.
`(2) The time taken to deliver the drug is
`important for patient compliance. The opti-
`mum time for nebulisation is 5–10 minutes.
`Patients will generally not accept long delivery
`times (fig 4), especially if the treatment is re-
`quired several times per day.29
`(3) The end point of nebulisation needs
`to be defined. There is some evidence that
`nebulising “to dryness” is confusing for patients
`and is diYcult for them to define (fig 5). Jet
`nebulisers nebulise continuously until the fill
`volume approaches the residual volume and
`“spluttering” occurs.36 At this point, although
`
`Table 5 Examples of nebuliser/compressor combinations
`suitable for corticosteroid therapy
`
`Compressor
`
`Nebuliser chamber
`
`Medic-Aid Porta-Neb
`
`Medic-Aid Ventstream
`Medic-Aid Sidestream
`Cirrus
`Hudson
`Turret
`Medic-Aid Ventstream
`Medic-Aid Freeway
`Medic-Aid CR60/CR50 Cirrus, A11
`DeVilbiss 646
`Hudson Up-draft II
`Turret
`MicroMist
`Medic-Aid Sidestream
`Medic-Aid Sidestream
`Pari LC Plus, LC Plus Junior
`Pari LC Plus, LC Plus Junior
`
`AFP Aquillon
`AFP Tourer
`AFP Ultima
`Pari TurboBoy
`Pari JuniorBoy
`
`Data from various sources. This list is not exhaustive and other
`devices may be suitable.
`
`

`

`S96
`
`Kendrick, Smith, Wilson
`
`Table 6 Nebuliser chambers suitable for use with proprietary pre-packaged nebuliser solutions
`
`Trade name
`
`Ampoule size (ml)
`
`Nebuliser chambers
`
`Drug
`
`Terbutaline
`
`Ipratropium†
`
`Salbutamol/ipratropium
`Salbutamol
`
`Bricanyl Respules
`
`Atrovent
`
`Steri-Neb ipratropium
`
`Combivent
`Steri-Neb Salamol
`Ventolin Nebules
`
`2.0
`
`2.0
`
`2.0}
`2.5 }
`
`2.5
`2.5
`
`Pari LC Plus, LC Plus Junior,
`Cirrus, Medic-Aid Sidestream,
`Flaem Nuova Types 2 and 3,
`MicroNeb,
`Medic-Aid Ventstream
`
`As 2.0 ml plus Respirgard
`
`All of above, plus A11, Hudson,
`Pari Boy
`
`Medic-Aid Ventstream,
`Cirrus, Turret,
`Hudson MicroMist,
`DeVilbiss 646,
`Pari LC Plus, LC Plus Junior
`
`As above for 2.0 ml
`
`Hudson UD II, Acorn, Medic-Aid
`Sidestream, Medic-Aid
`Ventstream, Aiolos, Pari LC Plus
`
`Fenoterol/ipratropium
`
`Duovent
`
`Budesonide
`
`Pulmicort Respules
`
`Sodium cromoglycate
`
`Intal
`
`Dornase alpha
`
`Pulmozyme
`
`4.0
`
`2.0
`
`2.0
`
`2.5
`
`It is taken that at least 50% of the drug solution should be available for nebulisation and without the need for dilution with
`normal saline. Data from British National Formulary.
`† Also available in 1.0 ml ampoules containing 250 lg/ml. The 2.0 ml ampoule contains 500 lg/ml. Use of the 1.0 ml ampoule
`will need dilution as no nebuliser chamber has a residual volume of less than 0.5 ml.
`
`volume output is reduced because of evap-
`oration, drug output remains high for a short
`period of
`time (fig 6). This suggests that
