Key findings:

The key findings of this abstract are the effectiveness of brachial plexus supraclavicular block in postoperative pain management, especially in high-risk patients with comorbidities. This technique offers superior analgesia, avoids common side effects of general anesthesia like postoperative nausea and vomiting, and the use of levobupivacaine is highlighted for its ability to prolong motor and sensory blockade while being less cardiotoxic and neurotoxic.

What is known and what is new?
The known aspects of this abstract include the importance of effective postoperative pain management and the use of brachial plexus blocks for this purpose. The new contribution is the specific recommendation of the brachial plexus supraclavicular block and the use of levobupivacaine, which provides prolonged analgesia with reduced cardiotoxicity and neurotoxicity, particularly for high-risk patients with significant comorbidities.

What is the implication, and what should change now?
The implication of this abstract is the importance of effective postoperative pain management, particularly in patients with significant comorbidities. Changes needed include adopting the brachial plexus supraclavicular block, which provides superior analgesia and avoids general anesthesia side effects, and using levobupivacaine, a less cardiotoxic and neurotoxic agent, for brachial plexus block.
 

Recent years have witnessed increasing interest in postoperative pain management. The aim of postoperative pain  management is to provide subjective comfort in addition to inhibiting trauma-induced nociceptive impulses to blunt  autonomic and somatic reflex responses to pain.  

Brachial plexus block remains the only practical alternative to general anaesthesia for significant surgery on the upper  limb. It provides a superior quality of analgesia and avoids the common side-effects associated with general anaesthesia  such as postoperative nausea and vomiting. The brachial plexus supraclavicular block is extremely useful in patients with  significant comorbidities such as severe respiratory and cardiovascular disease, morbid obesity and in those with  potential airway difficulties. These blocks are therefore particularly useful in the ambulatory surgical setting for a wide  variety of patients and procedures [1]. 

Many modifications were done over the years, but the ultrasound guided technique has become a standard because of  its simplicity and reproducible success. Ultrasound (USG) guided supraclavicular block is considered to be one of the  most effective anaesthetic procedures for upper extremity surgeries. The use of ultrasound has several benefits including  block under direct visualization, faster onset and reduction in the dose of local anaesthetic [2].  USG guidance also improves accuracy of needle placement, visualization of local anaesthetic spread in real time,  compensation for anatomical variation and avoidance of intraneural or intravascular injection.  

Various local anaesthetic agents like bupivacaine, levobupivacaine, ropivacaine and lignocaine have been used with  safety and efficacy in performing such blocks [3]. Local anaesthetic preferentially binds to the  inactivated state of voltage gated sodium channels, but has also been found to bind potassium channels, G-protein  coupled receptors, N-methyl-D-aspartate (NMDA) receptors, and calcium channels in vitro [4].  Concentration of local anaesthetics which has been used for a blockade of different local anaesthetics varies from 0.5%,  0.25% and 0.375%. It has been observed that it is not the concentration but volume that affects the effective dose of local  anaesthetic [5]. Out of various agents which are used for brachial plexus block,  levobupivacaine is the agent which not only prolongs motor and sensory blockade but is also less cardiotoxic and  neurotoxic.  

Local anaesthetics alone for supraclavicular brachial  plexus blocks provide good operative conditions but  have shorter duration of postoperative analgesia. This  problem can be overcome by using long acting local  anaesthetics like bupivacaine or by using adjuvant in  regional anaesthesia. Adjuvant added to brachial plexus  block should prolong the analgesia, without having  systemic side effects, prolong motor block and should  also reduce the total dose of local anaesthetic. Various  studies [6-7] have investigated several  adjuvants including opioids, clonidine, and neostigmine  added to local anaesthetics in brachial plexus block to  achieve quick, dense and prolonged block. However,  the results are either inconclusive or associated with  side effects.  

Dexamethasone, a high-potency long-acting  glucocorticoid has been shown to prolong peripheral  nerve blockade and duration of analgesia as perineural  adjuvant to bupivacaine [8]. The proposed mechanism of action may stem  from decreased nociceptive C-fiber activity via a direct  effect on glucocorticoid receptors and inhibitory  potassium channels. Other suggested mechanisms  include a local vasoconstrictive effect, resulting in  reduced local anaesthetic absorption or a systemic anti-inflammatory effect following vascular uptake of the  drug [9]. 

