Clinical, metabolomic, and genomic predictors of acute respiratory distress syndrome in hospitalized patients with community-acquired pneumonia.

1.      Patients will be recruited after written informed consent from patients/ legally acceptable representatives.

2.     Demographic profile of community acquired pneumonia (CAP) patient, Charlson co-morbidity index score, baseline vitals at hospitalization, and Sequential Organ Failre Assessment (SOFA) score, Pneumonia Severity Index (PSI) score, CURB-65 score, and NEWS-2 score will be recorded. Chest radiographs (CXR) will be evaluated for the worst Brixia CXR score within 24 hours. A bedside point of care ultrasound examination of the lungs will be performed. APACHE-2 score will be recorded for patients in ICU, which is standard practice. The worst SOFA score, PSI score, CURB-65 score, and NEWS- 2 score and Brixia chest x-ray score with 48 hours of hospital stay will be noted.

3.   Blood samples will be obtained within 24 hours for the analysis of the pulmonary biomarkers and metabolomic study. The biomarkers evaluated will be along with three novel pulmonary biomarkers – surfactant protein-D (SP-D), Angiopoietin-2 (Ang-2) and soluble receptor for advanced glycation end products (sRAGE).

4.  For metabolomics the study will be in Biochemistry laboratory using GC-MS coupled with a Shimadzu Mass Spectrometer (MS) (GC/MS -QP2020 NX SHIMADZU, Shimadzu Corp., Tokyo, Japan). Lipid, ketone body, fatty acid, energy, amino acid and organic acid metabolomics will be studied, with a total of about 160 metabolites.

5.    For the genome sequencing study, blood samples will be transported in dry ice blood to the Department of Medical Genetics and Kasturba Medical College, Manipal. Samples will then be outsourced to Medgenome company for Genome Wide Association Study and SNPs identification. Further GWAS analysis will be performed in Department of Medical Genetics and Kasturba Medical College, Manipal.

6.  Standard of care investigations like blood picture, coagulation profiles, tests of renal and liver function, c-reactive protein, procalcitonin, and arterial blood gas reports, will be noted from the available recorded data for 48 hours post hospitalization. The echocardiography findings will be noted from the records. The available microbiological culture reports will be followed up for the respiratory or blood specimens. Mode of ventilation and ventilator parameters will also be recorded like plateau pressure, driving pressure, positive end expiratory pressure, and peak pressure.

7.  Patients will be noted for ARDS development within the 48 hours of hospitalization and from the third to seventh-day post hospitalization, need for mechanical ventilation, days of ICU stay, need for renal replacement therapy in ICU, and development of acute kidney injury.

8.   Survival or mortality at 14 days post-hospitalization will be recorded.