Secure the windlass by tying one or both ends to the victim's arm or leg.
If possible, mark the time the tourniquet was placed by putting a "T" on the victim's forehead with the time/day.
For more information on when to properly use tourniquets, read Understanding Tourniquets.
Source:
Beebe, Richard, and Deborah Funk. Fundamentals of Emergency Care. 2001. Delmar.


