Available hind limb IR animal model are either artery vein ligation or tourniquet application (by rubber band or O-ring).

Possible treatments are the application of IR related-pathway derived drug/inhibitor and cell therapy. The study has been done a role for p53 in activating necrosis. During oxidative stress, p53 accumulates in the mitochondrial matrix and triggers mitochondrial permeability transition pore (PTP) opening. To the end of this, necrosis occurs by physical interaction with the PTP regulator cyclophilin D (CypD). The mitochondrial p53-CypD axis as an important contributor to oxidative stress-induced necrosis and implicates in disease pathology and possible treatment. Cyclosporine A, known as a potent the mitochondrial permeability transition pore (mPTP) opening inhibitor and extremely powerful in protecting cardiomyocytes from IR, normalized ROS production, decreased inflammation, and restored mitochondrial coupling during aortic cross-clamping in Rat hind limb IR model.

Pneumatic, surgical tourniquets are frequently applied in the controlled environment of the operating room in order to control blood loss during an upper or lower extremity operative case. Aside from lower blood loss in itself, this improves visualization and surgical efficiency. Modern examples are found in many different sizes to accommodate different patients and sites of applications, with adult cuffs approximately 4" wide. This distributes the pressure over, generally, a broader area than field (emergency, combat) tourniquets. The cuff is typically attached to an adjustable pneumatic pump with a built-in timer. Surgical tourniquet times in excess of 2 hours have been associated with an increased risk of nerve damage (e.g., neuropraxia), likely related to both direct nerve compression as well as decreased arterial inflow and oxygenation. The ischemia-reperfusion injury associated with surgical tourniquets is typically not clinically apparent when used for less than 2 hours.

Emergency field tourniquets have been used for many centuries, and have seen a resurgence in the recent combat operations in Afghanistan and Iraq, as well as expanded use in civilian trauma and mass casualty settings. Expedient and widespread tourniquet use in the modern combat setting is frequently cited as a primary driver for increased survival following major battlefield trauma. These tourniquets are often 1-2" in width, which concentrates the pressure to a narrow band of tissue. They can result in tissue necrosis if kept in place for long periods, and should only be applied after other methods to control bleeding (e.g., elevation or direct pressure to the wound) have failed, except in settings where time does not allow waiting. Generally, tissue distal to a field tourniquet that has been in place for greater than 6 hours is considered likely to be non-viable.

In the same way that external compression tourniquets reduce or eliminate arterial blood flow, aortic cross clamping has the same effect. The Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) device achieves this as well. By design, these devices induce ischemia to the lower extremities (as a secondary effect, or less commonly as their primary use). Releasing the cross clamp or removing the REBOA initiates reperfusion, and IR injury to the lower extremities may follow.

There are some preliminary studies that seem to indicate that treatment with hydrogen sulfide (HS) can have a protective effect against reperfusion injury.

A study of aortic cross-clamping, a common procedure in cardiac surgery, demonstrated a strong potential benefit with further research ongoing.

With treatment, approximately 80% of patients are alive (approx. 95% after surgery) and approximately 70% of infarcted limbs remain vital after 6 months.

The fact that the ischemic cascade involves a number of steps has led doctors to suspect that neuroprotectants such as calcium channel blockers or glutamate antagonists could be produced to interrupt the cascade at a single one of the steps, blocking the downstream effects. Though initial trials for such neuroprotective drugs led many to be hopeful, until recently, human clinical trials with neuroprotectants such as NMDA receptor antagonists were unsuccessful.

On October 7, 2003, a U.S. patent number 6630507 entitled "Cannabinoids as Antioxidants and Neuroprotectants" was awarded to the United States Department of Health and Human Services, based on research carried out at the National Institute of Mental Health (NIMH), and the National Institute of Neurological Disorders and Stroke (NINDS). This patent claims that cannabinoids are "useful in the treatment and prophylaxis of wide variety of oxidation associated diseases such as ischemia, inflammatory ... and autoimmune diseases. The cannabinoids are found to have particular application as neuroprotectants, for example in limiting neurological damage following ischemic insults, such as stroke and trauma..."

On November 17, 2011, in accordance with 35 U.S.C. 209(c)(1) and 37 CFR part 404.7(a)(1)(i), the National Institutes of Health, Department of Health and Human Services, published in the Federal Register, that it is contemplating the grant of an exclusive patent license to practice the invention embodied in U.S. Patent 6,630,507, entitled “Cannabinoids as antioxidants and neuroprotectants” and PCT Application Serial No. PCT/US99/08769 and foreign equivalents thereof, entitled “Cannabinoids as antioxidants and neuroprotectants” [HHS Ref. No. E-287-1997/2] to KannaLife Sciences Inc., which has offices in New York, U.S. This patent and its foreign counterparts have been assigned to the Government of the United States of America. The prospective exclusive license territory may be worldwide, and the field of use may be limited to: The development and sale of cannabinoid(s) and cannabidiol(s) based therapeutics as antioxidants and neuroprotectants for use and delivery in humans, for the treatment of hepatic encephalopathy, as claimed in the Licensed Patent Rights.

