SAFETY FIRST Keep the tourniquet inflation pressure to the minimum effective pressure and protect the skin under the tourniquet.

Pneumatic tourniquets are routinely applied to arms and legs in orthopedic cases to create a bloodless surgical field, but with little thought given to the complications they can cause — from nerve and muscle injury to deep vein thrombosis and damage to the skin beneath the cuff. Here's a quick look at ways to reduce the risk of an injury from the use of a tourniquet.

Q. What factors should I consider before every tourniquet case?
A. You should consider 3 factors: duration of occlusive pressure, inflation pressure and tourniquet design, according to "Safe Tourniquet Use: A Review of the Evidence," in the Journal of the American Academy of Orthopaedic Surgeons (osmag.net/DU5gBj).

Q. Should I inspect the tourniquet system before every case?
A. Yes, inspect the system before use to make sure it's complete, clean and functioning, says AORN. Inspection should include verifying that the tourniquet regulator is compatible with all associated components. Check the regulator for integrity — that it's functioning within the parameters set by the manufacturer. Inspect the cuff, tubing, connectors and o-rings for cracks, leaks and other damage. Verify the integrity of the hook and loop fasteners and tie ribbons. Confirm that there is a full battery power charge.

Q. What are safe pressure settings?
A. Here are suggestions from "Safe Tourniquet Use: A Review of the Evidence." A tourniquet pressure of 200 mmHg in the upper extremity and 250 mmHg in the lower extremity produces a bloodless field in normotensive persons of average build. This difference is presumably a function of limb girth, with occlusion occurring at a lower pressure in the upper limb. For anticipated inflation time of less than 2.5 hours, upper extremity pressure should be less than 250 mmHg and lower extremity pressure should be less than 300 mmHg. For procedures that will involve prolonged tourniquet times of more than 2.5 hours, you should measure limb occlusion pressure and use a safety margin of 50 mmHg to 75 mmHg.

Q. What advantages do personalized tourniquet systems offer?
A. Newer tourniquet systems automatically measure the minimum pressure required to occlude the limb, and recommend a cuff pressure to be used during surgery that is personalized for each patient. By delivering more efficient application of cuff pressure to the limb, they let you dial in the lowest limb occlusion pressure needed to occlude blood flow.

Q. What is LOP?
A. The optimal surgical tourniquet pressure setting for each patient is based on a measurement known as limb occlusion pressure (LOP). LOP is the minimum pressure required — at a specific time in a specific type of tourniquet cuff applied to a specific patient's limb at a specific location — to stop the flow of arterial blood into the limb distal to the cuff. Advances in tourniquet technology that let you measure LOP automatically have reduced the risk of nerve-related injury in recent years. These advances use distal sensors to automatically measure the individual's LOP.

Q. Does the patient's limb size and shape matter?
A. Yes. Always select a personalized tourniquet cuff that matches the limb size and shape, tissue characteristics and size of the patient. Also use personalized limb protection sleeves that minimize soft tissue injuries underneath the cuff on the limb. Personalized cuffs and sleeves designed to better match patient limb size and shape provide more efficient application of cuff pressure to the limb, letting you use lower and safer tourniquet pressures. The traditional "straight" tourniquet cuffs are best suited to cylindrical limb shapes. New types of cuffs are "variable contour cuffs" that let you adapt the shape of the tourniquet cuff to any of a wide range of non-cylindrical (tapered, for example) limb shapes. Cylindrical cuffs that are applied onto a tapered limb result in poor fits, requiring the use of higher pressures to occlude the limb. OSM