A tourniquet (TQT) is a life-saving device used to stop catastrophic bleeding from a limb injury. It is reserved for severe, life-threatening situations where massive hemorrhage cannot be controlled by direct pressure or wound packing. The device functions by applying constrictive pressure to completely occlude arterial blood flow to the injured extremity. This temporary intervention buys time until professional medical care can be reached.
Criteria for Tourniquet Application
The decision to apply a tourniquet is made only for uncontrollable, life-threatening external hemorrhage from an extremity. This bleeding is typically characterized by bright red blood spurting or rapidly soaking through bandages and clothing. Hemorrhage from major arteries or deep veins warrants this measure; bleeding that is easily controlled with simple direct pressure does not.
The device is also indicated when circumstances prevent the safe application of direct pressure, such as an active threat environment, a mass casualty event, or a traumatic amputation. It is important to utilize a commercially manufactured tourniquet, as these are highly effective at achieving complete arterial occlusion. Improvised devices often fail to generate sufficient pressure and may only occlude the venous system, which can dangerously increase blood loss.
The Standard Protocol for Release
The primary answer to how often a tourniquet should be released is simple: in the standard civilian pre-hospital setting, an effectively applied tourniquet is never released by a layperson or first responder. Once secured and bleeding is stopped, it must remain in place until the patient reaches a hospital or is under the care of a physician or highly trained medical personnel. Attempts to intermittently loosen or “release” the tourniquet in the field are extremely dangerous.
Intermittent release can lead to immediate, massive re-bleeding, potentially causing irreversible shock. This action also causes reperfusion injury, where toxic metabolic byproducts built up in the ischemic limb are flushed into the central circulation. This sudden systemic shock can overwhelm the patient, potentially leading to cardiac arrest. Only in rare circumstances, such as prolonged field care (PFC) with delayed transport, will specialized medical teams consider “converting” the tourniquet. This conversion involves replacing the tourniquet with a pressure dressing or wound packing, and is only attempted once the patient is medically stable under strictly controlled conditions.
Safety Limits for Continuous Application
While a tourniquet should not be released in the field, concern exists regarding how long it can remain continuously applied before causing irreversible damage. The accepted medical threshold is that a tourniquet is safe for up to two to three hours with a low risk of permanent complications. After this time, the risk of serious injury to the limb climbs dramatically.
The primary complications from prolonged application are limb ischemia and nerve damage. Ischemia, the restriction of blood supply, depletes oxygen and nutrients in the muscle and nerve tissue. After four to six hours of continuous application, the likelihood of permanent nerve injury, muscle necrosis, and eventual amputation increases substantially. Beyond six hours, the damage is often so extensive that amputation becomes almost certain due to tissue non-viability.
Monitoring and Documentation After Application
Once a tourniquet is applied and bleeding stops, the focus shifts to patient monitoring and documentation. Effectiveness is verified by the cessation of external bleeding and confirming the absence of a distal pulse. The device must be tight enough to overcome the patient’s systolic blood pressure to stop arterial flow.
The time of application must be recorded clearly, as “time is tissue.” This time should be written directly on the tourniquet or the patient’s forehead using a permanent marker (e.g., “TQT 10:45”). The tourniquet must never be covered, ensuring medical personnel can easily see and monitor the limb for re-bleeding.