Even ancient physicians knew that inhaling medically effective substances helped patients with respiratory problems. In modern medicine, inhalation with an aerosol device is considered a common form of therapy. All inhalation devices work on the same principle.
What is aerosol therapy?
In aerosol therapy, the patient inhales liquid or solid particles of active ingredient that are expelled by a device in a typical manner. To reach the lower airways, the particles must be smaller than 10 microns. In aerosol therapy, the patient inhales liquid or solid active ingredient particles that are ejected in a device-typical manner. In order to reach the lower airways, the particles must be smaller than 10 microns. However, only particles smaller than 3 microns reach the alveoli. These values apply to patients with healthy lungs. Lung areas that do not receive proper blood flow, as is the case with some lung diseases, generally cannot be effectively treated by the drug. For optimal effect, the drug should enter the airways in the full dose if possible. How it is distributed in the patient’s airways depends on several factors: The size, shape, density and electrical charge of the particles and the patient’s typical breathing pattern (respiratory flow and breath-to-volume) determine how the drug arrives. In addition, the aerosol should also be tailored to the individual characteristics of the patient’s lungs and other respiratory organs. Aerosol therapies offer many benefits to patients: For conditions associated with acute respiratory distress, the emergency drug immediately gets to where it needs to help. The larger absorption area ensures faster efficacy. In addition, the user of aerosol therapy needs only about 10% of the dose that would otherwise be required, which further reduces potential side effects.
Function, effect, and goals
The drug transported by aerosol is used for local and systemic treatment of respiratory diseases associated with hypersecretion, secretion retention, with edema and inflammation of the mucosa, or with spasm of the bronchial muscles. The most commonly used agents are glucocorticoids, beta-2 sympathomimetics, and antibiotics. Aerosol therapy is indicated for bronchial asthma, acute and chronic bronchitis, COPD (chronic obstructive pulmonary disease), and cystic fibrosis. Since there are four different aerosol application systems and each of them has strengths as well as weaknesses, the prescribing physician should be sure to tailor the system to be used to the specific requirements of his patient. Two of the systems are additionally suitable for use on the move (metered-dose aerosols with propellant gas and powder aerosols). The other two (nozzles and ultrasonic nebulizers) can only be used at the patient’s home. Metered dose inhalers (MDIs) are usually prescribed as an emergency medication for asthma and COPD. With them, the drug is sprayed into the airways via a propellant gas. The inhalation system has the disadvantage that about 10% of the dose is lost for technical reasons. In addition, 50% of the active ingredient usually remains in the mouth and cannot be inhaled. Powder inhalers (DPI) are similarly effective as MDI aerosols. A prerequisite for use is that the patient has a respiratory flow volume of at least 30, preferably 60 liters per minute. Nebulizer systems are optimal for patients with too weak lung function. There are nozzle nebulizers and ultrasonic nebulizers. In nozzle nebulizers, the drug solution or suspension is ejected through a nozzle at the end of the mouthpiece. In it, the flow rate is reduced so that the patient receives more active ingredient per single dose. Nebulizers are easier to use because they do not require the patient to use a special breathing technique, and the active drug ingredients are better distributed in the lungs. With nebulizers, too, the patient must hold the mouthpiece firmly with his lips. He must also hold the breathing mask during use. With ultrasonic nebulizers, the drug is distributed via ultrasound.
Risks, side effects and hazards
Aerosol therapy does not show side effects when used correctly, unless the medication prescribed by the physician is not tolerated by the patient or the dose is too high. In infants and small children, in individual cases, the small patient may start to cry or scream in the process.As long as he is so excited, the application should not be performed. If the child refuses the mask, the treating parent holds it in front of his mouth and nose at a distance of about 1 cm. Child patients need nebulizers that spray very small drops. Metered-dose inhalers and nebulizers (both with mask) are well suited for children under 3 years of age; from 3 years of age, they can use a spacer with mouthpiece. Patients between 3 and 6 years of age use nebulizers with mouthpieces. Children older than 6 years can already be prescribed dry powder inhalers by the doctor. It is important that young patients eat or drink something after each use to avoid corticosteroid or antibiotic buildup in the mouth. For older children and adult patients, it is sufficient to rinse their mouths immediately afterwards. It is also advisable to wash the face after inhalation. Particular hygiene is required when handling nebulizers. This applies to the solution prepared by the patient as well as to the device itself. After each use, any residual solution in the container must be disposed of. Afterwards, all parts of the nebulizer should be thoroughly cleaned. It must also be disinfected once a day. All parts except the tubing must be allowed to air dry and reassembled only when completely dry.