Dexamethasone has been used in different doses  ranging between 1 to 8 mg [10].  But, it has been found that 1, 2 and 4 mg  dexamethasone when added to 0.25% bupivacaine  resulted in similar prolongation of motor blockade and  analgesia [11]. Spinal  anaesthesia has enjoyed a long history of success and  has been in use for mankind for more than a century  now [12]. Spinal anaesthesia involves the  use of small amounts of local anaesthetic injected into  the subarachnoid space to produce a reversible loss of  sensation and motor function. The easy and long history  of spinal anaesthesia may give the impression that it is a  simple technique but this is not true.  
The injection of local anaesthetic in the  subarachnoid space can result in haemodynamic and  respiratory changes. If it was possible to limit  anaesthesia for the surgical field, certain undesirable  effects of spinal anaesthesia could be avoided. Spinal  anaesthesia is often used for orthopaedic surgery  especially in lower limb surgeries [13]. However, because of the high prevalence of  hypotension and bradycardia risk is always there  especially in elderly age groups because of their  compromised haemodynamic status [14-16].

Localized spinal analgesia in surgery was described  as early as 1909 by Jonnesco [17]. Since  that time various techniques have evolved, each  attempting to confine the extent of somatic and  sympathetic paralysis to the site of operation [18]. Among such techniques are segmental spinals, in which localization is affected by placing catheters to  predetermined levels in the subarachnoid space and  “unilateral” spinals in which limitation of spread is  accomplished by using hyperbaric or hypobaric  solutions.  

The term unilateral spinal anaesthesia is used when the block is of the operative side only with the absence of the block on the non-operative side [19]. When surgery  involves only one lower limb, such block is  advantageous as it minimizes cardiovascular effects,  avoids motor block of non-operative limb and facilitates  early discharge [20-21]. Although unilateral spinal is often practiced, the potential to control the speed of drug, thereby  restricting the distribution of spinal block to the  operative side, remains controversial and frequently  debated [22-23]. Low dose local anaesthetic solutions by using a  pencil-point needle and slow intrathecal injection have  been reported to obtain satisfactory unilateral spinal  anaesthesia (USpA) [24]. USpA techniques  allow the administration of small doses of local  anaesthetic and thus provide a more controllable  sensory and sympathetic level of anaesthesia. Finally,  USpA has more stable cardiovascular parameters  compared with conventional bilateral spinal block  [25]. 

USPA aims to limit the distribution of spinal block  to the operated side, because most of the operative  procedures involve only one lower limb [26]. Compared with the conventional technique, it  requires a bit longer preparation time to get the drug  fixed to the side to be operated in preference to non operating limb. It produces fewer haemodynamic side effects and has higher cardiovascular stability,  increased autonomy after surgery and better patient  acceptance [27]. It also reduces the  incidence of clinically relevant hypotension following  spinal anaesthesia. Hypotension is the most frequent  side effect of spinal anaesthesia, occurring in more than  30% of patients. 
Spinal anaesthesia typically causes decrease in  arterial blood pressure with only minor decrease in  heart rate, stroke volume, or cardiac output even with  poor left ventricular function. In conventional spinal  anaesthesia, it is not possible to limit the accompanied  sympathetic block that normally exceeds the sensory  block by 2-6 segments [28].  Hypotension occurs from decrease in systemic vascular  resistance from sympathetic block with vasodilation and  redistribution of central blood volume to lower extremities and splanchnic beds. Various prophylactic  and rescue regimens have been advocated for  haemodynamic disturbances with emphasis on  prevention of hypotension.  

A potential way for prophylaxis of hypotension is  by manipulation of spinal anaesthesia to achieve a  predominantly unilateral block [29].  The unilateral spinal anaesthesia has been claimed by  many as an alternative technique, to restrict the undesired sympathetic block [30].  Unilaterality can be maintained if the patient remains in a  lateral position for surgery; however, eventual turning  of the patient into a supine position results in partial  redistribution to bilateral anaesthesia. Thus a patient's  position during and immediately after spinal anaesthesia  influences the spinal distribution of drug i.e. patient  position is the fundamental basis for unilateral block  [31]. It also results in rapid  recovery and greater satisfaction among outpatients, in  addition to preventing unnecessary nerve block in the  contralateral limb. 

One of the major issues in orthopaedic surgery is the requirement of lateral position for many surgeries like  total hip replacement, bipolar hip arthroplasty etc.  Lateral position can lead to uneven distribution of  spinal anaesthesia in both lower limbs. 

While clinicians describing this unilateral technique  allude to an associated decrease in anaesthetic  morbidity, not many controlled clinical studies have  been reported comparing this technique to conventional  bilateral spinals. In some studies reported earlier the  true “unilaterality” of the sympathetic blockade was  termed dubious. Some clinicians have expressed doubt  that such unilateral sympathetic paralysis can be  obtained, and they feel, therefore, that the rationale  behind the unilateral spinal paralysis is fallacious.  

Funding: No funding sources.

Conflict of interest: None declared.

