Egan’s Chapter 36 Practice Questions:
1. Can you use a USN to administer undiluted bronchodilator to patients with severe bronchospasm?: Yes.
2. Conversion Solution for drug dosage: 1 ml of a 1% solution= 10mg
3. Dosage equation for drug dosage: dosage = volume x original concentration
4. How are DPIs categorized?: categorized by the design of their dose containers.
5. How are medical aerosols generated in the clinical setting?: with devices that physically disperse matter into small particles and suspend them in gas.
6. How does a Large Volume USN work?: incorporates air blowers to carry mist to the patient for delivery of bland aerosol therapy or sputum induction.
7. How do ultrasonic nebulizers work? (USNs): uses piezoelectric crystal to produce aerosol. The crystal converts electrical energy into high frequency vibrations to produce aerosol. Output is directly affected by amplitude setting
8. How do you prime an MDI?: Shake device and release one or more sprays into the air when MDI is new or hasn’t been used for a while
9. How is Aerosol Output measured?: By collecting the aerosol that leaves a nebulizer and collects on special filters.
10. How often do you assess a patient on continuous nebulization?: every 30 minutes for the first 2 hours then hourly. (For adverse drug responses)
11. Percent solution for drug dosage: Volume (ml)= Dosage desired (mg) / % original concentration
12. Ratio Solution for drug dosage: 1:100= 1% percent solution
13. What affects MDI performance and drug delivery?: Low temperature decreases output of CFC MDI’s. Debris build up on nozzle or actuator orifice reduces emitted dose.
14. What are 3 examples of aerosol devices?: 1. Atomizers, 2. Nebulizers, 3. Inhalers
15. What are 3 factors that determine particle size?: 1. Substance being nebulized, 2. Method used, 3. Environmental conditions
16. What are beneficial characteristics of an MDI?: 1. portable, 2. compact, 3. easy to use
17. What are heterodispersed aerosols?: aerosols with particles of different sizes
18. What are key mechanisms of aerosol deposition?: 1. inertial impaction, 2. Gravimetric sedimentation, 3. Brownian diffusion
19.What are medication delivery issues for infants and children?: Smaller airway diameter, faster breathing rate, Nose breathing filters out large particles, lower minute volumes, and spontaneous patient cooperation
20. What are Monodispersed aerosols?: aerosols with particles of similar sizes.
21. What are small volume USNs used for?: delivery of aerosolized medications (i.e. bronchodilators, antibiotics and anti-inflammatory agents.)
22. What are sub-hazards to aerosol drug therapy?: 1. infection, 2. airway reactivity, 3. pulmonary and systemic effects of bland aerosols, 4. drug concentration changes during nebulization, 5. eye irritation
23. What are therapeutic Aerosol depositions influenced by?: 1. Inspiratory flow rate, 2. Flow pattern, 3. Respiratory Rate, 4. Inhaled volume, 5. I:E ratio, 6. Breath-holding
24. What are two methods to measure medical aerosol particle distribution?: 1. Cascade impaction, 2. Laser diffraction
25. What contributes to aging of aerosols?: 1. Composition of aerosol, 2. Initial size of particles, 3. time in suspension, 4. Ambient condition
26. What does Assay measure?: Quantity of drug
27. What does Geometric standard deviation (GSD) describe?: Variability of particle sizes
28. What does Gravimetric analysis measure?: Aerosol weight
29. What happens to a solution placed in a USN?: Temperature of the solution increases
30. What is a dry powder inhaler (DPI): breath actuated dosing system by which a patient creates the aerosol by drawing air through a dose of finely milled drug powder. Dispersion of powder into respirable particles depends on creation of turbulent flow in inhaler. (THERE IS NO PROPELLANT)
31. What is Aerosol emitted dose?: the mass (amount) of drug leaving the mouthpiece as an aerosol
32. What is aerosol output?: The mass (amount) of fluid or drug contained in aerosol
33. What is aerosol output rate?: The mass (amount) of aerosol generated per unit of time. Varies depending on different nebulizers and inhalers used.
