Surgical tourniquet

Surgical tourniquets enable surgeons to work in a bloodless operative field by preventing blood flow to a limb. This allows surgical procedures to be performed with improved precision, safety and speed. Tourniquets are widely used in orthopedic and plastic surgery, as well as in intravenous regional anesthesia (Bier block anesthesia) where they serve the additional function of preventing local anesthetic in the limb from entering general circulation.

In the early 1980s, microprocessor-controlled pneumatic tourniquets were invented by James McEwen.[1][2] Automatic tourniquets based on this invention are now standard equipment in operating rooms worldwide, and these systems have significantly improved the safety and convenience of tourniquet use. In the 2000s, a modern mechanical tourniquet called either a silicone ring tourniquet, or elastic ring tourniquet, was invented by Prof. Noam Gavriely.[3] The surgical torunqiuet version of the device, and provides improved surgical accessibility due to its narrow profile that results in a larger surgical field. It can be used for most limb procedures, but it does not completely replace the use of contemporary tourniquet devices.[4]

Despite many advances in tourniquet technology, tourniquet-related injuries continue to be of concern.[5] High pressures under a tourniquet cuff can cause nerve, muscle and skin injury. Minimizing tourniquet pressure and reducing tourniquet time help to reduce the risk of tourniquet-related injury.

Surgical tourniquet equipment

Pneumatic Tourniquets

Modern pneumatic tourniquets have three basic components: an inflatable cuff, a compressed gas source, and an instrument which automatically monitors and controls cuff pressure. The cuff is secured around the limb proximal to the operative site. Pressure is exerted on the circumference of the limb by means of compressed gas which is introduced into the tourniquet cuff by a microprocessor-controlled source, via connection tubing. When sufficient pressure is exerted, vessels and arteries beneath the cuff become temporarily occluded, preventing blood flow past the cuff. While the cuff is inflated, the tourniquet system automatically monitors and maintains the pressure chosen by the user. Cuff pressure and inflation time are displayed, and an audiovisual alarm alerts the user to alarm conditions, such as a cuff leak.

Contoured cuffs

Wide, contoured thigh, arm and lower leg tourniquet cuffs

Studies have shown that tourniquet cuff pressures can be substantially reduced without compromising the quality of surgical field by using wide, contoured cuffs.[6] Wide cuffs also reduce the risk of injury to underlying tissue by dispersing the cuff’s force over a greater surface area. Standard cuffs are relatively narrow in width and are cylindrical in shape. Where there is a significant difference in limb circumference between the distal and proximal edges of the cuff, a contoured cuff with a tapered, conical shape provides a more anatomical fit and maximizes the contact area between cuff and limb. Wide cuffs with an adjustable, variable taper have recently been introduced, permitting one cuff to conform to a variety of limb shapes.[7]

Limb occlusion pressure

Limb occlusion pressure (LOP) is the minimum tourniquet pressure required to occlude blood flow to a specific patient's limb at a specific time, and takes into account a patient’s limb and vessel characteristics, and the type and fit of the cuff. LOP can be determined by gradually increasing tourniquet pressure until distal arterial pulses cease, as indicated by a device sensing blood flow, such as a Doppler stethoscope. Studies have shown that cuff pressure based on LOP measured immediately prior to surgery is generally lower than pressure from commonly used cuffs and is sufficient to maintain a satisfactory surgical field.[8] Traditionally, this method has not been used because it is time consuming and technically demanding. However, a pneumatic tourniquet that uses an automated plethysmographic system to calculate LOP in approximately 30 seconds at the beginning of surgery has recently been developed.[9] This device has similar accuracy to the standard Doppler technique and addresses the practicality of using LOP in the operating room.

Limb protection

Wide, contoured arm cuff applied over matching limb protection sleeve

For some cuffs, a matching limb protection sleeve is available to help protect soft tissues under the cuff.[7][10] Without proper protection, underlying soft tissue is prone to damage caused by wrinkling, pinching or shearing.[11] Sleeves are sized according to the cuff width and the patient’s limb circumference. They are intended to fit snugly and extend beyond the edge of the cuff to ensure that there is no direct contact between cuff and skin. Sleeve materials that do not shed loose fibers are chosen to avoid lint becoming trapped in the cuff’s hook and loop fasteners, which reduces their effectiveness.

