Our data indicate that even within one hospital, the approach to nebulization of antimicrobial drugs may be heterogeneous. This may partly be explained by the organizational structure of Charité – Universitätsmedizin Berlin, where ICUs are run by different departments on three different campuses. However, the range in practices may also reflect current national and international guidelines, which give conflicting advice [
1‐
3]. Only three out of eleven ICUs followed established protocols for administration of nebulized antibiotics. Physicians on these wards in particular had extensive experience with inhaled antimicrobials. In one ICU, which is a certified weaning center, inhalation of low dose gentamicin (i.e. 40 mg q24h) is prescribed to all invasively ventilated patients to prevent episodes of VAP. Gentamicin may be replaced by other antibiotics if the colonizing flora is resistant to gentamicin. In case of VAP, other inhaled antibiotics are administered at higher dosage (usually tobramycin 80 mg q8h) and systemic antibiotic treatment is added. Treatment with inhaled gentamicin is resumed after antibiotic therapy for VAP has ended. Physicians of this ward consider this strategy as safe and efficacious; however, further study is necessary to prove or refute its benefit. We found substantial uncertainty regarding nebulization of antimicrobials on most units. In some wards, physicians were unaware of the device used for nebulization and several physicians asked for recommendations on how to approach inhaled antimicrobials. Nonetheless, protocols for filter exchange were in place on all wards and filters were exchanged at least daily in 10 out of 11 units. In the international survey by Alves et al., daily filter changes were carried out in 83 of 216 (38.4%) units [
4]. The high percentage of daily filter exchange in our hospital may contribute to the perception of all respondents that nebulization of antibiotics was safe as adverse events in the literature have been linked to obstruction of the expiratory filter [
6]. However, respondents in the study by Alves et al. commonly described bronchospasm, cough, and a moderate decrease in oxygen saturation [
4]. All these adverse events may occur independently of frequent filter exchanges. Inhalation of antimicrobial drugs was regarded unanimously as efficacious although all respondents admitted that this was merely a subjective estimation. AMS programs face difficulties in giving sound advice on nebulization of antimicrobials. Limited evidence and risk of adverse events caution against liberate administration. On the other hand, there may be a role in treating MDROs and a potential in preventing episodes of VAP. Although the indications for nebulized antibiotics are debatable, technical requirements should be followed to minimize risks of treatment failure and adverse events [
7]. The observed heterogeneity of practices in our institution might constitute an argument for institutional-wide standardized procedures and standardized guidelines in general.