Early treatment is essential to keep the affected limb viable. The treatment options include injection of an anticoagulant, thrombolysis, embolectomy, surgical revascularisation, or amputation. Anticoagulant therapy is initiated to prevent further enlargement of the thrombus. Continuous IV unfractionated heparin has been the traditional agent of choice.

If the condition of the ischemic limb is stabilized with anticoagulation, recently formed emboli may be treated with catheter-directed thrombolysis using intraarterial infusion of a thrombolytic agent (e.g., recombinant tissue plasminogen activator (tPA), streptokinase, or urokinase). A percutaneous catheter inserted into the femoral artery and threaded to the site of the clot is used to infuse the drug. Unlike anticoagulants, thrombolytic agents work directly to resolve the clot over a period of 24 to 48 hours.

Direct arteriotomy may be necessary to remove the clot. Surgical revascularization may be used in the setting of trauma (e.g., laceration of the artery). Amputation is reserved for cases where limb salvage is not possible. If the patient continues to have a risk of further embolization from some persistent source, such as chronic atrial fibrillation, treatment includes long-term oral anticoagulation to prevent further acute arterial ischemic episodes.

Decrease in body temperature reduces the aerobic metabolic rate of the affected cells, reducing the immediate effects of hypoxia. Reduction of body temperature also reduces the inflammation response and reperfusion injury. For frostbite injuries, limiting thawing and warming of tissues until warmer temperatures can be sustained may reduce reperfusion injury.

Oxygen consumption of skeletal muscle is approximately 50 times larger while contracting than in the resting state. Thus, resting the affected limb should delay onset of infarction substantially after arterial occlusion.

Low molecular weight heparin is used to reduce or at least prevent enlargement of a thrombus, and is also indicated before any surgery. In the legs, below the inguinal ligament, percutaneous aspiration thrombectomy is a rapid and effective way of removing thromboembolic occlusions. Balloon thrombectomy using a Fogarty catheter may also be used. In the arms, balloon thrombectomy is an effective treatment for thromboemboli as well. However, local thrombi from atherosclerotic plaque are harder to treat than embolized ones. If results are not satisfying, another angiography should be performed.

Thrombolysis using analogs of tissue plasminogen activator (tPA) may be used as an alternative or complement to surgery. Where there is extensive vascular damage, bypass surgery of the vessels may be necessary to establish other ways to supply the affected parts.

Swelling of the limb may cause inhibited flow by increased pressure, and in the legs (but very rarely in the arms), this may indicate a fasciotomy, opening up all four leg compartments.

Because of the high recurrence rates of thromboembolism, it is necessary to administer anticoagulant therapy as well. Aspirin and low molecular weight heparin should be administered, and possibly warfarin as well. Follow-up includes checking peripheral pulses and the arm-leg blood pressure gradient.

Due to the risk of crush syndrome, current recommendation to lay first-aiders (in the UK) is to not release victims of crush injury who have been trapped for more than 15 minutes. Treatment consists of not releasing the tourniquet and fluid overloading the patient with added Dextran 4000 iu and slow release of pressure. If pressure is released during first aid then fluid is restricted and an input-output chart for the patient is maintained, and proteins are decreased in the diet.

The Australian Resuscitation Council recommended in March 2001 that first-aiders in Australia, where safe to do so, release the crushing pressure as soon as possible, avoid using a tourniquet and continually monitor the vital signs of the patient. St John Ambulance Australia First Responders are trained in the same manner.

The Infarct Combat Project (ICP) is an international nonprofit organization founded in 1998 to fight ischemic heart diseases through education and research.

The clinician must protect the patient against hypotension, renal failure, acidosis, hyperkalemia and hypocalcemia. Admission to an intensive care unit, preferably one experienced in trauma medicine, may be appropriate; even well-seeming patients need observation. Treat open wounds as surgically appropriate, with debridement, antibiotics and tetanus toxoid; apply ice to injured areas.

Intravenous hydration of up to 1.5 L/hour should continue to prevent hypotension. A urinary output of at least 300 ml/hour should be maintained with IV fluids and mannitol, and hemodialysis considered if this amount of diuresis is not achieved. Use intravenous sodium bicarbonate to keep the urine pH at 6.5 or greater, to prevent myoglobin and uric acid deposition in kidneys.

