Chapter 15: Humidity and Aerosol Therapy
Lack of Response to Inhaled Asthma Medication
-Incorrect inhalation technique -Inhalation from an empty canister -Failure to take preventive medications as prescribed -A change in the patient's environment -Misdiagnosis
What is the respirable range of aerosol droplets?
1 to 5 µM
The particle size of aerosols for medical purposes should be?
1 to 5 μm
Aerosol Drug Administration Aerosol generators produce particles with a MMAD of ____.
1-5 uM
For a pMDI, how long do you have to wait in between doses?
30 seconds
Multiple-Dose Dry Powder Inhaler Patient must produce an inspiratory flow greater than ________________ to inhale the medication.
35 LPM
Isothermic saturation boundary (ISB) is at
3rd generation of the airway, 5 cm below the carina
Inspired gas warmer than ________ may cause thermal injury
45 C
If a patient has a fresh lung transplant, what device is used?
Heated humidification circuit
If a patient has bloody, thick tenacious sputum, what device is used?
Heated humidification circuit.
What influences the delivery of aerosol medications?
Humidity
________________ is the addition of water to the gas delivered to the airways.
Humidity therapy
_________________ can be used effectively in patients receiving mechanical ventilation and in spontaneously breathing patients with a tracheostomy.
Nebulizers and pMDIs
*Nebulizers and pressurized metered dose inhalers* (pMDIs) with valved holding chambers are suggested for use with ____________ and _____________ who cannot coordinate the use of pMDI or dry-powder inhaler (DPI)
-children <4 years of age -adults
Advair
-contains bronchodilator and steroid
What are the primary factors affecting aerosol delivery? (DIGD)
-deposition -inertia -gravity -diffusion
Multiple Dose Dry Powder Inhaler
-device contains a month's prescription -Diskus -Flexhaler -Diskhaler (single) -BREO (Ellipta)
Devices used for Humidification Bubble Humidifier
-dry gas is directed into a water-filled reservoir, where the steam of gas is broken into bubbles -typically not heated and are used with simple oxygen devices.
Use of HMEs is limited by their __________ and their __________.
-effectiveness -dead space
Continuous Aerosol System
-gives continuous medication -has a Y-connector 1)one end->nonrepreating reservoir bag with valve 2)other end-> nebulizer
What devices used to deliver therapeutic aerosols?
-jet nebulizers -ultrasonic nebulizers -metered dose inhalers -metered dose inhalers with a spacer or holding chamber -dry powder inhalers.
Normal Heat and Moisture Exchange Air is a ____________ of heat, the mouth is ______________ than the nose at heating inspired air.
-poor conductor -less efficient
Single Dose Dry Powder Inhalers
-pt loads single dose capsule prior each use -handihaler -aerolizer -podhaler -neohaler
What are some of the factors that affect aerosol delivery by nebulizer?
-technical factors -manufacturer -gas flow -fill volume -solution characteristics -characteristics of driving gas -designs to enhance output -continuous vs. intermittent delivery -pt factors -breathing pattern -nose vs. mouth breathing -characteristics of gas -airway obstruction -positive pressure delivery -artificial airway and mechanical ventilation
Bland Aerosol Indications
-the presence of upper airway edema (cool bland aerosol) -Laryngotrachebronchitis (LTB) -subglottic edema -postextubation edema -postoperative management of the upper airway -the presence of a bypassed upper airway -the need for sputum or mobilization of secretions
What happens when cilia is damaged?
-thicker secretions -mucus plugging -decrease bronchopulmonary hygiene
Devices used for Humidification Jet Nebulizer
-uses a compressed gas that passes through a restricted orifice -The delivered *relative humidity is 100%* if condensate is seen in the delivery tubing near the patient's airway.
Devices used for Humidification Passive Humidifier
-uses exhaled heat and moisture to humidify inspired gas -directs gas over the surface of body of water -"artificial nose" -heat and moisture exchanger (HME)
Valved holding chamber with mask
-usually 140-750 mL in volume -allows the plume from the pMDI to expand and incorporates a one-way valve that permits the aerosol to be drawn from the chamber during inhalation only.
Should the temperature probe of a humidifier be placed inside an incubator or under a radiant heater?
No, because the surrounding air temperature affects humidifier function.
________________ all affect the ability of an aerosol to penetrate the mucous barrier.
Particle charge, solubility, and size and the biophysical properties of secretions
Deposition
The amount of aerosol (medication) that gets deposited in the lungs/airways.
What part of the airway is an efficient humidifier?
The upper airway
What is an In-Check DIAL Inhaler Technique Training and Assessment Device used for?
This is used to teach proper inspiratory flow to the patients.
True/False Passive humidification is not recommended for noninvasive mechanical ventilation.
