Prediction of ventilator-associated pneumonia outcomes according to the early microbiological response: a retrospective observational study

Risk factors of second ventilator-associated pneumonia in trauma patients: a retrospective cohort study

BACKGROUND

Ventilator acquired pneumonia (VAP) is a frequent and serious complication in ICU. Second episodes of VAP are common in trauma patients and may be related to severity of underlying conditions, treatment or bacterial factors of the first VAP. The aim of this study was to identify risk factors of second VAP episodes in trauma injured patients (defined as the development of a new pulmonary infection during or remotely following the first episode).

DESIGN

This is a single-center, retrospective cohort study of trauma injured patients who underwent a first episode of VAP between January 1, 2013 and December 31, 2020 at Beaujon Hospital.

RESULTS

A total of 533 patients with a first episode of VAP were analyzed, mostly with head and/or thoracic traumatic injury. A second episode of VAP occurred in one hundred sixty-seven patients (31.3%). The main risk factors found was the degree of hypoxemia at the time of the first episode [PaO2/FiO2 ratio 100-200, OR 3.12 (1.77-5.69); < 100, OR 5.80 (2.70-12.8)] and severe traumatic brain injury characterized by an initial GCS ≤ 8 [OR 1.65 (1.01-2.74)].

CONCLUSION

Depth of hypoxemia during the first VAP episode and severity of the initial brain injury are the main risk factors for VAP second episode in trauma injured patients.

Ventilator-Associated Pneumonia in COVID-19 Patients Admitted in Intensive Care Units: Relapse, Therapeutic Failure and Attributable Mortality-A Multicentric Observational Study from the OutcomeRea Network

Introduction: Ventilator-associated pneumonia (VAP) incidence is high among critically ill COVID-19 patients. Its attributable mortality remains underestimated, especially for unresolved episodes. Indeed, the impact of therapeutic failures and the determinants that potentially affect mortality are poorly evaluated. We assessed the prognosis of VAP in severe COVID-19 cases and the impact of relapse, superinfection, and treatment failure on 60-day mortality. Methods: We evaluated the incidence of VAP in a multicenter prospective cohort that included adult patients with severe COVID-19, who required mechanical ventilation for ≥48 h between March 2020 and June 2021. We investigated the risk factors for 30-day and 60-day mortality, and the factors associated with relapse, superinfection, and treatment failure. Results: Among 1424 patients admitted to eleven centers, 540 were invasively ventilated for 48 h or more, and 231 had VAP episodes, which were caused by Enterobacterales (49.8%), P. aeruginosa (24.8%), and S. aureus (22%). The VAP incidence rate was 45.6/1000 ventilator days, and the cumulative incidence at Day 30 was 60%. VAP increased the duration of mechanical ventilation without modifying the crude 60-day death rate (47.6% vs. 44.7% without VAP) and resulted in a 36% increase in death hazard. Late-onset pneumonia represented 179 episodes (78.2%) and was responsible for a 56% increase in death hazard. The cumulative incidence rates of relapse and superinfection were 45% and 39.5%, respectively, but did not impact death hazard. Superinfection was more frequently related to ECMO and first episode of VAP caused by non-fermenting bacteria. The risk factors for treatment failure were an absence of highly susceptible microorganisms and vasopressor need at VAP onset. Conclusions: The incidence of VAP, mainly late-onset episodes, is high in COVID-19 patients and associated with an increased risk of death, similar to that observed in other mechanically ventilated patients. The high rate of VAP due to difficult-to-treat microorganisms, pharmacokinetic alterations induced by renal replacement therapy, shock, and ECMO likely explains the high cumulative risk of relapse, superinfection, and treatment failure.

Defining Clinical and Microbiological Nonresponse in Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a severe complication of mechanical ventilation, with mortality reduced most effectively by adequate early antibiotic treatment. The clinical and microbiologic response can be assessed easily from 72 hours after starting antibiotic treatment. Evidence of nonresponse is based on several factors: (1) lack of clinical improvement, (2) radiographic progression, (3) an impaired Sequential Organ Failure Assessment (SOFA) score, (4) no improvement by days 3 to 5 on the Clinical Pulmonary Infection Score (CPIS), (5) no decreased in biomarkers on day 3, and (6) isolation of a new pathogen on day 3. Among the clinical markers of treatment failure, physicians should consider no improvement in the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂), persistence of fever or hypothermia, persistence of purulent respiratory secretions, and new-onset septic shock or multiple-organ dysfunction syndrome. Microbiological isolation of a new pathogen on day 3 is also associated with higher mortality, but persistence of the original pathogen does not seem to be associated with a worse prognosis. The real impact of changes to treatment after diagnosing nonresponsive VAP is unknown. Physicians must evaluate whether treatments are adequate in terms of sensitivity, dose, and route. Pharmacokinetically and pharmacodynamically optimized doses are recommended in these patients. Clinical stabilization of comorbidities or underlying conditions may be of benefit.