A 21-year-old man, presented with raw areas on both lower limbs with bilateral ankle subluxation following a scooter accident (Figure 4). The patient's hemogram, routine and microscopic urine examination, and renal function tests were all normal (blood urea 15 mg/dL, creatinine 0.9 mg/dL). He underwent wounddebridement in the emergency department and 3 days later was diagnosed with acute renal failure (blood urea 116 mg/dL, serum creatinine 3.0 mg/dL, and serum potassium 3.9 mEq/L). Limited Access Dressing II was applied and the same antibiotic and supportive treatment was continued. Blood urea and creatinine levels returned to normal levels (serum creatinine 1.3 mg/dL) over the course of the 6 days he was under observation by nephrologists (no further active interventions were taken in this period). Wound debridement was performed and a new LAD II was applied again after 15 days. Thirty-five days after the first LAD application, a splitthickness skin graft was applied.Subsequently,more than 98% graft take was seen on postoperative day 10.
A 55-year-old man was admitted with acute renal failure after being bitten by a Viper snake on the top of his right foot 2 days prior.Venous Doppler showed compressed veins in the right lower limb caused by tense subcutaneous edema. No evidence of thrombosis was present. Ultrasound of the abdomen showed bilateral grade I renal parenchymal changes. At the time of admission the renal function test was abnormal (blood urea 90 mg/dL, serum creatinine 4.7 mg/dL, K+ 4.6 mEq/L).A subsequent renal function test showed a deteriorating trend that required hemodialysis.After 2 days of hemodialysis, debridement was performed. Following the 5 hemodialysis treatments in 8 days, the patient's blood urea was 95 mg/dL, serum creatinine 5.3, and K+ 4.2 mEq/L. At this point treatment remained the same, and a LAD II was applied.After 5 days with the LAD, the serum creatinine level (without dialysis) was 4.7 mg/dL. His blood urea creatinine level slowly became normal (serum creatinine 1.3 mg/dL) in 26 days without dialysis. Split-thickness skin grafting was done after 42 days of LAD. Graft take of 100% was seen postoperative day 10. The patient was discharged 2 weeks thereafter.
Toxic Symptoms. Toxic symptoms associated with gangrene are not observed when gangrenous tissue and part of the body is covered in LAD even for longer duration (more than a week, Figure 5). This perhaps is because the major part of the pro-inflammatory cytokines (TNF-α and IL-1) responsible for SIRS are removed along with oozing by negative suction. In addition, infection was effectively prevented by LAD suction; hence, bacterial endotoxins and various inflammatory mediators released in infected tissue remains under control.
To avoid infection in acute, subacute, or chronic wounds. LAD is used for postoperativewounds in immunocompromised patients or patients with diabetes, also as a temporary cover for exposed bare bone, cartilage, tendon, and joints.Abdominal wall reconstruction and intra-LAD tissue expansion adjacent to the wound (Figure 6) are additional uses. It is technically difficult to apply the LAD over the face and perineum.
The LAD may be applied after abscess drainage and after 7 to 10 days (before skin edges retract significantly). Secondary suturing over the suction drain may be done to promote faster healing and a better quality scar.
To avoid wound infection and to control bad odor, the surface bacteria can be removed by mechanical saline wash through the LAD tubes. This keeps the wound in a dependent position and avoids liquefaction of hydrocolloid material from water and any leaks.The physician may instill the antimicrobial solution of choice after the wash.
When the triad of edema, immobility, and inflammation coexist, a vicious cycle develops with each feeding off the other, resulting in rapid stiffening of uninjured joints and tendon adhesions. Generally, a favorable situation results if 2 of the 3 factors are controlled.Edema was not a problem in any of the presented cases due to the intermittent compression produced via the negative pressure combined with early intra-LAD mobilization. Early intra-LAD physiotherapy helps minimize stiffness—the most common cause of persistent physical impairment in hand trauma cases.
LAD application over trauma areas reduces contamination and infection risk in acute wounds.A report (unpublished data) on wound infection studied wound swab cultures taken in the pre-LAD period and 7 days after LAD application.The results showed that in LAD I there was eradication of gram-negative infection in 98.74% (18/19 wounds), and in LAD II, eradication of gram-negative bacteria in 100% of cases.However, after 7 days new growth of gram-negative bacteria was seen in 50% of LAD I (14/28 wounds) and 57.14% of LAD II (12/21 wounds). Both LAD I (8 wounds) and LAD II (2 wounds) were effective in eradicating gram-positive bacteria in all cases and none of the wounds (LAD I, 0/28 wounds;LAD II, 0/21 wounds) showed new growth of gram-positive bacteria.
