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Reported are the solubility, diffusivity, and permeability data for various gases in five phosphonium-based ionic liquids at 30 °C, as determined with a lag-time technique. The ionic liquids have a viscosity range of 200-3000 cP. The gas solubilities and diffusivities of the phosphonium-based ionic liquids are of the same magnitude as the gas solubilities for the more familiar imidazolium-based liquids. The gas diffusivity appears to be inversely proportional to the viscosity with an average power of 0.35 for the phosphonium-based ionic liquids. This is in contrast to the power of 0.6 for the imidazolium-based ionic liquids, suggesting that the viscosity-diffusivity relationship varies for different classes of ionic liquids. Despite the generally higher viscosities of the phosphonium-based RTILs compared to the imidazolium-based RTILs, the similarity in thermodynamic and transport properties allows the consideration of the phosphonium-based RTILs as lowcost alternatives for reaction media or separation agents. The gases tested were carbon dioxide, ethylene, propylene, butene, and 1,3-butadiene. Also reported are the permeabilities of methane, nitrogen, and oxygen.

Background-Observational studies in adults have shown a worse outcome associated with hyperoxia after resuscitation from cardiac arrest. Extrapolating from adult data, current pediatric resuscitation guidelines recommend avoiding hyperoxia. We investigated the relationship between arterial partial oxygen pressure and survival in patients admitted to the pediatric intensive care unit (PICU) after cardiac arrest. Methods and Results-We conducted a retrospective cohort study using the Pediatric Intensive Care Audit Network (PICANet) database between 2003 and 2010 (nϭ122 521). Patients aged Ͻ16 years with documented cardiac arrest preceding PICU admission and arterial blood gas analysis taken within 1 hour of PICU admission were included. The primary outcome measure was death within the PICU. The relationship between postarrest oxygen status and outcome was modeled with logistic regression, with nonlinearities explored via multivariable fractional polynomials. Covariates included age, sex, ethnicity, congenital heart disease, out-of-hospital arrest, year, Pediatric Index of Mortality-2 (PIM2) mortality risk, and organ supportive therapies. Of 1875 patients, 735 (39%) died in PICU. Based on the first arterial gas, 207 patients (11%) had hyperoxia (PaO 2 Ն300 mm Hg) and 448 (24%) had hypoxia (PaO 2 Ͻ60 mm Hg). We found a significant nonlinear relationship between PaO 2 and PICU mortality. After covariate adjustment, risk of death increased sharply with increasing hypoxia (odds ratio, 1.92; 95% confidence interval, 1.80 -2.21 at PaO 2 of 23 mm Hg). There was also an association with increasing hyperoxia, although not as dramatic as that for hypoxia (odds ratio, 1.25; 95% confidence interval, 1.17-1.37 at 600 mm Hg). We observed an increasing mortality risk with advancing age, which was more pronounced in the presence of congenital heart disease. Conclusions-Both severe hypoxia and, to a lesser extent, hyperoxia are associated with an increased risk of death after PICU admission after cardiac arrest. (Circulation. 2012;126:335-342.)

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