Metabolic Profiling in Patients with Pneumonia on Intensive Care

Pneumonia has major implications for Intensive Care Units (ICU) on one hand Community acquired pneumonia (CAP) is the most common infectious reason for patient admission into EU ICUs. On the other, ventilator associated pneumonia (VAP) is a common complication in patients (8 – 28%) requiring mechanical ventilation. Current diagnostic techniques are subjective and lack sensitivity and specificity. Hence, a new diagnostic technique that will allow correct patient stratification and early identification of the disease is required.

Can Metabolic Profiling be used for Diagnosis of Pneumonia and correct stratification of CAP and VAP?

In this study 46 patients admitted in an ICU were recruited and samples were taken during their stay in hospital. 15 were diagnosed with CAP and 26 were accepted due to brain injury and they did not present any evidence of infection. 7 of these last patients developed VAP while in ICU.

Blood serum samples from the patients were analysed using the NPC nuclear magnetic resonance spectroscopy (NMR) platform to obtain their metabolic profiles. Multivariate statistical analysis was used to stratify the different ICU patients and to determine the metabolites whose concentration were changing between them. Receiver Operating Characteristic (ROC) curves were constructed to evaluate the diagnostic potential of the models.

The NMR analysis of serum from critically ill patients showed an ability to differentiate those with pneumonia from those without. These techniques may also be beneficial in determining those patients who go on to develop VAP. NMR spectroscopy has the potential to deliver biomarker profiles which may be translated into useful diagnostic tools in critical care.

Further work looking at different cohorts of intensive care patients needs to be done to clarify the specificity of these findings to pneumonia. In addition, this work looked at VAP in a cohort of brain injured patients, further work will be needed to establish if the current findings apply to other groups of critically ill patients and to all populations.

Metabolome to Product
A blood test based on changes in metabolite concentration for the early diagnosis of pneumonia and the correct stratification of CAP and VAP.

Acknowledgements: Infrastructure support was provided by the  National Institute for Health Research (NIHR) Imperial Biomedical Research Centre (BRC)

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