The aim of this study is to evaluate the speed and quality with which OASIS® Ultra (Healthpoint Biotherapeutics; Fort Worth, Texas) increases wound healing in the critical sized defect. The investigators intend on confirming the histological composition of the dermal substitute in order to delineate the amount of cellular recruitment, collagen deposition and neovascularization present compared with control wounds. The investigators hypothesize that OASIS® Ultra will provide a faster healing time as well as the re-establishment of a dermis for further skin graft application. The investigators anticipate that our study will define parameters for the application of OASIS® Ultra as well as potentially demonstrating the advantages in healing time, healed wound quality and hospital stay.

The eligible participants for this study include all patients >18 years with traumatic, infective or iatrogenic critical sized wound defects (50 sq cm or greater) with a quantitative wound culture < 105. Accrual of patients will take place at the Massachusetts General Hospital Churchill Surgical Service. All eligible patients will be identified by physician care givers on the Churchill service. Non-study affiliated physicians will then approach the patient and/or his or her healthcare proxy with a consent form and a direct description of the study. If the patient and/or his or her healthcare proxy agree to proceed with inclusion then the described protocol will be followed.

Patients with the following medical diagnoses will be excluded from the study:

• Wounds that cannot have a negative pressure wound device applied due to anatomical difficulty (i.e. proximity to perineum/anus) or exposed arteries/veins.
• Patients who are DNR/DNI
• Patients who are hemodynamically unstable or requiring pressors
• Patients that are immunodeficient or immunocompromised (ie HIV)
• Patients that have any allergy to porcine products
• Patients that have a religious or ethical necessity to avoid porcine products
• Patients whose wounds are derived from extension of mitotic lesions (ie ulcerative squamous cell carcinoma)
• Patients whose wounds are expected to heal in less than seven days or be ready for skin grafting in less than seven days with standard therapy
• Patients with full thickness burns
• Patients with wound surface area of <50 sq cm
• Pregnant patients (as confirmed by serum or urinary beta-Human Chorionic Gonadotrophin sampling or by History).

Subject Enrollment:

The study will take place between January 1, 2013 (or IRB approval date) and June 30, 2015. The eligible participants for this study include all patients >18 years with traumatic, infective or iatrogenic critical sized wound defects (50 sq cm or greater) with a quantitative wound culture < 105. Accrual of patients will take place at the Massachusetts General Hospital Churchill Surgical Service. All eligible patients will be identified by physician care givers on the Churchill service. Non-study affiliated physicians will then approach the patient and/or his or her healthcare proxy with a descriptive consent form and a verbal explanation of the study. If the patient and/or his or her healthcare proxy agree to proceed with inclusion then the described protocol will be followed.

Consent The consent form is written in non-medical 'lay' terms in order that all non-medical readers may understand the terminologies and ideas. If the patient is non-English speaking then a certified hospital translator will be obtained in order that the written and verbal discussions can be done in the patient's native language for full comprehension. The PHRC policy on Obtaining and Documenting Informed Consent of Subjects who do not Speak English will be followed. For this study, potential subjects will be given a written translation in a language understandable to them of the "short form" or of the entire English version of the consent form approved by the Partners Human Research Committee (PHRC). Once a patient has been identified as eligible for enrollment by a physician on the team, a verbal discussion will be had with the patient using the sections of the consent form ensuring to cover purpose of research, design of research, procedures, risks, benefits, discomforts, benefits, costs, alternatives and number of patients to be enrolled. After identification of eligible patients, verbal explanation of the study parameters while leaving the patient with the consent form to read, 24 hours will be allowed to pass in order that the patient may think about potential questions and/or issues he or she may have with the study. Upon return by a physician not affiliated with the study, they will answer any patient questions or concerns. If the patient is willing to proceed with consent the co-Investigator or principal investigator will be contacted in order that the patient and the investigator may co-sign the consent form. We will ensure that there are contact details on the patient's consent form should they have any questions or issues. If the patient wishes to withdraw consent prior to the completion of the study they will be allowed to do so and the IRB will be contacted for guidance. The informed consent authorizes the use of medical chart information, historical lab values and consent for photography.

The PHRC recommendations regarding categories of surrogates (listed in general order of preference) that may provide consent in writing on behalf of potential subjects incapable of providing informed consent will be followed:

i) court appointed guardian with specific authority to consent to participation in research or authority to make health care decisions for a class of diagnostic and therapeutic decisions inclusive of the proposed research;

ii) health care proxy/person with durable power of attorney with specific authority for making health care decisions inclusive of the proposed research; or

iii) spouse, adult child, or other close family member who knows the subject well and has been involved in their care. Assent of subjects will be a requirement for participation in the research unless the subject is incapable of giving assent due to his/her medical condition. If the individual objects to participation, s/he should not be enrolled. When surrogate consent is relied upon, the Investigator will ensure that the surrogate understands that his or her decisions should be based on "substituted judgment." This means that the decision reflects a potential subject's own views when s/he had the capacity to express them.

The Investigators will document the relationship of the surrogate to the subject in the research record.

Inclusion Criteria:

• all patients >18 years
• traumatic, infective or iatrogenic critical sized wound defects (50 sq cm or greater)
• quantitative wound culture < 105.

Exclusion Criteria:

• Wounds that cannot have a negative pressure wound device applied due to anatomical difficulty (i.e. proximity to perineum/anus) or exposed arteries/veins.
• Patients who are DNR/DNI
• Patients who are hemodynamically unstable or requiring pressors
• Patients that are immunodeficient or immunocompromised (ie HIV)
• Patients that have any allergy to porcine products
• Patients that have a religious or ethical necessity to avoid porcine products
• Patients whose wounds are derived from extension of mitotic lesions (ie ulcerative squamous cell carcinoma)
• Patients whose wounds are expected to heal in less than seven days or be ready for skin grafting in less than seven days with standard therapy
• Patients with full thickness burns
• Patients with wound surface area of <50 sq cm
• Pregnant patients (as confirmed by serum or urinary beta-Human Chorionic Gonadotrophin sampling or by History).

A total of 7 patients with 10 wounds were enrolled in the study.

This study is limited by its small sample size.