34. What is Aging when pertaining to aerosols?: process by which the aerosol suspension changes over time.
35. What is a Metered-dose inhaler? (MDI): A pressurized canister containing the prescribed drug in a volatile propellant combined with surfactant and a dispersing agent
36. What is an aerosol?: A suspension of solid or liquid particles in gas
37. What is a positive response indicated from Continuous nebulization?: increase in peak flow of >10% with a goal of at least 50%
38. What is a technical downfall of MDIs?: 80% of the aerosol hits the back of the throat depositing the medication in the oropharynx
39. What is a USN capable of?: higher aerosols outputs and higher aerosol densities than conventional jet nebulizers
40. What is Brownian diffusion?: The primary deposition mechanism for very SMALL particles and will deposit DEEP within the lung.
41. What is gravimetric sedimentation?: When aerosol particles settle out of suspension and are deposited due to the pull of gravity. Breath-holding after inhalation increases sedimentation and distribution in the lungs. the greater the mass of a particle the faster it settles
42. What is inertial impaction?: when aerosol in motion collides with and are deposited onto a surface. The greater the mass and velocity of a moving droplet, the greater the inertia and tendency of that droplet to continue moving along its set path.
43. What is Intrapulmonary percussive ventilation IPPV: Provides high-frequency oscilation of airway while administering aerosol particles
44.What is non-invasive ventilation?: Bi-Pap and C-Pap (pressurized assisted ventilation)
45. What is the blow-by technique?: used if patient cannot tolerate mask treatment, aerosol is directed from aerosol from nebulizer towards the patients nose and mouth from a distance of several inches from the face.
46. What is the fundamental principle of aerosol deposition?: Only a fraction of emitted aerosol will be inhaled and only a fraction of what is inhaled will make it to the lungs.
47. What is the most commonly prescribed method of aerosol therapy?: MDI
48. What is the primary hazard of aerosol drug therapy?: adverse reaction to medication
49. What is the relationship between GSD and the range of particle sizes?: The greater the GSD, the wider the range of particle sizes and therefore a more heterodispersed aerosol.
50. What’s the difference between spacers and holding chambers: Spacer: valve-less just adds distance from point of discharge to the mouth. Holding chamber: has valves for holding medication.
51. Where should the aerosol generator be placed with IPPV?: in circuit close to patient’s airway
52. Why would you prime an MDI?: To mix the drug and propellant and to ensure adequate dose is provided
53. Why would you use continuous nebulization?: for treatment of refractory bronchospasm. nebulized albuterol is dosed at 5-20mg/hour
Egan’s Chapter 36 Test Bank:
1. Two most common laboratory methods used to measure medical aerosol particle size distribution are:: cascade impaction; laser diffraction
2. Three Categories of DPIs: 1. Unit-Dose DPI, 2. Multiple unit-dose DPI, 3. Multiple Dose Drug Reservoir DPI
3. The AARC recommends that when monitoring trends,: the same unit be used for a given patient and that the patient’s range be reestablished if a different flowmeter is used
4. Additional techniques can be used for mechanically ventilated patients because: (1) a change in the differences between peak and plateau pressures (the most reliable indicator of a change in airway resistance during continuous mechanical ventilation) can be measured, (2) automatic positive end expiratory pressure levels may decrease in response to bronchodilators (see Chapter 41), and (3) breath-to-breath variations make measurements more reliable when the patient is not actively breathing with the ventilator.70
5. Aerocount Autohaler: flow triggered pMDI designed to eliminate the need for hand-breath coordination by automatically triggering in response to the patient’s inspiratory effort.24 To use the Autohaler, the patient cocks a lever on the top of the unit, which sets in motion a downward spring force. Using the closed-mouth technique, the patient draws through the mouthpiece. When the patient’s flow rate exceeds 30 L/min, a vane releases the spring, which forces the canister down and triggers the pMDI. In the United States, the Autohaler is available only with pirbuterol, a bronchodilator similar to albuterol.
