Cause of Device-Related Incident
Device factors; User errors

Clinical Specialty or Hospital Department
Anesthesia; Clinical/Biomedical Engineering; OR / Surgery; Orthopedics

Device Factors
Device failure; Improper maintenance, testing, repair, or lack or failure of incoming inspection

Document Type
Hazard Reports

External Factors
*Not stated

Mechanism of Injury or Death
Overdose

Support System Failures
*Not stated

Tampering and/or Sabotage
*Not stated

User Errors
Failure to perform pre-use inspection

UMDNS
Tourniquets, Pneumatic [14-074]; Tourniquets, Pneumatic, Automatic Rotating [10-234]

Pneumatic Tourniquets Used for Regional Anesthesia



Hazard [Health Devices Dec 1982;12(2):48-9]

Problem

In 1982, a British medical report (Health 1982) cited five deaths associated with the use of pneumatic tourniquets during administration of regional anesthesia by a technique known as intravenous regional anesthesia (IVRA) or Bier's block. At least three of these accidents were caused by personnel deflating the tourniquet prematurely. However, in some cases, equipment design and/or malfunction might have been contributing factors. We also know that tourniquet malfunction leading to accidental deflation has occurred in the United States. While nerve damage from tourniquet overinflation has long been a recognized hazard with these devices, the risks of underinflation or premature deflation (either deliberate or accidental) during regional anesthesia are not widely recognized.

Discussion

Surgical pneumatic tourniquets are frequently used on the extremities to help maintain a bloodless operative field. During operations performed with IVRA, the pneumatic tourniquet serves an additional role of preventing the infused local anesthetic from flowing out of the limb. Deflation of the tourniquet soon after venous infusion of the local anesthetic into a limb may result in the drug's entering the circulatory system in a high concentration, which can cause serious adverse reactions (e.g., cardiovascular collapse, respiratory depression, epileptic attack) or death.

IVRA is an alternative to general anesthesia for limb surgery and is typically administered by an experienced anesthesiologist; in some cases, however, the surgeon performs the anesthetizing procedure. First, blood is exsanguinated from the limb (usually by wrapping it with an elastic bandage, beginning distally and squeezing and wrapping toward the heart), and a tourniquet is inflated proximal to the operative site. The elastic bandage is removed and the local anesthetic (e.g., bupivacaine) is injected into the limb through an intravenous cannula. The local anesthetic remains in the limb as long as the tourniquet is inflated. About 20 minutes after infusion, most of the anesthetic has been absorbed into the limb tissues and deflation of the tourniquet will not result in release of the drug in high concentration.

The pneumatic tourniquet plays a vital role in the safety and success of IVRA; therefore, the tourniquet must be in good working order before use and must be closely monitored for proper pressure and operation, especially just after local anesthetic injection.

Premature tourniquet deflation may result from the intentional action of medical personnel who are not completely familiar with IVRA and its attendant risks, or may be accidental due to equipment failure. The former problem must be addressed by education; the latter, by effective equipment control, inspection, and preventive maintenance, accompanied by adequate tourniquet monitoring during the operation.

Accidental tourniquet deflation due to equipment failure may result from loose tubing connectors; deteriorated tubing (dry rot), especially over connector hose barbs; stopcock leaks; cuff bladder leaks; and worn cuff closures (e.g., Velcro-type fasteners).

Many pneumatic tourniquet cuffs contain two bladders side by side. If the patient feels excessive pain due to the high inflation pressure (up to 600 mm Hg), the second bladder is inflated. Then, the first bladder is deflated, thereby allowing the tissue beneath to recover. Even if the patient experiences no pain, the anesthesiologist may choose to alternate cuff bladders to lessen the possibility of nerve damage from compression. However, a second cuff bladder also increases the chances of equipment-related failure since additional tubing, connector, stopcocks, and cuff bladders are present. It is important that the bladders be alternated using the proper inflation/deflation sequence to ensure constant tourniquet application.

Other issues, such as the indications for use of IVRA, the comparative toxicity from sudden intravenous injection of different regional anesthetics, and emergency treatment for premature tourniquet deflation that results in a bolus of anesthetic entering the circulatory system, are discussed in the articles cited in the bibliography.

Recommendations

While the hazards of general anesthesia may be avoided by use of IVRA, this technique also carries potentially fatal risks. Surgical and anesthesiology personnel must be highly knowledgeable about the procedure and related equipment, including, particularly, the risks of premature tourniquet deflation. Inform all appropriate personnel of these recommendations.

