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Recommendations for Recommendations for Inhalation TherapyInhalation Therapy
(Focusing on bronchodilator)(Focusing on bronchodilator)
4A Intern
蔡宇承
Why and why not?
Advantages:
- Less systemic toxicity
- More rapid onset of medication
- Delivery to target of action
- Higher concentrations available in the lung Disadvantages:
- Time and effort consuming
- Limitation of delivery device
What are the Inhalant drugs? Antiallergic agents
Budesonide
Cromolyn sodium Bronchodilators
Ventolin nebules (βagonist)
Bricanyl solution (βagonist)
Atrovert nebulizer solution (anti- cholinergic)
Inhalant drugs
Mucolytic agents
Acetein (Acetylcysteine)
Mistabron (Mesna) Antimicrobials
Tobramycin
Pentamidine
Ribavirin
Amphotericin
Inhalant drugs
Immune modulators
Cyclosporine
Interferon α
Interferon γ Vaso-active
Prostacyclin
Nitric oxide
Inhalant drugs
Anesthetics
Opioids Other
Granulocyte-Macrophage Colony-Stimulating Factor
Surfactant
Interleukin II
Gene therapy vectors
Respiratory tract characteristics
Large surface area, good vascularization, immense capacity for solute exchange, ultra-thinness of the pulmonary epithelium
Conducting region :
Nasal cavity, nasopharynx, bronchi, bronchioles (first 16 generations)
Respiratory region :
respiratory bronchioles, alveolar ducts and sacs (17-23 generations)
Particle Size
MMAD: mass median aerodynamic diameter
MMAD <1μm: exhaledMMAD 1~5μm: targetMMAD >5μm: oropharynx
Strict control of MMAD of the particles ensures the reproducibility of aerosol deposition and retention.
Particle Size
Device for Inhalation Therapy
Selections of device include:– 1.Nebulizer(霧化器 ): small volume,
large volume, ultrasonic, pneumatic…– 2.Metered dose inhaler, MDI (定量吸入器 )– 3.Dry powder inhaler, DPI (粉末型吸入器 )
Metered-dose inhalers
A liquid propellant A metering valve that dispenses a constant volum
e of a solution or suspension of the drug in the propellant.
Inhalation technique is critical for optimal drug delivery – Actuating a MDI out of synchrony may cause negligible lower airway delivery
Mainly oropharyngeal deposition Protein denaturation
Metered-dose inhalers
Dry powder inhalers No propellant Breath-activated, and patient coordination is not
as important an issue. The drug is formulated in a filler and contained
in a capsule that is placed in the device and punctured to release the powder.
Proteins and macromolecules are more stable in dry powder form, this approach has been preferred for delivery of these compounds by the inhalational route
Nebulizers
Patient cooperation and coordination is not as critical
Commercially available nebulizers deliver 12% to 20% of the nebulized dose into the bronchial tree.
Heterogeneous drops Protein denaturation
Nebulizers
Nebulizers
Drugs Available for Nebulization
Inhaled beta-2 agonist bronchodilators– Short-acting (3~6hr)– Long-acting (>12hr)
Inhaled anti-cholinergics Inhaled corticosteroids
Inhaled Beta-2 Agonist Bronchodilators
Short-acting (3~6hr)– Salbutamol / Albuterol (Ventolin)– Terbutaline (Bricanyl)– Fenoterol (Berotec)
Long-acting (>12hr)– Salmeterol– Formoterol
Inhaled Anti-cholinergics
Ipratropium bromide (Atrovent)
Inhaled Corticosteroids
Beclomethasone Triamcinolone Flunisolide Budesonide (Pulmicort) Fluticasone
General Indications
Bronchodilator aerosol administration and evaluation of response is indicated whenever bronchoconstriction or increased airway resistance is documented or suspected in patients during mechanical ventilation
- AARC Clinical Practice Guideline
Criteria
Presence of one or more of the following criteria: Previous demonstrated response of bronchodilator Presence of auto-PEEP not eliminated by reduced rat
e, increased inspiratory flow, or decreased inspiratory to expiratory time ratio
Increased airway resistance evidenced by:• Increased peak inspiratory pressure and plateau pressure di
fference• Wheezing or decreased breathing sound• Intercostal or sternal retraction• Patient – ventilator dyssynchrony
Some Evidence Based Factsfrom American Journal of
Respiratory Critical Care Medicine
Mechanically Ventilated Patients (1)
Bronchodilator therapy is commonly used in the intensive care unit, although the indications for its use are not well defined
Patients with COPD demonstrate a significant decrease in airway resistance after administration of bronchodilators
Bronchodilators have been successfully used to treat acute bronchial spasm in the operating room, and they are widely used in mechanically ventilated patients with severe asthma
