How long does blood flow to the arm have to be cut off for before losing your arm?

Preventive measures: Many rules are in place to prevent limb loss: 60 minutes is the recommended inflation time for arms & 90 minutes for legs. When recommended time limit reached, it's recommended that cuff be deflated for 15 minutes to allow re-perfusion of the arm/leg; then cuff can be reinflated for another recommended time period, eg 60/90 min. Limb should be re-exsanguinated prior to reinflation to prevent clots.