Transversus abdominis plane block, paravertebral block and postoperative analgesia in patients undergoing inguinal hernia surgery

The heart rates (3-channel electrocardiograms), noninvasive blood pressure and peripheral oxygen saturation (SpO2) of all the patients were monitored. Thirty minutes before the induction of anaesthesia midazolam (1–2 mg) was administered IV as premedication. Before spinal anaesthesia, for postoperative analgesia, Group T received TAP block under ultrasonographic guidance, and Group P underwent PVB in combination with nerve stimulation. Investigators’s prior experience with both these techniques were enough (They did at least 80 times). For the transversus abdominis plane (TAP) block, a linear ultrasound (US) probe (6–13 MHz) (Logiq book XP, GE Medical Systems, China) and an 80 mm 22 G (Uniplex Nanoline, Pajunk, Germany) needle were used. As local anaesthetic, 0.5% bupivacaine (1.5 mg/kg, diluted to 20 ml with normal saline) was preferred. For the paravertebral block (PVB), a nerve stimulator (Stimuplex (registered trademark), B. Braun AG, Melsungen, Germany) was applied at the T11–12 and the L1 vertebral levels using an 80 mm 22 G (Uniplex Nanoline) needle. The stimulator was set at 2 mA, 9 V, 2 Hz for 0.1 msec. After insertion of the needle through the skin, contractions of the paraspinous muscle occur. When the paravertebral space is entered, these contractions disappear, and they are seen in the lower abdominal and inguinal regions. In the current study, when the contractions were observed at 0.8 mA, a local anaesthetic drug (0.5% bupivacaine, 5 ml at every level) was injected. We confirmed that the blocks with the icepack test. Both block success was 100%. Then the patients were positioned in the lateral decubitus position, and the L4–L5 interspinous space was entered with a 25 G Quincke needle. Spinal anaesthesia was administered using 10–12.5 mg heavy bupivacaine + 25 microgram fentanyl. The sensory block was then evaluated using the icepack test, and the operation commenced when the PVB and TAP block extended beyond the vertebral T9 level and above. The heart rate, noninvasive blood pressure, Sp02 and VAS values were recorded during the preoperative period every 3 min for 15 min and then at 5 min intervals after the induction of spinal anaesthesia. During the postoperative period, when the level of spinal anaesthesia dropped below T10, the patients were transferred to their room. During follow-up visits in their room, their blood pressure, heart rates and VAS values were recorded at 1 and 30 min and at 1, 3, 6, 12 and 24 h. If the VAS score was between 3 and 5, 75 mg IM diclofenac sodium were injected. If it was above 5 points, this was proceeded by 75 mg IM diclofenac Na. If this was ineffective within 30 min, an additional 25 mg IM meperidine were administered. When the SpO2 dropped below 95% during the intraoperative and recovery periods, oxygen was delivered by a face mask at a rate of 2–3 L min-1. When the mean arterial pressure dropped below 65 mm Hg, 5–10 mg IV ephedrine were injected. Intraoperative and postoperative complications and the treatment modalities were recorded. The type of surgery in both groups is used Lichtenstein's tension free technique.