True
If a patient DOES NOT have bloody, thick tenacious sputum, what device is used?
Use an HME
For patients who cannot use a mouthpiece, what can be an alternative?
a nebulizer, it can be fitted to an appropriate mask.
__________ humidifiers may be heated or unheated
active
Devices used for Humidification Active humidifier
adds water or heat or both to the inspired gas
Aerosol Drug Administration An ______________ is composed of particles suspended in air.
aerosol
Bland aerosol is primarily indicated to provide humidification of medical gases for patients with ______________.
bypassed upper airways.
The delivered relative humidity is 100% if __________________ is seen in the delivery tubing near the patient's airway.
condensate
Normal Heat and Moisture Exchange *During exhalation*, heat is transferred from exhaled gas to the tracheal and nasal mucosa by __________________.
convection
The efficiency of HMEs (inclines/declines) as the tidal volume, inspiratory flow, or fractional inspired oxygen concentration increases.
declines
Normal Heat and Moisture Exchange Inspired gas is ____________________ with water vapor at body temperature when it reaches the lung parenchyma.
fully saturated
What does it mean to "prime" the device?
getting the device ready for admin -shake, roll, warm canister in your hands -2 pumps -inspecting the mouthpiece for foreign objects
________ can be used to maintain heat and humidity in gas delivery.
heated circuits
A general rule, _______________ is *superior* to HME for a spontaneously breathing patient with a tracheostomy.
heated humidity
Bland aerosol therapy provides _______________ with solutions such as saline for therapeutic and diagnostic purposes.
humidification
The ______________- should be assessed for condensate near the patient.
humidity delivery device
Dosing of aerosolized medication is (precise/imprecise.)
imprecise
Heated Passover humidifier
most commonly used during mechanical ventilation
The ventilator circuit requires the __________ to be attached with connectors.
nebulizer or pMDI
For premature and newborn infants, a __________ thermal environment should be maintained.
neutral
The ____________ is an efficient humidifier.
nose
Aerosol Drug Administration Monodisperse
particles are basically the same size (under 1.2)
The HME forms a barrier between the _______________.
patient and the ventilator circuit
When providing humidification to patients with low tidal volumes, such as when lung-protective ventilation strategies are used, HMEs are not recommended because _______________________.
they contribute additional dead space, which can increase the ventilation requirement and PaCO2
The _____________ is an effective humidifier.
upper airway
Indications for a heated circuit instead of HME
- tracheostomy, lung transplant, or any fresh organ transplant - thick, bloody secretions - core temp less than 32 degrees celsius - if patient *NEEDS* 37 degrees celsius & RH 100% - if HME has to be replaced more often than every 48 hours
Diffusion
-*Brownian movement* is the primary mechanism of deposition of particles less than 3µm in the airway. -As gas reaches the distal regions of the lungs, its flow stops.
Spacer- must have an internal volume of more than _________ and provide distance of __________ between the MDI and first wall or baffle.
-100mL -10-13 cm
Normal Temperature and Humidity of Gas @ Airway Opening
-22 C -50% RH -10 mg/L
Normal Temperature and Humidity of Gas in the Pharynx
-29-32 C -95% RH -28-34 mg/L
Normal Temperature and Humidity of Gas in the Trachea
-32-34 C -100 RH -36-40 mg/L
When providing *active humidification* to patients who are *invasively ventilated*, it is suggested that the device provide a humidity level between _______ and ______ and gas temperature between ____ and _____ at the Y piece with relative humidity of 100%.
-33 mg H2O -44 mg H2O -34 C -41 C
Normal Temperature and Humidity of Gas Along the Respiratory Tract Isothermic Saturation
-37 C -100 RH -44 mg/L
You are asked to help a patient who is having difficulty using her pMDI. What would you do to help her improve her inhaled technique?
-A spacer -Coaching and educating the patient
Small Particle Aerosol Generator (SPAG)
-Administers Ribavirin only -Usually used to treat RSV -N-95 mask -Neg. pressured room -Usually seen with an aerosol mask -runs about ~14-16 hours
Respimat Soft Mist Inhaler
-Aerosol produced by the respimat moves much *slower* and has a more *prolonged duration* than a pMDI. -Spiriva (tiotropium bromide)
Device Selection for Humidity Therapy
-Does the patient have normal or diseased lungs? -Is there evidence of increased, thick secretions or a humidity deficit? -Are special needs imposed by dead space or the patient's size, age, ability to tolerate administration, or sensitivity to changes in the work of breathing?
Gravity
-Gravitational sedimentation occurs when aerosol particles settle out of suspension because of gravity. The greater the mass, the faster it settles. -Breath holding for *4 to 10* seconds after inhalation of an aerosol lengthens the residence time for particles in the lungs, increasing deposition- especially the last six generations of the airway. -Breath holding increases deposition up to 10%.