`patients should be told to nebulise until splut-
`tering occurs and then to continue for a further
`minute. Previous tests should have shown that,
`with the fill volume used, the system reaches
`this point in 10 minutes or less. It is essential
`that the compressor/nebuliser combination is
`working eYciently and has no faults.
`(4) During nebulisation (particularly with new
`units) large particles tend to adhere to the sides
`of the nebuliser. Adherence becomes less as the
`nebuliser ages. These large particles can be en-
`couraged to fall back into the well of the chamber
`by tapping the side of the nebuliser chamber
`once the nebuliser begins to “splutter”. There is
`evidence that this may improve output by up to
`50% over a given period of time (fig 7).
`
`Ease of use
`The choice of nebuliser chamber should, to
`some extent, be based on its ease of use. In
`general, chambers should (1) not contain com-
`ponents that can be easily swallowed by small
`children (ideally, all nebulisers should consist
`of a removable top and the single component
`chamber); (2) be easily disassembled and re-
`assembled by patients of all ages (this is par-
`ticularly important in the elderly and in patients
`whose manual dexterity is significantly im-
`paired); and (3) employ a chamber that can be
`left connected to the compressor, rest on a flat
`surface, or be mounted on the compressor
`itself, and so be filled easily.
`
`Mouthpieces/face masks and venting
`circuits
`Lung deposition is the same in adults or older
`children, when either a mouthpiece or face
`mask can be used.37 38 Face masks are better
`for infants and younger children, and for emer-
`gencies. Mouthpieces are recommended when
`steroids or anticholinergics are being nebulised.
`
`Acceptable
`
`Tolerable
`
`Unacceptable
`
`5
`
`10
`
`15
`20
`Nebulisation time (min)
`
`25
`
`30
`
`5
`
`10
`
`15
`20
`Nebulisation time (min)
`
`25
`
`30
`
`Adults
`50
`
`40
`
`30
`
`20
`
`10
`
`0
`
`Children
`50
`
`40
`
`30
`
`20
`
`10
`
`0
`
`Number
`
`Number
`
`Figure 4 Patient acceptability of diVerent durations of nebuliser treatments. Most patients
`preferred a treatment time of 10 minutes or less. Unpublished data from R S E Wilson.
`
`7–8
`
`8–9
`9–10
`Minutes
`
`10–11
`
`12
`
`10
`
`8 6 4 2
`
`0
`
`Number of patients
`
`Figure 5 Recognition by patients of “dryness” at the end
`of nebulisation. The combination of a Charles Austen
`compressor with a MiniNeb nebuliser would usually reach
`residual volume in 10 minutes with a fill volume of
`2.0–2.5 ml. Following explanation of the meaning of
`“dryness”, patients timed the system to “dryness” with a
`stopwatch in minutes and seconds (n = 39 episodes).
`Unpublished data from J Pugh and R S E Wilson.
`
`

