Comparative effectiveness of different opioid-free anesthesia regimens in patients with obesity (BMI ≥ 35 kg/m²): impact on respiratory outcomes, awakening time, and safety (narrative review)

The objective was to compare the effectiveness of different opioid-free anesthesia (OFA) regimens, including combinations with regional and fascial blocks, on respiratory outcomes, emergence time, and safety profile in patients with obesity (BMI ≥ 35 kg/m²).

Materials and methods. A literature search was conducted in PubMed/MEDLINE, Cochrane CENTRAL, Embase, Web of Science, and eLibrary/ RSCI (January 2014 – January 2026). RCTs, prospective observational studies, systematic reviews, and meta-analyses evaluating (1) diaphragmatic dysfunction, (2) spirometric parameters and desaturation, (3) awakening and extubation time, (4) bradycardia and hemodynamic stability, (5) and quality of recovery were included. Inclusion criteria: adults with BMI > 35 kg/m², bariatric and/or laparoscopic abdominal surgery, use of OFA ± regional anesthesia. Additionally, two studies, not limited to the obese population, were included to analyze the safety of dexmedetomidine (H. Beloeil et al. 2021) and bolus administration strategies (M. Xiong et al. 2025), with appropriate interpretation reservations.

Results. Eleven RCTs in the target population, 1 prospective observational cohort study (NOS 7/9), and 2 additional RCTs on mixed/general surgical populations (total n = 1385) were analyzed. Quantitative data from 3 systematic reviews/meta-analyses were used for evidence synthesis on bradycardia and comparative effectiveness of regional techniques. ESP block reduced postoperative diaphragmatic dysfunction (PODD) from 73% to 10% (OR 0.04; 95% CI 0.01–0.16; p < 0.001) based on a single RCT. Emergence time increased by 3–7 min with standard dexmedetomidine infusion (≥ 0,5 mkg∙kg^–1∙h^–1), but was not prolonged with bolus-only administration. Dexmedetomidine-induced bradycardia was dose-dependent: RR 2.81 (95% CI 1.34–5.91) at doses ≥ 0.7 μg/kg. The QLB block (blockage of the quadriceps muscle) provides the longest duration of analgesia with minimal effect on hemodynamics.

Conclusion. Based on limited evidence, a potentially promising OFA regimen for obese patients at high respiratory risk may include low-dose dexmedetomidine (bolus 0.5–0.6 mcg / kg without subsequent infusion), esketamine, lidocaine, and ESP or QLB block. This expert recommendation requires prospective validation. Large multicenter RCTs with primary respiratory endpoints are warranted.

1. Neimark M. I., Kiselev R. V. Mul’timodal’naya anal’geziya v bariatricheskoi khirurgii. Regionarnaya anesteziya i lechenie ostroi boli, 2016, vol. 10, no. 4, pp. 254–261. http://doi.org/10.18821/1993-6508-2016-10-4-254-261. (In Russ.).

2. Epshtein S. L., Azarova T. M., Storozhev V. Yu. et al. Obshchaya anesteziya bez opioidov v khirurgii morbidnogo ozhireniya. Zachem i kak? Regionarnaya anesteziya i lechenie ostroi boli, 2016, vol. 10, no. 1, pp. 47–54. http://doi.org/10.18821/1993-6508-2016-10-1-47-54. (In Russ.).

3. Baethge C., Goldbeck-Wood S., Mertens S. SANRA – a scale for the quality assessment of narrative review articles // Res Integr Peer Rev. – 2019. – Vol. 4. – Art. 5. http://doi.org/10.1186/s41073-019-0064-8.

4. Beloeil H., Garot M., Lebuffe G. et al. Balanced opioid-free anesthesia with dexmedetomidine versus balanced anesthesia with remifentanil for major or intermediate noncardiac surgery. The Postoperative and Opioid-free Anesthesia (POFA) Randomized Clinical Trial // Anesthesiology. – 2021. – Vol. 134, № 4. – P. 541–551. http://doi.org/10.1097/ALN.0000000000003725.

5. Bhardwaj S., Garg K., Devgan S. et al. Comparison of opioid-based and opioid-free TIVA for laparoscopic urological procedures in obese patients // J Anaesthesiol Clin Pharmacol. – 2019. – Vol. 35, № 4. – P. 481–486. http://doi.org/10.4103/joacp.JOACP_42_19.