Pressurized Metered Dose Inhaler w/ spacer or valved holding chamber
-If device produces a whistle, your *inspiration is too rapid*
Vented Breath-Enhanced Nebulizer
-Inlet allows the patient to inhale additional air through the nebulizer, increasing drug deliver on inspiration. -The inlet vent *closes on exhalation.* -*Reduces the aerosol waste.* -It *synchronizes aerosol generation with inspiration*, increasing the amount of drug for inspiration by up to fourfold. -There needs to be a nice tight seal over the mouthpiece *TOBI (antibiotic)* is the medication administered through this nebulizer
Inertia
-Is the tendency of an object with mass, once it is in motion, to travel in a straight line. The greater the mass and velocity of a particle, the greater the inertia that keeps it in motion. -This is the primary mechanism of deposition of aerosol particles *2µm - 5µm or larger*.
A hypothermic patient arrives in your emergency department. You are asked to provide warm humidified gas to speed rewarming. How effective do you think that will be?
-It wont be effective, there are other ways to provide warmth -Pt can not inhale over 45 C -Heating blanket would be a lot more efficient
Aerosol Medication Delivery Devices
-Jet nebulizer (SVN) -Mesh nebulizer -Soft mist inhaler -Ultrasonic nebulizer (USN) -Pressurized metered dose inhaler (pMDI) -Metered dose inhaler with spacer or holding chamber -Dry powder inhaler (DPI)
Nebulizer for Pentamadine Administration
-Nebulizer with valves and expiratory filter. -This device is called nebupent -PCP- pneumocystis carinii pneumonia -Usually seen in post lung pt with weak immune system or AIDs or immunosupressed pts -N-95 mask required
Heat and Moisture Exchanger
-Passive humidifier. -HME AKA *artificial nose.* -HME *increase* dead space, weight and resistance to the airway. -HMEs are about 70% efficient. -do not need to be changed more often than every 48 hours
Breath-Actuated Nebulizer
-Pneumatic breath-actuated nebulizer that *responds to the patients inspiratory flow*, producing aerosol during inspiration and ending during expiration. -*It has an option to only delivers medication when the patients inhales.* *Aeroclipse Neb Mostly seen with CF pts*
Omron *Mesh* Nebulizer
-Portable nebulizer -expensive -looks like a vape, lol.
Selection of an Aerosol Delivery Device
-The choice of device often is determined by patient preference or clinician bias. -*Proper patient education is critical*. -Aerosol therapy should be administered with some easily remembered activity of daily living.
What are the goals of humidity therapy?
-To provide adequate heat and humidity -To treat hypothermia -To prevent airway response to cold air -To aid removal of thick secretions
Mesh Nebulizer
-Use of a vibrating mesh (Aerogen, Aeroneb, Pari eFlow) contraction and expansion of a vibrational elements produces *upward and downward movement. * -has mesh, better deposition
Jet Neb
-Uses *Bernoullis principle.* -An effective small volume nebulizer (SVN) should deliver more than 50% of it's total dose -aerosol range (1-5 um) in 10 minutes or less of nebulization time. -*Use flow from 6-8 L/min* -One Medication-5-10 -More than one medication-10-12
HME use is effective in prevention of _________ compared with _________ humidification.
-VAP -active
What are the Factors Affecting Aerosol Delivery During Mechanical Ventilation?
-Ventilator Related -Device related- pMDI -Drug related -Circuit related -Device related -Patient related
Factors Influencing Aerosol Delivery During NIV
-Ventilator Related -Device related- pMDI -Drug related -Circuit related -Device related-nebulizer -Patient related -Breathing parameters -Type of interface
Device Selection for Humidity Therapy
-What source, temperature, and humidity of gas is the patient breathing? -What is the point of entry of gas into the airway? -What is the rate of inspiratory flow or minute volume? -Does the patient have an intact or a bypassed upper airway?
Bland Aerosol Hazards and Complications
-Wheezing or bronchospasm -broncoconstriction when artificial airway is employed -infection -overhydration -patient discomfort -edema of airway wall
Humidifiers can provide ________ or _______ humidification.
-active -passive
Gas density affects both _________ and _____________ to the lungs.
-aerosol generation -delivery of aerosol
What is nonivasive ventilation (NIV)?
-bipap or cpap machine -no artificial airway in place
Bland Aerosol Contraindications
-bronchoconstriction -history of airway hyperresponsiveness
How long should the patient hold their breath after administering medication via pMDI?
10 seconds or as long as you can
For a pMDI w/ spacer or valved holding chamber, how long do you have to wait in between doses?
