How Long Can a Tourniquet Be Left On?

Many people are afraid of applying a tourniquet to control bleeding because they think it will lead to limb amputation, but knowing the timeframe for tourniquet use can reassure civilians that—when applied correctly—the benefits far outweigh the risks.

How long can a tourniquet be left on?

  • Ambulance response time in the United States: 6-30 minutes
  • Average application time with no complications from a tourniquet: 78 minutes
  • Time until permanent muscle damage occurs: 2 hours
  • Time until muscle damage is complete: 6 hours

In most cases, the injured person will arrive at the hospital long before the tourniquet does any damage.

Tourniquets Should Not Be Left On for More than 2 Hours

Medical journals recommend 2 hours as the time limit for tourniquet application—after which muscle injury, vascular injury (including compartment syndrome), nerve damage, and skin necrosis may be permanent. However, most of the studies cited apply to pneumatic tourniquets used during extremity surgery on normovolemic subjects—not windlass tourniquets applied in a pre-hospital setting to people experiencing significant blood loss.

A battlefield study, published by Lakstein et al., provides real data on pre-hospital tourniquet applications (using a silicone or improvised tourniquet rather than a pneumatic tourniquet). In this study, 5.5% of 110 pre-hospital tourniquets led to neurological complications, all of which were applied for between 109 and 187 minutes. None of the affected limbs required amputation. The mean time for tourniquet application with no complications in this study was 78 minutes.

After 6 hours, muscle damage is complete with likely required amputation. For this reason, it's extremely important to keep the tourniquet visible, note the time of application in a visible place, and get the victim to a hospital (via ambulance or private transportation) as soon as possible.

Emergency Medical Services Usually Arrive in 15 Minutes

Realistically, emergency medical services arrive in far less time than it would take to sustain a permanent ischemic injury (an injury caused by a lack of blood supply). According to 2015 data, ambulances in the United States typically reach urban patients in 7 minutes, suburban patients in 7.7 minutes, and rural patients in 14.5 minutes. Around 10% of the rural patients included in the data waited for nearly 30 minutes before an ambulance arrived—this is still far shorter than the 2-hour timeframe it would take for a tourniquet to damage an injured limb.

If you or someone near you experiences gunshot wounds or stab wounds or is involved in an accident, you should call 911 immediately, apply direct pressure to the wound, and—if the bleeding doesn't slow significantly—apply a tourniquet. 

After the bleeding stops, make sure the tourniquet is tightly secured and visible (don't cover it with clothing), and write the time of tourniquet application on the tourniquet or on the person's forehead with a black marker: "T: TIME." When the paramedics arrive, inform them that the patient has a tourniquet and the time it was applied. Then, leave the rest to the professionals.

Tips for Reducing the Risks

Call 911 or Head Straight to the Emergency Room

As soon as you become injured or witness an injury, call 911 or have someone call 911, get a bleeding control kit, and apply measures to stop the bleed. If there is an emergency department nearby, stabilize the bleed and go directly to the hospital. Tourniquet application is essential for preventing deaths due to traumatic blood loss in the first few minutes following a laceration or crushed limb. 

In fact, survival is six times higher for patients with peripheral vascular injuries or blunt trauma to the extremities when pre-hospital tourniquets are applied by a layperson. However, tourniquets are only a temporary measure, and the patient should be taken to the hospital as soon as possible following application.

Try Applying Direct Pressure First

In many cases, a tourniquet application isn't needed. If the blood flow is moderate (i.e. the blood is not squirting out), apply direct pressure first and see whether the bleeding stops after a few minutes. 

Hemostatic gauze can be particularly effective for promoting clotting in a wound but should never be used on the head (where it could touch the brain) or the eye. Of course, in cases of partial or complete limb amputation or where the affected limb is entrapped, the best course of action is to apply a tourniquet right away.

Use a Commercial Tourniquet, If Available

To stop bleeding from a limb, commercial tourniquets or improvised tourniquets can be used. There are several reasons why it's best to use commercial tourniquets:

  • Commercial tourniquets are the correct width to stop blood flow without injuring the skin. An improvised tourniquet is much more likely to cause damage to the muscles and skin and less likely to be effective at occluding arterial blood flow.
  • Commercial tourniquets have straps to tie the windlass securely in place. Improvised tourniquets can become loose, leading to further bleeding and death if they are not retightened.
  • The windlass on a commercial tourniquet is strong and won't break. Needless to say, a broken windlass renders any tourniquet ineffective, leading to more bleeding as mentioned above.
  • Many commercial tourniquets have white space for noting the time of application, making it unnecessary to write directly on the patient's skin. However, in a life-threatening emergency, it's better to write on a patient with a marker than for them to die from blood loss or lose their limb.

Keep the Tourniquet Tight

Tourniquets prevent extreme blood loss by cutting off the blood supply to a wound. This is referred to as "occlusion." If the tourniquet isn't tight enough, it won't stop the arterial blood flow and the patient is at risk of death. Lay rescuers sometimes loosen a tourniquet because they are afraid of the loss of the limb or because the patient is in a lot of pain. In reality, neither of these concerns should be placed above the survival of the patient. Keep the tourniquet tight.

Write Down the Time of Tourniquet Application

It's been stated before, but it's worth stating again. Write down the time of tourniquet application in a visible place on the patient. A tourniquet should only ever be left on for "too long" because the nearest hospital is a long distance away—not because the medical professionals have no idea when the tourniquet was applied, or worse still, have no idea that one was applied at all!

Don't Remove the Tourniquet Yourself

Removing the tourniquet for any reason can cause rebleeding and death. Leave the tourniquet on and leave the rest to the medical personnel. In some cases, the bleeding may slow down after 2 hours and a medical professional will apply a pressure dressing in place of the tourniquet. In other cases, an advanced technique such as surgery will be required to stop the bleed. Once the patient is safely in the hospital, a much wider range of treatments will be available to stabilize the bleeding. Your job is simply to keep them alive until they get there.

If You Can't Get to a Hospital in 2 Hours

In some rare cases, such as while traveling abroad, you may be too far from a hospital to get there in 2 hours. To protect the limb, keep it elevated and cool it to help slow inflammation and muscle damage. Call for a rescue helicopter, if available. If you are a trained, experienced medical professional, you can loosen the tourniquet and try replacing it with a pressure dressing instead, replacing the tourniquet if the bleeding continues. This is referred to as a “last resort tourniquet.” Untrained rescuers should leave the tourniquet on and try to get the patient to a hospital as close to the two-hour mark as possible.

The Benefits Usually Outweigh the Risks

Knowing how long a tourniquet can be left on (2 hours or less) should give you the confidence that this technique is generally low-risk and effective for stopping bleeding that doesn't respond to direct pressure. 

As long as you call emergency services right away, apply the tourniquet correctly, and write down the time of application, the tourniquet should keep the patient alive until they can receive comprehensive care.

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