Reduction of bacterial resistance with inhaled antibiotics in the intensive care unit
Authors: Palmer LB, Smaldone GC.
Am J Respir Crit Care Med 2014; 189: 1225–1233.
Summary: It has been postulated that inhaled antibiotics have an advantage over systemic antibiotics in respiratory infections by delivering higher concentrations to the airways and limiting systemic toxicity. Within an intubated population, delivery of aerosolised antibiotics is simple and effective as they are already connected to a closed-circuit ventilator system, maximising dose delivery. Critically unwell patients are at high risk of colonisation by multidrug-resistant (MDR) organisms; this is due to multiple factors such as prolonged hospitalisation and longer term exposure to systemic antibiotics. Inhaled antibiotics may, therefore, be an excellent yet previously unconsidered option in intubated and mechanically ventilated patients in the intensive care unit (ICU) setting.
Palmer and Smaldone conducted a double-blind, randomised, placebo-controlled trial of critically ill, intubated ICU patients in order to explore this theory. Patients with evidence of respiratory infection were randomised to receive either aerosolised antibiotics (vancomycin in patients with Gram-positive organisms and gentamicin or amikacin in patients with Gram-negative organisms) or placebo. This was in addition to appropriate systemic antibiotics.
In patients who received aerosolised antibiotics, 26 out of 27 pathogens were eradicated. Remarkably this included 14 out of 16 multidrug-resistant pathogens. This compared with 2 out of 23 eradicated in the placebo group (1 out of 11 MDR pathogens). An additional positive finding was that no resistance to the aerosolised antibiotics was seen; this may be especially important given that resistance to systemic antibiotics was found to be much higher in the placebo group. The outcomes were primarily microbiological; however, there were small beneficial effects on clinical outcomes seen in the group receiving aerosolised antibiotics, including reduced tracheal secretions and lower white cell counts.
It …