`

`Selecting and using nebuliser equipment
`
`S97
`
`potential problems in patients with glaucoma.
`There have been no long term studies but short
`term studies in normal subjects and in patients
`with narrow angle glaucoma show that up to
`four times the recommended dose of inhaled
`ipratropium has no eVect on intraocular pres-
`sure, pupil diameter, or accommodation.39–41
`However, prolonged pupillary dilation occurs
`if ipratropium is sprayed directly into the eye.42
`The addition of salbutamol intensifies the risk,
`especially in patients with glaucoma,43 44 so
`patients should be carefully instructed in the
`use of nebulised anticholinergic agents, en-
`suring that a face mask is tight fitting, or pre-
`ferably,
`that administration occurs via a
`mouthpiece.
`
`antibiotics
`There are possible risks to staV associated with
`exposure to antibiotics (see paper by Webb and
`Dodd on pp S69–71), so it is important that
`the circuit should contain either a filter or the
`exhaled air be vented directly to the external
`atmosphere by wide bore tubing through an
`open window. Where appropriate filters are
`available, these should be used in preference
`to venting. Mouthpieces should be used.
`Appropriate antibiotic T-pieces and circuitry
`is important to prevent waste from the system
`polluting the surrounding atmosphere, al-
`though there is no published medical evidence
`to indicate that pollution of the hospital at-
`mosphere may lead to the establishment of
`resistant organisms.
`
`steroids, pentamidine
`Mouthpieces are the preferred option.
`
`Albuterol delivered (mg)
`
`Albuterol delivered (mg)
`
`Albuterol delivered (mg)
`
`Single use or single patient use?
`The Medical Devices Agency has recently is-
`sued a bulletin45 regarding the use of devices
`such as nebulisers for single use or single patient
`use. Where nebulisers are marked by the manu-
`facturer as “single use” they may only be used
`once and should then be discarded. Where
`nebulisers are marked “single patient use” then
`they are reusable items that are capable of being
`reused, with or without reprocessing, by an
`individual patient. Some nebuliser chambers
`are reusable and so may be used on diVerent
`patients as long as appropriate reprocessing, as
`indicated by the manufacturer, is followed.
`Whilst nebuliser chambers have been cate-
`gorised as “single patient use” for many years
`throughout the world, this new clearly defined
`categorisation of the use of devices means that
`both the manufacturer and physician in charge
`should define the extent and the methods by
`which “single patient use” devices should be
`If a face mask is used it should be closely fitting
`used and reprocessed. Within the letter of the
`to the face and should not be held away from law, devices marked “single use” should only
`the face.
`be used once and then discarded. Reusing such
`devices may leave the physician and/or the
`respiratory team open to litigation should any
`problem arise as a result of using a “single
`use” device as a “single patient use” device.
`Manufacturers should mark the packaging of
`
`0
`
`0
`
`50
`
`100
`
`150
`
`200
`Time (s)
`
`Figure 6 Aerosol output rate (percentage of aerosol delivered every five seconds) and
`drug output for initial fill volumes of (A) 1.5 ml, (B) 2.5 ml, and (C) 3.5 ml plotted
`over six minutes of nebulisation. A DeVilbiss 646 jet nebuliser and a Pulmo-Aide 5610D
`compressor were used. With a fill volume of 1.5 ml there was an abrupt fall in output
`after 45 seconds whilst with fill volumes of 2.5 ml and 3.5 ml the fall-oV points were 160
`seconds and 320 seconds, respectively. Each of these abrupt fall-oV points corresponded to
`the onset of nebuliser “spluttering” – the point where the droplet rain-oV from the nebuliser
`walls is insuYcient to supply aerosol for renebulisation. There is an audible change in
`pitch and air bubbles can be seen sporadically. Drug output was observed to decrease at
`approximately these points with the 1.5 ml and 2.5 ml fill volumes. Redrawn with
`permission from reference 36.
`
`bronchodilators
`Usually the choice depends on patient pref-
`erence. Use of
`ipratropium bromide poses
`
`Aerosol volume
`Drug delivered
`
`1.0
`
`0.8
`
`0.6
`
`0.4
`
`0.2
`
`50
`
`100
`
`150
`
`200
`Time (s)
`
`250
`
`300
`
`350
`
`0.0
`400
`
`1.0
`
`0.8
`
`0.6
`
`0.4
`
`0.2
`
`50
`
`100
`
`150
`
`200
`Time (s)
`
`250
`
`300
`
`350
`
`0.0
`400
`
`1.4
`
`1.2
`
`1.0
`
`0.8
`
`0.6
`
`0.4
`
`0.2
`
`250
`
`300
`
`350
`
`0.0
`400
`
`A
`
`10
`
`8
`
`6
`
`4
`
`2
`
`0
`
`0
`
`B
`
`4
`
`3
`
`2
`
`1
`
`0
`
`0
`
`C
`
`4
`
`3
`
`2
`
`1
`
`% of delivered aerosol volume
`
`% of delivered aerosol volume
`
`% of delivered aerosol volume
`
`

