Feldmeier J J, Hopf H W, Warriner R A, Fife C E, Gesell L B, Bennett M
Medical College of Ohio, USA.
Undersea Hyperb Med. 2005 May-Jun;32(3):157-68.
A small body of literature has been published reporting the application of topical oxygen for chronic non-healing wounds . Frequently, and erroneously, this form of oxygen administration has been referred to as "topical hyperbaric oxygen therapy" or even more erroneously "hyperbaric oxygen therapy." The advocates of topical oxygen claim several advantages over systemic hyperbaric oxygen including decreased cost, increased safety, decreased complications and putative physiologic effects including decreased free radical formation and more efficient delivery of oxygen to the wound surface. With topical oxygen an airtight chamber or polyethylene bag is sealed around a limb or the trunk by either a constriction/tourniquet device or by tape and high flow (usually 10 liters per minute) oxygen is introduced into the bag and over the wound. Pressures just over 1.0 atmospheres absolute (atm abs) (typically 1.004 to 1.013 atm abs) are recommended because higher pressures could decrease arterial/capillary inflow. The premise for topical oxygen, the diffusion of oxygen into the wound adequate to enhance healing, is attractive (though not proven) and its delivery is certainly less complex and expensive than hyperbaric oxygen. When discussing the physiology of topical oxygen, its proponents frequently reference studies of systemic hyperbaric oxygen suggesting that mechanisms are equally applicable to both topical and systemic high pressure oxygen delivery. In fact, however, the two are very different. To date, mechanisms of action whereby topical oxygen might be effective have not been defined or substantiated. Conversely, cellular toxicities due to extended courses of topical oxygen have been reported, although, again these data are not conclusive, and no mechanism for toxicity has been examined scientifically. Generally, collagen production and fibroblast proliferation are considered evidence of improved healing, and these are both enhanced by hyperbaric oxygen therapy. Paradoxically, claims of decreased collagen production and fibroblast inhibition in wounds subjected to topical oxygen have been reported in studies of topical oxygen as a benefit of topical oxygen therapy. The literature on topical oxygen is mostly small case series or small controlled but not randomized trials. Moreover, the studies generally are not aimed at specific ulcer types, but rather at "chronic wounds." This non-specific approach is recognized as a major design flaw in any study of therapies designed to improve impaired wound healing. The only randomized trial for topical oxygen in diabetic foot ulcers actually showed a tendency toward impaired wound healing in the topical oxygen group. Contentions that topical oxygen is superior to hyperbaric oxygen are not proven. There are potentially plausible mechanisms that support both possibly beneficial and detrimental effects of topical oxygen therapy, and thus well designed and executed basic science research and clinical trials are clearly needed. There is some ongoing research in regard to the role of topical oxygen at established wound laboratories. Neither CMS nor other third party payors recognize or reimburse for topical oxygen. Therefore, the policy of the Undersea and Hyperbaric Medical Society in regard to topical oxygen is stated as follows: 1. Topical oxygen should not be termed hyperbaric oxygen since doing so either intentionally or unintentionally suggests that topical oxygen treatment is equivalent or even identical to hyperbaric oxygen. Published documents reporting experience with topical oxygen should clearly state that topical oxygen not hyperbaric oxygen is being employed. 2. Mechanisms of action or clinical study results for hyperbaric oxygen cannot and should not be co-opted to support topical oxygen since hyperbaric oxygen therapy and topical oxygen have different routes and probably efficiencies of entry into the wound and their physiology and biochemistry are necessarily different. 3. The application of topical oxygen cannot be recommended outside of a clinical trial at this time based on the volume and quality of scientific supporting evidence available, nor does the Society recommend third party payor reimbursement. 4. Before topical oxygen can be recommended as therapy for non-healing wounds, its application should be subjected to the same intense scientific scrutiny to which systemic hyperbaric oxygen has been held.
已有少量文献报道了局部用氧在慢性难愈合伤口治疗中的应用。这种给氧方式常被错误地称为“局部高压氧治疗”，甚至更错误地称为“高压氧治疗”。局部用氧的支持者声称，与全身高压氧相比，它具有多种优势，包括成本降低、安全性提高、并发症减少，以及假定的生理效应，如自由基形成减少和向伤口表面的氧输送更高效。使用局部用氧时，通过收缩/止血带装置或胶带在肢体或躯干周围密封一个密闭腔室或聚乙烯袋，然后将高流量（通常为每分钟10升）的氧气引入袋中并覆盖伤口。建议绝对压力略高于1.0个大气压（atm abs）（通常为1.004至1.013 atm abs），因为更高的压力可能会减少动脉/毛细血管的血流。局部用氧的前提，即氧气扩散到伤口中足以促进愈合，很有吸引力（尽管尚未得到证实），而且其实施肯定比高压氧治疗更简单、成本更低。在讨论局部用氧的生理学原理时，其支持者经常引用全身高压氧的研究，暗示相关机制同样适用于局部和全身高压氧输送。然而，事实上，两者有很大不同。迄今为止，局部用氧可能有效的作用机制尚未明确或得到证实。相反，尽管这些数据也不确凿，且尚未对毒性机制进行科学研究，但已有报道称长期使用局部用氧会产生细胞毒性。一般来说，胶原蛋白生成和成纤维细胞增殖被认为是愈合改善的证据，而这两者在高压氧治疗中均会增强。矛盾的是，在局部用氧治疗的研究中，有报道称接受局部用氧的伤口胶原蛋白生成减少和成纤维细胞受到抑制，却将此作为局部用氧治疗的益处。关于局部用氧的文献大多是小病例系列或小型对照但非随机试验。此外，这些研究通常并非针对特定的溃疡类型，而是针对“慢性伤口”。这种非特异性方法在旨在改善受损伤口愈合的任何治疗研究中都被认为是一个主要的设计缺陷。唯一一项关于局部用氧治疗糖尿病足溃疡的随机试验实际上显示，局部用氧组的伤口愈合有受损的趋势。局部用氧优于高压氧的观点尚未得到证实。局部用氧治疗可能有益和有害的影响都有潜在合理的机制支持，因此显然需要精心设计和执行的基础科学研究及临床试验。一些伤口研究实验室正在进行关于局部用氧作用的研究。医疗保险和医疗补助服务中心（CMS）及其他第三方支付方均未认可或报销局部用氧治疗费用。因此，水下和高压氧医学协会关于局部用氧的政策如下：1. 局部用氧不应被称为高压氧，因为这样做有意或无意地暗示局部用氧治疗等同于甚至与高压氧相同。报道局部用氧经验的已发表文献应明确说明所采用的是局部用氧而非高压氧。2. 不能也不应挪用高压氧的作用机制或临床研究结果来支持局部用氧，因为高压氧治疗和局部用氧进入伤口的途径不同，可能效率也不同，其生理学和生物化学必然存在差异。3. 基于现有科学支持证据的数量和质量，目前在临床试验之外不建议应用局部用氧，该协会也不建议第三方支付方报销费用。4. 在局部用氧被推荐作为难愈合伤口的治疗方法之前，其应用应接受与全身高压氧相同严格的科学审查。
