Upper limb fracture surgery will be performed with the aid of pneumatic tourniquet. General anesthesia will be induced with intravenous (IV) thiopental sodium and fentanyl.

Rocuronium will be used as the neuromuscular blocking agent. Endotracheal tube will be placed and anesthesia will be maintained with sevoflurane and IV fentanyl while the lungs were ventilated with O2-N2O (50-50%) to achieve an EtCO2 at 30-35 mm Hg.

Multiple injection axillary block will be performed with the aid of a nerve stimulator. When the slight twitching of the motor response from the relevant muscles is achieved (at 0.4 mA, 2Hz, 0.1 ms) % 18-20 ml of Bupivacaine 0.5 (90-100 mg) will be injected.

Upper limb fracture surgery will be performed with the aid of a pneumatic tourniquet.

The cuff (11 cm) of the tourniquet will be placed around the arm with the distal edge 5 cm above the olecranon. AOP estimation formula according to initial systolic blood pressure (SBP) and Tissue Padding Coefficient (KTP) values (AOP= [SBP+10]/KTP) from a list (Table 1) will be used to calculate AOP (17). After calculation of AOP, a safety margin of 20 mmHg will be added to AOP to determine the TP (TP=AOP+20 mm Hg). Exsanguination of the limb will be provided with an Esmarch bandage and the cuff will be inflated to the predetermined TP. TP will be manually raised in response to each 10 mmHg increase in SBP during the surgical procedure.

Initial and maximal systolic blood pressures define the systolic blood pressures measured and recorded by the patient monitor just before tourniquet inflation and during tourniquet application respectively.

Arterial occlusion pressure is the minimal tourniquet pressure required to cease arterial blood flow to the limb and calculated with AOP estimation formula according to initial SBP and Tissue Padding Coefficient (KTP) values (AOP= [SBP+10]/KTP) from a list.

Initial and maximal tourniquet pressures define first adjusted and maximal tourniquet pressures during surgery.

Tourniquet time defines the time period between the inflation and deflation of the tourniquet cuff at the beginning and end of the surgery respectively.

The quality of bloodless surgical area will be evaluated by the surgeon respect to the amount of blood using a 4-point scale (1: Excellent= No blood in the surgical field, 2: Good= Some blood in the surgical field but no interference with surgery, 3: Fair= Blood in the surgical field but no significant interference with surgery, 4: Poor= Blood in the surgical field obscures the view) at the beginning, in the middle, and at the end of the surgical procedure.