The Effect of Topical Application of Tranexamic Acid on Postoperative Bleeding in Patients Undergoing Tangential Skin Excision

One or more paired donor sites will be created for each patient using the Zimmer dermatome. Paired wounds withcomparable size, depth, and location and will be labeled "A" and "B." A study nurse not involved in the operation will prepare two identical vials of 20 ml saline, marking them "A" and "B." A sealed numbered study envelope will state which vial should receive TXA. In the study drug vial, 5 ml will be replaced with 5 ml of 100 mg/ml TXA, yielding a solution of 25 mg/ml TXA. Both vials will receive 0,1 ml epinephrine 1 mg/ml, yielding an epinephrine concentration of 5 µg/ml to match the hemostatic saline-epinephrine solution applied topically to donor wounds at the burn center. The sets of vials and the corresponding study ID numbers will be delivered to the operating theatre. Prior to bandaging, the respective study wounds will be moistened with the corresponding study fluid. Gloves will be changed between each application to avoid cross-contamination. The study wounds will then be covered with an innermost non-absorbent layer of Vaseline gauze and five dry surgical gauzes to absorb the blood and exudate. The weight of a single dry gauze is consistent (27.5 g). The dressings will be marked "A" and "B" according to the drug vials used.

On the first postoperative day, the dressings will be removed except for the innermost Vaseline gauze. The wound surface area and the area of the blood stain on the innermost gauze will be measured. Dressing weight gain will be calculated by weighing the five dry gauzes and subtracting the dry weight (137.5 g). The paired gauzes will be visually compared for bleeding.and photo documented for later direct comparison.

During the first 24 h and over the following days and weeks, the participants will be monitored for possible adverse events, postoperative complications, and time to re-epithelialization.

Randomization Computer-generated randomization, production of corresponding sealed study envelopes, and organization of electronic case report forms will be provided by the Clinical Research Unit of St. Olav's University Hospital, Trondheim, Norway. Randomization instructions will be executed by a study nurse who was otherwise not connected to surgical procedures or patient follow-ups. All participants and personnel involved in surgery, follow-up, data collection, and statistical analysis will be blinded to the randomization.

Study end points The primary endpoint will be postoperative bleeding, defined as the net weight gain of the dressings per wound area. The secondary endpoints will be blood stain to wound area ratio and visual comparison of the amount of blood between paired dressings. All variables will be recorded on the first postoperative day. Additional secondary outcomes will be time to re-epithelialization, defined as no oozing in the dressings, and the occurrence of complications, such as wound infections and thromboembolic events.