Effect of Position Change After Induction of Spinal Anesthesia with Hyperbaric 0.5% Bupivacaine on Duration of Analgesia and Opioid Demand in Percutaneous Nephrolithotomy Candidates

Abstract

Background: Post-induction positioning influences the onset speed of the sensory block by affecting anesthetic distribution. Techniques such as using opioids and extending recovery stays aim to enhance this process. Objectives: This study aimed to evaluate the impact of transitioning patients from a sitting to a lateral position immediately after the induction of 0.5% hyperbaric bupivacaine spinal anesthesia on postoperative pain and opioid consumption. Methods: In this prospective, randomized clinical trial, patients scheduled for percutaneous nephrolithotomy (PCNL) under spinal anesthesia at Shahid Labafinejad Hospital in 2023 were divided into intervention (lateral position) and control (supine position) groups. Blood pressure, mean arterial pressure (MAP), and heart rate were recorded upon entering recovery, then every 10 minutes up to 60 minutes, and every 15 minutes up to 120 minutes post-operation. Pain levels were assessed using the Visual Analogue Scale (VAS) at specified intervals. Patient satisfaction with analgesia quality was also evaluated. Results: The study included 35 patients in the lateral group and 34 in the supine group. Pain levels significantly differed between the groups over time (P = 0.0001). The lateral group had a longer analgesia duration (28.8 ± 10.0 minutes vs. 22.9 ± 2.9 minutes, P = 0.105) and lower total narcotic consumption (21.7 ± 5.8 mg vs. 30.4 ± 10.2 mg, P = 0.012). Mean arterial pressure changes showed no significant difference (P = 0.061). Patient satisfaction was significantly higher in the lateral group (P = 0.0001). Conclusions: Transitioning from the sitting to lateral position post-induction with hyperbaric bupivacaine enhances hemodynamic stability, improves drug distribution in the cerebrospinal fluid (CSF), and enhances sensory block quality. This approach increases postoperative analgesia duration, reduces opioid use and related complications, and decreases the duration of surgery.