Chronic wounds such as diabetic foot ulcers (DFUs) and venous leg ulcers (VLUs) pose a major health burden to the patients but also to the healthcare system because of their distorted healing capacity. This is mainly due to a prolonged treatment duration, high recurrence rates and substantial healthcare costs in wound care. Current guidelines exist that outline the standard wound care (SWC) in these patient groups but it often fails to achieve timely healing. Cold atmospheric plasma (CAP) is an emerging technology with promising antimicrobial and wound healing properties. In vitro and in vivo studies have highlighted the ability of CAP to reduce the bacterial biofilm load and stimulate tissue regeneration and microcirculation. This Randomized Controlled Trial (RCT) aims to evaluate the clinical effectiveness and cost-effectiveness of CAP in addition to SWC in patients with a DFU and VLU.

Inclusion Criteria:

• 1. is referred to one of the participating hospitals for treatment of a diabetic foot ulcer (DFU) or venous leg ulcer (VLU) with healing stagnation and

  a. For VLU: i. An ulcer on the lower leg resulting from malfunctioning venous valves in the leg veins.

  b. For DFU: i. An ulcer on the foot or lower leg in person with currently or previously diagnosed diabetes mellitus and usually accompanied by neuropathy and/or peripheral artery disease (PAD) in the lower extremity Note: In patients with both diabetes and chronic venous insufficiency, ulcers will be categorized as DFU in case of symptoms of diabetic neuropathy or loss of protective sensation, and otherwise categorized as VLU.

  2. has a wound with a minimum wound surface area of 0.5 cm2 and a maximum diameter of 6 cm (~28 cm2 wound surface area for circular wounds; measured after debridement),

  3. has a minimum age of 18 years old.

Exclusion Criteria:

• 1. the participant has one or more of the following contraindications for PLASOMA:

  1. extreme exudative wounds, i.e. wounds in which moisture is visible within seconds after patting dry;

  2. any implanted active electronic device, such as a pacemaker, is present;

  3. an electronic medical device attached to the body, for example electronic life support equipment, a hearing aid, insulin pump or dialysis machine. If this medical device can be disconnected, PLASOMA treatment may be performed. If the sole purpose of this medical device is monitoring, such as a glucose sensor, PLASOMA treatment is not contra-indicated but note that use of PLASOMA together with such devices has not been tested and may lead to erroneous operation of the attached device during PLASOMA treatment;

  4. metal in the area 10 cm around pad-electrode area, e.g. metal sutures and implants;

  5. connection from outside the body to (near) the heart is present, e.g. a central venous catheter;

  6. the participant has epilepsy;

  7. the participant is pregnant.

     2. the participant has more than one wound that requires professional wound care.

     3. for DFU the WIfI-classification is wound grade 3, defined as an extensive, deep ulcer involving forefoot and/or midfoot; deep, full thickness heel ulcer + calcaneal involvement.

     4. presence of ischemia grade 2 or 3, according to the WIfI classification (= the ankle-brachial pressure index (ABI) is ≤0.59 OR the ankle systolic pressure is ≤69 mmHg OR the toe pressure is ≤39 mmHg; there should be at least one of these three measurements available).

     5. a deep infection defined as an infection of the wound involving structures deeper than skin and subcutaneous tissues (e.g., abscess, osteomyelitis, septic arthritis, fasciitis).

     6. the wound is located on a toe.

     7. the participant receives treatment with immunosuppressive agents or oral corticosteroids; no exclusion if participant has received a stable dose for at least 2 months and the oral corticosteroid dose does not exceed 7.5 mg/day prednisone or equivalent.

     8. the participant is receiving or likely to receive offloading with a total contact cast or advanced wound therapies - such as negative pressure therapy, hyperbaric oxygen therapy, biologicals (e.g. skin substitutes, growth factors), electrophysical therapy - for the to be-treated wound. Advanced wound dressings (including but not limited to hydrocolloid, hydrogel, alginate, collagen and antimicrobial dressings) are not excluded.

     9. presence of a chronic or active skin disorder that may negatively influence wound healing (such as Marfan or Ehlers-Danlos syndrome).

     10. the participant takes part in another study that is likely to compromise the outcome of this study or the feasibility of the participant fulfilling this study.

     11. the participant is lactating.

     12. the participant is unable to provide consent.