Aerosol delivery during invasive mechanical ventilation: a systematic review

Area of Science:

• Pulmonary Medicine
• Pharmacology
• Biomedical Engineering

Background:

• Systematic review assessing inhaled drug delivery in mechanically ventilated patients and animal models.
• Analysis of whole lung and regional deposition, ventilator circuit, artificial airways, and administration techniques.

Purpose of the Study:

• To evaluate inhaled drug delivery efficiency in mechanically ventilated subjects.
• To analyze factors influencing aerosol deposition in the lungs.

Main Methods:

• Systematic search of four databases for in vivo studies on lung deposition during invasive mechanical ventilation.
• Independent eligibility and risk of bias assessment by two investigators.

Main Results:

• Twenty-six clinical and ten experimental studies included; 30-43% drug loss to the ventilator circuit.
• Whole lung deposition up to 16% (nebulizers) and 38% (metered-dose inhalers) of nominal dose.
• Scintigraphic studies showed proximal deposition; however, substantial antibiotic concentrations found in infected lung fluids and tissues suggest distal deposition.

Conclusions:

• Lung deposition with nebulizers is <20% and predominantly proximal.
• Further research is required to correlate antibiotic concentrations in infected fluids with pulmonary deposition.
• Nebulizer administration techniques in ventilated patients need optimization for efficiency, safety, feasibility, and reproducibility.