15 seconds
(Active/Passive) humidification is suggested for noninvasive mechanical ventilation, as it may improve adhere and comfort.
Active
Pneumatic jet nebulizers use the ________________ to *drive a high-pressure gas through a restricted orifice.*
Bernoulli principle
______________ is used for therapeutic and diagnostic purposes.
Bland aerosol therapy
Multiple-Dose Dry Powder Inhaler Not recommended for ______________.
Children under 5 y/o.
What dictates which aerosol options are available for delivery of a specific medication.
Drug formulations
______________ create aerosols by drawing air through a dose of powdered medication.
Dry powder inhalers (DPIs)
Approved devices for specific drug formulations Formulation: Pentamadine (NebuPent)
FDA- Approved Device Marquest Respirgard II
Approved devices for specific drug formulations Formulation: Ribavirin (virazole)
FDA- Approved Device SPAG
Approved devices for specific drug formulations Formulation: Aztreonam (cayston)
FDA- Approved Device altera nebulizer system
Approved devices for specific drug formulations Formulation: Iloprost (ventavis)
FDA- Approved Device i-neb adaptive aerosol delivery (AAD) system
Approved devices for specific drug formulations Formulation: treprostinil (tyvaso)
FDA- Approved Device optineb
Approved devices for specific drug formulations Formulation: Dornase alfa (pulmozyme)
FDA- Approved Device: Hudson T Up-draft II, Marquest Acorn II, Pari LC, Durable sidestream, pari baby
Approved devices for specific drug formulations Formulation: Tobramycin (TOBI)
FDA- Approved Device: Pari LC
True or False Water in inspired gas is essential to a unhealthy respiratory tract.
False Water in inspired gas is essential to a *healthy* respiratory tract.
When providing *passive humidification* to patients undergoing *invasive mechanical ventilation*, it is suggested that the ______________________.
HME provide a minimum of 30 mg H2O/L
Heat and moisture exchanger bypass during aerosol delivery
HME- heat + moisture AEROSOL- just aerosol (medicated or bland)
The Afrezza Inhaler
Is rapid-acting inhaled insulin indicated to *improve glycemic control in adult patients with diabetes mellitus.*
A patient receiving low-flow oxygen therapy by cannula complains of nasal drying. Do you think a bubble humidifier will help? What other options might you suggest?
Yes- the bubble humidifier will help, 4 L/min or higher
A mechanically ventilated patient has a respiratory acidosis. How might an HME contribute to this problem?
You exhale CO2, if there's something blocking that HME, the CO2 is not going to pass through the HME tube
A valved holding chamber allows the plume from the pMDI to expand and incorporates a one-way valve that permits the aerosol to be drawn from the chamber ________________.
during inhalation only
What is invasive ventilation?
endotracheal tube or tracheostomy tube
Humidification is recommended on every patient receiving _________ mechanical ventilation.
invasive
The _________________ is the point at which inspired gas reaches body temperature and humidity.
isothermic saturation boundary (ISB)
What is the primary goal of humidity therapy?
maintain normal physiologic conditions by providing heat and humidity in the inspired gas.
Aerosol Drug Administration The geometric size of the particles is expressed as the ___________.
mass median aerodynamic diameter (MMAD).
Aerosolized drugs are often administered to ____________ patients.
mechanically ventilated
The _______________ is the most commonly prescribed method of aerosol delivery and is used to administer bronchodilators, anticholinergics, anti-inflammatory agents, and steroids.
pressurized metered dose inhaler (pMDI)
Devices used for Humidification Nebulizer
produces an aerosol, or suspension of particles in gas
When absolute humidity drops below 24 mg/L in the inhaled gas, the beat frequency of the cilia is _______________.
reduced
*Gravitational sedimentation* occurs when aerosol particles _______________.
settle out of suspension because of gravity.
A ________________ is a simple open-ended tube or bag that provides space for the pMDI plume to expand by allowing the propellant to evaporate.
spacer
The interface between the atmosphere and the lungs is mediated through _____________.
the fluid lining of the airways
Either a nebulizer, pMDI, pMDI with a spacer or valved holding chamber, or DPI can be used effectively if_____________.
the patient uses good technique
What can possibly cause the decline efficacy of HMEs?
the tidal volume, inspiratory flow, or fractional inspired oxygen (FiO2) concentration increasing
Aerogen *Mesh* Nebulizer
usually found in the ICU
It is suggested that HMEs are not used as a prevention strategy for ____________.
ventilator-associated pneumonia
Aerosol Drug Administration Heterodisperse
wider range of particle sizes (more than 1.2). *Most aerosols are ___________.*
Can medication be administered to the patient if they are on mechanical ventilation?
yes