Ethical approval: The study was approved by the Institutional Ethics Committee of Dr. Rajendra Prasad Government Medical College.
 

1. Bruce, Benjamin G., et al. "Brachial plexus blocks for upper extremity orthopaedic surgery." JAAOS-Journal of the American Academy of Orthopaedic Surgeons 20.1 (2012): 38-47. DOI: 10.5435/JAAOS-20-01-038

2. Chan, Vincent WS, et al. "Ultrasound-guided supraclavicular brachial plexus block." Anesthesia & Analgesia 97.5 (2003): 1514-1517. DOI: 10.1213/01.ANE.0000062519.61520.14

3. Santorsola, R., et al. "Levobupivacaine for peripheral blocks of the lower limb: a clinical comparison with bupivacaine and ropivacaine." Minerva anestesiologica 67.9 Suppl 1 (2001): 33-36. https://europepmc.org/article/med/11778092 

4. Marban, Eduardo, Toshio Yamagishi, and Gordon F. Tomaselli. "Structure and function of voltage-gated sodium channels." The Journal of physiology 508.Pt 3 (1998): 647. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2230911/ 

5. Gupta, P. K., and P. M. Hopkins. "Effect of concentration of local anaesthetic solution on the ED50 of bupivacaine for supraclavicular brachial plexus block." British journal of anaesthesia 111.2 (2013): 293-296. https://academic.oup.com/bja/article-abstract/111/2/293/254157 

6. Swami, Sarita S., et al. "Comparison of dexmedetomidine and clonidine (α2 agonist drugs) as an adjuvant to local anaesthesia in supraclavicular brachial plexus block: A randomised double-blind prospective study." Indian journal of anaesthesia 56.3 (2012): 243-249. https://journals.lww.com/ijaweb/fulltext/2012/56030/comparison_of_dexmedetomidine_and_clonidine___2.6.aspx 

7. Kapse, Upendrakumar S., and Pradnya M. Bhalerao. "Comparison of bupivacaine with fentanyl and bupivacaine with butorphanol for brachial plexus block by axillary approach–A prospective, double blind, randomized study." Int J Res Med Sci 5.4 (2017): 1415. https://www.researchgate.net/profile/Pradnya-Bhalerao/publication/315989673_Comparison_of_bupivacaine_with_fentanyl_and_bupivacaine_with_butorphanol_for_brachial_plexus_block_by_axillary_approach-_a_prospective_double_blind_randomized_study/links/620a5709634ff774f4ccadbb/Comparison-of-bupivacaine-with-fentanyl-and-bupivacaine-with-butorphanol-for-brachial-plexus-block-by-axillary-approach-a-prospective-double-blind-randomized-study.pdf 

8. Dhumane, Pradeep, and N. Shakir. "Supraclavicular Brachial Plexus Block with and without Dexamethasone as an Adjuvant to local anaesthetics: a Comparative Study." International Journal of Biomedical and Advance Research 7.9 (2016): 456-459. https://www.academia.edu/download/57570440/11.3625-Article_Text-9741-2-10-20160929.pdf 

9. Albrecht, E., C. Kern, and K. R. Kirkham. "A systematic review and meta‐analysis of perineural dexamethasone for peripheral nerve blocks." Anaesthesia 70.1 (2015): 71-83. https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/abs/10.1111/anae.12823 

10. Woo, Jae Hee, et al. "Dose-dependency of dexamethasone on the analgesic effect of interscalene block for arthroscopic shoulder surgery using ropivacaine 0.5%: a randomised controlled trial." European Journal of Anaesthesiology| EJA 32.9 (2015): 650-655. DOI: 10.1097/EJA.0000000000000213 11. Knezevic, Nebojsa Nick, Utchariya Anantamongkol, and Kenneth D. Candido. "Perineural dexamethasone added to local anesthesia for brachial plexus block improves pain but delays block onset and motor blockade recovery." (2015). https://indigo.uic.edu/articles/journal_contribution/Perineural_dexamethasone_added_to_local_anesthesia_for_brachial_plexus_block_improves_pain_but_delays_block_onset_and_motor_blockade_recovery/10762901/files/19275119.pdf 

12. Wulf, Hinnerk FW. "The centennial of spinal anesthesia." The Journal of the American Society of Anesthesiologists 89.2 (1998): 500-506. https://doi.org/10.1097/00000542-199808000-00028 

13. Grandhe, R. P., J. Wig, and L. N. Yaddanapudi. "Evaluation of bupivacaine-clonidine combination for unilateral spinal anaesthesia in lower limb orthopedic surgery." Journal of Anaesthesiology Clinical Pharmacology 24.2 (2008): 155-158. https://journals.lww.com/joacp/abstract/2008/24020/evaluation_of_bupivacaine_clonidine_combination.5.aspx 

