never
Once you apply a tourniquet, you should never loosen it until you are ready to remove it.
never
Only qualified medical personnel should loosen a tourniquet once it has been applied. The reason for this is because the cells of the body part that has been cut off from blood flow continue to perform metabolism to live, but use anaerobic metabolism, which produces toxic byproducts. If these byproducts accumulate and are released back into the body, they can cause heart arrhythmias. This is why tourniquets are used as a last resort, and it is why they should never be removed once applied, except by someone who has been trained to do so.
Daily
When applying the Combat Application Tourniquet (CAT), it should be tightened until the bleeding stops, typically requiring you to turn the windlass rod until the blood flow is controlled. You should not loosen the tourniquet once it is applied; doing so can lead to renewed bleeding. The CAT is designed for single-use, and if bleeding persists, a second tourniquet can be applied above the first. Always monitor the casualty for signs of shock and seek immediate medical assistance.
what is the maximum amount of time a tourniquet should left on
According to CLSI the tourniquet should not be left on for more than a minute. If a suitable vein has not been found, remove the tourniquet, leave it off for two minutes, then reapply the tourniquet to look for suitable veins and/or perform the venipuncture.
A tourniquet should not be removed at all. Tourniquets are a LAST RESORT method. They are hard to apply, they cause a lot of pain, and they can lead to the loss of any limb below wherever the tourniquet was applied. However, if the choice is your LIFE or your LIMB, choose the life. Apply the tourniquet and tighten it until the bleeding stops. Secure the stick to make sure the tourniquet does not loosen and DO NOT TOUCH IT. Get the victim to a hospital immediately. Once there, the doctors and nurses are trained in how to remove tourniquets and treat the wounds. If you leave a tourniquet on too long, the person might lose their arm/leg/whatever. If you take it off too soon, they can easily bleed to death.
Modern medicine frowns on any use of tourniquets. Unless its for phlebotomy purposes. Applying pressure is a much better method.
At the wrist.
I most cases a tourniquet should not be taken off once applied until the patient is in a surgical setting with a trauma physician.
what is the maximum amount of time a tourniquet should left on