The Use of Near Infrared Spectroscopy in the Diagnosis of Acute Compartment Syndrome in Trauma Patients (NIRS)

Swelling builds up in a severely injured leg (for example, a broken leg). In up to 20% of very bad injuries, the swelling can be so great that it acts to cut off blood supply to the leg, strangulating it from the inside. When this occurs, it is called Acute Compartment Syndrome (ACS). This is a painful and bad situation, which needs to be diagnosed and then surgically treated in an urgent fashion. Currently, the standard way most physicians diagnose ACS is by clinical examination. By asking the patient questions, moving and inspecting the patient's leg and typically inserting a needle in the patient's legs to measure the amount of pressure in each leg. Physicians compile this information and make the final diagnosis. This method of diagnosis can be painful and requires measurements, sometimes invasive, to be made at points in time. ACS is a disease process that develops over time therefore someone may not have ACS at the time of examination, but may develop it several hours later. The treatment for ACS is called a fasciotomy. This treatment involves making a large incision from the knee to the ankle on each side of the lower leg.

The NIRS device has already been cleared by the FDA for detecting blood flow to the brain during anesthesia. NIRS may also be helpful in diagnosing ACS. Two of the primary advantages of this device are that it is noninvasive (not painful) and it collects data continuously, so that if the disease develops, it can be detected early and treated appropriately. In order to prove this, the device must first be tested by taking a series of measurements on people that are uninjured (control groups), those with serious leg injuries (investigational groups), and people in a critically injured state, but without leg injuries (critical controls).

The goal of this study is to collect the information necessary to understand and then create decision-making guidelines that use NIRS monitoring to diagnose and direct treatment for ACS. Information for this study will be collected in the hospital. The study participants will be grouped into 2 categories:

Cohort 1: Patients who are critically injured, but have no lower leg injuries Cohort 2: Patients who have lower leg injuries that fall into certain high-energy categories (see Eligibility Criteria, Section 7.1)

This is an observational study, which means the data collected is not intended to impact the patient's course of care. At all points in time, treatment will be directed by the patient's doctor including decisions regarding operative care, non-operative care and in-patient management. In fact, this study will be blinded, which means that the doctor treating the study patients will not be able to see the NIRS values. This study will enroll approximately 120 subjects over three sites: Athens Regional Medical Center, Atlanta Medical Center, and Grady Memorial Hospital, over a period of approximately 18 months. Participation will last for 48 hours, unless the patient develops signs of compartment syndrome in which case monitoring may be extended up to 72 hours or until completion of an assessment after the patient is treated for ACS.

Participants will undergo the following procedures:

Beyond the standard of care:

1. Patient interview to collect information on medical history, medications, and mechanism of injury
2. Photograph(s) will be taken to document NIRS pad placement over muscle compartments and injury severity (face will not be included).
3. Ultrasound measure of the thickness of the fat layer (BX 2000) to detect the distance from the patient's skin surface to the underlying muscle
4. Light scan measurement of skin color (Dermaspectrometer) to see if the patient's skin color affects NIRS readings
5. Near-infrared Spectroscopy (NIRS) to measure patient's muscle oxygen levels. These devices are completely noninvasive, which means there are no sharp or painful portions of the device or measurement process. The NIRS device uses a small pad, like an EKG pad, that sticks to the patient's skin and gives off a harmless, painless light that can continually measure the patient's muscle oxygen level. These measures are recorded in the monitor and will later be downloaded and used to evaluate the device's ability to detect critical changes in muscle oxygen levels.

Standard of care:

1. Data will be recorded from the patient's medical record based on procedures ordered by the patient's provider, including: lab values, Stryker measurements, vital signs.
2. Among Cohort 2 patients, data associated with some surgical procedures will be collected and recorded in the operating room. This will be data that is gathered as standard of care, such as blood pressure

All of this information will be kept private and secure, and no sensitive information will be collected.