Drains are placed in wounds and surgical incisions under three circumstances: (1) to drain interstitial fluid or blood and prevent accumulation into a seroma or hematoma, respectively; (2) to maintain a tract so pus can drain from an infected area; or (3) to allow for drainage from a contaminated location and prevent an abscess from forming.28 Drains allow for near-complete wound closure in circumstances where closure would otherwise be impeded by fluid, pus, or blood accumulation. Drains can be categorized as (1) gauze packing to maintain open drainage and collect the exudate, (2) open systems using soft rubber (e.g., Penrose drain) or silicone tubing to direct drainage onto external gauze dressings, or (3) closed systems using silicone tubing and attached fluid collection reservoirs. Drains can be placed either through the suture line of the initial wound or incision or through an adjacent incision made specifically for drain access.
The most common type of wound drain placed in the ED is 1/4- to 1-in. (0.6- to 2.5-cm) ribbon gauze used to pack an abscess cavity after incision and drainage. Dressings over draining abscesses may initially require frequent changes. The internal packing should be replaced daily as long as the wound continues to produce exudate. Once the purulence stops, internal packing is no longer required, and daily cleaning with external dressing changes should continue until enough granulation tissue forms and the wound stops draining. Maintaining a moist, clean environment promotes wound healing. Equivalent outcomes in otherwise healthy patients with subcutaneous abscesses can be obtained with alternatives to traditional packing: no packing,29,30,31 incision and loop drainage,32,33,34,35 modified Pezzar catheter,36 and silver-containing hydrofiber dressing.37
Open drainage using soft rubber tubing (e.g., Penrose drains) has been used for years to drain infected or contaminated wounds that have been partially or completely closed. A safety pin placed through the tubing can prevent the drain from inappropriately advancing into the wound. As the exudate diminishes and the wound heals, the Penrose drain can be pulled out a portion each day to allow the wound to heal from the "bottom up." The disadvantage of open drains, such as the Penrose, is the access they provide for bacteria into the wound.
For many wounds, especially postsurgical wounds, closed drainage systems have replaced open wound drains. The collection reservoir for closed drainage systems often has a self-inflating ability so it can be squeezed before attachment to the tubing in order to place vacuum suction in the wound to enhance drainage (e.g., Jackson-Pratt®, Cardinal Health, Dublin, OH; Hemovac®, Zimmer, Inc., Warsaw, IN; ConstaVac®, Stryker Corp., Kalamazoo, MI). Assessment of the tubing and emptying of the reservoir should be done with sterile technique (similar to dressing changes for indwelling lines). The reservoir may require emptying several times per day, depending on the drainage volume. It is common practice to remove closed drains when the amount of fluid drained each day reaches low levels (typically 30 to 40 mL per day). If a drainage tube is accidentally pulled out, it should not be reinserted. In many surgical settings, the benefit of closed drainage systems is unproven.38–47
Vacuum-assisted closure or negative-pressure wound therapy is a method used to close difficult wounds.48,49,50,51 The vacuum-assisted closure technique consists of insertion of an open-cell foam sponge into the wound, sealing with an adhesive drape, and subsequent application of negative, subatmospheric pressure, usually at 125 mm Hg.50 Vacuum-assisted closure promotes wound healing by removing localized edema, which improves vascular and lymphatic flow by reducing bacteria density, by promoting angiogenesis, and by increasing granulation tissue formation.48,49,50 There is no proven role for vacuum-assisted closure in the management of lacerations closed in the ED.