After LAD, elastic crepe bandages in cases of bleeding wounds (over extremities) and in cases of bone, joint, ligament, tendon, or nerve injuries appropriate splints may be applied.
LAD is applied after thorough mechanical wash and surgical removal of dead tissue (Figure 7). After about 1 week (time determined by appearance of soft and relatively loose slough),if deemed necessary, the wound is debrided again. During debridement, slough is removed easily with minimal blood loss. In compound comminuted fracture cases, as much bone pieces as possible should be preserved to increase the chance of survival while the wound is under the LAD.
Applying a pressure bandage or continuous suction initially prevents intra-LAD hematoma. Once hematoma is formed it is gently broken with finger pressure under LAD,hydrogen peroxide (H2O2) wash and intermittent suction usually over 1 to 2 days assists in removing hematoma.Without vascular surgery in casesof complete arterial block LAD may fail to produce a desirable effect. In these cases, pressure exerted by tight LAD bag/tubes may produce ulceration over toes and other parts under the LAD. LAD is not effective if the target tissue is not exposed to negative pressure (ie, subcutaneous infection with intact skin). In these situations, 1 tube is inserted in deep-seated infection site before applying LAD.
LAD I Application. After minimal wound debridement (under regional block/intravenous anesthesia/local anesthesia), a closed suction drain and 12 French feeding tubes are placed either over the skin surface or through a puncture wound.The surrounding skin is cleansed with ether and the wound is covered with Hydrocoll. As an additional measure to secure the LAD, an additional adhesive polyurethane film (OpSite) is used and if required, the Hydrocoll stitched to the skin around the wound with a 3-0 nonabsorbable monofilament suture.
LAD IB Application. In LAD IB the wound is covered with a polythene sheet of suitable size after placement of the 2 tubes and is then covered with the larger size Hydrocoll. A central hole is cut in the Hydrocoll to increase visibility through polythene sheet, and the polyurethane film is applied as done in LAD I.
LAD II Application. For LAD II either ethylene oxide sterilized polythene (0.15-mm thick) sheet/bags (presealed adult size bags for extremities) are used; or based on the size, shape, and wound site, customized bags or tubes can be sealed using a semiautomatic sealing machine and sterilized by immersion in 2.45% w/v glutaraldehyde solution for 20 minutes.
After placing 2 tubes (12-14 FR tubes with multiple holes), the wound is covered with a polythene sheet that is neither permeable to water vapor nor to bacteria, and is sealed with Hydrocoll (after cleaning the skin with ether). Additional adhesive polyurethane film (OpSite) was applied to cover and secure the position of the hydrocolloid and to create a watertight seal. Plaster slab immobilization was done in suitable cases. Three basic designs of the polythene cover were used in LAD II— bag, tubular, and patch design.
One LAD tube was attached to a suction drain bottle and through other tube intermittent suction (-30 mmHg) was applied for 30 minutes every 4 hours from an ordinary hospital suction machine capable of generating 300 mmHg of negative pressure. Minor leaks noted during application of suction were ignored. For instance, maintaining negative pressure > 30 mmHg was possible in spite of leak. For moderate leaks resealing was done (ie, maintaining negative pressure > 30 mmHg was possible after applying a pressure dressing at the site of sealing). If a major leak occurred and maintaining a negative pressure > 30 mmHg was not possible and wound secretion was noted just after the end of suction period in spite of resealing, the LAD was changed.
Also, the amount of leakage was monitored subjec-tively based on reduction in compression, compared to that at the time of application felt by the patient. Leakage amount was monitored objectively by the amount of force required to pull the folds of polythene away from the wound surface after negative pressure application.
Split-thickness skin grafts with the LAD were covered with a non-stick,polyolefin mesh that was sutured to normal skin to avoid accidental displacement of the graft under the LAD.The LAD was removed on postoperative day 10.Two layers of non-stick, polyolefin mesh covered donor areas in all cases with 14 French tubes between them, which were covered with an adhesive polyurethane film. In the postoperative period, LAD intermittent suction (30 minutes suction, 4 hours rest) was applied over the recipient and donor areas.
Wounds. 2008;20(2):49-59. © 2008 HMP Communications
Copyright © 1999 by HMP Communications, LLC All rights reserved.
Cite this: Limited Access Dressing - Medscape - Feb 01, 2008.