An evaluation of the Oxylog as a portable device with which to measure oxygen consumption

Abstract

The Oxylog, a portable device for measuring oxygen consumption, was evaluated under standard, laboratory conditions and with exercising human subjects. The difference in oxygen partial pressure between room air and a series of test gases measured by the Oxylog showed good agreement with results obtained using a paramagnetic analyser and stable values were obtained for at least 6 h. The measurement of oxygen consumption by the Oxylog was assessed under simulated conditions, with an anaesthetic ventilator, and in exercising human subjects. With a simulated steady-state oxygen consumption there was an initial delay of 2 min before any oxygen consumption was recorded. Subsequent increases in simulated oxygen consumption were detected within one minute. The oxygen consumption of exercising human subjects measured with the Oxylog showed very good agreement with simultaneous measurements obtained using the Douglas bag technique. The application of an appropriate conversion factor allows the individual's energy expenditure to be estimated from the oxygen consumption: in this study a factor of 20.08 kJ per litre oxygen consumption gave the best agreement with the Douglas bag estimate.

Health hazard evaluation report: HETA-91-405-2340, Big Bear Grocery Warehouse, Columbus, Ohio.

“…The order was judged to be of average size and difficulty. Each participant was fitted with an Oxylog portable oxygen consumption meter (Morgan Instruments, Inc.) and a Polar portable heart rate monitor (Polar USA Inc.) (Ballal and Macdonald 1982). Heart rate data were collected from a combination electrode-transmitter band that was worn on the chest and a watch-like receiver that was worn on the wrist.…”

Comparison of a Face-Mask and a Mouthpiece for Measuring Resting Energy Expenditure with the ‘Oxylog’

“…Subjects were measured in the supine position, after a period of at least 10 min rest, in a thermoneutral environ ment. No attempt was made to standardize the time between the last meal and the measurement which varied from 0.5 to 4 h. After an adaptation period of at least 5 min, for the subject to get used to the facemask or mouthpiece and to achieve a steady-state condition for the Oxylog [5], the 18-min REE mea surement started. The expired air of the subject, lying inside the hood, was first led through the Oxylog and was then collected and pumped to the analysers of the ventilated hood.…”

“…The face-mask was reported to be 'totally unsuitable' for use during exercise, because it tended to lift off in the upright position, causing substantial risk of leakage. Ballal and Macdonald [5] compared the Oxylog with simultaneous Douglas bag measurements of energy expen diture in exercising subjects, but used an RAF mask insted of the original Oxylog facemask. An evaluation of the Oxylog in resting subjects has been reported by McNeill et al [3], who compared two Oxylogs with simul taneous Douglas bag measurements of REE, using the Oxylog with a mouthpiece in con junction with a noseclip.…”

Comparison of three field methods for measuring oxygen consumption

“…The corrections were not made because when the OX is used in real work situations the true R values are not available, and the influence of the RH is negligible. If the individual's energy expenditure should be calculated on the basis of VOl measured by the OX the application of the Weir formula (Weir 1949), described by Ballal and Macdonald (1982), can be used.…”

“…The OX (Humphrey and Wolff 1977, Ballal and Macdonald 1982, Harrison et al 1982consists of a halfface mask fitted with a turbine flow meter on the inspiratory side, and an expiratory hose connected to an analyser. The OX measures the volume of inspired air, the partial pressure of oxygen with two polarographic oxygen sensors for inspired and expired air, and air temperature.…”