Skip to main content

The influence of dexmedetomidine added to ropivacaine for transversus abdominis plane block on perioperative neurocognitive disorders after radical colorectal cancer surgery: randomized, double-blind, controlled trial

Abstract

Objective

Perioperative Neurocognitive Disorders (PND) is a common neurological complication after radical colorectal cancer surgery, which increases adverse outcomes. So, our objective is to explore the influence of dexmedetomidine added to ropivacaine for transversus abdominis plane block (TAPB) on perioperative neurocognitive disorders, and to provide a new way to reduce the incidence of PND.

Methods

One hundred and eighty patients submitted to radical laparoscopic colorectal cancer surgery were randomly divided into Control group and Dex group. Ultrasound guided TAPB was performed after anesthesia induction: 0.5% ropivacaine 20 ml was injected into each transversus abdominis plane in Control group, 0.5% ropivacaine + 1 μg/kg dexmedetomidine (amounting to 20 ml) in Dex group. We observed the incidence of PND within 30 days after surgery.

Results

One hundred and sixty-nine cases were finally analyzed, including 84 cases in Control group and 85 cases in Dex group. Compared with Control group, there was no significant difference in terms of the incidence of PND on the 3rd day and the 7th day (P > 0.05), but the incidence significantly decreased at the 6th hour, at the 24th hour and on the 30th day after surgery (P < 0.05) in Dex group.

Conclusion

Dexmedetomidine added to ropivacaine for TAPB can reduce the incidence of PND in the first 24 h after surgery and on the 30th postoperative day, which may be related to reduce the consumption of general anesthetics and provide satisfactory postoperative analgesia.

Trial registration

29 /05/ 2021, ChiCTR2100046876.

Peer Review reports

Background

Colorectal cancer is the second leading cause of cancer death in the United States, and radical resection is the most commonly used and effective procedure for it [1]. Patients often suffer from perioperative neurocognitive disorders(PND) after this procedure, which increases morbidity, mortality and the economic burden. PND was known as postoperative cognitive dysfunction(POCD) previously [2], which is related to age, general anesthetic, surgery and postoperative pain [3,4,5,6]. At present, there is no effective treatment for PND. Previous studies have shown that nerve block or dexmedetomidine can significantly reduce the incidence of PND [7, 8]. Therefore, we speculate that the combination of nerve block and dexmedetomidine may confer greater efficacy in preventing PND. Professor Brummett [9] found that dexmedetomidine added to ropivacaine for perineural nerve block can prolong the duration of analgesia and enhance the analgesic efficacy of ropivacaine. So, we wondered whether this effect is the possible mechanism that reduce the incidence of PND. Transversus Abdominis Plane Block (TAPB) is a new regional nerve block which is beneficial to the analgesia of abdominal surgery [10, 11]. Therefore, we designed this randomized, double-blinded and controlled trial to explore the influence of dexmedetomidine added to ropivacaine for transversus abdominis plane block on perioperative neurocognitive disorders after radical colorectal cancer surgery. If our hypothesis is substantiated by scientific inquiry, this approach will effectively mitigate the incidence of PND and the adverse outcomes of PND.

Methods

Sample size calculation

We used software PASS15.0 to calculate the sample size: 1-β = 0.9, α = 0.05. According to our preliminary experiment, we hypothesized the difference between Control group and Dex group as 17%, The incidence of PND in Dex group was 10%. A total of 172 patients were required. But some patients may not successfully complete the study. Taking this into account, the total number of patients were 180.

Participants

This research was approved by the Ethics Committee of The Second People's Hospital of Yibin City. We used software SAS 9.4® to generate random numbers. One hundred and eighty patients submitted to laparoscopic radical resection of colorectal cancer were randomly divided into Control group (n = 90) and DEX group (n = 90) before surgery by the random numbers.

All patients signed informed consent. Briefly, we enrolled patients at the age of 60 years old or above, whose Barthel Index [12] (A tool to assess activities of daily living) scored 95 or above. We excluded patients if they were drug users, or who had regular binge drinking history (within three months), or diagnosed with cognitive dysfunction or mental disabilities. We also excluded participants if they were diagnosed with coagulation dysfunction and diabetes. All eligible patients were performed bilateral TAPB with ultrasound guided after induction by the same anesthesiologist who didn’t participate in data collection. We announced the withdrawal of participants who were operated less than 2 h, or turned to laparotomy operation during the surgery, or transferred to intensive care unit (ICU) after surgery.

