Ambrisko Tamas D, Klide Alan M
Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6010, USA.
Am J Vet Res. 2006 Jun;67(6):936-40. doi: 10.2460/ajvr.67.6.936.
To examine the accuracy and precision of isoflurane and sevoflurane anesthetic vaporizers.
5 identical isoflurane and 5 identical sevoflurane vaporizers.
Oxygen flow rates from 0.02 to 10 L/min were used with different vaporizer dial settings. Agent concentrations were measured at the common gas outlet by use of a refractometer. Accuracy was defined as the difference between measured agent concentrations, and dial settings were expressed as a percentage of the applied dial settings. Precision was defined as SD of the measured agent concentrations for each combination of dial setting and flow.
Isoflurane values were generally greater than the dial settings. Accuracy of the isoflurane vaporizer was > 20% when 0.6% and 1% was dialed. Accuracy of the sevoflurane vaporizer was always within +/- 20% but decreased at 0.02 L/min flow and at combinations of high flow and high dial settings. Overall precision of the isoflurane vaporizer was better than that of the sevoflurane vaporizer.
A possible explanation for the inaccuracy of the isoflurane vaporizer may be that it was manufactured to be accurate with air but not oxygen, which must be accounted for when using the vaporizer with oxygen, especially with nonrebreathing systems. The sevoflurane vaporizer may not deliver accurate agent concentrations at high flow and high dial settings. Both vaporizers are suitable for clinical use with a wide range of oxygen flow rates if these precautions are properly addressed.
检测异氟烷和七氟烷麻醉蒸发器的准确性和精确性。
5台相同的异氟烷蒸发器和5台相同的七氟烷蒸发器。
使用不同的蒸发器刻度设置，氧气流速范围为0.02至10L/分钟。通过折射仪在共同气体出口处测量麻醉剂浓度。准确性定义为测量的麻醉剂浓度与刻度设置之间的差值，并将刻度设置表示为所应用刻度设置的百分比。精确性定义为每个刻度设置和流速组合下测量的麻醉剂浓度的标准差。
异氟烷的值通常大于刻度设置。当刻度设置为0.6%和1%时，异氟烷蒸发器的准确性>20%。七氟烷蒸发器的准确性始终在+/-20%以内，但在流速为0.02L/分钟以及高流速和高刻度设置组合时会降低。异氟烷蒸发器的总体精确性优于七氟烷蒸发器。
异氟烷蒸发器不准确的一个可能解释可能是，它在设计时是针对空气而非氧气准确的，在将蒸发器与氧气一起使用时，尤其是在使用无重复吸入系统时，必须考虑这一点。七氟烷蒸发器在高流速和高刻度设置下可能无法提供准确的麻醉剂浓度。如果正确处理这些注意事项，两种蒸发器在广泛的氧气流速范围内都适用于临床使用。
