Thomas P S, Hakim T S, Trang L Q, Hosain S I, Camporesi E M
Department of Anesthesiology, State University of New York Health Science Center, Syracuse 13210, USA. hschosp.umag.thomasp.
Anesth Analg. 1999 Jan;88(1):67-71. doi: 10.1097/00000539-199901000-00013.
The benefit of hyperbaric oxygen (HBO2) exposure is dependent on the oxygen delivery. Such benefit may be limited by the fact that hyperoxia causes vasoconstriction and decreases blood flow. The aim of this study was to determine whether regional sympathectomy attenuates this vasoconstriction response and thus improves oxygen delivery. In a double-blinded manner, healthy volunteers were subjected to HBO2 in a monoplace chamber on two occasions separated by at least 1 wk. Transcutaneous oxygen (tcPO2) and carbon dioxide (tcPCO2) on the forearm were monitored continuously, and blood flow in the axillary artery was measured using angiodynography before and after exposure to HBO2. During one visit, each volunteer received a sympathetic block to the upper extremity by an injection of lidocaine into the brachial plexus at the axilla. During a second visit, the volunteer received a placebo injection of isotonic sodium chloride solution into the brachial plexus of the same side. Skin temperature was recorded on the back of the hand. All subjects exhibited a small but significant increase in skin temperature (2.5%) and in upper limb blood flow (23%) (P < 0.05%) after sympathectomy, but not after isotonic sodium chloride solution injection. Sympathectomy increased tcPO2 marginally while in room air. However, during HBO2, tcPO2 was substantially and significantly higher (409.8+/-98.8 mm Hg) after sympathectomy compared with that after isotonic sodium chloride solution injection (171.3+/-38.1 mm Hg). tcPCO2 did not change significantly after sympathectomy or during HBO2. Thus, sympathectomy presumably improved oxygen delivery by preventing vasoconstriction during hyperoxia. The results suggest that sympathectomy may be a useful adjunct to HBO2 therapy in patients in whom vascular resistance is increased because of sympathetic tone or hyperoxia.
Sympathetic nerve block of the extremities markedly enhances tissue oxygen delivery during hyperbaric oxygen treatment. Sympathectomy may be a beneficial adjunct treatment to hyperbaric oxygen in peripheral vascular insufficiency.
高压氧（HBO2）治疗的益处取决于氧气输送。这种益处可能会受到高氧导致血管收缩和血流量减少这一事实的限制。本研究的目的是确定局部交感神经切除术是否能减轻这种血管收缩反应，从而改善氧气输送。以双盲方式，健康志愿者在单人舱内接受两次HBO2治疗，两次治疗间隔至少1周。连续监测前臂的经皮氧分压（tcPO2）和二氧化碳分压（tcPCO2），并在暴露于HBO2前后使用血管动力学造影术测量腋动脉的血流量。在一次就诊期间，每位志愿者通过在腋窝处向臂丛神经注射利多卡因接受上肢交感神经阻滞。在第二次就诊期间，志愿者在同侧臂丛神经接受等渗氯化钠溶液的安慰剂注射。记录手背部的皮肤温度。所有受试者在交感神经切除术后皮肤温度（2.5%）和上肢血流量（23%）均有小幅但显著的升高（P<0.05%），而在注射等渗氯化钠溶液后则无此变化。交感神经切除术在室内空气中时使tcPO2略有升高。然而，在HBO2治疗期间，交感神经切除术后的tcPO2（409.8±98.8mmHg）显著高于注射等渗氯化钠溶液后的（171.3±38.1mmHg）。交感神经切除术后或在HBO2治疗期间，tcPCO2无显著变化。因此，交感神经切除术可能通过在高氧期间防止血管收缩来改善氧气输送。结果表明，对于因交感神经张力或高氧导致血管阻力增加的患者，交感神经切除术可能是HBO2治疗的有用辅助手段。
肢体交感神经阻滞在高压氧治疗期间显著增强组织氧气输送。交感神经切除术可能是外周血管功能不全患者高压氧治疗的有益辅助治疗方法。
