ABSTRACT 97

Abstract

Background and aims: Nitric Oxide (NO) is used readily for pulmonary hypertension in the Pediatric Intensive Care Unit (PICU). PaO2 and central venous pressure (CVP) changes are often used as the primary bedside indicators of a positive response to NO. Aims: We sought to investigate if a bedside marker of alveolar dead space and therefore pulmonary blood flow, the end tidal alveolar dead space fraction (AVDSf=(PaCO2-PETCO2)/PaCO2), decreases with NO. Methods: This was a single center retrospective review of mechanically ventilated children placed on NO and monitored with arterial blood gases in the PICU (January 2012-March 2013). The Children’s Hospital Los Angeles Investigational Review Board approved this study. Results: 21 children, median age of 0.42 years (IQR 0.08, 4.8) were studied. 9 children had cyanotic congenital heart disease. In all cases, PaO2 increased significantly after NO administration though there was no statistically significant change in AVDSf. However, in the 12 children with elevated dead space at baseline (AVDSf >0.2), AVDSf decreased significantly after NO. Hemodynamic variables did not change with NO.Variables Pre-NO and Post-NOConclusions: Critically ill children with elevated AVDSf placed on NO have a substantial decrease in AVDSf. This suggests AVDSf should be investigated further as an additional bedside marker of pulmonary blood flow when assessing the response to NO.