Outpatient Surgery Magazine

Manager's Guide to Surgery's Orthopedic Surgery - August 2015

Outpatient Surgery Magazine, providing current information on Surgical Services, Surgical Facility Administration, Outpatient Surgery News and Trends, OR Excellence and more.

Issue link: http://outpatientsurgery.uberflip.com/i/548655

Contents of this Issue

Navigation

Page 58 of 64

A U G U S T 2 0 1 5 O U T P A T I E N TS U R G E R Y. N E T 5 9 Nerve injuries from tourniquet use Despite advances in pneumatic tourniquet technology, tourniquet-related nerve injury is a risk that remains a potentially harmful complication of tourniquet use. Researchers have shown that in most cases nerve damage is limited to the part of the nerve that is underneath and near the edges of the cuff, and that the under- lying cause of tourniquet paralysis is compressive neurapraxia rather than ischemic neuropathy or muscle damage. Compression of the large myelinated fibers underneath the tourniquet cuff results in displacement of the node of Ranvier from its usual position under the Schwann-cell junction. Studies of the distribution of pressure beneath tourniquet cuffs demonstrate high tourniquet inflation pressures in narrow, uncontoured tourniquet cuffs result in high pres- sure gradients near the cuff edges. This in turn results in higher compressive pressures and higher pressure gradients along the underlying nerves and soft tis- sues. Consequently, higher levels of tourniquet inflation pressure and higher pres- sure gradients beneath tourniquet cuffs are associated with a higher risk of nerve-related injury. What's the LOP? 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. Until recently, the use of personalized tourniquet settings based on LOP has been limited by how difficult it is to manually measure LOP. Using Doppler ultra- sound and a distal blood-flow sensor, surgical staff would detect the presence of arterial pulsations in the limb distal to a tourniquet cuff as an indicator of arterial blood flow past the cuff and into the distal limb. An operator would then slowly increase tourniquet cuff pressure from zero, while monitoring arterial pulsations in the limb distal to the cuff until the pulsations could no longer be detected.

Articles in this issue

Archives of this issue

view archives of Outpatient Surgery Magazine - Manager's Guide to Surgery's Orthopedic Surgery - August 2015