To prevent hyperkalemia/hypocalcemia, consider the following adult doses:

- calcium gluconate 10% 10ml or calcium chloride 10% 5 ml IV over 2 minutes

- sodium bicarbonate 1 meq/kg IV slow push

- regular insulin 5–10 U

- 50% glucose 1–2 ampules IV bolus

- kayexalate 25–50 g with sorbitol 20% 100 ml by mouth or rectum.

Even so, cardiac arrhythmias may develop; electrocardiographic monitoring is advised, and specific treatment begun promptly.

The ischemic (ischaemic) cascade is a series of biochemical reactions that are initiated in the brain and other aerobic tissues after seconds to minutes of ischemia (inadequate blood supply). This is typically secondary to stroke, injury, or cardiac arrest due to heart attack. Most ischemic neurons that die do so due to the activation of chemicals produced during and after ischemia. The ischemic cascade usually goes on for two to three hours but can last for days, even after normal blood flow returns.

A cascade is a series of events in which one event triggers the next, in a linear fashion. Thus "ischemic cascade" is actually a misnomer, since the events are not always linear: in some cases they are circular, and sometimes one event can cause or be caused by multiple events. In addition, cells receiving different amounts of blood may go through different chemical processes. Despite these facts, the ischemic cascade can be generally characterized as follows:

1. Lack of oxygen causes the neuron's normal process for making ATP for energy to fail.

2. The cell switches to anaerobic metabolism, producing lactic acid.

3. ATP-reliant ion transport pumps fail, causing the cell to become depolarized, allowing ions, including calcium (Ca), to flow into the cell.

4. The ion pumps can no longer transport calcium out of the cell, and intracellular calcium levels get too high.

5. The presence of calcium triggers the release of the excitatory amino acid neurotransmitter glutamate.

6. Glutamate stimulates AMPA receptors and Ca-permeable NMDA receptors, which open to allow more calcium into cells.

7. Excess calcium entry overexcites cells and causes the generation of harmful chemicals like free radicals, reactive oxygen species and calcium-dependent enzymes such as calpain, endonucleases, ATPases, and phospholipases in a process called excitotoxicity. Calcium can also cause the release of more glutamate.

8. As the cell's membrane is broken down by phospholipases, it becomes more permeable, and more ions and harmful chemicals flow into the cell.

9. Mitochondria break down, releasing toxins and apoptotic factors into the cell.

10. The caspase-dependent apoptosis cascade is initiated, causing cells to "commit suicide."

11. If the cell dies through necrosis, it releases glutamate and toxic chemicals into the environment around it. Toxins poison nearby neurons, and glutamate can overexcite them.

12. If and when the brain is reperfused, a number of factors lead to reperfusion injury.

13. An inflammatory response is mounted, and phagocytic cells engulf damaged but still viable tissue.

14. Harmful chemicals damage the blood–brain barrier.

15. Cerebral edema (swelling of the brain) occurs due to leakage of large molecules like albumins from blood vessels through the damaged blood brain barrier. These large molecules pull water into the brain tissue after them by osmosis. This "vasogenic edema" causes compression of and damage to brain tissue (Freye 2011; Acquired Mitochondropathy-A New Paradigm in Western Medicine Explaining Chronic Diseases).

Compartment syndrome is a condition in which increased pressure within one of the body's compartments results in insufficient blood supply to tissue within that space. There are two main types: acute and chronic. The leg or arm are most commonly involved.

Symptoms of acute compartment syndrome may include severe pain, poor pulses, decreased ability to move, numbness, or a pale color of the affected limb. It is most commonly due to physical trauma such as a bone fracture or crush injury. It can also occur after blood flow returns following a period of poor blood flow. Diagnosis is generally based upon a person's symptoms. Treatment is by surgery to open the compartment performed in a timely manner. If not treated within six hours, permanent muscle or nerve damage can result.

In chronic compartment syndrome there is generally pain with exercise. Other symptoms may include numbness. Symptoms typically resolve with rest. Common activities that trigger it include running and biking. It does not generally result in permanent damage. Other conditions that may present similarly include stress fractures and tendinitis. Treatment may include physical therapy or if that is not effective surgery.

Acute compartment syndrome occurs in about 3% of those who have a midshaft fracture of the forearm. Rates in other areas and for chronic cases is unknown. The condition more often occurs in those under the age of 35 and in males. Compartment syndrome was first described in 1881 by Richard von Volkmann. Untreated, acute compartment syndrome can result in Volkmann's contracture.

Treatment approaches can include osmotherapy using mannitol, diuretics to decrease fluid volume, corticosteroids to suppress the immune system, hypertonic saline, and surgical decompression to allow the brain tissue room to swell without compressive injury.