6. AeroEclipse: A unique, spring-loaded, one-way valve design draws the jet to the capillary tube during inspiration and causes nebulization to cease when the patient’s inspiratory flow decreases below the threshold or the patient exhales into the device. Expiratory pressure on the valve at the initiation of exhalation moves the nebulizer baffle away from its position directly above the jet orifice, reduces the pressure, and stops aerosolization
7. Aerosol: A suspension of a solid or liquid particles in gas
8. Aerosol administration by a VM nebulizer has been estimated to deliver greater than: 10% deposition in adults and infants without the addition of gas into the ventilator circuit. The low residual drug volume and small particle size are associated with higher efficiency. Similar to the USN, the VM nebulizer does not add gas flow into the ventilator circuit, so ventilator parameters and alarms do not need to be adjusted before, during, or after nebulization. In contrast to jet SVNs and USNs, the medication reservoir of the VM nebulizer is above the circuit and separated from the ventilator tubing by the mesh, reducing the risk of retrograde contamination of medication in the reservoir from the ventilator circuit. Because of the nature of the mesh, the reservoir can be opened and medication can be added to the nebulizer without creating a perceptible leak during ventilation.
9. Aerosol generators include: pMDIs (w/ or w/o spacers & holding chambers), DPIs, Small and Large Volume (jet) nebulizers, Hand-Bulb atomizers, Ultrasonic Nebulizers, Vibrating Mesh Nebulizers
10. Aerosol Output: the mass of fluid or drug contained in the aerosol product by a nebulizer. The mass of aerosol generated per unit of time.
11. Aerosol particle size depends on:: the substance for nebulization, method used to generate the aerosol, and The environmental conditions surrounding the particle.
12. Aerosols occur in nature as:: pollens, Spores, Dust, Smoke, Fog, and Mist
13. Aersol particle can change size as a result of: evaporation or hygroscopic water absorption.
14. After CBT is started, the patient is carefully assessed every: 30 minutes for the first 2 hours and thereafter every hour. A positive response is indicated by an increase in PEFR of at least 10% after the first hour of therapy. The goal is at least 50% of the predicted value. For small children, improved oxygenation (oxygen saturation by pulse oximeter [SpO2] >92% on room air) with evidence of decreased work of breathing indicates a favorable response. Once the patient “opens up,” intermittent SVN administration is resumed, or a pMDI dose-response assessment is conducted.
15. Aging: The process by which an aerosol suspension changes over time.
16. The aim of medical aerosol therapy is to:: Deliver a therapeutic dose of the selected agent (drug) to the desired site of action.
17. All patients with acute airway obstruction should be monitored for oxygenation status with: pulse oximetry. This value can be used in conjunction with observational assessment to titrate the level of inspired O2 given to the patient (see Chapter 35). Arterial blood gases are not essential for determining patient response to bronchodilator therapy but may be needed for patients in severe distress to assess for hypercapnic respiratory failure
18. Another special-purpose large volume nebulizer: a small particle aerosol generator (SPAG). The SPAG was manufactured by ICN Pharmaceuticals specifically for administration of ribavirin (Virazole) to infants with respiratory syncytial virus infection. Incorporates a drying chamber with its own flow control to produce a stable aerosol.
19. Another type of off-label use involves drugs that: have not been approved for inhalation, ranging from heparin to certain antibiotics. Although physicians may order such drugs via inhalation, the risk to the patient and institution is greater when the administration of such drugs via inhalation has not been thoroughly studied. All forms of off-label use should be avoided when approved and viable alternatives exist. Likewise, off-label
administration should always be backed by appropriate departmental or institutional policies and procedures.
20. appropriate airway clearance techniques should accompany any aerosol therapy designed to help mobilize secretions.
21. Baffle: is a surface on which large particles impact and fall out of suspension, whereas smaller particles remain in suspension, reducing the size of particles remaining in the aerosol.
22. Basic Concepts for spacer devices include:: 1. Small volume adapters, 2. Open Tube Designs, 3. Bag reservoirs, 4. Valved holding chambers.
23. Before initial use and after storage, every pMDI should be: primed by shaking and actuating the device to atmosphere one to four times. without the priming, the initial dose actuated from a new pMDI cansiter contains less active substance than subsequent actuations. waste a single does when it has not been used for 4-6 hours
24. Booths or stations should be used for: sputum induction and aerosolized medication treatments given in any area where more than one patient is treated. The area should be designed to provide adequate airflow to draw aerosol and droplet nuclei from the patient into an appropriate filtration system or an exhaust system directly to the outside. Booths and stations should be adequately cleaned between patients
25.Breath-Actuated Nebulizers: -aerosol device that is responsive to the patient’s inspiratory effort and reduces or eliminates aerosol generation during exhalation. generate aerosol only during inspiration. eliminates waste of aerosol during exhalation and increases the delivered dose threefold or more over continuous and breath-enhanced nebulizers.