6. Clanet M. M., Touihri K., El Haddad C. et al. Effect of opioid-free versus opioid-based strategies during multimodal anaesthesia on postoperative morphine consumption after bariatric surgery: a randomised double-blind clinical trial // BJA Open. – 2024. – Vol. 9. – Art. 100263. http://doi.org/10.1016/j.bjao.2024.100263.

7. Dagher C., Mattar R., Aoun M. et al. Opioid-free anesthesia in bariatric surgery: a prospective randomized controlled trial // Eur J Med Res. – 2025. – Vol. 30. – Art. 320. http://doi.org/10.1186/s40001-025-02565-9.

8. De Cassai A., Boscolo A., Geraldini F. et al. Regional anesthesia techniques for bariatric and metabolic surgery: a narrative review // Curr Opin Anaesthesiol. – 2025. – Vol. 38, № 5. – P. 574–582. http://doi.org/10.1097/ACO.0000000000001482.

9. De Cassai A., Geraldini F., Sella N. et al. Regional anesthesia for bariatric and metabolic surgery: a network meta-analysis // Obes Surg. – 2023. – Vol. 33, № 9. – P. 2687–2694. http://doi.org/10.1007/s11695-023-06737-6.

10. De Cassai A., Sella N., Geraldini F. et al. Preoperative dexmedetomidine and intraoperative bradycardia in laparoscopic cholecystectomy: a meta-analysis with trial sequential analysis // Korean J Anesthesiol. – 2022. – Vol. 75, № 3. – P. 245–254. http://doi.org/10.4097/kja.21359.

11. Feenstra M. L., Jansen S. A. M., Smeeing D. P. J. et al. Opioid-free versus opioid-based anesthesia for adults undergoing surgery: a systematic review and meta-analysis // J Clin Anesth. – 2023. – Vol. 90. – Art. 111215. http://doi.org/10.1016/j.jclinane.2023.111215.

12. Gao M. H., Li J., Zhang Y. X. et al. Bradycardia in opioid-free general anesthesia: a systematic review and meta-analysis // Signa Vitae. – 2024. – Vol. 20, № 7. – P. 10–18. http://doi.org/10.22514/sv.2024.050.

13. Helmy M. A., Mostafa M. S., Saber A. T. et al. Erector spinae plane block and its impact on postoperative diaphragmatic dysfunction in morbidly obese patients undergoing laparoscopic sleeve gastrectomy: a double-blind randomized control trial // Obes Surg. – 2025. – Vol. 35, № 12. – P. 5228–5236. http://doi.org/10.1007/s11695-025-08337-y.

14. Hung K. C., Wu S. C., Hu J. C. et al. Impact of opioid-free anesthesia on analgesia and recovery following bariatric surgery: a meta-analysis of randomized controlled studies // Obes Surg. – 2022. – Vol. 32, № 10. – P. 3113–3124. http://doi.org/10.1007/s11695-022-06213-7.

15. Ibrahim M., Elnabtity A. M., Hegab A. et al. Combined opioid free and loco-regional anaesthesia enhances the quality of recovery in sleeve gastrectomy done under ERAS protocol: a randomized controlled trial // BMC Anesthesiol. – 2022. – Vol. 22, № 1. – Art. 29. http://doi.org/10.1186/s12871-021-01561-w.

16. Karaveli A., Kaplan S., Kavakli A. S. et al. The effect of ultrasound-guided erector spinae plane block on postoperative opioid consumption and respiratory recovery in laparoscopic sleeve gastrectomy: a randomized controlled study // Obes Surg. – 2025. – Vol. 35, № 1. – P. 112–121. http://doi.org/10.1007/s11695-024-07576-9.

17. Mieszczanski P. P., Górniewski G., Ziemiański P. et al. Comparison between multimodal and intraoperative opioid free anesthesia for laparoscopic sleeve gastrectomy: a prospective, randomized study // Sci Rep. – 2023. – Vol. 13, № 1. – Art. 12677. http://doi.org/10.1038/s41598-023-39856-2.

18. Mieszczanski P. P., Kołacz M., Trzebicki J. Opioid-free anesthesia in bariatric surgery: is it the one and only? A comprehensive review of the current literature // Healthcare (Basel). – 2024. – Vol. 12, № 11. – Art. 1094. http://doi.org/10.3390/healthcare12111094.

19. Mistry T., Nair A. S. Opioid-free anaesthesia: a meta-analytic mirage or a methodological misstep? // J Anesth Analg Crit Care. – 2025. – Vol. 5. – Art. 69. http://doi.org/10.1186/s44158-025-00300-8.

