Daily Anesthesiology Research Analysis
Three anesthesiology-focused studies stand out today. A Bayesian network meta-analysis identifies dexmedetomidine plus melatonin as the most effective pharmacologic strategy to prevent postoperative delirium after cardiac surgery. Two randomized trials refine regional anesthesia practice: mixing lidocaine with ropivacaine shortens block duration without speeding onset, and a modified serratus anterior plane block improves early analgesia and pulmonary function after VATS.
Summary
Three anesthesiology-focused studies stand out today. A Bayesian network meta-analysis identifies dexmedetomidine plus melatonin as the most effective pharmacologic strategy to prevent postoperative delirium after cardiac surgery. Two randomized trials refine regional anesthesia practice: mixing lidocaine with ropivacaine shortens block duration without speeding onset, and a modified serratus anterior plane block improves early analgesia and pulmonary function after VATS.
Research Themes
- Postoperative delirium prevention in cardiac surgery
- Optimization of regional anesthesia drug mixtures
- Thoracic surgery analgesia and pulmonary recovery
Selected Articles
1. Effect of peri-operative pharmacological interventions on postoperative delirium in patients having cardiac surgery: a systematic review and Bayesian network meta-analysis.
Across 79 RCTs (24,827 patients), dexmedetomidine plus melatonin ranked best for preventing postoperative delirium after cardiac surgery (RR 0.31 vs placebo) and was associated with shorter ICU and hospital stays. Other agents showed inconsistent signals with low to very low certainty, emphasizing the need for confirmatory trials.
Impact: This network meta-analysis synthesizes the largest RCT evidence base to date and provides an actionable regimen (dexmedetomidine plus melatonin) for delirium prevention in a high-risk surgical population.
Clinical Implications: Consider incorporating dexmedetomidine with adjunctive melatonin for high-risk cardiac surgery patients within multimodal delirium prevention pathways, while monitoring for bradycardia/hypotension and acknowledging the low certainty of evidence.
Key Findings
- Across 79 RCTs (n=24,827), dexmedetomidine plus melatonin reduced postoperative delirium versus placebo (RR 0.31, 95%CrI 0.13–0.69).
- The combination was associated with shorter ICU stay (~2.4 days decrease; 95%CrI −3.50 to −1.10) and hospital stay (~1.32 days decrease; 95%CrI −2.09 to −0.57).
- Other agents (e.g., ketamine, risperidone) showed possible benefit but with low/very low certainty; overall certainty of evidence was low.
Methodological Strengths
- Comprehensive Bayesian network meta-analysis with SUCRA ranking across 79 RCTs
- Sensitivity analyses and GRADE assessment to appraise robustness and certainty
Limitations
- Overall low certainty of evidence and heterogeneity across trials and interventions
- Potential publication bias and variable delirium assessment methods across RCTs
Future Directions: Head-to-head, adequately powered RCTs testing dexmedetomidine plus melatonin versus standard care and versus dexmedetomidine alone, with standardized delirium assessments and safety endpoints.
INTRODUCTION: Postoperative delirium is a common complication following cardiac surgery. Despite its known impact on patient outcomes, effective preventative strategies remain elusive. We aimed to perform a comprehensive Bayesian network meta-analysis of randomised controlled trials assessing the effect of pharmacological interventions on the incidence of postoperative delirium. METHODS: Databases were searched from inception to September 2024. Our search was updated in January 2025. Eligible studies included randomised controlled trials reporting the incidence of postoperative delirium in patients having cardiac surgery treated with pharmacological interventions. Bayesian models were used to estimate risk ratios (RR) and mean differences with 95%CrI through Markov chain Monte Carlo. Interventions were ranked using the surface under the cumulative ranking curve. Sensitivity analyses and grading of recommendations, assessment, development and evaluation assessment were conducted to evaluate the robustness and certainty of evidence. RESULTS: Seventy-nine randomised controlled trials comprising 24,827 patients were included, with 29 pharmacological interventions compared. Dexmedetomidine combined with melatonin was the most effective intervention, reducing the incidence of postoperative delirium compared with placebo (risk ratio 0.31, 95%CrI 0.13-0.69; low certainty). Dexmedetomidine with melatonin also significantly decreased intensive care unit stay (2.4 days, 95%CrI -3.50-1.10) and hospital stay (1.32 days, 95%CrI -2.09 to -0.57). Other interventions, including ketamine and risperidone, showed potential efficacy but with low or very low certainty of evidence. DISCUSSION: We identified dexmedetomidine with melatonin as the most effective pharmacological strategy for preventing postoperative delirium following cardiac surgery. Whilst these findings highlight potential benefits, the low certainty of evidence underscores the need for more high-quality primary evidence.