Inhaled Bronchodilator Therapy in Mechanically Ventilated Patients Am J Respir Crit Care Med Vol. 156. pp. 3-10, 1997
Mechanically Ventilated Patients (2)
A heterogeneous group of mechanically ventilated patients, including some patients without a previous diagnosis of airway obstruction, have shown improvement in their expiratory airflow after bronchodilator administration
Although ARDS is primarily a disease affecting the alveoli, nebulized metaproterenol sulfate produced a decrease in airway resistance in patients with this disorder
Inhaled Bronchodilator Therapy in Mechanically Ventilated PatientsAm J Respir Crit Care Med Vol. 156. pp. 3-10, 1997
Mechanically Ventilated Neonates and Infants (1)
Pressure-limited, time-cycled modes of mechanical ventilation are widely used in neonates and infants
Several investigators have reported that the small diameter of the endotracheal tubes and ventilator tubing and the low tidal volumes used for ventilating neonates and infants decrease aerosol delivery to the respiratory tract
Inhaled Bronchodilator Therapy in Mechanically Ventilated Patients Am J Respir Crit Care Med Vol. 156. pp. 3-10, 1997
Mechanically Ventilated Neonates and Infants (2)
The lung deposition to be as low as 0.98 ± 0.2% and 0.22 ± 0.1% with an MDI and spacer or a jet nebulizer, respectively
Even such low levels of drug deposition are adequate when considered in terms of the body weight of the patient (mg of drug deposited per kg body weight)
Inhaled Bronchodilator Therapy in Mechanically Ventilated Patients Am J Respir Crit Care Med Vol. 156. pp. 3-10, 1997
Mechanically Ventilated Neonates and Infants (3)
Inhaled beta-adrenergic and anticholinergic drugs are effective in ventilator-supported neonates and infants with acute, subacute, and chronic lung disease
The use of inhaled corticosteroids has also been advocated in infants with bronchopulmonary dysplasia
Inhaled Bronchodilator Therapy in Mechanically Ventilated Patients Am J Respir Crit Care Med Vol. 156. pp. 3-10, 1997
Current Guideline of Bronchodilator Usage in NTUH SICU
Ventoline: first choice as Bronchodilator to reduce airway resistance in mechanically ventilated patients
Atrovent: recommended to given patient with Asthma & COPD history, as a combination with Bronchodilator. Old age, long-term use, might be an indication of this combination also.
Pulmicort: first line to treat pulmonary inflammatory disease.
Give Ventoline before Pulmicort.
Indication for Bronchodilator (1)
Short-acting inhaled Beta-2 Agonist Bronchodilators– Acute asthma for quickly relieving symptoms– AECOPD, maybe can combine inhaled Anti-cholin
ergics– Stable COPD combine inhaled Anti-cholinergics f
or short term use seems more effective than either alone
– In mechanically ventilated patients which present auto-PEEP or evidently increased airway resistance
Indication for Bronchodilator (2)
Inhaled Anti-cholinergics– AECOPD can be used or be added to short-acting
inhaled beta-2 agonist bronchodilators– Stable COPD combine short-acting inhaled beta-2
agonist bronchodilators for short term use seems more effective than either alone
– In mechanically ventilated patients which present auto-PEEP or evidently increased airway resistance
AARC Recommendation I
Ventilator setting:
- tidal volume > 500
- Addition of inspiratory pulse (in case the inspiratory flow demands of the patient are met)
- Spontaneous breath should not be suppressed
AARC Recommendation II
Humidifier use:
- reduce aerosol delivery by 40%
- Humidified gas should still be used for dry gas associated risk
- Increase dose for compensation
AARC Recommendation III
Metered Dose Inhaler
- Delivered dose significantly reduced due to failure to actuate the inhaler with the onset of inspiration
- Actuate the inhaler manually for synchronizing the inspiration
AARC Recommendation IV
Nebulizer Use:
- Change nebulizer every 24 hours
- Leave it 30 cm proximal to endotracheal tube if possible
- It may be necessary to add a filter in the expiratory limb of the circuit to maintain expiratory flow-sensor accuracy
AARC Recommendation V
Patient monitoring:
- Volume ventilation: peak inspiratory pressure and the difference between peak and plateau pressure
- Pressure ventilation: tidal volume
- Auto-PEEP
- Peak Expiratory Flow and Flow-Volume Loop
- Breath Sound
Thank you for your attention!
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