Extravascular lung water index and global end-diastolic volume index should be corrected in children

PurposeThe aim of the present study was to explain why extravascular lung water index (EVLWI) is higher and why global end-diastolic blood volume index (GEDVI) is lower in young children when measured with the PiCCO system (Pulsion, Munich, Germany).Materials and MethodsWe pooled available data from literature from children concerning organ weight derived from autopsy studies and computed tomographic lung measurements. These data include age, height, body weight, body surface area (BSA), and lung and heart weights. For standard, age-dependent weight and height, we used published data from the World Health Organization. From the available data, we calculated the lung weight-to-body weight ratio, the heart weight-to-BSA ratio, and the end-diastolic volume-to-BSA ratio. We compared these ratios to body growth and development.ResultsLung weight develops more slowly and with less magnitude than does body weight. In addition, the (relatively) greater lung weight in younger children results in a higher amount of pulmonary blood volume. This explains the higher EVLWI in young children. End-diastolic blood volume and heart weight increase faster and are more pronounced compared with BSA. This explains the lower GEDVI in young children. We propose correction factors for comparing EVLWI and GEDVI with adult reference values.ConclusionsExtravascular lung water index is higher and GEDVI is lower in young children because of changing organ-to-body weight relationships during growth.