Effect of adding midazolam to bupivacaine during rectus sheath block: a randomised controlled trial

Primary outcomes and anticipated effect sizes in randomised clinical trials assessing adjuncts to peripheral nerve blocks: A scoping review

BACKGROUND

Prolonging effects of adjuncts to local anaesthetics in peripheral nerve blocks have been demonstrated in randomised clinical trials. The chosen primary outcome and anticipated effect size have major impact on the clinical relevance of results in these trials. This scoping review aims to provide an overview of frequently used outcomes and anticipated effect sizes in randomised trials on peripheral nerve block adjuncts.

METHODS

For our scoping review, we searched MEDLINE, Embase and CENTRAL for trials assessing effects of adjuncts for peripheral nerve blocks published in 10 major anaesthesia journals. We included randomised clinical trials assessing adjuncts for single-shot ultrasound-guided peripheral nerve blocks, regardless of the type of interventional adjunct and control group, local anaesthetic used and anatomical localization. Our primary outcome was the choice of primary outcomes and corresponding anticipated effect size used for sample size estimation. Secondary outcomes were assessor of primary outcomes, the reporting of sample size calculations and statistically significant and non-significant results related to the anticipated effect sizes.

RESULTS

Of 11,854 screened trials, we included 59. The most frequent primary outcome was duration of analgesia (35/59 trials, 59%) with absolute and relative median (interquartile range) anticipated effect sizes for adjunct versus placebo/no adjunct: 240 min (180-318) and 30% (25-40) and for adjunct versus active comparator: 210 min (180-308) and 17% (15-28). Adequate sample size calculations were reported in 78% of trials. Statistically significant results were reported for primary outcomes in 45/59 trials (76%), of which 22% did not reach the anticipated effect size.

CONCLUSION

The reported outcomes and associated anticipated effect sizes can be used in future trials on adjuncts for peripheral nerve blocks to increase methodological homogeneity.

The effect of perioperative benzodiazepine administration on postoperative nausea and vomiting: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Despite recent systematic reviews suggesting their benefit for postoperative nausea, vomiting, or both (PONV) prevention, benzodiazepines have not been incorporated into guidelines for PONV prophylaxis because of concerns about possible adverse effects. We conducted an updated meta-analysis to inform future practice guidelines.

METHODS

We included randomised controlled trials (RCTs) of all languages comparing benzodiazepines with non-benzodiazepine comparators in adults undergoing inpatient surgery. Our outcomes were postoperative nausea, vomiting, or both. We assessed risk of bias for RCTs using the Cochrane Risk of Bias tool. We pooled data using a random-effects model and assessed the quality of evidence for each outcome using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

We screened 31 413 abstracts and 950 full texts. We included 119 RCTs; 104 were included in quantitative synthesis. Based on moderate certainty evidence, we found that perioperative benzodiazepine administration reduced the incidence of PONV (52 studies, n=5086, relative risk [RR]: 0.77, 95% confidence interval [CI] 0.66-0.89; number needed to treat [NNT] 16; moderate certainty), postoperative nausea (55 studies, n=5916, RR: 0.72, 95% CI 0.62-0.83; NNT 21; moderate certainty), and postoperative vomiting (52 studies, n=5909, RR: 0.74, 95% CI 0.60-0.91; NNT 55; moderate certainty).

CONCLUSIONS

Moderate quality evidence shows that perioperative benzodiazepine administration decreases the incidence of PONV. The results of this systematic review and meta-analysis will inform future clinical practice guidelines.

SYSTEMATIC REVIEW PROTOCOL

The protocol for this systematic review was pre-registered with PROSPERO International Prospective Register of Systematic Reviews (CRD42022361088) and published in BMJ Open (PMID 31831540).

Analgesic efficacy of Clonidine as an adjuvant in ultrasound-guided rectus sheath block for midline incisional hernia repair - A randomized double-blind controlled trial

Background and Aims

Clonidine as an adjuvant has not been evaluated in rectus sheath block (RSB) for postoperative pain management in incisional hernia repair. The study aims to evaluate clonidine as an adjuvant in single-shot RSB along with general anesthesia (GA).

Material and Methods

This randomized, double-blind controlled study was conducted following IEC-Human approval and written informed consent from 30 patients of either sex, aged 16 to 60 years, ASA physical status I or II undergoing midline incisional hernia repair under GA. All patients received ultrasound-guided bilateral RSB following administration of GA. The subjects enrolled in the study were randomly allocated to receive either normal saline 1 mL (group B) or clonidine 1 μg/kg diluted to 1 mL with normal saline (group BC) as adjuvant along with 9 mL bupivacaine hydrochloride 0.25%. Inj. tramadol 1 mg/kg was administered for rescue analgesia. The primary outcome was the time to first request for analgesia, and secondary outcomes were total consumption of rescue analgesic over 24 h, numerical rating score (NRS), patients' satisfaction, hemodynamics, and side effects. Unpaired t-test and Chi-square test were used.

Results

On intergroup analysis, the mean time to first request for analgesia (in min) was significantly higher in group BC i.e., [9.60 (± 5.23) vs 5.33 (± 3.53); (P < 0.034]; whereas, the mean rescue analgesic consumption in 24 h (in mg) was higher in group B i.e., [(88.00 ± 60.97) vs (46.00 ± 48.08)]; (P < 0.045)]. Hemodynamic parameters i.e., mean blood pressure and heart rate were comparable between the two groups, and there were no side effects.

Conclusion

Clonidine as an adjuvant in single-shot ultasonography (USG)-guided RSB along with GA is efficacious for postoperative pain management following midline incisional hernia repair.

Efficacy of Adding Midazolam to Bupivacaine for Transversus Abdominis Plane Block on Postoperative Analgesia after Hysterectomy: A Randomized Controlled Study

Background and Aim:

Different adjuncts have been utilized to promote the quality and prolong the duration of local anesthetics for a variety of regional block techniques. This study aimed to assess the effects of midazolam coadministered with bupivacaine in transversus abdominis plane (TAP) block on the 24-h morphine consumption, the postoperative analgesia duration and adverse effects.

Settings and Design:

A prospective, randomized, controlled double-blind trial that was carried out at a university hospital.

Patients and Methods:

Eighty-two females subjected to open total abdominal hysterectomy under general anesthesia were involved in this trial. Participants were allocated randomly to either of two groups (41 each). Control group: received TAP block with 20 mL of 0.25% bupivacaine or midazolam group: received TAP block using the same volume of bupivacaine plus 50 μg/kg midazolam/side. Postoperative cumulative 24-h morphine consumption, analgesia duration, pain score, sedation score, and adverse events were recorded.

Statistical Analysis:

Student's t-test, Mann–Whitney U-test, and Chi-square test were used.

Results:

Patients in the midazolam group had a lower cumulative 24-h morphine consumption [median doses (interquartile range): 15 (10–19.50) mg compared to 25 (17.50–37) mg, P < 0.001], lower postoperative pain score at rest at the 4^th, 6^th, and 12^th h (P = 0.01, 0.02, and 0.02, respectively) and on movement at 2, 4, 6, and 12 h (P < 0.001), longer time till the first postoperative demand for rescue analgesia (430.11 ± 63.02 min) compared to 327.78 ± 61.99 min (P < 0.001), and less sedation, nausea and/or vomiting, and pruritus.

Conclusions:

Adding midazolam as a bupivacaine adjuvant for TAP block reduces the 24-h morphine consumption, extends the postoperative analgesia duration, and decreases the incidence of adverse effects following abdominal hysterectomy.