2. The effect of combining lidocaine and ropivacaine on the duration and onset time of an ultrasound-guided infraclavicular brachial plexus nerve block: A randomised controlled trial.
In a blinded randomized trial of 78 patients receiving lateral infraclavicular blocks, adding lidocaine-epinephrine to ropivacaine shortened analgesia by 177–311 minutes without improving sensory onset (17–18 minutes across groups). The duration penalty was independent of the ropivacaine dose.
Impact: This pragmatic RCT directly challenges a common regional anesthesia practice of mixing short- and long-acting local anesthetics to hasten onset, showing no onset benefit and a clinically meaningful reduction in block duration.
Clinical Implications: Avoid mixing lidocaine with ropivacaine when prolonged postoperative analgesia is desired for infraclavicular blocks; consider pure long-acting local anesthetic or alternative adjuvants if duration is critical.
Key Findings
- Analgesia duration was 847 min with ropivacaine 150 mg vs 536 min (−311 min) with ropivacaine 100 mg + lidocaine-epinephrine and 671 min (−177 min) with ropivacaine 150 mg + lidocaine-epinephrine.
- Sensory onset times were similar across all groups (17–18 minutes), indicating no onset advantage from adding lidocaine-epinephrine.
- The shortening of duration occurred irrespective of ropivacaine dose, suggesting a class effect of the mixture.
Methodological Strengths
- Randomized, blinded, active-controlled superiority design with prespecified outcomes
- ClinicalTrials.gov registration and appropriate statistical comparisons with CIs
Limitations
- Single-center study focused on lateral infraclavicular block limits generalizability to other blocks
- Adverse events, motor block characteristics, and rebound pain were not primary outcomes
Future Directions: Evaluate mixtures across different peripheral nerve blocks, quantify motor block and rebound pain, and test alternative adjuvants that preserve duration while optimizing onset.
BACKGROUND: The combination of short- and long-acting local anaesthetics is traditionally associated with reduced block duration, though evidence remains inconsistent. OBJECTIVES: To investigate the effects of a fixed or reduced dose of a long-acting local anaesthetic (ropivacaine) mixed with a short-acting agent (lidocaine-epinephrine) on duration of analgesia and sensory onset time in lateral infraclavicular blocks. DESIGN: Randomised, blinded, active-controlled superiority trial. SETTING: A tertiary hospital in the Capital Region of Denmark, from 18 April to 23 November 2024. PATIENTS: Seventy-eight patients undergoing hand surgery under lateral infraclavicular brachial plexus nerve block. INTERVENTION: Patients were allocated to three groups: R150: 30 ml ropivacaine 5 mg ml -1 , R100-L200: 20 ml ropivacaine 5 mg ml -1 + 10 ml lidocaine-epinephrine 20 mg ml -1 + 5 μg ml -1 and R150-L200: 20 ml ropivacaine 7.5 mg ml -1 + 10 ml lidocaine-epinephrine 20 mg ml -1 + 5 μg ml -1 . MAIN OUTCOME MEASURES: The primary outcome was duration of analgesia, and secondary outcomes included sensory onset time. RESULTS: The duration of analgesia was 847 (152) min in the R150 group, 536 (198) min in the R100-L200 group, and 671 (234) min in the R150-L200 group. Compared with that in the R150 group, the mean duration of analgesia was reduced by 311 min (95% confidence interval [CI], 212 to 411; P < 0.001) in the R100-L200 group and by 177 min (95% CI, 64 to 289; P = 0.003) in the R150-L200 group. The difference between the R100-L200 and R150-L200 groups was not statistically significant after adjustment for multiple testing (135 min; 95% CI, 13 to 257; P = 0.031). Sensory onset times ranged insignificantly from 17 to 18 min across groups. CONCLUSION: Mixing lidocaine-epinephrine with ropivacaine significantly shortened the duration of analgesia by up to 5 h without affecting the sensory onset time. This effect was independent of the ropivacaine dose. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT06381622.
