Trial of antibiotic restraint in presumed pneumonia: A Surgical Infection Society multicenter pilot

Desirability of Outcome Ranking and Response Adjusted for Antibiotic Risk (DOOR/RADAR) Post Hoc Analysis Supports Equipoise for Antibiotic Initiation Strategies in Intensive Care Unit-Acquired Pneumonia

Background: Pneumonia is the most common intensive care unit (ICU)-acquired infection and source of potential sepsis in ICU populations but can be difficult to diagnose in real-time. Despite limited data, rapid initiation of antibiotic agents is endorsed by society guidelines. We hypothesized that a post hoc analysis of a recent randomized pilot study would show no difference between two antibiotic initiation strategies. Patients and Methods: The recent Trial of Antibiotic Restraint in Presumed Pneumonia (TARPP) was a pragmatic cluster-randomized pilot of antibiotic initiation strategies for patients with suspected ICU-acquired pneumonia. Participating ICUs were cluster-randomized to either an immediate initiation protocol or a specimen-initiated protocol where a gram stain was required for initiation of antibiotics. Patients in the study were divided into one of seven mutually exclusive outcome rankings (desirability of outcome ranking; DOOR): (1) Survival, No Pneumonia, No adverse events; (2) Survival, Pneumonia, No adverse events; (3) Survival, No Pneumonia, ventilator-free-alive days ≤14; (4) Survival, Pneumonia, ventilator-free-alive days ≤14; (5) Survival, No Pneumonia, Subsequent episode of suspected pneumonia; (6) Survival, Pneumonia, Subsequent episode of suspected pneumonia; and (7) Death. These rankings were further refined using the duration of antibiotics prescribed for pneumonia (response adjusted for antibiotic risk; RADAR). Results: There were 186 patients enrolled in the study. After applying the DOOR analysis, a randomly selected patient was equally likely to have a better outcome in specimen-initiated arm as in the immediate initiation arm (DOOR probability: 50.8%; 95% confidence interval [CI], 42.7%-58.9%). Outcome probabilities were similar after applying the RADAR analysis (52.5%; 95% CI, 44.2%-60.6%; p = 0.31). Conclusions: We found that patients for whom antibiotic agents were withheld until there was objective evidence (specimen-initiated group) had similar outcome rankings to patients for whom antibiotic agents were started immediately. This supports the findings of the TARPP pilot trial and provides further evidence for equipoise between these two treatment strategies.

Provider Perceptions of Antibiotic Initiation Strategies for Hospital-Acquired Pneumonia

Background: The practice of rapidly initiating antibiotic therapy for patients with suspected infection has recently been criticized yet remains commonplace. Provider comfort level has been an understudied aspect of this practice. Hypothesis: We hypothesized that there would be no significant differences in provider comfort level between the two treatment groups. Methods: We prospectively surveyed critical care intensivists who provided care for patients enrolled in the Trial of Antibiotic Restraint in Presumed Pneumonia (TARPP), which was a multicenter cluster-randomized crossover trial that evaluated an immediate antibiotic initiation protocol compared with a protocol of specimen-initiated antibiotic initiation in ventilated patients with suspected new-onset pneumonia. At the end of each enrollment arm, physicians at each center were surveyed regarding their overall comfort level with the recently completed treatment arm, and perception of adherence. Both a paired and unpaired analysis was performed. Results: We collected 51 survey responses from 31 unique participants. Providers perceived a higher rate of adherence to the immediate initiation arm than the specimen-initiated arm (Always Adherent: 37.5% vs. 11.1%; p = 0.045). Providers were less comfortable waiting for objective evidence of infection in the specimen-initiated arm than with starting antibiotic agents immediately (Very Comfortable: 83.3% vs. 40.7%; p = 0.004). For the smaller paired analysis, there was no longer a difference in comfort level. Conclusions: There may be differences in provider comfort levels and perceptions of adherence when considering two different antibiotic initiation strategies for suspected pneumonia in ventilated patients. These findings should be considered when planning future studies.

Immediate vs. culture-initiated antibiotic therapy in suspected non-severe ventilator-associated pneumonia: a before-after study (DELAVAP)

BACKGROUND

Ventilator-associated pneumonia (VAP) is the leading nosocomial infection in critical care and is associated with adverse outcomes. When VAP is suspected, starting antibiotic therapy (AT) immediately after pulmonary sampling may expose uninfected patients to unnecessary treatment, whereas waiting for bacteriological confirmation may delay AT in infected patients. As no robust data exist to choose between these strategies, the decision must balance the pre-test diagnostic probability, clinical severity, and risk of antimicrobial resistance. The objective of this study in patients with suspected non-severe VAP was to compare immediate AT started after sampling to conservative AT upon receipt of positive microbiological results. The outcomes were antibiotic sparing, AT suitability, and patient outcomes.

METHODS

This single-center, before-after study included consecutive patients who underwent distal respiratory sampling for a first suspected non-severe VAP episode (no shock requiring vasopressor therapy or severe acute respiratory distress syndrome). AT was started immediately after sampling in 2019 and upon culture positivity in 2022 (conservative strategy). The primary outcome was the number of days alive without AT by day 28. The secondary outcomes were mechanical ventilation duration, day-28 mortality, and AT suitability (active necessary AT or spared AT).

RESULTS

The immediate and conservative strategies were applied in 44 and 43 patients, respectively. Conservative and immediate AT were associated with similar days alive without AT (median [interquartile range], 18.0 [0-21.0] vs. 16.0 [0-20.0], p = 0.50) and without broad-spectrum AT (p = 0.53) by day 28. AT was more often suitable in the conservative group (88.4% vs. 63.6%, p = 0.01), in which 27.9% of patients received no AT at all. No significant differences were found for mechanical ventilation duration (median [95%CI], 9.0 [6-19] vs. 9.0 [6-24] days, p = 0.65) or day-28 mortality (hazard ratio [95%CI], 0.85 [0.4-2.0], p = 0.71).

CONCLUSION

In patients with suspected non-severe VAP, waiting for microbiological confirmation was not associated with antibiotic sparing, compared to immediate AT. This result may be ascribable to low statistical power. AT suitability was better with the conservative strategy. None of the safety outcomes differed between groups. These findings would seem to allow a large, randomized trial comparing immediate and conservative AT strategies.