20. Mostafa S. F., Abdelghany M. S., Abu Elyazed M. M. Ultrasound-guided erector spinae plane block in patients undergoing laparoscopic bariatric surgery: a prospective randomized controlled trial // Pain Pract. – 2021. – Vol. 21, № 4. – P. 445–453. http://doi.org/10.1111/papr.12975.

21. Mulier J. P., Wouters R., Dillemans B. et al. A randomized controlled, double-blind trial evaluating the effect of opioid-free versus opioid general anaesthesia on postoperative pain and discomfort measured by the QoR-40 // J Clin Anesth Pain Med. – 2018. – Vol. 2, № 6. – 015.

22. Myles P. S., Myles D. B., Galagher W. et al. Minimal clinically important difference for three quality of recovery scales // Anesthesiology. – 2016. – Vol. 125, № 1. – P. 39–45. http://doi.org/10.1097/ALN.0000000000001158.

23. Olausson A., Svensson C. J., Andrell P. et al. Total opioid-free general anaesthesia can improve postoperative outcomes after surgery, without evidence of adverse effects on patient safety and pain management: a systematic review and meta-analysis // Acta Anaesthesiol Scand. – 2022. – Vol. 66, № 2. – P. 170–185. http://doi.org/10.1111/aas.13994.

24. Page M. J., McKenzie J. E., Bossuyt P. M. et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews // BMJ. – 2021. – Vol. 372. – Art. n71. http://doi.org/10.1136/bmj.n71.

25. Pershad A., Elvir Lazo O. L., Wong R. Opioid-free anesthesia: a scoping review of efficacy, safety, and implementation challenges // Front Anesthesiol. – 2025. – Vol. 4. – Art. 1714040. http://doi.org/10.3389/fanes.2025.1714040.

26. Song B., Li Y., Zhang X. et al. Effect of opioid-free versus opioid anesthesia on the quality of recovery in obese patients undergoing laparoscopic bariatric surgery: a randomized controlled trial // Obes Surg. – 2025. – Vol. 35, № 8. – P. 3120–3130. http://doi.org/10.1007/s11695-025-08008-y.

27. Stenberg E., Dos Reis Falcão L. F., O’Kane M. et al. Guidelines for perioperative care in bariatric surgery: Enhanced Recovery After Surgery (ERAS) Society recommendations: a 2021 update // World J Surg. – 2022. – Vol. 46, № 4. – P. 729–751. http://doi.org/10.1007/s00268-021-06394-9.

28. Tripodi V. F., Trovato G., Cardia L. et al. Effectiveness and safety of opioid-free anesthesia compared with opioid-based anesthesia in adult surgery: a systematic review with meta-analysis and trial sequential analysis // J Anesth Analg Crit Care. – 2025. – Vol. 5, № 1. – Art. 53. http://doi.org/10.1186/s44158-025-00272-9.

29. Ulbing S., Infanger L., Fleischmann E. et al. The performance of opioid-free anesthesia for bariatric surgery in clinical practice // Obes Surg. – 2023. – Vol. 33, № 6. – P. 1687–1693. http://doi.org/10.1007/s11695-023-06584-5.

30. Xiong M., Liu Y., Liang Y. et al. Opioid-free versus opioid-sparing anesthesia for postoperative pain and early recovery after laparoscopic cholecystectomy: a randomized controlled trial // J Pain Res. – 2025. – Vol. 18. – P. 2137–2146. http://doi.org/10.2147/JPR.S506147.

31. Xu Y., Zhong M., Li S. Opioid-free anesthesia in enhanced recovery after surgery for gastrointestinal surgery: current status, challenges, and prospects // Front Pharmacol. – 2025. – Vol. 16. – Art. 1662818. http://doi.org/10.3389/fphar.2025.1662818.

32. Zhao X., Xue Q., Dong L. et al. Effects of peripheral neural blocks in laparoscopic sleeve gastrectomy on cognitive recovery and inflammation markers // Obes Surg. – 2023. – Vol. 33, № 3. – P. 912–920. http://doi.org/10.1007/s11695-022-06319-y.

33. Ziemann-Gimmel P., Goldfarb A. A., Koppman J. et al. Opioid-free total intravenous anaesthesia reduces postoperative nausea and vomiting in bariatric surgery beyond triple prophylaxis // Br J Anaesth. – 2014. – Vol. 112, № 5. – P. 906–911. http://doi.org/10.1093/bja/aet551.