Data collection

Baselines: age, body weight, body mass index (BMI), sex, education background, and The Mini-Mental State Examination (MMSE) [13] score were obtained before surgery. Primary outcomes: the incidence of PND, which was assessed by MMSE at the 6th hour, at the 24th hour, on the 3rd day, on the 7th day and on the 30th day after surgery. Comparing with the MMSE scores before operation, if the figure decreased by more than 2 points [14], the patient shall be diagnosed with PND. Secondary outcomes: Intraoperative information (duration of operation and anesthesia, consumption of general anesthetics, fluid intake, urine and blood loss), Visual Analog pain scores (VAS) in the rest at the 6th hour, at the 24th hour, on the 3rd day, and on the 7th day after surgery. All data were collected by a blind investigator who did not know the intervention.

Intervention

All participants, prepared preoperative fasting according to the guidelines [15], were randomly divided into Control group and Dex group by the random numbers. Both two groups of the participants were performed anaesthesia induction with the same proposal before being performed TAPB: sufentanil 0.30 μg·kg−1, midazolam 0.04 mg·kg−1, cisatracurium 0.15 mg·kg−1 and etomidate 0.20 mg·kg−1. We used lateral approach [16] with ultrasound technology to implement bilateral TAPB (Fig. 1).The only difference between the two groups was the local anesthetics of TAPB: 0.5% ropivacaine 20 ml was injected into each transversus abdominis plane in Control group, while 0.5% ropivacaine + 1 μg/kg dexmedetomidine (amounting to 20 ml) in Dex group. The remifentanil (0.05 ~ 0.3 μg·kg−1·min−1) and propofol (2 ~ 6 mg·kg−1·min−1) were continuously intravenously pumped to maintain anesthesia depth (Bispectral Index 40 ~ 60). Cisatracurium was administered (0.10 ~ 0.15 mg·kg−1·h−1) to maintain satisfactory muscle relaxation. Vasoactive drugs were used to maintain intraoperative blood pressure and heart rate fluctuations within about 20% of the participants’ baseline. The surgeon closed the incision with stitches were regarded as the operation is finished. Patients were sent back to the ward after surgery, and were given 100 mg tramadol intravenously for analgesia on time according to the degree of postoperative pain within 7 days after surgery.

Fig. 1
figure 1

EO, externus obliquus abdominis. IO, internus obliquus abdominis. TA, Transversus abdominis

Statistical analysis

Statistical software SPSS 19.0 and Graphpad Prism7.0 were used to describe and analyze the statistical results. Data were described by mean ± standard deviation (‾x ± s), median and range interquartile(IQR). T-tests, Chi-square test and Wilcoxon rank sum test were used to analyze the differences between the two groups. A value of P < 0.05 was considered a significant difference.

Results

Baseline characteristics

One hundred and eighty patients were enrolled in this trial from January 2022 to December 2022. 4 cases had the surgical process converted to laparotomy, 2 cases discontinued the surgical process due to the tumor extensive abdominal metastasis, and 5 cases were sent to intensive care unit. So, 169 cases (84 cases in Control group and 85 cases in Dex group) finally completed this study (Fig. 2).

Fig. 2
figure 2

The flowchart of the trial. TAPB, Transversus Abdominis Plane Block

There were no significant baseline differences between those two groups (Table 1).

Table 1 Comparison of basic conditions before surgery

Intra-operative findings

There were no significant differences in operation types, operation and anesthesia duration, fluid intake, urine volume and blood loss between the two groups (P > 0.05). However, the consumption of propofol and remifentanil in Dex group was significantly lower than that in Control group ((1.22 ± 0.42) g vs. (0.82 ± 0.33) g, (1.48 ± 0.60) mg vs. (1.17 ± 0.40) mg, P < 0.05) (Table 2).

