In our study of invivo lipid peroxidation, we measured levels of expired alkane gases in preterm neonates using respiratory circuits. Ethane, pentane, butane, propane and hexane levels were measured by gas chromatography(Shimadzu 14A with a flame ionization detector, silica gel and Poropak-Q® columns, H2 carrier gas) with aliquots of 50ml collected in hydrocarbon(HC) free gas tight glass syringes. Propane cannot be distinguished by our technique unless C3-C5 analyte levels are <50ppb. At the outset, we noted a persistent, frequent and often unpredictable background contamination. Thus, we conducted a systematic evaluation of both gas sterilized (ethylene dioxide) and cold sterilized (H2O2) equipment (such as syringes, respiratory circuits, etc), the neonate's micro-environment (isolette with various gas sterilized equipments e.g. bag and mask), the ICN macro environment (Intensive and Transitional rooms ventilated with recirculated filtered air) and the wall outlet gas supplies. The HC levels in ppb at several sites are listed below: Table The consistently highest HC concentrations were measured in equipment that had undergone gas sterilization. The presence of significant HC pollution both in the micro and macro environment is of concern and further studies are needed to evaluate risk/benefit of gas sterilization of equipment and its contribution to environmental hydrocarbons.

Table 1