Nebulized Antibiotic Therapy in Critical Care: Current Knowledge and Perspectives

Abstract

Aerosols are frequently prescribed in intensive care units, even among ventilated patients, but the use of inhaled antibiotics remains confidential. Nebulization induces a high concentration of antibiotic at the pulmonary level, much higher than intravenous administration. The amount of antibiotic reaching the systemic circulation is lower, potentially decreasing side effects. In order to ensure pulmonary deposition of antibiotics in ventilated patient, one needs to optimize the nebulization conditions by adapting the ventilator settings (assisted-controlled ventilation, increasing inspiratory time, and decreasing the inspiratory flow and the respiratory rate) and placing the nebulizer in the inspiratory limb 15 to 40 cm upstream of the Y piece. The heat and moisture exchanger needs to be removed. It is important to place a filter on the expiratory limb and change it regularly to protect the ventilator to avoid potentially serious side effects. Small sample size studies suggest that inhaled antibiotic therapy may be more effective in treating patients with ventilator-associated pneumonia with lower toxicity and less occurrence of resistant bacteria. Similarly, studies show a potential interest for preventing pneumonia and/or the transition from tracheobronchial infection to pneumonia. Nevertheless, in the absence of large randomized data demonstrating a clear benefit for patients, by now the use of nebulized antibiotic therapy in ventilated patients can only be considered on a case-by-case basis after careful evaluation of the benefit/risk ratio.