Stimuplex a

In the anesthesia preparation room, patients were monitored according to ASA standards and than sedated with midazolam (0.04 mg/Kg). An experienced anesthesiologist performed unilateral, single-injection TPVB at T5 level of the operation side with ultrasound guided (USG) in lateral position before anesthesia induction. A low-frequency convex array USG probe (2 to 5 MHz; Konica Minolta Sonimage HS1,Shanghai,China.) was placed longitudinally 2.5 cm lateral to the tip of spinous process to identify the hyperechoic image of pleura between shadows of consecutive transverse processes. Peripheral block needle (22 gauge; Stimuplex® A; B Braun, Melsungen, Germany) was advanced to the pleura using in-plane technique. After negative aspiration, downward displacement of the pleura by administration of saline was visualized on USG and then block was achieved with 20 ml of 0.375% ropivacaine. Local anesthetic distribution above pleura was checked by moving the probe up and down to confirm success of block (Fig. 1).Fig. 1

Paramidsagittal ultrasonography of T5 transverse process and thoracic paravertebral block performing figures. (A) Sonographic anatomy, (B) Needle direction, (C) Craniocaudal spread of local anesthetic

All femoral nerve blocks were performed with ultrasound guidance by anesthesiologists experienced in administering regional anesthesia. All blocks were performed in the preoperative area prior to induction of general anesthesia. Using the same previously described single-shot technique [18 (link)], the femoral nerve was located distal to the inguinal ligament under ultrasound guidance in each patient. Following sterile skin preparation, a 22- or 21-gauge needle (Stimuplex A, B. Braun Medical Inc., PA, USA) was used to administer 25–30 mL of either 0.5% or 0.1–0.125% bupivacaine with epinephrine 1:200,000 lateral to the femoral nerve in an in-plane technique. Muscle stimulators were not used. Normal saline was used for bupivacaine dilution. In addition to observing perineural spread of local anesthetic, success of the block was determined by the anesthesia team assessing tactile sensation along with the femoral nerve distribution.

The appropriate level was determined by palpating the inferior angle of the scapula to identify the approximate level of the thoracic (T) 7 level. The T5–6 level could then be ascertained relative to the T7 level by scanning in the cranial direction with ultrasound visualization. A left-sided ESP block at the T5–6 level was performed under ultrasound guidance (Sonosite S-Nerve Ultrasound System fitted with an L38 £ 10- to 5-MHz transducer; Sonosite, Inc., Bothell, WA, USA) with a 22-gauge, 2-in. stimulating needle (Stimuplex^® A; B. Braun Medical Inc., Bethlehem, PA, USA) using an in-plane technique with the needle advancing in a cranial-to-caudal direction through the erector spinae muscle until the transverse process was contacted. A total of 20 mL of 0.25% bupivacaine was administered between the transverse process and the erector spinae muscle (Figure 2). In the surgical infiltration group, 30 mL of 0.25% bupivacaine was injected into the implantation and tunneling sites before the incision. The patients in the ESP group did not receive any additional local anesthetics from the operating electrophysiologist team. Patients were administered an intravenous propofol infusion with intermittent boluses of intravenous midazolam and/or fentanyl as needed.