26. Breath-Actuated Pressurized Metered Dose Inhaler: a variation of a pMDI that incorporates a trigger that is activated during inhalation. This trigger reduces the need for the patient or caregiver to coordinate MDI actuation with inhalaiton.
27. Breath-Enhanced Nebulizers: nebulizers that entrain room air in direct relationship to the inspiratory flow of the patient, they generate aerosol continuously, using a system of vents and one-way valves to minimize aerosol waste
28. Breath holding after inhalation of an aerosol increases…..: The residence time for the particles in the lung and enhances distribution across the lungs and sedimentation
29. Brownian Diffusion: The primary mechanism for deposition of small particles (< 3um), mainly in the respiratory region where bulk gas flow ceases
30. Careful, ongoing patient assessment is: is key to an effective bronchodilator therapy protocol. To guide practitioners in implementing effective bedside assessment, the AARC has published Clinical Practice Guideline: Assessing Response to Bronchodilator Therapy at Point of Care.
31. Cascade impactors: are designed to collect aerosols of different sizes ranges on a series of stages or plates
32. The CDC recommends that nebulizers: be cleaned and disinfected, or rinsed with sterile water, and air-dried between uses.
33. Characteristics of Drug Fomulation: Viscosity, Surface tension, Homogeneity
34. Chlorofluorocarbons (CFCs): gaseous chemical compounds that were originally used to power metered dose inmhalers but currently phased out of use
35. Cleaning of holding chambers and spacers: should be cleaned regularly, typically monthly, as recommended by the manufacturer. Use of dilute liquid dishwashing soap, with or without rinsing, and allowing to air dry are recommended.
36. Clinical efficacy varies according to: both patient technique and device design. For these reasons, the best approach to aerosol drug therapy is to use an assessment-based protocol that emphasizes individually tailored therapy modified according to patient response.
37. Cold air and high-density aerosols can cause:: Reactive bronchospasm and increased airway resistance.
38. Cold Freon Effect: -occurs when the cold aerosol plume reaches the back of the mouth and the patient stops inhaling. Can be reduced by using a spacer or holding chamber.
39. Components of pMDI, including function of the metering valve: …
40. Concerns in the use of disposable nebulizers with compressors at home involve: possible degradation of performance of the plastic device over multiple uses
41. Continuous Drug Delivery: when nebulization occurs over extended periods. this is the greatest effect.
42. Continuous pneumatic nebulizers produce the greatest amount of: secondhand aerosol, with most (60%) of the aerosol produced passing directly into the environment. The Respirgard II (Vital Signs, Totowa, NJ) nebulizer was developed for administration of pentamidine, adding one-way valves and an expiratory filter to contain aerosol that is exhaled and not inhaled. Breath-actuated nebulizers, DPIs, and pMDIs tend to generate less secondhand aerosol.
43. Continuous Small Colume Nebulizers with Collection Bags: – hold the aerosol generated during exhalation and allow the small particles to remain in suspension for inhalation with the next breath, while larger particles rain out, attributed to a 30% to 50% increase in inhaled dose
44. conventional spirometry: remains the standard for determining bronchodilator response.
45. Deposition: where the aerosol particle connects or lands to the body
46.Depth & Penetration & deposition of a particle in the respiratory tract vary…: with size and tidal volume. With this knowledge it may be possible to target aerosol deposition to specific areas of the lung by using the proper particle size and breathing pattern.
47.Determinant of Deposition (where a particle of any specific size is deposited): particle size, inspiratory flow rate, flow pattern, respiratory rate, inhaled volume, ratio of inspiraton time to expiratory time, and breath holding.
48. Determine Dose Left in Pressurized MDI with dose counters: 1.Determine how many puffs of drug the pMDI has when full. 2.Learn to read the counter display because each dose counter has a different way of displaying doses left in the canister. 3.Check the counter display to track the pMDI actuations remaining in the canister. 4.Reorder the pMDI when there are a few days of drug remaining. 5.Dispose of the pMDI properly, after the last dose is dispensed.