Silicone Ring Tourniquets

Silicone ring tourniquets, or elastic ring tourniquets, are self-contained mechanical devices that do not require any electricity, wires or tubes. The tourniquet comes in a variety of sizes. To determine the correct product size, the patient's limb circumference at the desired occlusion location should be measured, as well as their blood pressure to determine the best model.[12] Once the correct model is selected, between two sterile medical personnel will be needed to apply the device. It should be noted, unlike with the pneumatic tourniquet, the silicone ring tourniquet should be applied after the drapes have been placed on the patient. This is due to the device being completely sterile.[13] The majority of the devices require a two man operation (with the exception of the extra large model):

  1. One person is responsible for holding the patient's limb, the other will place the device on the limb (with the extra-large there are two people needed).
  2. Application:
    1. Place the elastic ring tourniquet on the hand/foot. Take care to ensure that all the fingers/toes are enclosed within the device.
    2. The handles of the tourniquet should be positioned medial-lateral on the upper extremity or posterior-anterior on the lower extremity.
    3. The person applying the device should start rolling the device while the individual responsible for the limb should hold the limb straight and maintain axial traction.
    4. Once the desired occlusion location is reached, the straps can be cut off or tied just below the ring.
    5. A window can be cut or the section of stockinet can be completely removed.
    6. Once the surgery is completed the device is cut off with a supplied cutting card.

The elastic ring tourniquet follows similar recommendations noted for pneumatic tourniquet use:

  1. It should not be used on a patient's limb for more than 120 minutes.
  2. The tourniquet should not be placed on the ulnar/peroneal nerve.
  3. The silicone ring device cannot be used on patients with blood problems such as DVT, edema, etc.
  4. A patient suffering from skin lesions or a malignancy should use this type of tourniquet.[14]

See also

References

  1. ↑ McEwen, James A. US Patent No. 4,469,099, September 4, 1984, “Pneumatic Tourniquet”.
  2. ↑ McEwen, James A. US Patent No. 4,479,494, October 30, 1984, “Adaptive Pneumatic Tourniquet”.
  3. ↑ Tang, DH; Olesnicky, BT; Eby, MW; Heiskell, LE (6 December 2013). "Auto-transfusion tourniquets: the next evolution of tourniquets". Open Access Emergency Medicine 2013 (5): 29–32. doi:10.2147/OAEM.S39042.
  4. ↑ Drosos, GI; Ververidis, A; Mavropoulos, R; Vastardis, G; Tsioros, KI; Kazakos, K (September 2013). "The silicone ring tourniquet in orthopaedic operations of the extremities". Surg Technol Int 23: 251–7.
  5. ↑ Murphy CG, Winter DC, Bouchier-Hayes DJ. “Tourniquet injuries: Pathogenesis and modalities for attenuation.” Acta Orthop Belg. 2005; 71(6):635-645.
  6. ↑ Pedowitz RA, Gershuni DH, Botte MJ, et al. “The use of lower tourniquet inflation pressures in extremity surgery facilitated by curved and wide tourniquets and an integrated cuff inflation system.” Clin Orthop Relat Res. 1993; 287:237-244.
  7. 1 2 Delfi Medical Specialty tourniquets
  8. ↑ McEwen JA, Inkpen KB, Younger A. “Thigh tourniquet safety: Limb occlusion pressure measurement and a wide contoured cuff allow lower cuff pressure.” Surg Tech. 2002; 34:8-18.
  9. ↑ McEwen, James A; Jameson, Michael. US Patent No. 5,607,447, March 4, 1997, “Physiologic Tourniquet”.
  10. ↑ McEwen, James A. US Patent No. 6,361,548, March 26, 2002, “Limb Protection Sleeve for Matching Tourniquet Cuff”.
  11. ↑ McEwen JA, Kelly DL, Jardanowski T, Inkpen K. “Tourniquet safety in lower leg applications.” Orthop Nurs. 2002; 21(5):55-62.
  12. ↑ Drosos, GI; Ververidis, A; Stavropoulos, NI; Mavropoulos, R; Tripsianis, G; Kazakos, K (June 2013). "Silicone ring tourniquet versus pneumatic cuff tourniquet in carpal tunnel release: a randomized comparative study". J Orthop Traumatol 14 (2): 131–5. doi:10.1007/s10195-012-0223-x.
  13. ↑ Thompson, SM; Middleton, M; Farook, M; Cameron-Smith, A; Bone, S; Hassan, A (November 2011). "The effect of sterile versus non-sterile tourniquets on microbiological colonisation in lower limb surgery". J Ann R Coll Surg Engl 93 (8): 589–90. doi:10.1308/147870811X13137608455334.
  14. ↑ Norman, D; Greenfield, I; Ghrayeb, N; Peled, E; Dayan, L (December 2009). "Use of a new exsanguination tourniquet in internal fixation of distal radius fractures". J Orthop Traumatol 13 (4): 173–5. doi:10.1097/BTH.0b013e3181b56187.
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