Medication Delivery Modalities

Objectives - Describe the proper use of respiratory medication delivery devices; demonstrate providing a patient treatment utilizing the small volume nebulizer.

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Aerosol Particle Size

Deposition site in the respiratory tract varies with:

• Particle mass produced by nebulizers
• Inspiratory flow

Key Terms

• MMAD: mass median aerodynamic diameter; the average particle size with respect to measure of central tendency
• Heterodispersed: medical gas particles vary in size, forming an aerosol
• Coalescence: particles combine and impact size
• Particle mass: increased particle mass increases deposition and sedimentation

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Respiratory Medication Delivery Devices

The devices in this lesson include:

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Metered Dose Inhaler (MDI)

An MDI is a small portable aerosol device that is hand-operated and powered by an HFA propellant.

• Each activation delivers a pre-determined dose of medication in mcg
• New MDIs include dose-counting devices

Valved Holding Chambers and Spacers

Valved holding chambers are also called spacers.

Spacers:

• Slow the velocity of aerosol particles
• Help maintain particles within the optimal respirable size range
• Reduce the coordination required for optimal drug delivery
• Increase the quantity of medication delivered with each dose
• Provide the best respirable dose particle size compared with MDI use without a spacer

Spacers should always be used with MDIs.

MDI Spacer Technique

1. Shake the inhaler thoroughly and place it in the spacer or VHC.
2. Hold the canister vertically.
3. Have the patient sit or stand straight up.
4. Have the patient exhale completely.
5. Place the mouthpiece between the teeth.
6. Actuate the MDI at the beginning of inhalation.
7. Inhale slowly and prevent the spacer whistle.
8. Withdraw the mouthpiece and hold breath for 10 seconds or longer.
9. Wait at least 30 seconds between breath actuations.

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Pneumatic Jet Nebulizers

Pneumatic jet nebulizers deliver a wide variety of inhaled medications and require an external compressed gas source.

Small volume nebulizers and handheld nebulizers with a reservoir tube or mask are the cheapest and most widely used nebulizers.

Aerosol Formation

1. A high-pressure jet stream creates low pressure lateral to the capillary tube.
2. Low pressure pulls fluid up the capillary tube.
3. Fluid is drawn into the jet stream and driven into the baffle.
4. The baffle creates a particulate mist or aerosol small enough to reach the lower airways during inhalation.

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Breath-Enhanced Jet Nebulizer (BEN)

Breath-enhanced jet nebulizers release more aerosol during inspiration.

BEN features:

• Two one-way valves
• Prevent aerosol lost to the environment
• Contain nebulized aerosol until the patient inhales
• During inspiration, a one-way valve opens and directs aerosol from the reservoir to the patient airway

Examples listed in the source:

• Pari LC Plus
• NebuTech

Higher viscosity solutions, such as gentamicin, require gas flow rates of 10 to 12 L/min to produce suitable aerosol particles.

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Breath-Actuated Nebulizer (BAN)

Breath-actuated nebulizers have two settings:

• Inspiration only, or breath actuation
• Continuous

BAN devices:

• Eliminate waste because nebulization stops during exhalation
• Increase delivered dose more than three times compared with continuous nebulizers

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Administration of SVN

Before Treatment

First, verify the physician order and review the patient chart before all therapy.

Then:

• Introduce yourself and explain the purpose of the visit
• Provide therapy instructions
• Answer questions to affect understanding and compliance
• Assemble the device:
  • Flowmeter
  • "Xmas tree adaptor"
  • Small bore tubing
  • Interface such as mask, trach collar, or mouthpiece
• Label therapy devices with the patient label and equipment change date according to local policy, usually every 48 hours

Treatment

• Seat the patient upright whenever possible
• Perform a physical assessment
• Auscultate breath sounds, cough effort, and sputum production
• Measure heart rate and respiratory rate
• Measure oxygen saturation (SpO2)
• Perform peak flow measurement
• Add medication and adjust gas flow to 6 L/min or greater
• Have the patient breathe normally, with occasional slow deep breaths and 2 to 3 second breath holds
• Hold the nebulizer upright during treatment
• Continue until aerosol is no longer produced or the nebulizer sputters

After Treatment

• Rinse the nebulizer with sterile or distilled water and allow it to air dry
• Store equipment in a clean patient bag at the bedside
• Reassess the patient, including post-treatment peak flow
• Document therapy the same as for MDI administration

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Drug Delivery on Mechanical Ventilators

Respiratory medications are delivered through adapters on the inspiratory limb of the ventilator circuit before the circuit wye.

Devices include:

• Nebulizer adapters or HHN
• MDI adapters or collapsible holding chamber

DPIs cannot deliver medication to mechanically ventilated patients.

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Dry Powder Inhaler (DPI)

DPIs use micronized drug particles and no propellants.

The patient must actively inhale through the device to suspend drug particles.

The source notes that DPI delivers the most medication to the lung compared with other devices.

DPI Instructions

1. Check that the patient has the correct medicine.
2. Remove the inhaler cap.
3. Add or load a dose.
4. Exhale completely.
5. Do not exhale into the inhaler because this can blow powder out of the inhaler.
6. Avoid moist exhaled air because it can cause dry powder to clump and clog the inhaler.
7. Place the inhaler in the mouth and form a tight seal around the mouthpiece.
8. Inhale quickly and deeply through 2 or 3 seconds.
9. Hold breath for 10 seconds.

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Small Particle Aerosol Generator (SPAG)

SPAG is used to deliver Ribavirin (Virazole), an antiviral drug.

Treatment indications listed in the source:

• Respiratory Syncytial Virus (RSV)
• Parainfluenza Virus (PIV)

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High-Yield Review

Objectives Checklist

• Describe proper use of respiratory medication delivery devices
• Demonstrate providing a patient treatment with a small volume nebulizer

Device Selection Points

SVN Treatment Sequence

1. Verify order and review chart.
2. Explain therapy and assemble labeled equipment.
3. Seat patient upright and assess before treatment.
4. Run gas flow at 6 L/min or greater.
5. Coach normal breathing with occasional slow deep breaths and short breath holds.
6. Continue until sputtering or aerosol stops.
7. Rinse, air dry, store equipment, reassess, and document.