  1. Inspect the tourniquet in the operating room before each use for IVRA for proper operation and good general condition. Check the condition of the cuff and tubing before placing the unit on the patient. The cuff should not have torn stitching, and its closure should hold firmly. The tubing should fasten securely to all connectors and be free of kinks, cracks, and deteriorated material. Similarly, tubing connectors (frequently luer taper fittings or luer locks) should mate securely.
  2. Verify that the unit maintains adequate pressure on the patient's limb before injecting the regional anesthetic.
  3. Do not leave the tourniquet unattended during the surgical procedure, especially during the first 20 minutes after infusion of the anesthetic. Although the surgeon may deliver IVRA without assistance from anesthesia personnel, once his or her attention is directed to the operative procedure, a second person should be assigned to effectively monitor and operate the pneumatic tourniquet.
  4. Be sure that the tubing that leads to the cuff from the machine is protected from accidental contact by personnel near the patient. Consider temporarily clamping the tubing leading to the inflated cuff during the period immediately following infusion of the local anesthetic. If clamping is used, place the clamp between the cuff and the first tubing connection.
  5. Tourniquets are typically inflated with air (supplied by a hand pump or from a compressed air outlet or cylinder), nitrogen (from a compressed gas cylinder), or Freon (from a disposable canister). On some pneumatic tourniquets, separate gauges are provided for supply gas pressure and cuff pressure. Personnel responsible for monitoring and/or operating the tourniquet should be especially aware of gauge functions. Be sure to monitor the cuff pressure gauge, if present, for cuff inflation pressure.
  6. When a double-bladder cuff is used, fully inflate the second bladder and confirm its ability to maintain pressure before deflating the first one.
  7. Ensure that surgical pneumatic tourniquets are included in a routine equipment inspection and preventive maintenance program. Follow the manufacturer's recommended procedures for inspection and repair. In addition, be sure to check for the problems listed in this report and in Recommendation 1.

Bibliography

We have grouped the references by subject to aid in obtaining specific information.

Background information on regional anesthesia and surgical pneumatic tourniquets

Chan KM, Ma GFY, Chow YN, et al. Intravenous regional anaesthesia in hand surgery experience with 632 cases. Hand 1981;13:193-8.

Fitzgerald B. Intravenous regional anaesthesia in children. Br J Anaesth 1976;48:485-6.

Heath ML. Deaths after intravenous regional anaesthesia. Br Med J 1982;285(Oct 2):913-4.

Inappropriate use of oxygen to inflate or power medical devices. Health Devices 1982;12(Dec):54.

Inflating surgical pneumatic tourniquets. Health Devices 1981;10(Jun):197.

McEwen JA, Auchinleck. Advances in surgical tourniquets. AORN J 1982;36(Nov):889-96.

Rawlings ID, Staniforth P. Intravenous regional anaesthesia in upper limb trauma. Injury 1979;10:231-4.

Ware RJ. Intravenous regional analgesia using bupivacaine: A double blind comparison with lignocaine. Anaesthesia 1979;34:231-5.

Wildsmith JAW. Techniques of local anaesthesia. Update 1981;22:693-702.

Complications with regional anesthesia and toxicity of anesthetics used

Albright GA. Cardiac arrest following regional anesthesia with etidocaine or bupivacaine. Anesthesiology 1979;51(Oct):285-7.

Gooding JM, Tavakoli MM, Fitzpatrick WO, et al. Bupivacaine: Preferred agent for intravenous regional anesthesia. South Med J 1981;74:1282-3.

Ware RJ, Caldwell J. Clinical and pharmacological studies of IV regional analgesia using bupivacaine. Br J Anaesth 1976;48:1124-5.

Wildsmith JAW, Tucker GT, Cooper S, et al. Plasma concentrations of local anaesthetics after interscalene brachial plexus. Br J Anaesth 1977;49:461-6.

Wildsmith JAW, Scott DHT, Brown DT. Intravenous regional analgesia using bupivacaine. Anaesthesia 1979;34:919-20.

Wildsmith JAW, Scott DHT, Scott DB. Adverse reaction to bupivacaine.

Br Med J 1980;281(Nov):1287.

Treatment of toxic reactions to regional anesthetics

Moore DC, Thompson, GE, Crawford RD. Long acting local anesthetic drugs and convulsions with hypoxia and acidosis. Anesthesiology 1982;56(Mar):230-2.

Scott DB. Toxicity caused by local anaesthetic drugs. Br J Anaesth 1981;53(Jun):553-4.

UMDNS Terms

  • Tourniquets, Pneumatic [14-074]
  • Tourniquets, Pneumatic, Automatic Rotating [10-234]

Cause of Device-Related Incident

Device factors: Device failure; Improper maintenance, testing, repair, or lack or failure of incoming inspection

User error: Failure to perform pre-use inspection

Mechanism of Injury or Death

Overdose


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