Küntscher Markus V, Hartmann Bernd, Germann Günter
BG, Department of Hand, Plastic, and Reconstructive Surgery, Trauma Center Ludwigshafen, and Department of Plastic and Hand Surgery, University of Heidelberg, Heidelberg, Germany.
Microsurgery. 2005;25(4):346-52. doi: 10.1002/micr.20123.
Ischemic preconditioning (IP) is defined as a brief period of ischemia ("preclamping") followed by tissue reperfusion, thereby increasing ischemic tolerance for a subsequent longer ischemic period. Several studies showed the effectiveness of classic local IP by preclamping the flap pedicle. There are two temporally and mechanically different types of IP: acute preconditioning, which is induced by preclamping the flap pedicle briefly before flap ischemia, and late preconditioning, induced by a preclamping procedure 24-48 h before flap ischemia. However, both types of local ischemic preconditioning are rarely used clinically, most likely since they can be applied only by invasive means, significantly increase operation time, or even require a second surgical procedure. Several studies from our laboratory showed, in different experimental models, that acute IP, enhancement of flap survival, and improvement of reperfusion microcirculation can be achieved not only by preclamping the flap pedicle, but also by induction of an ischemia/reperfusion event in a body area distant from the flap prior to elevation. This new acute remote IP procedure can be applied without invasive means, using limb tourniquet ischemia briefly before flap ischemia. The effectiveness of acute remote IP was confirmed by other authors in large animal models. Another of our studies showed that late remote IP using a limb tourniquet 24 h before flap ischemia attenuates ischemia/reperfusion in muscle flaps, whereas it was ineffective in adipocutaneous flaps. The exact mechanism of "classic" as well as remote IP is not yet finally determined, although several studies demonstrated that endogenous nitric oxide plays an important role. In summary, the use of a tourniquet to induce limb ischemia before flap ischemia could provide a new, alternative, noninvasive remote IP protocol, although late remote IP might be effective only in muscle flaps. However, the possible future clinical application for late IP is elective flap surgery, whereas acute remote IP could even be used in emergency flaps.
缺血预处理（IP）的定义是短暂的缺血期（“预夹闭”）后组织再灌注，从而增加对随后更长缺血期的缺血耐受性。多项研究表明，通过夹闭皮瓣蒂进行经典局部缺血预处理是有效的。缺血预处理在时间和机制上有两种不同类型：急性预处理，即在皮瓣缺血前短暂夹闭皮瓣蒂诱导产生；延迟预处理，在皮瓣缺血前24 - 48小时通过夹闭程序诱导产生。然而，这两种局部缺血预处理在临床上很少使用，最可能的原因是它们只能通过侵入性手段应用，会显著增加手术时间，甚至需要进行第二次手术。我们实验室的多项研究表明，在不同的实验模型中，急性缺血预处理、提高皮瓣存活率以及改善再灌注微循环不仅可以通过夹闭皮瓣蒂来实现，还可以通过在皮瓣掀起前在远离皮瓣的身体部位诱导缺血/再灌注事件来实现。这种新的急性远程缺血预处理程序可以在不采用侵入性手段的情况下应用，即在皮瓣缺血前短暂使用肢体止血带造成缺血。其他作者在大型动物模型中证实了急性远程缺血预处理的有效性。我们的另一项研究表明，在皮瓣缺血前24小时使用肢体止血带进行延迟远程缺血预处理可减轻肌皮瓣的缺血/再灌注，而在脂肪皮瓣中则无效。尽管多项研究表明内源性一氧化氮起重要作用，但“经典”缺血预处理以及远程缺血预处理的确切机制尚未最终确定。总之，在皮瓣缺血前使用止血带诱导肢体缺血可以提供一种新的、替代性的、非侵入性的远程缺血预处理方案，尽管延迟远程缺血预处理可能仅在肌皮瓣中有效。然而，延迟缺血预处理未来可能的临床应用是择期皮瓣手术，而急性远程缺血预处理甚至可用于急诊皮瓣手术。