3. Ultrasound-guided modified versus conventional serratus anterior plane block as a preemptive analgesic for unilateral video-assisted thoracoscopic surgery.
Among 99 VATS patients randomized to no block, conventional SAP, or a modified SAP technique, the modified approach yielded the lowest 24-hour tramadol use, longest time to rescue, and superior early (first 8 hours) respiratory function. Early pain scores favored both block techniques vs control, with the modified block lowest at 8 hours.
Impact: Provides randomized evidence that a modified serratus anterior plane technique improves analgesic efficiency and early pulmonary recovery versus the conventional approach, informing ERAS-thoracic pathways.
Clinical Implications: For VATS, consider the modified SAP technique to reduce opioid consumption and support early respiratory recovery; ensure competency in the modified sonographic approach and integrate within multimodal analgesia.
Key Findings
- Modified SAP (MSAP) led to the lowest 24-hour tramadol consumption and the longest time to first rescue analgesia versus conventional SAP and no block.
- Early postoperative pain scores (2–6 h) were lower in both block groups vs control; at 8 h, MSAP had the lowest VAS.
- MSAP yielded the best respiratory function in the first 8 postoperative hours; intraoperative HR/MAP were higher in control vs both block groups.
Methodological Strengths
- Prospective randomized three-arm design including an active comparator and control
- Objective assessment of early postoperative respiratory function alongside analgesic outcomes
Limitations
- Single-center study; blinding status not clearly described
- Short follow-up (primarily first 24 hours) limits assessment of longer-term outcomes
Future Directions: Multicenter, blinded RCTs comparing MSAP vs CSAP with standardized motor/sensory mapping, opioid-sparing endpoints, and longer-term pulmonary outcomes.
PURPOSE: Various approaches to serratus anterior plane (SAP) block have been discussed in the literature. The present study aimed to compare the analgesic efficacy and postoperative pulmonary function recovery of modified serratus anterior plane block (MSAP) and conventional serratus anterior plane block (CSAP) in patients undergoing video-assisted thoracoscopic surgery (VATS). METHODS: A total of 99 patients who underwent thoracoscopic surgery were randomly divided into three equal groups: a control group (C group) that received no block, a CSAP group that received preoperative conventional serratus anterior plane block, and an MSAP group that received preoperative modified serratus anterior plane block. The primary outcome was the first 24-hour tramadol consumption. The secondary outcomes were first-time-to-rescue analgesia, postoperative visual analogue score (VAS), postoperative respiratory function, and perioperative hemodynamics. RESULTS: The lowest tramadol consumption and longest time to first rescue analgesia were observed in the MSAP group. The postoperative VAS score at 2, 4, and 6 h was significantly greater in the control group, but it was comparable between the two block groups. At 8 h, the VAS score was the lowest in the MSAP group. At 12, 16, and 24 h, the VAS scores were comparable among the three groups. The MSAP group presented the best respiratory function during the first postoperative 8 h. Heart rate and mean arterial blood pressure were similar in both block groups but were greater in the control group during the intraoperative period. CONCLUSION: The modified serratus anterior plane block is more efficient than the conventional serratus anterior plane block at reducing opioid consumption, prolonging rescue analgesic time, and improving pulmonary function recovery in patients undergoing video-assisted thoracoscopic surgery. TRIAL REGISTRATION: This clinical trial was approved by the Zagazig University Institutional Review Board (IRB #10060/30-10-2022), was first submitted to clinical trials.gov on 1/12/2022 and was subsequently registered retrospectively on 22/12/2022 (NCT05661253). The first research participant was enrolled on 2/12/2022.