Table 2 Comparison of intra-operative findings

Postoperative situation

Postoperative pain

There was no significant difference in the VAS pain scores between the two groups on the 3rd day and the 7th day after surgery (P>0.05), while the VAS pain scores of Dex group at the 6th hour and the 24th hour after surgery were significantly lower than those of Control group (P<0.05) (Fig. 3). Analgesia frequency within 7days after surgery were significantly lower than that in Control group (P<0.05) (Table 3).

Fig. 3
figure 3

Visual analog pain scores (VAS) at rest after surgery. *There was a statistically significant difference between the two groups (P < 0.05)

Table 3 Visual analog pain scores (VAS) and analgesia frequency after surgery

Primary outcome: the incidence of PND

There were some patients in both groups suffering from PND within 30 days after surgery. In terms of the incidence of PND, compared with the Control group, there was no significant difference on the 3rd day and the 7th day (P > 0.05), but significantly decreased at the 6th hour, on the 24th day and the 30th day after surgery in Dex group (17.9%vs.7.1%, 14.3% vs. 4.7%, 11.9% vs. 3.5%, P < 0.05)(Table 4).

Table 4 The incidence of PND in different time after surgery

Discussion

Perioperative Neurocognitive Disorders (PND) is a common neurological complication after surgery and anesthesia, which mainly manifests as cognitive impairment. Some researchers have found that intraoperative general anesthesia may impair neurocognitive function [3, 17]. Therefore, it is our goal to reduce the consumption of general anesthetics as much as possible. In our study, there were three kinds of differences between the two groups: the consumptions of general anesthetics (propofol and remifentanil) during operation, the degree of postoperative pain and analgesia frequency, and the incidence of PND.

Firstly, the consumptions of propofol and remifentanil in the Dex group were significantly lower than that in the Control group (Table 2). We shared professor Brummett’s view [9] that dexmedetomidine added to ropivacaine for TAPB before surgery enhanced the analgesic efficacy of ropivacaine which helped to reduce the consumptions of propofol and opioid. Another reason we speculated was that the dexmedetomidine in the Dex group might be slowly absorbed into blood to produce analgesic and sedative effects. And these effects were more enduring than those caused by dexmedetomidine used continuously intravenously pumping. But it was our conjecture, we required further dynamic monitoring of the concentration of dexmedetomidine in the blood and compared the effects of dexmedetomidine used in different ways on analgesia. Secondly, VAS pain scores and analgesia frequencies of the Dex group were significantly lower than those of the Control group overall (Fig. 3, Table 3). Several studies concluded that dexmedetomidine added to ropivacaine achieved better local anaesthesia and it would not cause any major side effects in patients undergoing abdomen operation [18, 19]. And finally, the incidence of PND in the Dex group was significantly lower than that in the Control group (Table 4). We analyzed the possible reasons as follows: Reducing the consumptions of propofol and remifentanil. At present, some scholars believe that opiates play an important role in the occurrence of PND [20, 21]. However, the mechanism is still unclear. At the same time, the effect of propofol on postoperative cognitive function remains controversial. Laalou et al. [22] suggest that propofol can maintain natural sleep–wake cycle which may be beneficial to reduce postoperative neurocognitive damage. But another opinion [23] is that propofol has the potential to induce postoperative neurocognitive damage. So, we need further researches to confirm these findings. Pain. Pain and PND are closely linked through complex relationship. This relationship is relevant to the central and peripheral nervous system and cholinergic neuron. painful conditions activate the central and peripheral nervous system. And then the nervous system releases inflammatory factors, such as bradykinins, interleukins, tumor necrosis factor-α and prostaglandins, which may cause changes in cognitive function [24, 25]. The effect of dexmedetomidine. Dexmedetomidine as a α2-adrenergic agonist has good analgesic and sedative effects. At present, a large number of reports have proved that dexmedetomidine, as a maintenance agent for general anesthesia, can reduce the incidence of postoperative cognitive dysfunction (POCD) in patients undergoing cardiac surgery and non-cardiac surgery [26, 27]. In the end, we found that it is worth noticing that the differences in the incidence of PND between the two groups were mainly shown at 6th hour, at 24th hour and on the 30th day after surgery. The differences observed in the early postoperative period were primarily attributed to variations in the intensity of postoperative pain and the effectiveness of TAPB analgesia. Postoperative pain in patients undergoing abdominal surgery mainly occurs at the 8th hour to the 16th hour after surgery, while dexmedetomidine added to ropivacaine has sensory block durations of 505.1 ± 113.9 min [28]. On the 30th day after surgery, the incidence of PND showed a difference again. The exercise and mood [29] of patient after surgery may make a difference in neurocognitive function. In addition, patients might review the contents of the MMSE scale, which could influence the result. therefore, we should take more factors into account in our further study.

