Role of biomarkers for management of VAP

Procalcitonin is a biomarker for acute inflammation and is elevated during bacterial infection. However, other factors can also cause an elevation in procalcitonin concentration (eg trauma, burns, surgery, pancreatitis, gastrointestinal tract ischaemia), so procalcitonin has poor utility as a diagnostic tool for ventilator-associated pneumonia (VAP). Do not use procalcitonin to decide whether to start antibiotics in a patient with suspected VAP.

Procalcitonin monitoring can be used as an aid to clinical judgement when deciding whether to de-escalate or stop antibiotic therapy in a patient with VAP. A number of randomised controlled trials for VAP demonstrated that procalcitonin concentration can be used to reduce the duration of antibiotic therapy, and reduce overall antibiotic exposure, without adversely affecting clinical outcomes. Studies used various procalcitonin algorithms to guide de-escalating or stopping antibiotics; the algorithms presented in the ProVAP study¹Stolz, 2009 or PRORATA study²Bouadma, 2010 may be useful. In general, procalcitonin concentration is measured when starting treatment, after 72 hours, and then 24-hourly thereafter. The algorithms compare the initial and subsequent procalcitonin results to guide decisions about de-escalating or stopping antibiotics. A single procalcitonin concentration on day 5 to 7 is unlikely to be helpful without a baseline concentration for comparisonBeye, 2019Hamade, 2020Iankova, 2018Katz, 2021Pepper, 2019Shehabi, 2014Torres, 2017.