49. Determine Dose Left in Pressurized MDI without dose counters: 1.Read the label to determine how many puffs of drug the pMDI has when full. 2.Calculate how long the pMDI will last by dividing the total number of puffs in the pMDI by the total puffs used per day. If the pMDI is used more often than planned, it will run out sooner. 3.Identify the date that the medication will run out, and mark it on the canister or on a calendar. 4.For drugs that are prescribed to be taken as needed, track the number of puffs of drug administered on a daily log sheet and subtract them from the remaining puffs to determine the amount of medication left in the pMDI. 5.Keep the daily log sheet in a convenient place, such as taped to the bathroom mirror. 6. Refill the pMDI prescription when there are a few days of use remaining in the pMDI. 7.Dispose of the pMDI properly when the last dose is dispensed.
50.Determining Doses Left in the Dry Powder Inhaler is important to know for the patient.
51. Direct pMDI actuation by simple elbow adapters typically results in the least: pulmonary deposition, with most of the aerosol impacting in either the ventilator circuit or the tracheal airway. Higher aerosol delivery percentages occur only when an actuator or spacer is placed in-line in the ventilator circuit. These spacers allow an aerosol “plume” to develop before the bulk of the particles impact on the surface of the circuit or endotracheal tube. The result is a more stable aerosol mass that can penetrate beyond the artificial airway and be deposited mainly in the lung. This situation leads to a better clinical response at lower doses
52. Dose Counters: – a serious limitation of pMDIs is the lack of a “counter” to indicate the number of doses remaining in the canister.
53. DPIs SHOULD NOT BE USED FOR: the management of acute bronchospasm.
54. Droplet size and nebulization time are inversely proportional to gas flow through the jet.: higher the flow of gas to the nebulizer, the smaller the particle size generated, and the shorter is the time required for nebulization of the full dose.
55. Drug Concentration: what increases solute concentrations during nebulization: evaporation, heating, baffling, and recycling of drug solutions
56. Drugs for nebulization that escape from the nebulizer into the atmosphere or are exhaled by the patient can be inhaled by: anyone in the vicinity of the treatment. The risk imposed by this environmental exposure is clear and is associated with a range of drugs and patients with infectious disease. Pentamidine and ribavirin were associated with health risks to health care providers even when used in conjunction with filters on exhalation ports of nebulizers, containment and scavenger systems, and high-efficiency particulate air (HEPA) filter hoods and ventilation systems (Figure 36-36).
57. Dry Powder Inhaler (DPI): typically a breath-actuated dosing system. patient creates the aerosol by drawing air though a dose of finely milled drug powder with sufficient force to disperse and suspend the powder in the air. dispersion of the powder into respirable particles depends on the creation of turbulent flow in the inhaler. Turbulent flow is a function of the ability of the patient to inhale the powder with a sufficiently high inspiratory flow rate
58. Emitted Dose: The mass of drug leaving the mouthpiece of a nebulizer or inhaler as aerosol
59. Every drug approved for inhalation to date has been designed for and tested in: populations of ambulatory patients with moderate disease. As patients with lung disease become acutely and critically ill, the approved label doses, frequency of administration, and devices may not be practical or effective, especially for treatment of patients requiring ventilatory support. In such cases, clinicians may explore and consider nonstandard methods (doses, frequency, and devices) for administration of approved inhaled drugs to patients in the acute care environment, known as off-label use
60. exhalation into the device before inspiration can result in: – loss of drug delivery to the lung
61. Eye irritation is caused by:: aerosol asministered via face mask which causes the drug to be deposited in the eyes.
62. Personal protective equipment is recommended when: caring for any patient with a disease that can be spread by the airborne route.84 The greatest risk is communication of tuberculosis or chickenpox.
63. pMDI: used to administer bronchodilators, anticholinergics, & steroids. Are easy to use but commonly misused.
64. pMDI is: a pressurized canister that contains the prescribed drug in a volatile propellant combined with a surfactant and dispersing agent.
65. pMDI steroid aerosol impaction occurs deep in the hypopharynx, which cannot be easily rinsed with gargling for this reason…: steroid pMDIs should not be used alone but always in combination with a spacer or valved holding chamber.