14. Carpenter, Randall L., et al. "Incidence and risk factors for side effects of spinal anesthesia." Anesthesiology 76.6 (1992): 906-916. https://europepmc.org/article/med/1599111 

15. Arndt, Joachim O., et al. "Incidence and time course of cardiovascular side effects during spinal anesthesia after prophylactic administration of intravenous fluids or vasoconstrictors." Anesthesia & Analgesia 87.2 (1998): 347-354. DOI: 10.1213/00000539-199808000-00021

16. Racle, J. P., et al. "Spinal analgesia with hyperbaric bupivacaine: influence of age." British journal of anaesthesia 60.5 (1988): 508-514. https://www.sciencedirect.com/science/article/pii/S0007091217494980 
 

17. Jonnesco, Thomas. "Remarks on general spinal analgesia." British medical journal 2.2550 (1909): 1396. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2321640/ 

18. Bonica, J. J. "The Management of Pain, with Special Emphasis on the use of Analgesic Block in Diagnosis, Prognosis and Treatment." Philadelphia, Lea and Fabiger (1953): 1404-1405.

19. Brown, Seymour. "Fractional segmental spinal anesthesia in poor risk surgical patients: report of 600 cases." The Journal of the American Society of Anesthesiologists. Vol. 13. No. 4. The American Society of Anesthesiologists, 1952. https://pubs.asahq.org/anesthesiology/article-abstract/13/4/416/14431 

20. Hander, H.T. "Unilaterale Lumbale Spinale Anästhesie mit Hyperbarer Lösung." Der Anästhesist, vol. 5, 1959, pp. 145-146..  

21. Enk, Dietmar, et al. "Success rate of unilateral spinal anesthesia is dependent on injection flow." Regional anesthesia and pain medicine 26.5 (2001): 420-427. https://doi.org/10.1053/rapm.2001.26489 

22. Fanelli, Guido, et al. "Unilateral bupivacaine spinal anesthesia for outpatient knee arthroscopy." Canadian Journal of Anesthesia 47 (2000): 746-751. https://link.springer.com/article/10.1007/BF03019476 

23. Kuusniemi, Kristiina S., Kalevi K. Pihlajamäki, and Mikko T. Pitkänen. "A low dose of plain or hyperbaric bupivacaine for unilateral spinal anesthesia." Regional Anesthesia & Pain Medicine 25.6 (2000): 605-610. https://rapm.bmj.com/content/25/6/605.abstract 

24. Kelly, D., D. McCoy, and C. Wall. "Hemodynamic changes induced by equivalent levels of sympathetic denervation during bilateral or unilateral spinal anesthesia." Anesth Analg 82 (1996): S223.

25. Casati, Andrea, et al. "A prospective, randomized, double-blind comparison of unilateral spinal anesthesia with hyperbaric bupivacaine, ropivacaine, or levobupivacaine for inguinal herniorrhaphy." Anesthesia & Analgesia 99.5 (2004): 1387-1392. DOI: 10.1213/01.ANE.0000132972.61498.F1

26. Casati, Andrea, et al. "Frequency of hypotension during conventional or asymmetric hyperbaric spinal block." Regional anesthesia and pain medicine 24.3 (1999): 214-219. https://www.sciencedirect.com/science/article/pii/S109873399990130X 

27. Casati, A., et al. "Block distribution and cardiovascular effects of unilateral spinal anaesthesia by 0.5% hyperbaric bupivacaine. A clinical comparison with bilateral spinal block." Minerva anestesiologica 64.7-8 (1998): 307-312. https://europepmc.org/article/med/9796239 

28. Esmaoglu, Aliye, et al. "Bilateral vs. unilateral spinal anesthesia for outpatient knee arthroscopies." Knee Surgery, Sports Traumatology, Arthroscopy 12 (2004): 155-158. https://link.springer.com/article/10.1007/s00167-003-0350-2 

29. Fanelli, Guido, et al. "Unilateral bupivacaine spinal anesthesia for outpatient knee arthroscopy." Canadian Journal of Anesthesia 47 (2000): 746-751. https://link.springer.com/article/10.1007/BF03019476 

30. Liu, Spencer S., et al. "Dose-response characteristics of spinal bupivacaine in volunteers: clinical implications for ambulatory anesthesia." The Journal of the American Society of Anesthesiologists 85.4 (1996): 729-736. https://doi.org/10.1097/00000542-199610000-00007 

31. Green, N.M. "The Area of Differential Block during Spinal Anaesthesia with Hyperbaric Tetracain." Anesthesiology, vol. 19, 1958, pp. 45-50.