Effect of Remote Ischemic Conditioning on Trauma Patients With Hemorrhagic Shock

Dysfunction of vital organs is one of the major reasons why trauma victims die after sustaining a major injury, even though the organs themselves may not have been directly injured. The inability to clot blood as a result of inflammation further contributes to complications in a majority of these patients. One intervention proposed to protect against impaired organ function is called "Remote Ischemic Conditioning", wherein application of intermittent occlusion and release of blood flow to the arm by sequentially inflating and deflating a blood pressure cuff can protect against the development of distant organ injury and inflammation following a severe traumatic event. In a pilot study, we will investigate the effects of remote ischemic conditioning in trauma patients with hemorrhagic shock, with a view to evaluate its effects on the immune system and coagulation profiles, both of which are known to be deranged in these patients. These studies will potentially benefit patients and will serve as a proof of principle for the use of remote ischemic conditioning in the trauma setting.

Inclusion criteria

• Age ≥16 years of age or estimated weight ≥50kgs if age is unknown;
• Victim of blunt or penetrating trauma
• Hemorrhagic shock defined as:
• One or more episodes of systolic blood pressure ≤90mmHg at any time prior to enrollment into the study;
• An identified source of blood loss (abdomen, chest, pelvis/retroperitoneum, extremities, external) or
• Blood products (RBC, Platelets, Plasma, etc.) has been ordered to the trauma room.
• Admitted to St. Michael's Hospital directly from the scene of injury within 3 hours of the injury
• Application and completion of Remote Ischemic Conditioning (RIC) within 4 hours of the injury

Exclusion criteria

• Pregnancy
• Non-hemorrhagic shock (i.e. tension pneumothorax, cardiac tamponade, spinal shock, etc.)
• Major burns > 20% total body surface area
• Fracture of both lower extremities (i.e. traumatic amputation, fractures)
• Absence of vital signs prior to admission, ongoing CPR, possibly dead on admission or not expected to survive beyond a few hours.
• Injury in both legs (traumatic amputation, fractures, etc.)
• Patients with a systolic blood pressure above 200mmHg
• Patients treated with anticoagulants, antiplatelet therapy (Warfarin, Aspirin), steroids or with a known bleeding disorder or known abnormality of blood flow to the limb (if known)
• Patients with osteoporosis or other bone disorders, peripheral nerve injury, abnormal nerve supply, peripheral neuropathy (if known) or preexisting traumatic injury to the limb.
• Morbid obesity (largest cuff size won't fit)
• If RIC is done clinically before research protocol begins.