A long-lasting porcine model of ARDS caused by pneumonia and ventilator-induced lung injury.

BACKGROUND: Animal models of acute respiratory distress syndrome (ARDS) do not completely resemble human ARDS, struggling translational research. We aimed to characterize a porcine model of ARDS induced by pneumonia-the most common risk factor in humans-and analyze the additional effect of ventilator-induced lung injury (VILI). METHODS: Bronchoscopy-guided instillation of a multidrug-resistant Pseudomonas aeruginosa strain was performed in ten healthy pigs. In six animals (pneumonia-with-VILI group), pulmonary damage was further increased by VILI applied 3 h before instillation and until ARDS was diagnosed by PaO2/FiO2 < 150 mmHg. Four animals (pneumonia-without-VILI group) were protectively ventilated 3 h before inoculum and thereafter. Gas exchange, respiratory mechanics, hemodynamics, microbiological studies and inflammatory markers were analyzed during the 96-h experiment. During necropsy, lobar samples were also analyzed. RESULTS: All animals from pneumonia-with-VILI group reached Berlin criteria for ARDS diagnosis until the end of experiment. The mean duration under ARDS diagnosis was 46.8 ± 7.7 h; the lowest PaO2/FiO2 was 83 ± 5.45 mmHg. The group of pigs that were not subjected to VILI did not meet ARDS criteria, even when presenting with bilateral pneumonia. Animals developing ARDS presented hemodynamic instability as well as severe hypercapnia despite high-minute ventilation. Unlike the pneumonia-without-VILI group, the ARDS animals presented lower static compliance (p = 0.011) and increased pulmonary permeability (p = 0.013). The highest burden of P. aeruginosa was found at pneumonia diagnosis in all animals, as well as a high inflammatory response shown by a release of interleukin (IL)-6 and IL-8. At histological examination, only animals comprising the pneumonia-with-VILI group presented signs consistent with diffuse alveolar damage. CONCLUSIONS: In conclusion, we established an accurate pulmonary sepsis-induced ARDS model.

Methicillin-susceptible staphylococcus aureus in community-acquired pneumonia: Risk factors and outcomes.

OBJECTIVES: We aimed to describe the prevalence, risk factors and outcomes of Methicillin-susceptible S. aureus (MSSA) community-acquired pneumonia (CAP) and compare them with those associated with CAP due to Streptococcus pneumoniae, the most frequent causative microorganism, in a large cohort of patients. METHODS: This was an observational study of prospectively collected data of consecutive adults with CAP and a definitive etiology enrolled between 2004 and 2018. Patients were divided into MSSA CAP and pneumococcal CAP groups for analysis. RESULTS: A microbial etiology was established in 1,548 (33%) cases: S. aureus caused 6% of microbiologically-confirmed CAP cases. In the latter, 52 were due to MSSA (60% of S. aureus CAP cases, and 3% of microbiologically-confirmed CAP cases) and 34 were due to MRSA (40% of S. aureus CAP cases, and 2% of microbiologically-confirmed CAP cases). S. pneumoniae was identified in 734 (47%) microbiologically-confirmed CAP cases. The presence of fever was independently associated with a lower risk of MSSA CAP (OR 0.53; 95% CI, 0.28-0.99). Patients with MSSA CAP had higher 30-day mortality than patients with pneumococcal CAP, both before and after adjustment for potential confounders (21% vs 7%, p = 0.002). MSSA was independently associated with 30-day mortality in the overall population. CONCLUSION: MSSA CAP was associated with worse outcomes than pneumococcal CAP in our cohort. MSSA was an independent factor of mortality.

Factors associated with revisits by patients with SARS-CoV-2 infection discharged from a hospital emergency department. / Factores asociados a revisita en pacientes con diagnóstico de infección por SARS-CoV-2 dados de alta de un servicio de urgencias hospitalario.

