Wagstaff T A J, Soni N
Magill Department of Anaesthesia, Intensive Care and Pain Management, Chelsea and Westminster Hospital, London, UK.
Anaesthesia. 2007 May;62(5):492-503. doi: 10.1111/j.1365-2044.2007.05026.x.
The administration of a known concentration of oxygen is an important part of routine care of the sick patient. Many devices are currently available. The actual concentration of oxygen that can be delivered by these devices can be affected by several factors, both from the patient as well as the device itself. Measuring the F(i)o(2) delivered to the lungs in vivo can be both difficult and potentially uncomfortable for the subjects. We constructed a model using a resuscitation manikin, a ventilator and a set of bellows to simulate ventilation. With this model we tested a series of devices - variable performance, fixed performance and high flow - at two fixed tidal volumes. The respiratory rate was increased and its effect on the oxygen concentration assessed. Variable performance systems such as the Hudson mask deliver a significantly reduced oxygen concentration at high respiratory rates. Fixed performance systems delivering 24-40% oxygen deliver appropriate oxygen concentrations across the range of respiratory rates, whereas those delivering 60% show a reduction in performance. High flow systems show no failure of performance at increased respiratory rates.
给予已知浓度的氧气是患病患者常规护理的重要组成部分。目前有许多设备可供使用。这些设备能够输送的实际氧气浓度会受到多种因素的影响，包括患者自身以及设备本身的因素。在体内测量输送到肺部的吸入氧分数（F(i)o(2)）对于受试者来说既困难又可能会带来不适。我们使用复苏人体模型、呼吸机和一组波纹管构建了一个模型来模拟通气。利用这个模型，我们在两个固定潮气量下测试了一系列设备——可变性能设备、固定性能设备和高流量设备。增加呼吸频率并评估其对氧气浓度的影响。可变性能系统，如哈德逊面罩，在高呼吸频率下输送的氧气浓度会显著降低。输送24% - 40%氧气的固定性能系统在整个呼吸频率范围内都能输送合适的氧气浓度，而输送60%氧气的系统则表现出性能下降。高流量系统在呼吸频率增加时未出现性能故障。
