Background: Ventilator-associated pneumonia is a frequent complication in the ICU, especially in critically ill patients infected by the SARS-CoV-2. This study aimed to characterize episodes of VAP, identify risk factors associated with its development and assess the impact on the progression of COVID-19-related ARDS.
Methodology: Retrospective monocentric study using data collected during the ICU stay of critically- ill COVID-19 patients with invasive mechanical ventilation during the first and second wave of the COVID-19 pandemic in 2020 in the Adult ICU of the Lausanne University Hospital (CHUV), Switzerland.
Results: Three hundred and seven patients [231 men (75.2%) and 76 women (34.5%)] were included in the final cohort. The median age was 65.4 [58.8-72.4] years old and had a median body mass index of 28.3 [25.3-32.4]. In median, the time from the ICU admission to intubation was of 23.9 [4.15-72] hours. On admission, 224 (73%) patients had a severe ARDS, 76 (25%) a moderate ARDS and only 3 (1%) a mild ARDS. They were 162 patients (53%) who developed at least one episode of VAP during their ICU stay and 155 (47%) who did not. Within the VAP population, 115 (25.7%) developed only one episode, 40 (18.3%) developed two episodes and 7 (1%) patients had 3 or more episodes, meaning a total of 29% of recurrence. Two hundred and eighteen episodes of VAP were diagnosed, mostly Gram- Negative microorganisms (Klebsiella pneumoniae, Pseudomonas aeruginosa) and Staphylococcus aureus were identified and 2% were polymicrobial infections with 7 cases of Aspergillus spp. The prior use of antibiotics was identified as an independent risk factors for VAP onset. Regarding outcomes, patients with VAP had a significantly longer ICU-stay [25 (16-40.5) days vs 8.7 (4.7-13.3) days, P=0.001], a length of mechanical ventilation prolonged [20.4 (13.3-32) days vs 5.4 (3.4-9.7) days, P=0.003] and less free days ventilation [3 (0-11.8) days vs 18.5 (0-22) days, P<0.001] but the mortality did not differ between the two populations. This population’s stay was significantly highly associated with many complications during the ICU stay such as: septic shock (25% vs 15%, P<0.001), bacteriemia (26% vs 14.5%, P=0.006), hemorrhages (25% vs 6.2%, P>0.001), thrombo-embolic complications (35% vs 24%, P=0.013), renal failures (50% vs 30.4%, P=0.0013), COP (5% vs 0.7%, P=0.02) and need of an ECMO (9.3% vs 1.4%, P=0.0025).
Conclusion: Ventilator-associated pneumonia has a higher incidence in SARS-CoV-2 critically ill patients. The prior antibiotic use and respiratory tract interventions were identified as risk factor for VAP onset. Although VAP did not significantly impact on mortality rates, it prolonged ICU stays, increased mechanical ventilation duration, and reduced ventilator-free days. Also, the specific characteristics of VAP episodes and their association with multiple complications in this population are a challenge for an effective treatment.