Effect of Vitamin E on Exhaled Ethane in Cigarette Smokers: Exhaled breath
Compliance with taking the vitamin was confirmed by pill count and blood levels.
Each subject was studied on four occasions, 3 weeks apart. On each visit, exhaled breath ethane was measured and samples of serum were taken for measurement of vitamin E and ^-carotene. Between visits 1 and 2, subjects were asked to refrain from taking supplemental vitamins and were given a placebo to take for the 3-week run-in period. This was included to assess compliance. Between visits 2 and 3, subjects took vitamin E (dl-a-tocopherol; 400 IU bid; Roche Vitamins Inc), again refraining from the use of other vitamin supplements. After visit 3, they were asked to refrain from using supplemental vitamins for the next 3 weeks until after the final samples were collected.
Breath ethane was collected and sampled as previously described. Briefly, seated subjects breathed hydrocarbon-free air (Ultra Zero Air; Tucson, AZ) via a one-way valve (Hans-Rudolf; Kansas City, MO) from a five-layer reservoir bag (Calibrated Instruments; Hawthorne, NY) for a total of 10 min add comment canadianfamilypharmacy. During the first 8 min, subjects were asked to take vital capacity breaths to completely flush out the lungs with the inspirate. This 8-min sample was then discarded to remove all room air from the lungs. The exhalate from the last 2 min of this 10-min breathing period was collected in a second five-layer bag that was analyzed for ethane content. Ethane content of the hydrocarbon-free air was also measured to determine background ethane content.
The exhalate collected in the bag was drawn through duplicate cold traps of activated charcoal at — 70°C and 400 mL/min for 15 min. We had determined previously that this flow rate was able to trap ethane as efficiently as a flow rate of 200 mL/min. Each cold trap adsorbed the ethane from 6 L of exhalate. The remaining volume of exhalate in the five-layer bag was quantitated using a spirometer. The five-layer bags were flushed with hydrocarbon-free air and evacuated under vacuum after each use.