Failure to relieve the pressure can result in necrosis of tissue in that compartment, since capillary perfusion will fall leading to increasing oxygen deprivation of those tissues. This can cause Volkmann's contracture in affected limbs. As intercompartmental pressure rises during compartment syndrome, perfusion within the compartment is reduced leading to ischemia, which if left untreated, results in necrosis of nerves and muscles of the compartment (Shears, 2006). Rhabdomyolysis and subsequent renal failure are also possible complications.

The choice of fluids for resuscitation remains an area of research, the Surviving Sepsis Campaign an international consortium of experts, did not find adequate evidence to support the superiority crystalloid fluids versus colloid fluids. Drugs such as, pyridoxalated hemoglobin polyoxyethylene, which scavenge nitric oxide from the blood have been investigated. As well as methylene blue which may inhibit the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway which has been suggested to play a significant role in distributive shock.

The treatment of mesenteric ischemia depends on the cause, and can be medical or surgical. However, if bowel has become necrotic, the only treatment is surgical removal of the dead segments of bowel.

In non-occlusive mesenteric ischemia, where there is no blockage of the arteries supplying the bowel, the treatment is medical rather than surgical. People are admitted to the hospital for resuscitation with intravenous fluids, careful monitoring of laboratory tests, and optimization of their cardiovascular function. NG tube decompression and heparin anticoagulation may also be used to limit stress on the bowel and optimize perfusion, respectively.

Surgical revascularisation remains the treatment of choice for mesenteric ischaemia related to an occlusion of the vessels supplying the bowel, but thrombolytic medical treatment and vascular interventional radiological techniques have a growing role.

If the ischemia has progressed to the point that the affected intestinal segments are gangrenous, a bowel resection of those segments is called for. Often, obviously dead segments are removed at the first operation, and a second-look operation is planned to assess segments that are borderline that may be savable after revascularization.

Septic shock is associated with significant mortality and is the leading non cardiac cause of death in intensive care units (ICUs).

Blue toe syndrome is a situation that may reflect atherothrombotic microembolism, causing transient focal ischaemia, occasionally with minor apparent tissue loss, but without diffuse forefoot ischemia. The development of blue or violaceous toes can also occur with trauma, cold-induced injury, disorders producing generalized cyanosis, decreased arterial flow, impaired venous outflow, and abnormal circulating blood.

The terms "blue toe syndrome", "grey toe syndrome" and "purple toe syndrome" are sometimes used interchangeably.

Studies may include echocardiography, thoracic and abdominal CT or MRI, peripheral arterial run off imaging studies, hypercoagulopathy labs, and interrogation of syndromes that lead to peripheral vascular pathology.

Phlegmasia alba dolens (also colloquially known as milk leg or white leg) is part of a spectrum of diseases related to deep vein thrombosis. Historically, it was commonly seen during pregnancy and in mothers who have just given birth. In cases of pregnancy, it is most often seen during the third trimester, resulting from a compression of the left common iliac vein against the pelvic rim by the enlarged uterus. Today, this disease is most commonly (40% of the time) related to some form of underlying malignancy. Hypercoagulability (a propensity to clot formation) is a well-known state that occurs in many cancer states. The incidence of this disease is not well reported.

Cerebral edema is excess accumulation of fluid in the intracellular or extracellular spaces of the brain.

The prognosis depends on prompt diagnosis (less than 12–24 hours and before gangrene) and the underlying cause:

- venous thrombosis: 32% mortality

- arterial embolism: 54% mortality

- arterial thrombosis: 77% mortality

- non-occlusive ischemia: 73% mortality.

In the case of prompt diagnosis and therapy, acute mesenteric ischemia can be reversible.

People who suffer from neurotmesis often face a poor prognosis. They will more than likely never regain full functionality of the affected nerve, but surgical techniques do give people a better chance at regaining some function. Current research is focused on new ways to regenerate nerves and advance surgical techniques.

When someone presents with an ischemic event, treatment of the underlying cause is critical for prevention of further episodes.

Anticoagulation with warfarin or heparin may be used if the patient has atrial fibrillation.

Operative procedures such as carotid endarterectomy and carotid stenting may be performed if the patient has a significant amount of plaque in the carotid arteries associated with the local ischemic events.

Intracerebral hemorrhages is a severe condition requiring prompt medical attention. Treatment goals include lifesaving interventions, supportive measures, and control of symptoms. Treatment depends on the location, extent, and cause of the bleeding. Often, treatment can reverse the damage that has been done.

A craniotomy is sometimes done to remove blood, abnormal blood vessels, or a tumor. Medications may be used to reduce swelling, prevent seizures, lower blood pressure, and control pain.