Bedside monitoring of ventilation distribution and alveolar inflammation in community-acquired pneumonia

It is unclear whether bedside monitoring tools such as exhaled nitric oxide measurements (FENO) and electrical impedance tomography (EIT) could help guiding patient management in community-acquired pneumonia (CAP). We hypothesized that exhaled NO would be increased in CAP patients and could be used to assess resolution of inflammation in the course of CAP therapy. Feasibility of multiple-breath (mb) and single-breath (sb) approach has been investigated. EIT was compared with chest X-ray at admission and used to assess whether the inhomogeneous ventilation changes due to treatment. 24 CAP patients were enrolled. Measurements were accomplished at admission (T0: EIT + FENO), after 3 days (T1: FENO) and 5-6 days after admission (T2: EIT + FENO). We computed an EIT distribution index (D_EIT), which reflects the uniformity of ventilation. FENO measurements showed a significant decrease in NO after the beginning of antibiotic therapy [p = 0.04 (sb); p = 0.003 (mb)]. Correlation between sb method and mb method was significant (p < 0.001, r = 0.70). EIT detects right-sided and left-sided ventilation disorders due to pneumonia in correspondence to chest X-ray (p < 0.01). EIT images at T2 showed a more homogeneous ventilation distribution in displayed EIT. FENO could be a prospective supplementary tool to describe local lung inflammation as individual trend parameter. EIT could be a suitable supplementary tool to monitor functional lung status in CAP.