The role of regional anaesthesia techniques in the management of acute pain

Ultrasound-Guided Subclavian Perivascular Brachial Plexus Block Using 0.5% Bupivacaine with Dexmedetomidine as an Adjuvant: A Prospective Randomized Controlled Trial

Background:

Ultrasound guidance has dramatically improved the accuracy of nerve localization, and various adjuvants prolong the block and extend analgesia.

Aims:

This study aimed to evaluate the effects of dexmedetomidine added to 0.5% bupivacaine on the onset and duration of motor and sensory blockade and the duration of analgesia.

Settings and Design:

This is a prospective, randomized double-blind, study.

Materials and Methods:

Sixty adult patients aged 20–60 years of either sex undergoing orthopedic procedures on the forearm were randomly allocated into two groups of thirty each: Group BS (bupivacaine + saline) and Group BD (bupivacaine + dexmedetomidine). All patients were administered subclavian perivascular brachial plexus block under ultrasound guidance. Group BS: Patients in this group were administered 20-mL 0.5% bupivacaine + 0.75-mL saline. Group BD: Patients in this group were administered 20-mL 0.5% bupivacaine + 0.75-mL dexmedetomidine (75 μg).

Statistical Analysis:

Statistical analysis was performed with IBM SPSS software Version 21.0. Quantitative data were expressed as mean ± standard deviation. Independent sample t-test was used for comparisons between the two groups. P < 0.05 was considered statistically significant.

Results:

Demographic data and surgical characteristics were similar in both groups. The onset times for sensory and motor blocks were statistically significantly shorter in Group BD compared to Group BS (P < 0.01), whereas the duration of blocks and analgesia were statistically significantly longer (P < 0.01) in Group BD.

Conclusion:

The addition of dexmedetomidine to 0.5% bupivacaine for supraclavicular brachial plexus block shortens the onset time and prolongs both the duration of the block and analgesia.

The Effect of Rectus Sheath Block as a Supplement of General Anesthesia on Postoperative Analgesia in Adult Patient Undergoing Umbilical Hernia Repair

BACKGROUND

Ultrasound guided rectus sheath block can block the ventral rami of the 7th to 12th thoracolumbar nerves by injection of local anesthetic into the space between the rectus muscle and posterior rectus sheath. The aim of this randomized double-blind study was to evaluate the analgesic effect of the bilateral ultrasound guided rectus sheath block as supplement of general anesthesia on patents undergoing elective umbilical hernia repair.

METHODS

After the hospital ethics committee approval, 60 (ASA I-II) adult patients scheduled for umbilical hernia repair were included in this study. The group I (n=30) patents received only general anesthesia. In the group II (n = 30) patents after induction of general anesthesia received a bilateral ultrasound guided rectus sheath block with 40 ml of 0.25% bupivacaine. In this study we assessed demographic and clinical characteristics, pain score - VAS at rest at 2, 4, 6, 12 and 24 hours after operation and total analgesic consumption of morphine dose over 24-hours.

RESULTS

There were statistically significant differences in VAS scores between the groups I and II at all postoperative time points - 2hr, 4 hr, 6 hr, 12 hr and 24 hr. (P < 0.00001). The cumulative 24 hours morphine consumption after the operation was significantly lower in the group II (mean = 3.73 ± 1. 41) than the group I (mean = 8.76 ± 2.41). This difference was statistically significant (p = 0.00076).

CONCLUSION

The ultrasound guided rectus sheath block used for umbilical hernia repair could reduce postoperative pain scores and the amount of morphine consumption in 24 hours postoperative period.

Reducing postoperative opioid consumption by adding an ultrasound-guided rectus sheath block to multimodal analgesia for abdominal cancer surgery with midline incision

Background:

Many multimodal analgesia techniques have been tried to provide adequate analgesia for midline incisions extending above and below the umbilicus aiming at limiting the perioperative use of morphine thus limiting side effects. Ultrasound (US) guidance made the anesthesiologist reconsider old techniques for wider clinical use. The rectus sheath block (RSB) is a useful technique under-utilized in the adult population.

Objectives:

Our study examined the efficacy of a preemptive single-injection rectus sheath block in providing better early postoperative pain scores compared to general anesthesia alone.

Patients and Methods:

Sixty patients were recruited in this randomized controlled trial. These patients were divided into two groups: RSB group had an RSB after induction of anesthesia and before surgical incision, and GA (general anesthesia) group had general anesthesia alone. Both groups were compared for verbal analogue scale (VAS) score, opioid consumption and hemodynamic variables in the post-anesthesia care unit (PACU). Analgesic requirements in surgical wards were recorded in postoperative days (POD) 0, 1 and 2.

Results:

The median VAS score was significantly lower in RSB group compared with GA group in all 5 time points in the PACU (P ˂ 0.05). Also PACU morphine consumption was lower in RSB group than GA group patients (95% confidence interval [CI] of the difference in means between groups, −4.59 to −2.23 mg). Morphine consumption was also less in the first 2 postoperative days (POD0 and POD1).

Conclusions:

Ultrasound-guided rectus sheath block is an easy technique to learn. This technique, when it is used with general anesthesia, will be more effective in reducing pain scores and opioid consumption compared with general anesthesia alone.

Posterior tibial nerve sensory blockade duration prolonged by adding dexmedetomidine to ropivacaine

BACKGROUND

Dexmedetomidine, an α(2)-receptor agonist, prolongs analgesia when used in neuraxial and IV blocks. We evaluated the effect of dexmedetomidine added to ropivacaine for tibial nerve block on the duration of the sensory blockade.

METHODS

For this prospective, randomized, controlled, double-blind, crossover trial, 14 healthy volunteers were allocated to 2 groups. All volunteers received an ultrasound-guided tibial nerve block 4 to 5 cm proximally to the medial malleolus. In group R, 10 mL of 0.5% ropivacaine was injected for the block; in group RD, 10 mL of a solution containing 0.5% ropivacaine with 1 μg/kg of dexmedetomidine was administered. After the injection, monitoring of vital signs, evaluation of onset and resolution of sensory block, and level of sedation (Observer's Assessment of Alertness/Sedation scale) were performed. Three weeks later, the same procedure was repeated, but the study subjects were allocated to the other group in a crossover fashion. The primary end point was the duration of sensory blockade. The time and carryover effects were also evaluated. Secondary outcomes were the onset time and the presence of adverse effects such as hypotension, bradycardia, hypoxia, and sedation.

RESULTS

Sensory blocks lasted longer in group RD than in group R (21.5 vs 16.2 hours; mean pairwise difference 5.3 hours [95% confidence interval: 3.9-6.7 hours]; P < 0.0001). Onset times were similar between groups. The mean systolic and diastolic blood pressure levels were stable throughout the study period in group R. In group RD, a noticeable decrease in systolic and diastolic blood pressure was observed between 60 and 480 minutes (P < 0.05); 2 volunteers experienced a 30% decrease in systolic blood pressure when compared with the baseline value as compared with none in group R. Heart rate was similar between groups except at 60 minutes (P < 0.01).

CONCLUSION

Dexmedetomidine added to ropivacaine for tibial nerve block prolongs the duration of sensory blockade with similar onset time. However, patients should be monitored for potential adverse effects such as hypotension, bradycardia, and sedation.