66. Poor patient response to bronchodilator therapy often occurs because: an inadequate amount of drug reaches the airway. To determine the “best” dose for patients with moderate obstruction, the respiratory therapist (RT) should conduct a dose-response titration.
67. A potential problem with continuous bronchodilator therapy (CBT): is increase in drug concentration. Patients receiving CBT need close monitoring for signs of drug toxicity (e.g., tachycardia and tremor).
68. Practitioner demonstration followed by repeated patient return demonstration is a: must and should be done frequently, such as with each office or clinic visit.
69. precise amount of drug delivered to the patient’s airways can be measured in terms of:: -patient’s clinical response to aerosol drug therapy including the desired therapeutic effects and any unwanted adverse effects.
70. Preliminary assessment should balance: the need versus the risk of aerosol therapy
71. The primary hazard of aerosol drug therapy is: an adverse reaction to the medication being administered. Other hazards include infection, airway reactivity, systemic effects of bland aerosols, and drug reconcentration
72. Priming: Shaking the device and releasing one or more sprays into the air when the pMDI is new or has not been used for a while. done to mix the drug and the propellant required to provide an adequate dose.
73. The Problem of Drug precipitation can jam breathing valves or occlude the ventilator circuit cn be overcome by:: (1) placing a one-way valve between the SPAG and the circuit and
(2) filtering out the excess aerosol particles before they reach the exhalation valve, changing filters frequently to avoid increasing expiratory resistance.
74. procedures to help reduce contamination and infection associated with respiratory care equipment: nebulizers should be sterilized between patients, nebulizers should frequently be replaced with disinfected or sterile units or rinsed with sterile water (not tap water) and air dried every 24 hours.
75. Propellant: something that propels or provides thrust, as the propellant in a metered dose inhaler
76. Pulmonary and Systemic Effects Excess water can cause:: overhydration
77. Range of particle size for common aerosols in the environment and the influence of inertial impactions, sedimentation, and diffusion.:
78. Regardless of the device used, the clinician must be aware of: the limitations of aerosol drug therapy. First, depending on the device and patient, 10% or less of drug emitted from an aerosol device may be deposited in the lungs (Figure 36-30). As indicated in Box 36-7, additional reductions in lung deposition can occur in many clinical situations that sometimes necessitate the use of higher dosages.
79. A reservoir on the expiratory limb of the nebulizer: conserves drug aerosol
80. Residual Drug Volume: or dead volume, is the medication that remains in the SVN after the device stops generating aerosol and “runs dry.” The residual volume of a 3-ml dose can range from 0.5 to more than 2.2 ml, which can be more than two-thirds of the total dose. Residual volume also depends on the position of the SVN.
81. The Respimat soft mist inhaler (Boehringer, Ingelheim am Rhein, Germany) is a: small hand-held inhaler that uses mechanical energy to create an aerosol from liquid solutions to produce a low-velocity spray (10 mm/sec) that delivers a unit dose of drug in a single actuation. To operate the device, patients twist the body of the device to load an internal spring, place the mouthpiece of the Respimat between the lips, and press a button to release the drug through a uniblock to create spray, which is released over 1.1 to 1.4 seconds, depending on the formulation configuration. The Respimat device requires hand-breath coordination on the part of the patient, as does a pMDI, but because of the longer spray time, it seems more likely to get a greater percent of emitted dose despite coordination issues. Because of the small particle size and low-velocity spray, pulmonary deposition of 40% is independent of inspiratory flows with oral deposition (40%) half the oral dose used with most pMDIs and DPIs (80%). The Respimat is currently available with several drugs in Europe and is slated for introduction with tiotropium in the United States.
82. Respirable Mass: proportion of aerosolized drug of the proper particle size to reach the lower respiratory tract
83. Restlessness, diaphoresis, and tachycardia also may indicate: severity of airway obstruction but must not be confused with bronchodilator overdose
84. Risk for Caregivers and Bystanders: risk the above hazards as a result of exposure to secondhand aerosol drugs.
85. Scintigraphy: photograph showing the distribution and intensity of radioactivity in various tissues and organs after administration of a radiopharmaceutical.
