Infectious Diseases I
| (c) | The rate of MDR pathogens during a recurrent VAP episode was higher in patients in the |
|---|
15-day group.
ii.
Two meta-analyses that included the results of the PneumA trial suggest limited benefit of
prolonged duration of definitive antibiotic therapy for treating VAP (Chest 2013;144:1759-67;
Cochrane Database Syst Rev 2015;8:CD007577). Synopsis includes:
| (a) | Any increase in VAP recurrence rate is small; |
|---|---|
| (b) | Mortality and clinical cure do not appear to be affected by shorter durations; |
| (c) | Evidence for recurrence from subgroup analyses has important limitations. |
iii.
Guidelines acknowledge that situations may exist in which shorter or longer durations of
definitive antibiotic therapy may be indicated, depending on the rate of clinical and radiologic
improvement. A single-center, retrospective study suggested that patients with “possible VAP”
who had minimal and stable ventilator settings at diagnosis are appropriate for short-course
therapy (i.e., 1-3 days) (Clin Infect Dis 2017;64:870-6). However, application of these findings
is limited, given that only 39% of short-course patients had an identified pathogen on tracheal
aspirate or BAL culture, bringing into question the likelihood of confirmed pneumonia.
iv.
The iDIAPASON Trial was a randomized, controlled, open-label trial that compared 8 versus
15 days of antibiotic therapy solely for the treatment of Pseudomonas aeruginosa ventillator-
associated pneumonia (PA-VAP). The primary noninferiority endpoint was a composite
outcome of death and PA-VAP recurrence during the ICU stay until day 90. Duration of therapy
Major study findings were the following:
| (a) | Short duration was not associated with an increased mortality, longer duration of mechanical |
|---|
ventilation, or length of ICU stay.
| (b) | While not significant, there was a trend toward higher proportion of recurrence in |
|---|
the 8 days of therapy compared with 15 days (17% vs. 9.2%; confidence interval [CI],
–0.5% –16.8%).
Response to antibiotic therapy should be assessed serially using clinical signs and symptoms of infection
(e.g., oxygenation requirements, blood pressure, WBC, temperature) and status of VAP-related organ
dysfunction.
Lack of response in signs and symptoms of VAP beyond treatment day 3 necessitates reassessment
of diagnosis, causative pathogen(s), antibiotic regimen, and presence of pneumonia-related
complications (e.g., ARDS).
Patients thought to have persistent VAP should undergo repeat lower respiratory tract culture and
receive empiric antibiotic therapy considering previous pathogen(s) and antibiotic exposure.
Characteristic
2005 Guidelines
2016 Guidelines
Methodology
Expert opinion based on level of evidence
ranging from Level I (high) to III (low)
GRADE criteria to identify “recommended”
(strong) or “suggested” (weak) guidance based
on level of evidence categories “very low,” “low,”
“moderate,” and “high quality”
Diagnosis
Clinical strategy or bacteriologic strategy
Suggest clinical suspicion with noninvasive
sampling and semiquantitative cultures
If invasive sampling is used, suggest that
antibiotics be withheld rather than continued
if quantitative culture results are below the
diagnostic threshold for VAP