A new measuring device for non-invasive determination of oxygen partial pressure and oxygen conductance of the skin and other tissues.
A new measuring device for non-invasive determination of oxygen partial pressure and oxygen conductance of the skin and other tissues.
复制标题
一种用于无创测定皮肤和其他组织的氧分压和氧电导的新型测量装置。
DOI：
--
复制
发表时间：
1999
影响因子：
--
通讯作者：
W. Barnikol
中科院分区：
文献类型：
--
作者：
K. Niehoff;W. Barnikol
皮肤消耗的氧气中约有50%是通过表面扩散提供的。在动脉闭塞的情况下，这部分皮肤氧气供应变得非常重要。上层的氧渗透系数（P）和皮肤内的氧压力场决定了从外部的扩散氧摄取。据我们所知，渗透系数（P）到目前为止仅通过实用性很小的间接方法来估计（Baumberger等人，1951年; Eberhard等人，1978年）。皮肤的氧分压通常通过改进的RISK型电极来测量。这种所谓的经皮电极的缺点是其耗氧量以及耗氧量与待确定的氧压的固定耦合。因此，测量总是引起系统误差（所谓的搅拌效应），其取决于电极下皮肤的氧可用性等因素。该新设备结合了基于氧猝灭发光的无消耗氧分压检测器和通过有源电流链（银铅元件）实现的独立工作的特定氧消耗器。该链允许通过在电路内选择不同的电阻器来改变电极电流，从而将任何氧气质量流量（mO 2）设置在一定范围内。根据扩散定律，被测量的表面氧压（ePO 2）是指向阴极的氧流量（mO 2）的线性函数：ePO 2等于-（1/P）。(mO2/A）+icPO 2; A：阴极下的面积。皮内氧分压（icPO 2）是由给定方程定义的虚拟量。只有通过使用有源电极，才能设置不同的氧气质量流量，因此可以评估上皮肤层的氧传导率。在成人臀部区域的人体皮肤上进行的第一次实验提供了渗透系数（P）的估计值：在42 ℃皮肤表面温度下为2.2.10（-5）ml O2（STPD）/（atm.s.cm2）;获得的皮内分压为5.5 kPa（41 mmHg）（STPD：气体的“标准温度压力干燥”条件）。在42摄氏度的皮肤温度下，不会发生燃烧。测定的O2-电导率与之前估计的范围相同（见上文）。确定的皮内氧分压似乎是42 ℃下组织的实际值。通过使用技术膜进行体外测量，验证了新装置和程序，并给出了氧传导率的精确值。因此，该新方法可用于氧通量光电管的校准（Holst等人，1993年）。氧渗透系数（P）可能是一个重要的参数，用于评估皮肤病学应用（试图增加P）在治疗局部真皮缺氧。皮内氧分压发现是一个合理的值为42度的表面温度。由于确定的O2分压和O2消耗的独立性，新设备没有显示出搅拌效应，并且它提供了对传统经皮氧测量的局限性的更多了解。
About fifty percent of the oxygen consumption of the skin is supplied by diffusion through the surface. This portion of the skin oxygen supply becomes of high importance in case of arterial occlusion. The oxygen permeation coefficient (P) of the upper layers and the oxygen pressure field within the skin determine the diffusive oxygen uptake from the outside. To our knowledge, the permeation coefficient (P) until now was only estimated by indirect methods of little practicability (Baumberger et al., 1951; Eberhard et al., 1978). An oxygen partial pressure of the skin is conventionally measured by modified CLARK type electrodes. A disadvantage of this so-called transcutaneous electrode is its oxygen consumption and the fixed coupling of the consumption with the oxygen pressure to be determined. Therefore the measurement always induces a systematic error (the so-called stirring effect) which depends, among other factors, on the oxygen availability of the skin under the electrode. The new device combines a consumption-free oxygen partial pressure detector on the basis of luminescence quenching by oxygen with an independently working specific oxygen consumer realized by an active galvanic chain (silver-lead element). The chain permits setting any oxygen mass flow (mO2) in a certain range by varying the electrode current choosing different resistors within the electrical circuit. According to the diffusion law, the surface oxygen pressure (ePO2) being measured is a linear function of the oxygen flow (mO2) directed to the cathode: ePO2 identical to -(1/P).(mO2/A) + icPO2; A: area under the cathode. The intracutaneous oxygen partial pressure (icPO2) is a virtual quantity defined by the equation given. Only by using an active electrode different oxygen mass flows can be set and so the oxygen conductance of the upper skin layers can be assessed. First experiments on human skin in the gluteal region of an adult delivered an estimated value of the permeation coefficient (P): 2.2.10(-5) ml O2 (STPD)/(atm.s.cm2) at 42 degrees C skin surface temperature; the intracutaneous partial pressure obtained was 5.5 kPa (41 mmHg) (STPD: "standard temperature pressure dry" conditions of the gas). At 42 degrees C skin temperature no burning occurs. The determined O2-conductance is in the same range as estimated formerly (see above). The intracutaneous oxygen partial pressure determined seems to be a realistic value of the tissue at 42 degrees C. By in vitro measurements with technical membranes the new device and procedure was validated giving precise values of the oxygen conductance. Hence the new method may be used for calibration of the oxygen flux optode (Holst et al., 1993). The O2-permeation coefficient (P) could be an important parameter for evaluating dermatological applications (which attempt to increase P) in the treatment of local dermal oxygen deficiency. The intracutaneous oxygen partial pressure found is a reasonable value for a surface temperature of 42 degrees. Because of the independence of the O2-partial pressure determined and the O2-consumption the new device exhibits no stirring effect and it provides more insight into the limitations of conventional transcutaneous oxygen measurement.