Importance of a registered and structured protocol when conducting systematic reviews: comments about nebulized antibiotics for ventilator-associated pneumonia

We appreciate Gu’s [1] interest in our study. We apologize and agree with his comment about attributing units to standardized mean difference (SMD). Nevertheless, similar to the SMD, results in mean difference (control – nebulized) were unaffected by nebulized antibiotics (2.67 days, 95 % confidence interval (CI) –2.89, 8.23 for ICU length of stay (LOS); and 0.70 days, 95 % CI −3.40, 4.80 for mechanical ventilation). However, we strongly disagree with other points raised by the letter. First, the study protocol was defined a priori [2]. We disagree that combining observational studies with intervention studies is reserved only for safety evaluation. This topic has been discussed in the literature and combining both types of studies was adequate for our aim [3]. Furthermore, we presented the main results separating interventional studies from observational studies, thereby allowing the reader to interpret both analyses independently.