86. Sedimentation: Occurs when aerosol particles settle out of suspension & are deposited owing to gravity. The greater mass of the particle the faster it settles.
87. A simple albuterol dose-response titration involves: giving an initial 4 puffs (90 mcg/puff) at 1-minute intervals through a pMDI with a holding chamber. After 5 minutes, if airway obstruction is not relieved, the RT gives 1 puff per minute until symptoms are relieved, heart rate increases to more than 20 beats/min, tremors increase, or 12 puffs are delivered. The best dose is the dose that provides maximum relief of symptoms and the highest PEFR without side effects.
88. The site of deposition in the respiratory tract varies with the size of the particle. Use of nebulizers that produce particles in a specific size range improves the targeting of aerosols for deposition to a desired site in the respiratory tract, as follows:
89. Small volume nebulizers (SVNs): most commonly used for medical aerosol therapy hold 5 to 20 ml of medication.
90. Small volume USNs have been promoted for administration of a wide variety of formulations ranging from: bronchodilators to antiinflammatory agents and antibiotics
91. Sole dependence on tests of expiratory airflow for assessing patient response to therapy is: unwise because not all patients can perform these maneuvers. Other components of patient assessment useful in evaluating bronchodilator therapy include patient interviewing and observation, measurement of vital signs, auscultation, blood gas analysis, and oximetry.
92. Spacer: A spacer is a simple valveless extension device that adds distance between the pMDI outlet and the patient’s mouth. This distance allows the aerosol plume to expand and the propellants to evaporate before the medication reaches the oropharynx.
93. Spacers and Valved holding Chambers: -are pMDI accessory devices designed to reduce both oropharyngeal deposition and the need for hand-breath coordination. All spacers add distance between the pMDI and the mouth, reducing the initial forward velocity of the pMDI droplets. Reduces foul taste.
94. SPAG: duces medical gas source from the normal 50 pounds per square inch gauge (psig) line pressure to 26 psig with an adjustable regulator. The regulator is connected to two flowmeters that separately control flow to the nebulizer and drying chamber. The nebulizer is located within the glass medication reservoir, the fluid surface and wall of which serve as primary baffles. As it leaves the medication reservoir, the aerosol enters a long, cylindrical drying chamber. Here the second (separate) flow of dry gas is entrained, reducing particle size by evaporation, creating a monodisperse aerosol with an MMAD of 1.2 to 1.4 µm. Nebulizer flow should be maintained at approximately 7 L/min with total flow from both flowmeters not less than 15 L/min. The latest model operates consistently even with back pressure and can be used with masks, hoods, tents, or ventilator circuits.
95. Spontaneous breathing in all patients, including pediatric and neonatal patients, results in: greater deposition of aerosol from an SVN than occurs with positive pressure breaths (e.g., intermittent positive pressure ventilation). This mode of ventilation reduces aerosol deposition more than 30% compared with the effect of spontaneously inhaled aerosols
96. Tail-off effect: refers to variability in the amount of drug dispensed toward the end of the life of the canister.
97. Technique for using a SVN: -Slow inspiratory flow optimizes SVN aerosol deposition. deep breathing and breath holding during SVN therapy do little to enhance deposition over normal tidal breathing. As long as the patient is mouth breathing, there is little difference in clinical response between therapy given by mouthpiece and therapy given by mask
98. temperature: Decreased temperature (<10° C) has been shown to decrease the output of CFC pMDIs.
99. three categories of nebulizers include: (1) pneumatic jet nebulizers, (2) USNs, and (3) VM nebulizers.
100. Through preliminary patient instuction: can last 10-30 min, should include: demonstration, Practice, Confirmation of patient performance
101. Timing of Actuation Intervals: Manufacturers recommended 30 sec to 1 min between actuations. Very rapid acutation of multiple puffs per breath reduces inhaled drug per puff
102. To avoid opportunistic oral yeast infection:: rinse the mouth after steriod use.
103. Two specific problems are associated with SPAG use to deliver ribavirin.: 1. Caregiver exposure to the drug aerosol. 2.Drug precipitation can jam breathing valves or occlude the ventilator circuit.