Limitation

First, this study was implemented in a single center. There are some shortcomings such as small sample size and narrow population coverage. One single-center experiment is prone to Berkson's bias. Besides, in terms of patients, it is thoughtless to compare the difference in type of operation (laparoscopic radical resection of colon cancer and laparoscopic radical resection). The stage of colorectal cancer should be taken into account. The stage of tumor significantly affects the postoperative complication rate, which may bring different mood. Depressed mood [29] may exert an influence on neurocognitive function. In order to resolve these problems, we need more samples, specify the stage of tumor and organize multicenter studies in our further study.

Conclusion

Our single-center randomized controlled study shows that dexmedetomidine added to ropivacaine for TAPB can reduce the incidence of PND in the first 24 h after surgery and on the 30th postoperative day, which may be related to reduce the consumption of general anesthetics and provide satisfactory postoperative analgesia.

Availability of data and materials

The datasets used and analysed during the current study are available from the corresponding author on reasonable request.

Abbreviations

BMI:

Body mass index

ICU:

Intensive care unit

MMSE:

Mini-Mental State Examination

PND:

Perioperative neurocognitive disorders

POCD:

Postoperative cognitive dysfunction

TAPB:

Transversus abdominis plane block

VAS:

Visual analog pain scores

References

  1. Benson AB, Venook AP, Al-Hawary MM, Azad N, Chen YJ, Ciombor KK, Cohen S, Cooper HS, Deming D, Garrido-Laguna I, Grem JL, Gunn A, Hecht JR, Hoffe S, Hubbard J, Hunt S, Jeck W, Johung KL, Kirilcuk N, Krishnamurthi S, Maratt JK, Messersmith WA, Meyerhardt J, Miller ED, Mulcahy MF, Nurkin S, Overman MJ, Parikh A, Patel H, Pedersen K, Saltz L, Schneider C, Shibata D, Skibber JM, Sofocleous CT, Stotsky-Himelfarb E, Tavakkoli A, Willett CG, Gregory K, Gurski L. ectal Cancer, Version 2.2022, NCCN clinical practice guidelines in oncology. J Natl Compr Canc Netw. 2022;20(10):1139–67.

    Article  CAS  PubMed  Google Scholar 

  2. Evered L, Silbert B, Knopman DS, et al. Recommendations for the nomenclature of cognitive change associated with anaesthesia and surgery-2018. Br J Anaesth. 2018;121(5):1005–12.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Belrose JC, Noppens RR. Anesthesiology and cognitive impairment: a narrative review of current clinical literature. BMC Anesthesiol. 2019;19(1):241.

    Article  PubMed  PubMed Central  Google Scholar 

  4. Kapoor P, Chen L, Saripella A, Waseem R, Nagappa M, Wong J, Riazi S, Gold D, Tang-Wai DF, Englesakis M, Norman R, Sinha SK, Chung F. Prevalence of preoperative cognitive impairment in older surgical patients.: A systematic review and meta-analysis. J Clin Anesth. 2022;76:110574. https://doi.org/10.1016/j.jclinane.2021.110574. Epub 2021 Nov 5. PMID: 34749047.

    Article  PubMed  Google Scholar 

  5. Kok WF, Koerts J, Tucha O, et al. Neuronal damage biomarkers in the Identification of patients at risk of long-term postoperative cognitive dysfunction after cardiac surgery. Anaesthesia. 2017;72(3):359.

    Article  CAS  PubMed  Google Scholar 

  6. Droc G, Isac S, Nita E, Martac C, Jipa M, Mihai DI, Cobilinschi C, Badea AG, Ojog D, Pavel B, Tanasescu MD, Isac T. Postoperative cognitive impairment and pain perception after abdominal surgery-could immersive virtual reality bring more? a clinical approach. Medicina (Kaunas). 2023;59(11):2034.

