Home oxygen therapy equipment options have increased over the past several decades, in response to innovations in technology, economic pressure from third-party payers, and patient demands. The delivery of oxygen in the home has evolved from packaged gas systems containing 99% United States Pharmacopeia oxygen provided by continuous-flow delivery to intermittent-flow delivery, with oxygen concentrators delivering < 99% oxygen purity. The majority of published papers indicating the value of long-term oxygen therapy have been based on continuous-flow delivery of 99% United States Pharmacopeia oxygen. The lack of research on new home oxygen therapy devices requires more clinical involvement from physician and respiratory therapist to evaluate the performance of oxygen devices used in the home to ensure the patient is provided adequate oxygenation at all activity levels. New standards of care are required to address the need to have consistent titration of long-term oxygen therapy to meet the patient's home needs at all activity levels. Consistent labeling of metering devices on home oxygen equipment will need to be developed RESPIRATORY CARE • JANUARY 2013 VOL 58 NO 1 6 5 by professional medical societies to be implemented by standards organizations that direct industrial manufacturers. Home oxygen therapy will need professionally trained respiratory therapists reimbursed for skills and service to ensure that patients receive optimal benefits from home oxygen equipment to improve patient outcomes and prevent complications and associated costs.

A gas chromatographic (gc) method has been developed to measure solubility isotherms of a low molecular weight solvent in a high polymer. This method depends on the elution of the injected solvent on a concentration plateau of the same solvent in nitrogen carrier gas. The measured solubility is used to calculate the vapor-solid equilibrium ratio (Q = a~/ w~) , along with the solvent-polymer interaction parameter X, as a function of solution composition. Based on the Flory-Huggins and Maron theories, a mathematical correlation permits computation of Q values, usually with less than 5 deviation from those measured experimentally. The following polymer-solvent systems have been studied: polystyrene with benzene and ethylbenzene at 120" and with ethylbenzene at 185", polyethylene with n-decane at 185", and atactic polypropylene with hexane at 80". The computed i2 values range from about 4 to 5 .he urgent need for reliable process design data has led

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A gas chromatographic (GC) method has been developed to measure solubility isotherms of a low molecular weight solvent in a semicrystalline polymer. This method depends on the elution of the injected solvent on a concentration plateau of the same solvent in nitrogen carrier gas. The measured solubility in the amorphous phase is used to calculate the vapor-solid equilibrium ratio (fi = a\jw{), along with the polymer-solvent interaction parameter , as a function of solution composition. The following polymer-solvent systems have been studied: high-density polyethylene with re-hexane and hexane-isopropyl alcohol azeotrope at 80°and with cyclohexane at 100°; and stereoregular polypropylene with hexane at 80°. The values range from about 4.5 to 5.5.