OBJECTIVES: To analyze emergency department (ED) revisits from patients discharged with possible coronavirus disease 2019 (COVID-19). MATERIAL AND METHODS: Retrospective observational study of consecutive patients who came to the ED over a period of 2 months and were diagnosed with possible COVID-19. We analyzed clinical and epidemiologic variables, treatments given in the ED, discharge destination, need to revisit, and reasons for revisits. Patients who did or did not revisit were compared, and factors associated with revisits were explored. RESULTS: The 2378 patients included had a mean age of 57 years; 49% were women. Of the 925 patients (39%) discharged, 170 (20.5%) revisited the ED, mainly for persistence or progression of symptoms. Sixty-six (38.8%) were hospitalized. Odds ratios (ORs) for the following factors showed an association with revisits: history of rheumatologic disease (OR, 2.97; 95% CI, 1.10-7.99; P = .03), digestive symptoms (OR, 1.73; 95% CI, 1.14-2.63; P = .01), respiratory rate over 20 breaths per minute (OR, 1.03; 95% CI, 1.0-1.06; P = .05), and corticosteroid therapy given in the ED (OR, 7.78; 95% CI, 1.77-14.21, P = .01). Factors associated with hospitalization after revisits were age over 48 years (OR, 2.57; 95% CI, 1 42-4.67; P = .002) and fever (OR, 4.73; 95% CI, 1.99-11.27; P = .001). CONCLUSION: Patients under the age of 48 years without comorbidity and with normal vitals can be discharged from the ED without fear of complications. A history of rheumatologic disease, fever, digestive symptoms, and a respiratory rate over 20 breaths per minute, or a need for corticosteroid therapy were independently associated with revisits. Fever and age over 48 years were associated with a need for hospitalization.

OBJETIVO: Analizar las revisitas y los factores asociados a la misma en pacientes con diagnóstico de posible COVID-19 dados de alta de un servicio de urgencias hospitalario (SUH). METODO: Estudio observacional, retrospectivo que incluyó pacientes consecutivos que consultaron al SUH en un periodo de 2 meses y fueron diagnosticados de posible de COVID-19. Se analizaron variables clínico-epidemiológicas, tratamiento administrado en urgencias, destino final, revisita al SUH y motivo de esta. Se hizo un análisis comparativo entre ambos grupos (revisita sí/no) y se identificaron factores asociados a la revisita. RESULTADOS: Se incluyeron 2.378 pacientes (edad media 57 años; 49% mujeres). De los pacientes dados de alta (39% del total; n = 925), 170 (20,5%) reconsultaron al SUH, principalmente por persistencia o progresión de síntomas, y 66 (38,8%) precisaron ingreso. Los factores relacionados con la revisita fueron: antecedentes de enfermedad reumatológica [OR: 2,97 (IC 95%: 1,10-7,99, p = 0,03)], síntomas digestivos [OR: 1,73 (IC 95%: 1,14-2,63, p = 0,01)], frecuencia respiratoria $ 20 [OR: 1,03 (IC 95%: 1,0-1,06, p = 0,05)] y haber recibido tratamiento con esteroides en urgencias [OR: 7,78 (IC 95%: 1,77-14,21, p = 0,01)]. Los factores asociados al ingreso en la revisita fueron la edad $ 48 años [OR: 2,57 (IC 95%: 1,42-4,67, p = 0,002)] y presentar fiebre [OR: 4,73 (IC 95%: 1,99-11,27, p = 0,001)]. CONCLUSIONES: Los pacientes con posible COVID-19 menores de 48 años, sin comorbilidad y con signos vitales normales podrían ser dados de alta desde urgencias sin temor a sufrir complicaciones. Los antecedentes de enfermedad reumatológica, fiebre, sintomas digestivos, frecuencia respiratoria $ 20/min o necesidad de tratamiento con esteroides fueron factores independientes de revisita, y la fiebre y edad $ 48 años de necesidad de ingreso.