104. Two types of VM nebulizers, active and passive, are available commercially.: Active VM nebulizers use a dome-shaped aperture plate, containing more than 1000 funnel-shaped apertures. This dome is attached to a plate that is also attached to a piezoceramic element that surrounds the aperture plate. Electricity applied to the piezoceramic element causes the aperture plate to be vibrated at a frequency of approximately 130 kHz (or one-tenth that of a USN), moving the aperture plate up and down by 1 µm or 2 µm, creating an electronic micropump. The plate actively pumps the liquid through the apertures, where it is broken into fine droplets. The exit velocity of the aerosol is low (<4 m/sec), and the particle size can range from 2 to 3 µm (MMAD), varying with the exit diameter of the apertures.
105. a typical SVN is powered by: a high-pressure stream of gas directed through a restricted orifice (the jet). The gas stream leaving the jet passes by the opening of a capillary tube immersed in solution. Because it produces low lateral pressure at the outlet, the high jet velocity draws the liquid up the capillary tube and into the gas stream, where it is sheared into filaments of liquid that break up into droplets. This primary spray produces a heterodisperse aerosol with droplets ranging from 0.1 to 500 µm.
106. Unit-Dose DPIs: dispense individual doses of drug from punctured gelatin capsules.
107. The USN uses a piezoelectric crystal to: generate an aerosol. The crystal transducer converts an electrical signal into high-frequency (1.2- to 2.4-MHz) acoustic vibrations. These vibrations are focused in the liquid above the transducer, where they disrupt the surface and create oscillation waves (Figure 36-25). If the frequency of the signal is high enough and its amplitude strong enough, the oscillation waves form a standing wave that generates a geyser of droplets that break free as fine aerosol particles.
108. Valved holding chambers: protect the patient from poor hand-breath coordination, with exhaled gas venting to the atmosphere, allowing aerosol to remain in the chamber available to be inhaled with the next breath. allow infants, small children, and adults who cannot control their breathing pattern to be treated effectively with pMDIs.
109. A variety of booths and specially designed stations are available for delivery of pentamidine or ribavirin: The Emerson containment booth (Figure 36-37) is an example of a system that completely isolates the patient during aerosol administration. The AeroStar Aerosol Protection Cart (Respiratory Safety Systems, San Diego, CA) is a portable patient isolation station for administration of hazardous aerosolized medication. It has been used during sputum induction and for pentamidine treatment. The patient compartment is collapsible with a swing-out counter and three polycarbonate walls. Captured aerosols are removed with a HEPA filter. A prefilter is used to retain larger dust particles and to prevent early loading of the more expensive HEPA filter.
110.Volume Mean Diameter (VMD): the median diameter of an aerosol particle measured in units of volume.
111. well-designed baffling systems decrease both: the MMAD (size) and the GSD (range of sizes) of the generated aerosol.
112. When ribavirin or pentamidine is given, the treatment is provided in a: a private room. The room should be equipped for negative pressure ventilation with adequate air exchanges (at least six per hour) to clear the room of residual aerosols before the next treatment. HEPA filters should be used to filter room or tent exhaust, or the aerosol should be scavenged to the outside.
113. When used in conjunction with high-frequency oscillatory ventilation, administration of albuterol sulfate via a VM nebulizer placed between the ventilator circuit and the patient airway has been reported to: deliver greater than 10% of dose to both infants and adults.79,80 A pMDI with adapter placed immediately proximal to the endotracheal tube achieved similar results in adult patients ventilated via high-frequency oscillatory ventilation.81
114. Where aerosol particles are deposited in the respiratory tract depends on their: size, shape, and motion and on the physical characteristics of the airways. Key mechanisms causing aerosol deposition include inertial impaction, sedimentation, and brownian diffusion.
115. Whether aerosol particles that are inhaled into the lungs are deposited into the respiratory tract depends on:: size, shape, and motionof the particles and on the physical characteristics of the airways and breathing pattern.
116. With continuous or bias flow through the ventilator circuit, the delivery is reduced: as flow increases, whereas placement of a VM nebulizer near the ventilator increases delivery
117. with ipratropium use: the closed-mouth technique to avoid spraying in the eyes.
118. without a dose counter: there is no viable method to determine remaining drug in a pMDI other manually keeping a log of every dose taken.
119. Workplace exposure to aerosol may be detectable in: the plasma of bystanders & health care providers.