`

`Kendrick, Smith, Wilson
`
`Conversation
`
`Busy street
`at 50 cm
`
`traffic
`
`radio
`Quiet
`
`Turboneb
`Econoneb
`Pari
`Aquillon
`Aeroneb Standard
`Aeroneb HP
`PortaNeb 50
`Atomolette
`Medix AC2000
`Medix World Traveller
`Medix Minor
`Pulmo-Aide
`Nebu Pump
`AFP Classic
`AFP Traveller
`Inspiron
`Novair II
`
`0
`
`10
`
`20
`
`50
`40
`30
`Noise (dB)
`
`60
`
`70
`
`Figure 8 Range of noise encountered when using various
`nebuliser/compressor systems. Noise was measured one
`metre from the combination of nebuliser/compressor using
`standard equipment. Data from reference 7.
`
`Turboneb
`Econoneb
`Henleys HCU-1
`Aerolyser 216
`Aerolyser CF1R
`Aerolyser CF1B
`Pari
`Aquillon
`Aeroneb Standard
`Aeroneb HP
`PortaNeb
`Atomolette
`Medix AC2000
`Medix World Traveller
`Medix Minor
`Pulmo-Aide
`Nebu Pump
`AFP Classic
`AFP Traveller
`Inspiron
`Novair II
`
`0
`
`2
`
`4
`6
`Mass (kg)
`
`8
`
`10
`
`Figure 9 Variation in weight for a number of nebuliser/
`compressor units. Data from references 7 and 17.
`
`is particularly important to patients who have
`to travel with their system.7 16 The weights of
`various compressor/nebuliser combinations are
`shown in fig 9.
`
`costs
`Running costs may be an important con-
`sideration for patients with limited income.
`Low energy consumption units would therefore
`be appropriate for these patients, so long as
`the other performance requirements were met.
`Figure 10 shows the relative costs of various
`compressors where a patient has four 15 minute
`year.7 These
`nebulisations/day
`for one
`costs are calculated from the power rating
`
`Acorn
`Mini-Neb
`Sandoz
`
`Free standing
`
`Attached to
`compressor
`
`Tapping nebuliser
`unit
`
`2
`
`1
`
`0
`
`S98
`
`Output (ml)
`
`Figure 7 EVects of “tapping” on the volume output from 10 nebuliser units. The in-
`circuit flow was 6–8 l/min, the fill volume was 2.0 ml, and the nebulisation time was over
`10 minutes. Data from reference 14.
`
`nebuliser chambers as “single use” or “single
`patient use” and provide instructions for re-
`processing of “single patient use”. The user
`must ensure that he or she uses the correct
`type of device and, if in doubt, should contact
`the supplier directly. Items that contain no
`indication of use should be avoided.
`One major problem with nebuliser chambers
`is their potential for cross-infection. To date
`there does not appear to be any evidence that
`these devices are responsible for the acquisition
`of infecting organisms, although bacterial cul-
`tures of non-pathogenic organisms have been
`reported.46 47 It is therefore important that good
`hygienic practice is followed48 to reduce, as far
`as possible, any risk of infecting organisms
`being colonised within the nebuliser chamber.
`Further research into this and into aspects
`of the degradation of nebuliser performance
`with time are required to clarify the need for
`carefully defining how nebuliser chambers are
`used in practice.
`
`Compressors: other factors for
`consideration
`standards
`All compressors should be certificated to British
`Standard 5724 or to an European equivalent.
`The certificate should be from an independent
`testing authority which should be stated by the
`manufacturer.
`
`noise
`Noise can be an important factor in the ac-
`ceptability of treatment, both to the patients
`and to their families and friends. The system
`should be as quiet as possible. An assessment
`of the noise of a range of devices is depicted
`in fig 8 which shows the range and how it
`relates to a variety of defining points used to
`assess noise pollution.7
`
`weight
`To be portable, the compressor and associated
`components should be as light as possible. This
`
`

`

`Selecting and using nebuliser equipment
`
`S99
`
`constant rate, with the particle size such that
`most are less than 5 lm. For other substances
`the evidence is less clear.
`
`For the future
`The major problem encountered in choosing
`the appropriate combination of nebuliser and
`compressor is the scarcity of consistent in-
`formation. There is clearly a need for the as-
`sessment of all possible combinations currently
`available, and there must also be a clear con-
`sensus as to what information is essential and
`what is helpful but secondary in use.
`To provide information on every com-
`bination of nebuliser and compressor will be
`diYcult, time consuming, and expensive. How-
`ever, if a number of laboratories were to be
`accredited to perform comparisons to set
`protocols, much of the diYculty in making
`statements about nebuliser and compressor
`combinations for the various nebulised drugs
`would be reduced.
`
`1 Brain JD, Valberg PA. Deposition of aerosol in the respiratory
`tract. Am Rev Respir Dis 1979;120:1325–73.
`2 O’Callaghan C. How to get drugs into the respiratory tract.
`Arch Dis Child 1993;68:441–3.
`3 Rees BJ, Clark TJH. The importance of particle size in
`response to inhaled bronchodilators. Eur J Respir Dis