© Copyright, 2014, J.A. McEwen
Last updated December 2014

Why is the inspection and testing of tourniquet cuffs, tubing and connectors important?

Leakage of pressurized gas from the tourniquet cuff, from pneumatic tubing between the instrument and cuff, and from connectors that attach the tubing to the cuff and instrument may affect tourniquet safety, performance, and reliability. Accordingly, the 2009 Recommended Practices for the Use of the Pneumatic Tourniquet in the Perioperative Practice Setting (RPs) of the (US) Association of periOperative Nurses (AORN) recommend that the tourniquet cuff, tubing, and connectors should be kept clean and in good working order. The AORN RPs further recommend, based on published literature, that the tourniquet cuff, tubing and connectors should be inspected for cracks and leaks because unintentional pressure loss can result from loose tubing connectors, deteriorated tubing, or cuff bladder leaks, and may result in patient injury [1]. At present, such inspections and checking are performed manually and often inconsistently, or only after a hazardous incident or patient injury has occurred.

To best comply with the 2009 AORN Recommended Practices regarding inspection and checking of tourniquet cuffs, connectors, and tubing, their pneumatic integrity should be routinely checked between surgical procedures and surgical staff should be alerted to any potential hazards found so that remedial action can be taken promptly. If this is not done, then leaking and potentially hazardous tourniquet cuffs, connectors, and tubing may be used for surgery, and may remain in use for long periods of time. Also, users may not be alerted to defects which may be small initially but which may increase to become significant hazards for patients, either slowly or very rapidly. Additionally, unauthorized reprocessing and reuse of cuffs manufactured to be single-use disposable cuffs may introduce leakage hazards if such cuffs are not carefully inspected before each reuse, or after each reuse, because improper, uncontrolled and unlimited reprocessing may impair the shape and integrity of the pneumatic seals of cuff connectors. Even if disposable tourniquet cuffs are used as single-use products, and if it is assumed that such cuffs are not leaking at time of first use, the tubing and connectors that connect the disposable cuffs to the tourniquet instrument may leak and such leakage may go undetected, allowing the leaking tubing or connectors to remain in use until an obvious patient hazard or injury occurs, and during which time other limitations in tourniquet safety, performance and reliability are produced.

Pneumatic leakage in tourniquet systems that is not detected by routine inspections and checking is undesirable in surgery and may be hazardous. Undetected pneumatic leakage may lead users to set tourniquet pressures at levels that are substantially higher than required physiologically, to compensate for intraoperative reductions in cuff pressure that users had observed but had not been able to attribute to obvious leakage. However, setting tourniquet pressures to unnecessarily high levels is hazardous because, in the medical literature, higher tourniquet pressure levels have been associated with higher probabilities of patient injuries to nerves and soft tissues[2-4].

Some surgical tourniquet systems have attempted to compensate for undetected levels of pneumatic leakage in the design of their pressure regulators. In typical systems, the pressure regulator is designed to maintain cuff pressure within a predetermined pressure range from a reference pressure, and any fluctuations beyond that range are offset by actuation of a pump, reservoir, or valve in an effort to bring the cuff pressure back within the range. If there is pneumatic leakage sufficient to cause the cuff pressure to decrease beyond the predetermined pressure range, actuation of the pressure regulator may bring it back within range, and if not a pressure-regulation alarm is produced. In some cases, such systems may compensate for significant levels of sustained, undetected leakage without producing any indication of leakage or alarm for the user. Further, sustained leakage may produce an error in the indicated tourniquet cuff pressure in single-port tourniquet systems which estimate cuff pressure by measuring pneumatic pressure within the tourniquet instrument

For typical surgical tourniquet systems, three limitations in the performance and reliability of their pressure regulators exist in the presence of undetected pneumatic leakage. First, tourniquet cuff pressure fluctuates unnecessarily as decreases in cuff pressure are offset by the actuations of the pressure regulator. Second, unnecessarily frequent actuation of the pressure regulator reduces the operational life and reliability of its mechanical components, increases the cost of maintaining and replacing those components, and may increase capital costs by necessitating early replacement of the entire tourniquet instrument. Third, operation of tourniquet systems on battery power is impaired. Typical tourniquet systems may be powered either by external AC power or by an internal battery, so that they can continue to operate safely in the event of a sudden interruption of external power, and independently of external AC power for a prolonged period of time, for example during transportation of a patient from a preoperative room to the operating room, or to facilitate surgery under emergency or battlefield conditions. However, in the presence of sustained leakage pneumatic leakage, the operational time of a tourniquet system when powered by an internal battery for surgery may be substantially reduced due to unnecessary actuations of the pressure regulator. Additionally, the overall life of the internal battery may be significantly reduced, reducing the performance and reliability of the tourniquet system and thereby increasing costs and hazards.

In an effort to overcome these limitations, some of the most modern surgical tourniquet systems have included technology to automatically check the integrity of all pneumatic components prior to each use, or after each use, and to alert users to possible hazards identified by such checking.

References for educational viewing only

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  [1] AORN. Recommended Practices for the Use of the Pneumatic Tourniquet in the Perioperative Practice Setting, Ass’n of periOperative Registered Nurses, 2009.

[2] Ochoa J, et al. "Anatomical changes in peripheral nerves compressed by a pneumatic tourniquet". Journal of Anatomy. 113 (1972): 433-455.

[3] Gilliatt R and Ochoa J. The cause of nerve damage in acute compression. Trans Am Neurol Ass 1974: 99: 71-4.

[4] Shaw J and Murray D. The relationship between tourniquet pressure and underlying soft tissue pressure in the thigh. J Bone Joint Surg 1982: 64A(8):1148-52.

© Copyright, 2014, J.A. McEwen
Last updated December 2014
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