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Biomedical subjects

A Aberman

Publications and source records attributed to A Aberman.

32 records · Page 2Linked to original sources
PubMed1975

Measurement of intratracheal oxygen concentrations during face mask administration of oxygen: a modification for improved control.

Direct measurement of the inspired tracheal oxygen concentration was made in patients breathing through standard aerosol face masks. Factors affecting the tracheal FIO2 were analyzed using both mechanical and mathematical models. When oxygen is delivered to the face mask at low flow rates, there is considerable patient variation in the measured tracheal FIO2. Delivery of oxygen at higher flow rates (15 litres per minute or greater), reduces such variation. Furthermore, turbulent air currents within and around the face mask reduce the measured FIO2 and contribute to fluctuations in the FIO2. This effect may be virtually eliminated by placing shields around the mask orifices as described. Using the shielded mask, it is possible to deliver the desired oxygen concentration to the patient more accurately and to maintain humidification of the delivered gases. Changes desired in inspired oxygen concentration are accomplished by changing the concentration of the incoming gas mixture, and not by merely changing the flow rate of oxygen delivered to the system. Using the shielded mask, it is possible to deliver an inspired oxygen concentration of 100 per cent. This is not true with most other commonly used face masks, and, therefore, caution should be used to avoid administration of unnecessary high inspired oxygen concentrations with this type of mask.

Air Movements↗
PubMed1975

Blood P50 calculated from a single measurement of pH, PO2, and SO2.

P50 was calculated from a single measurement of pH, Po2, and So2 at a known temperature in 135 blood samples from 21 normal nonsmokers and eight patients. In the 92 blood samples with So2 between 20 and 90 per cent, the standard deviation of repeated calculated P50's on the same sample of blood at different So2 was plus or minus 1.0 Torr. Below So2 of 20 per cent and above So2 of 90 per cent, the standard deviations were plus or minus 5.5 and plus or minus 2.4 Torr, respectively. Combined measurement errors of plus or minus 1 Torr in Po2, plus or minus 1 percent in So2, plus or minus 0.01 in pH, and plus or minus 0.1 degree C in temperature are sufficient to explain the observed variation in calculated P50 in 90 per cent of 135 blood samples from 29 subjects and account for the greater observed variation at So2 less than 20 per cent and greater than 90 per cent.

Carbon Dioxide↗