Clinical Applications

Surgical Settings Non - Surgical Settings Contraindications to Tourniquet Use

Pneumatic tourniquets and other pneumatic compression devices have applications in both surgical and nonsurgical settings.

Surgical Settings

With the exception of phlebotomy, the primary objective of tourniquet use in surgical settings is the creation of a bloodless operative field. In certain situations, tourniquets may be useful for preventing the undesirable escape of vascular fluids into body areas or to confine local anesthetics to an extremity. Orthopaedics and plastic surgery are two specialties that frequently utilize pneumatic tourniquets. Intravenous regional anesthesia also requires the application of a tourniquet.

Orthopaedics

Orthopaedic uses for tourniquets include procedures undertaken to diagnose and/or correct pathology of nerves, tendons, muscles, joints, and bones of either upper or lower extremities. The following are examples of orthopaedic procedures that utilize pneumatic tourniquets:

• Reduction of certain fractures.
• Kirschner wire removal.
• Replacement or revision of the joints of the knee, wrist, digits, hand, or elbow.
• Arthroscopy of the knee, elbow, wrist, hand, or digits.
• Bone grafts.
• Graft and repair of lacerated tendons.
• Subcutaneous fasciotomy.
• Repair of traumatic nerve damage.
• Carpal tunnel release.
• Traumatic or nontraumatic amputation.
• Correction of a hammer toe.
• Podiatry.

Plastic and Reconstructive Surgery

The goal of plastic and reconstructive surgery is to improve a patient's self - image or level of function, thereby improving the quality of life. Plastic surgery involves primarily the subcutaneous tissue, up to and including the skin. Examples of plastic repair procedures that might utilize a pneumatic tourniquet include:

• Repair of burn contractures.
• Excision of lesions or tumors of the limbs.
• Split - thickness skin grafts on burned patients.

By using a tourniquet, larger burn areas may be excised and grafted because of the bloodless field; a compression dressing is applied before the tourniquet is released.

Reconstructive surgery is more extensive than plastic surgery and may include:

• Amputations or replantations.
• Repair of bone, cartilage, tendons, nerves, or blood vessels.
• Resection of invasive tumors or lesions.
• Repair of congenital anomalies (e.g., syndactyly or polydactyly).
• Bilateral extremity surgery (e.g., foot - to - hand transfer of digits, related to the amputation).

Intravenous Regional Anesthesia

Regional anesthesia is the interruption of sensory nervous conduction in an isolated part of the body. Intravenous refers to the route by which the anesthetic agent is introduced. In intravenous regional anesthesia (IVRA), local anesthesia and a bloodless operative field are produced by inflation of a dual - bladder tourniquet proximal to the operative site, followed by injection of a local anesthetic agent distal to the tourniquet.

When used appropriately, IVRA is a safe and effective anesthesia technique for extremity surgery. The inflated tourniquet cuff prevents the anesthetic agent from entering the systemic circulation. However, if a bolus of local anesthetic and metabolic waste products inadvertently enters the general circulation after tourniquet release, particularly if hypersensitivity to the anesthetic agent exists, there is a risk of toxic reactions. Hence, IVRA is not used on trauma patients whose physiological status may already be impaired or who probably do not have a premorbid physical history available. IVRA is best used for elective surgery patients who have had a physical assessment and are able to tolerate the procedure.

Use in a Non - surgical Setting

The nonsurgical use of pneumatic compression devices is commonly directed toward manipulation of venous and arterial circulation for the purpose of reducing primary or secondary circulatory problems. In the rotating tourniquet approach, tourniquets might be used to increase blood pressure in shock patients; by limiting the area over which the circulating blood must be distributed, the circulating volume is also raised, resulting in increased blood pressure. Likewise, tourniquets might be used to decrease blood pressure in patients whose pressure is dangerously elevated; by isolating blood in the extremities, the pressure in the nonisolated portions of the circulatory system is decreased.

Some pneumatic compression devices do not look like tourniquets. Two such devices are external pneumatic calf compression boots and the MAST suit.

External Pneumatic Calf Compression

External pneumatic calf compression is a preventive therapy for patients at risk for deep venous thrombosis. Knee - length inflatable plastic boots with an alternating pressure cycle are used to prevent sluggish venous blood flow.

MAST Suit

Military Anti - Shock Trousers (MAST suits) can be used for early treatment of hypovolemic shock in trauma victims. The trouser pressure acts like an inflatable tourniquet to reverse shock by redirecting blood from the legs and pelvis into central circulation, thus raising the blood pressure and increasing perfusion to vital body organs.

Contraindications to Tourniquet Use

The final decision on whether or not to use a tourniquet rests with the attending physician. A few possible contraindications that the physician may take into consideration are:

• Open fractures of the leg.
• Post - traumatic lengthy hand reconstruction.
• Severe crushing injuries.
• Elbow surgery (with concomitant excess swelling).
• Severe hypertension
• Skin grafts (to help distinguish all bleeding points).
• Compromised circulation (e.g., peripheral artery disease).
• Diabetes mellitus.

The presence of sickle cell disease is a relative contraindication to tourniquet use. The use of a tourniquet has been discouraged in patients who carry the sickle cell gene, because tourniquet use may lead to circulatory stasis, acidosis, and hypoxemia - the triad of clinical conditions that is known to induce sickling. However, recent studies have suggested that the use of a tourniquet in sickle cell patients may not be associated with harmful effects, provided that optimum acid - base status and oxygenation are maintained throughout anesthesia. Before using a tourniquet on patients with sickle cell disease or trait, it may be useful to test for hemoglobin type and level. If the decision is made to apply a tourniquet, exsanguinate the limb carefully and closely monitor the patient's PO₂ and pH.