ABSTRACT
Therapeutic aerosols are commonly used in mechanically ventilated patients, yet information
regarding their efficacy and optimal technique of administration has been limited.
The advantages of aerosol therapy include a smaller dose, efficacy comparable with
that observed with systemic administration of the drug, and a rapid onset of action.
Inhaled drugs are delivered directly to the respiratory tract, their systemic absorption
is limited, and systemic side effects are minimized. Inhaled bronchodilators are routinely
used with mechanically ventilated patients in the intensive care unit, but a variety
of drugs ranging from antibiotics to surfactants has been administered. Nebulizers
and metered-dose inhalers (MDIs) are commonly used aerosol generators because they
produce respirable particles with a mass median aerodynamic diameter (MMAD) between
1 and 5 μm. Due to the limitation of available formulations, MDIs are chiefly used
to deliver bronchodilators and steroids, whereas nebulizers have greater versatility
and can be used to administer bronchodilators, antibiotics, surfactant, mucokinetic
agents, and other drugs. The delivery of inhaled drugs in mechanically ventilated
patients differs from that in ambulatory patients in several respects. Until recently,
the consensus of opinion was that the efficiency of aerosol delivery to the lower
respiratory tract in mechanically ventilated patients was much lower that that in
ambulatory patients. Data suggest that this might be overly pessimistic and that the
endotracheal tube may actually facilitate greater aerosol delivery compared with the
normal airway when a variety of variables effecting aerosol delivery during mechanical
ventilation are optimized.
KEYWORD
Aerosols - nebulizers - pulmonary mechanics - bronchodilators - beta-agonists
