The effects of anesthetic technique and ambient temperature on thermoregulation in lower extremity surgery

patients were divided into three groups according to their applied anesthesia technique: Group EA (epidural anesthesia, n=30) and Group FS (femoral sciatic block, n=30). Then, these groups were divided into two each based on the ambient temperature of the operating room, which was either 20-22 degrees C or 23-25 degrees C. The final distribution of the patients into four subgroups is as follows: Group EA I = patients undergoing epidural anesthesia (EA) (n=15) with a surgical room temperature (RT) of 20-22 degrees C, Group EA II = patients undergoing EA (n=15) with a surgical RT of 23-25 degrees C, Group FS I = patients undergoing femoral sciatic block (FS) (n=15) with a surgical RT of 20-22 degreesC, and Group FS II = patients undergoing FS (n=15) with a surgical RT of 23-25 degrees C. After the skin was cleaned with antiseptic solution, the EA group patients were seated and locally anesthetized by 2 ml 2% lidocaine subcutaneous infiltration at the L4-5 level in the midline skin. Epidural anesthesia was performed by using a 16 G Touhy needle according to the loss of resistance technique. After reaching the epidural space, an 18 G epidural catheter was inserted through a Touhy needle and directed towards the head. After the absence of intravascular and intrathecal area was assessed by negative aspiration, the catheter tip was placed 3-4 cm within the epidural space. Three ml of 2% lidocaine was given as a test dose and waited for 5 minutes. After receiving a negative response to the test dose, 10-20 ml of 0.5% levobupivacaine and 50 micro g fentanyl was administered. Three L/min oxygen was given to patients with a facemask. The level of sensory block was checked in 5-minute intervals by the Pinprick test, and additional doses were administered as needed. Patients with the sensory block degree up to T10 were included in the study, but patients who developed higher levels of sensory block were excluded. Patients in Group FS were applied a sciatic block by using the classical Labat technique. After patients were placed at a lateral decubitus position, the posterior superior iliac spine and trochanter major were localized and marked. The vertical medial line was drawn in the middle of the line connecting those two points and the injection point was determined to be 4 cm along this line. After the area was cleaned with antiseptic solutions and covered, 1 ml of 2% lidocaine was injected subcutaneously to create local anesthesia at the injection point. The block, together with the nerve stimulator (Stimuplex HNS 11, Braun Freiburg, Germany), was made with a 150 mm block needle entering vertical to the skin. The initial current of the nerve stimulator was set to 1.5-2 mA, and after the plantar or dorsal flexion was obtained, the current was reduced to 0.3-0.5 mA. After a negative aspiration test was observed, 25 ml of 0.375% levobupivacaine solution was injected. The patient was laid in the supine position for the femoral block and the inguinal ligament was determined by drawing a line connecting the to the anterior superior spine iliac and lateral corner of simfisis pubis. An injection point was marked 2 cm lateral to the pulse of the femoral artery and 2 cm distal to the inguinal ligament line. The area was cleaned with an antiseptic solution and wraped with a sterile. An eighty-mm-long nerve block needle was connected to the nerve stimulator and was forwarded in the cranial direction parallel to the femoral artery at an angle 30-40° to the skin surface. The needle was forwarded until quadriceps femoris muscle contractions and patella movements were seen. Then, the stimulation current intensity was reduced to 0.3-0.5 mA and was followed by observance of negative aspiration, after which a 20 ml 0.375% levobupivacaine solution was injected.