Don’t Let the Tourniquet Time Run Long



Don’t Let the Tourniquet Time Run Long


Byron D. Fergerson MD

Randal O. Dull MD, Phd



A senior anesthesiologist once facetiously remarked to the authors that tourniquet use requires its own little anesthetic plan—discussion of risks and benefits, inflation (equals induction?), maintenance, deflation (equals emergence?), and post-tourniquet (equals postoperative?) pain management. There is a kernel of truth in this.

Tourniquets are used by surgeons during surgery on extremities to decrease overall blood loss and to facilitate operating conditions by keeping the surgical field clear of blood. To deliver effective care to patients, anesthesia providers must carefully maintain a state of vigilance over all aspects of tourniquet use. Surgeons inform patients of plans to use a tourniquet during the procedure, and plans for tourniquet use may be noted in consents as well. However, planned tourniquet use may necessitate a separate discussion between the anesthesia provider and the patient, especially if a regional block is planned to counteract pain resulting from tourniquet use.

Application of the tourniquet is often preceded by exsanguination of the limb by circumferential wrapping of the limb in an Esmarch bandage. An alternative to using an Esmarch bandage is elevating the limb for 5 minutes (at 90°- and 45°-angles for upper and lower extremities, respectively). The cuff should be from 7 to 15 cm greater that the circumference of the limb and should be placed at the site of maximal circumference. The padding placed under the cuff should have no obvious folds. It is recommended that the cuff be inflated to a level 50 mmHg above the level at which distal pulse is lost, as assessed by Doppler, or to a level 50 mmHg above the patient’s systolic-pressure level for upper-limb procedures and 100 mmHg above the patient’s systolic-pressure level for lower-limb procedures. Most authors agree that from 1.5 to 2 hours is the outer limit for safe use of a tourniquet. This period can be extended by cooling the limb or allowing for 10 minutes of reperfusion for every hour of cuff inflation. Paying vigilant attention to the length of tourniquet use, inflation pressure, and proper cuff fit is important in preventing complications. Communicating with the surgeons also helps; do not be shy about asking questions and expressing concerns, especially if the length of tourniquet use is running long. Establishing open communication before a crisis arises will facilitate resolution of any problem, so discuss plans
and target goals for the length of tourniquet use with the surgeons before beginning the procedure.

Tourniquets are among the oldest medical devices in history. There is a considerable body of literature on the consequences of tourniquet application, and the physiologic effects are protean.


MUSCLE

Predictably, tourniquet use affects muscle tissue. During tourniquet inflation, the combination of acute ischemia and pressure may cause increased microvascular permeability. Cellular hypoxia occurs within minutes of inflation. Ischemic cells release lactic acid, lysozymes, myoglobin, proteolytic enzymes, and inflammatory mediators, including histamine, leukotrienes, platelet-activating factors, and oxygen radicals. All of these substances are redistributed into the systemic circulation immediately after tourniquet deflation and may cause significant vasodilatation and hypotension. In addition, venous stasis distal to tourniquets allows the accumulation of high levels of CO2 and metabolic byproducts, including potassium, which may cause arrhythmias. After tourniquet deflation, reperfusion hyperemia can lead to compartment syndrome, rhabdomyolysis, and the post-tourniquet syndrome of stiffness, pallor, and weakness without paralysis or numbness.

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Jul 1, 2016 | Posted by in ANESTHESIA | Comments Off on Don’t Let the Tourniquet Time Run Long
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