    Article  PubMed  Google Scholar 

  7. Kim SY, Lee J, Na HS, Koo BW, Lee KO, Shin HJ. The impact of regional nerve blocks on postoperative delirium or cognitive dysfunction following thoracic surgery: a systematic review and meta-analysis. J Clin Med. 2023;12(24):7576.

    Article  PubMed  PubMed Central  Google Scholar 

  8. Singh A, Brenna CTA, Broad J, Kaustov L, Choi S. The effects of dexmedetomidine on perioperative neurocognitive outcomes after cardiac surgery: a systematic review and meta-analysis of randomized controlled trials. Ann Surg. 2022;275(5):864–71.

    Article  PubMed  Google Scholar 

  9. Brummett CM, Hong EK, Janda AM, et al. Perineural Dexmedetomidine added to ropivacaine for sciatic nerve block in rats prolongs the duration of analgesia by blocking the hyperpolarization-activated cation current. Anesthesiology. 2011;115(4):836–43.

    Article  CAS  PubMed  Google Scholar 

  10. Nedeljkovic SS, Kett A, Vallejo MC, Horn JL, Carvalho B, Bao X, Cole NM, Renfro L, Gadsden JC, Song J, Yang J, Habib AS. Transversus abdominis plane block with liposomal bupivacaine for pain after cesarean delivery in a multicenter, randomized, double-blind. Controlled Trial Anesth Analg. 2020;131(6):1830–9.

    Article  CAS  PubMed  Google Scholar 

  11. Tian C, Lee Y, Oparin Y, Hong D, Shanthanna H. Benefits of Transversus abdominis plane block on postoperative analgesia after bariatric surgery: a systematic review and meta-analysis. Pain Physician. 2021;24(5):345–58.

    PubMed  Google Scholar 

  12. Mahoney FI, Barthel DW. Functional evaluation: the barthel index. Md State Med J. 1965;14:61–5.

    CAS  PubMed  Google Scholar 

  13. Folstein MF, Folstein SE, McHugh PR. “Mini-mental state” A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975;12(3):189–98.

    Article  CAS  PubMed  Google Scholar 

  14. Deng LQ, Hou LN, Song FX, Zhu HY, Zhao HY, Chen G, Li JJ. Effect of pre-emptive analgesia by continuous femoral nerve block on early postoperative cognitive function following total knee arthroplasty in elderly patients. Exp Ther Med. 2017;13(4):1592–7.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. American Society of Anesthesiologists Committee. Practice guideline for Preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures. Anesthesiology. 2017;126:376–93.

    Article  Google Scholar 

  16. Tran DQ, Daniela B, Leurcharusmee P, Neal JM. Transversus abdominis plane block: a narrative review. Anesthesiology. 2019;131(5):1166–90.

    Article  CAS  PubMed  Google Scholar 

  17. Daiello LA, Racine AM, Yun Gou R, et al. Postoperative delirium and postoperative cognitive dysfunction: Overlap and divergence. Anesthesiology. 2019;131:477–91.

    Article  PubMed  Google Scholar 

  18. Zhang JP, Zhang N, Chen X, Zhou Y, Jiang Z, Gao C, Xie YH, Wang S, Zhang W. Efficacy of dexmedetomidine as an adjunct to ropivacaine in bilateral dual-transversus abdominis plane blocks in patients with ovarian cancer who underwent cytoreductive surgery. BMC Anesthesiol. 2022;22(1):20. https://doi.org/10.1186/s12871-021-01542-z. Retraction in: BMC Anesthesiol. 2022 Jun 17;22(1):188.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  19. Neethirajan SGR, Kurada S, Parameswari A. Efficacy of dexmedetomidine as an adjuvant to bupivacaine in ultrasound-guided transverse abdominis plane block for laparoscopic appendicectomy: a randomised controlled study. Turk J Anaesthesiol Reanim. 2020;48(5):364–70.

