The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

EXHALED BREATH CONDENSATE AND TRACHEAL ASPIRATES IN MECHANICALLY VENTILATED NEWBORNS-A WINDOW INTO THE LUNG.

Maria I. Rosso2,3, Susan A. Roark1, Esther Taylor1, Theresa W. Gauthier2,3; 1NICU, CHOA, Atlanta, GA; 2Department of Pediatrics,Division of Neonatal-Perinatal Medicine, Emory University, Atlanta, GA; 3Emory ChildrenÂ’s Center for Developmental Lung Biology, Emory University, Atlanta, GA

Background:Monitoring of exhaled breath condensate (EBC) has been shown to be valuable in determining the extent of acute lung injury.Decreased pH in EBC can be seen in inflammatory processes such as asthma,COPD,and pneumonia. Exhaled nitric oxide in EBC may also be useful in titrating steroid therapy in patients with asthma.Premature and ill newborns are at increased risk for oxidant-induced injury,particularly in the lung.Glutathione(GSH),an essential antioxidant in the lung is gestationally deficient in the premature newborn and is required for optimal functioning of resident cells in the lung,such as the alveolar macrophage(AM).Determining the GSH status of the neonatal lung requires invasive measurements such as collection of tracheal aspirates(TA) from intubated newborns.EBC have been described as a less invasive technique to evaluate oxidative stress markers in the lung,but little data exists of its use in the premature population.We hypothesized that GSH in the TA of mechanically ventilated newborns would directly correlate to the GSH found in EBC.Further,we hypothesized that the GSH status of the resident AM would be reflected in the TA and/or EBC. Methods:TA and EBC measurements were obtained after informed consent on 16 stable neonates in the newborn intensive care unit. An R-tube(Respiratory Research,AustinTx) was adapted to the expiratory limb of the circuit proximal to the airway and EBC samples were collected over thirty minutes.GSH and the percentage of oxidized glutathione disulfide (%GSSG) were measured via high performance liquid chromatography( HPLC).AM were isolated from TA and cellular GSH status determined via immunofluorescence. Statistical analyses was performed via SPSS. Results:TA GSH and %GSSG significantly correlated with EBC GSH(p=0.002) and %GSSG (p=0.002). Furthermore,EBC GSH significantly correlated with AM GSH(p=0.029).Finally,TA and EBC GSH negatively correlated with the fraction of inspired oxygen on the ventilator. Conclusion:Our preliminary data suggests that redox measurements of a non-invasive EBC highly correlates to TA measurements and are indicative of cellular status.Further studies are necessary to determine whether EBC measurements in premature newborns are indicative of adverse clinical outcomes.Early identification of the premature newborn most at-risk for oxidant-induced injury may help tailor potential patient specific therapies. Sponsored Research - None