Tschirhart J M, Rao M K
Saginaw Cooperative Hospitals, Inc., Department of Surgery, MI 48602.
Am Surg. 1988 Jun;54(6):326-8.
An unresolved complication of the use of totally implantable central venous access ports (e.g., Mediport, Infusa-port) is persistent withdrawal occlusion (PWO), i.e. the unimpeded capacity for infusion of fluids accompanied by the inability to withdraw blood. This study demonstrates the mechanism of persistent withdrawal occlusion and describes a method for resolving this complication. Of 42 cancer patients with totally implantable central venous access ports, 8 (19%) patients developed 11 episodes of PWO. Venograms demonstrated a sheath around the catheter beginning at the catheter entrance to the central vein and extending 1-5 cm beyond the catheter tip. Each episode of PWO was treated with 250,000 units of urokinase dissolved in 150cc D5/W infused through the port over 90 minutes. Venograms were obtained immediately after each urokinase infusion. Follow-up ranged from 13-130 days. After urokinase infusion the venogram showed no change in the sheath in 1 episode of PWO and complete dissolution of the sheath in 10 episodes of PWO. PWO recurred once in one patient and twice in another patient. PWO resolved only in the 10 episodes in which sheath dissolution was demonstrated. Urokinase infusion, as described, is effective in resolving persistent withdrawal occlusion. The method is repeatable and safe. That resolution of PWO by urokinase infusion was accompanied by dissolution of the sheath suggests that the sheath is composed primarily of fibrin and that flap action of the sheath is the mechanism causing PWO.
完全植入式中心静脉通路端口（如Mediport、Infusa-port）使用中一个尚未解决的并发症是持续性回血阻塞（PWO），即输液顺畅但无法回血。本研究揭示了持续性回血阻塞的机制，并描述了一种解决该并发症的方法。在42例使用完全植入式中心静脉通路端口的癌症患者中，8例（19%）发生了11次持续性回血阻塞事件。静脉造影显示导管周围有一层鞘膜，从导管进入中心静脉处开始，延伸至导管尖端以外1 - 5厘米。每次持续性回血阻塞事件均通过将25万单位尿激酶溶解于150cc 5%葡萄糖溶液中，经端口在90分钟内输注进行治疗。每次尿激酶输注后立即进行静脉造影。随访时间为13 - 130天。尿激酶输注后，静脉造影显示1次持续性回血阻塞事件中鞘膜无变化，10次持续性回血阻塞事件中鞘膜完全溶解。1例患者持续性回血阻塞复发1次，另1例患者复发2次。仅在鞘膜溶解的10次事件中持续性回血阻塞得到解决。所述的尿激酶输注有效地解决了持续性回血阻塞。该方法可重复且安全。尿激酶输注解决持续性回血阻塞的同时鞘膜溶解，这表明鞘膜主要由纤维蛋白组成，且鞘膜的瓣状作用是导致持续性回血阻塞的机制。
