Tourniquet time < 2 h is considered safe
The general conclusion is that a tourniquet can be left in place for 2 h with little risk of permanent ischemic injury. However, the majority of the literature looks at pneumatic tourniquets in elective theatre cases with normovolemic patients. In hypovolemic trauma patients with non‐pneumatic tourniquets these figures may not be applicable.
There is very little data on the complication rate of clinically indicated pre‐hospital tourniquet application and therefore there is no safe tourniquet time. One study identified that 5.5% of 110 pre‐hospital tourniquet applications resulted in neurological complications, with an ischemic time between 109–187 min. None of these resulted in limb loss. The mean ischemic time for use of a tourniquet with no complications was 78 minutes.
From PHTLS 8th Ed...