    Article  CAS  PubMed  Google Scholar 

  20. Alldred DP. Avoid benzodiazepines and opioids in people at risk of delirium. Evidenc-Based Nursing. 2011;14(3):75–6.

    Article  Google Scholar 

  21. Arezoomandan M, Zhiani R, Mehrzad J, Motavalizadehkakhky A, Eshrati S, Arezoomandan R. Inflammatory, oxidative stress and cognitive functions in patients under maintenance treatment with methadone or buprenorphine and healthy subjects. J Clin Neurosci. 2022;101:57–62.

    Article  CAS  PubMed  Google Scholar 

  22. Laalou FZ, Egard M, Guillot M, et al. Influence of preoperative cognitive status on propofol requirement to maintain hypnosis in the elderly[J]. Br J Anaesth. 2010;105(3):342–6.

    Article  CAS  PubMed  Google Scholar 

  23. Goswami U, Babbar S, Tiwari S. Comparative evaluation of the effects of propofol and sevoflurane on cognitive function and memory in patients undergoing laparoscopic cholecystectomy:A randomised prospective study. Indian J Anaesth. 2015;59(3):150–5.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. O’Gara BP, Gao L, Marcantonio ER, Subramaniam B. Sleep, Pain, and cognition: modifiable targets for optimal perioperative brain health. Anesthesiology. 2021;135(6):1132–52.

    Article  PubMed  Google Scholar 

  25. Naser PV, Kuner R. Molecular, Cellular and circuit basis of cholinergic modulation of pain. Neuroscience. 2018;387:135–48.

    Article  CAS  PubMed  Google Scholar 

  26. Liu X, Xie G, Zhang K, Song S, Song F, Jin Y, Fang X. Dexmedetomidine vs propofol sedation reduces delirium in patients after cardiac surgery: A meta-analysis with trial sequential analysis of randomized controlled trials. J Crit Care. 2017;38:190–6.

    Article  PubMed  Google Scholar 

  27. Duan X, Coburn M, Rossaint R, et al. Efficacy of perioperative dexmedetomidine on postoperative delirium: systematic review and meta-analysis with trial sequential analysis of randomised controlled trials[J]. Br J Anaesth. 2018;121(2):384–97.

    Article  CAS  PubMed  Google Scholar 

  28. Wang Q, Li H, Wei S, Zhang G, Ni C, Sun L, Zheng H. Dexmedetomidine added to ropivacaine for ultrasound-guided erector spinae plane block prolongs analgesia duration and reduces perioperative opioid consumption after thoracotomy: a randomized, controlled clinical study. Clin J Pain. 2021;38(1):8–14.

    Article  PubMed  PubMed Central  Google Scholar 

  29. Ellis RJ, Heaton RK, Tang B, Collier AC, Marra CM, Gelman BB, Morgello S, Clifford DB, Sacktor N, Cookson D, Letendre S. Peripheral inflammation and depressed mood independently predict neurocognitive worsening over 12 years. Brain Behav Immun Health. 2022;10(21):100437.

    Article  Google Scholar 

Download references

Acknowledgements

None.

Funding

This work was supported by research funds (2022NSFSC0709) from Sichuan Provincial Science and Technology Department (to Deshui Yu).

Author information

Authors and Affiliations

Authors

Contributions

L Y and DS Y undertook the design of this study. L Y was responsible for the writing the manuscript. DeShui Yu was the corresponding author and responsible for the review of the research process. RF X as the blind investigator to collect data. S W and XQ Ch finished statistical analysis. All authors read and approved the final manuscript.

Corresponding author

Correspondence to DeShui Yu.

Ethics declarations

Ethics approval and consent to participate

This research was approved by the Ethics Committee of The Second People’s Hospital of Yibin City (ClinicalTrials.gov Identifier: 2019–015-01).

Informed consent is signed by all participants. Our study followed the Criterions for the Quality Control of Clinical Trial of drugs.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Yang, L., Xiong, R., Chen, X. et al. The influence of dexmedetomidine added to ropivacaine for transversus abdominis plane block on perioperative neurocognitive disorders after radical colorectal cancer surgery: randomized, double-blind, controlled trial. BMC Anesthesiol 24, 186 (2024). https://doi.org/10.1186/s12871-024-02569-8

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s12871-024-02569-8

Keywords