Effect of dexmedetomidine on sedation and analgesia in supraclavicular brachial plexus block in children - A prospective Randomized, double blinded study

 

Subhashree J^1*, Rajasekhar T², Pradeep Kumar K³, Subrahmanyam G⁴

 

Abstract               Background: Brachial plexus block is a well-accepted technique in children for upper limb procedures. Several adult human studies have concluded the superiority of dexmedetomidine as an adjuvant to local anesthetic during brachial plexus block. But similar evidence is lacking in pediatric population. Thus we conducted this prospective, randomized, double blind clinical efficacy study to evaluate the effectiveness of adding dexmedetomidine to bupivacaine in supraclavicular brachial plexus block in children, in terms of duration of analgesia, intraoperative sedation and postoperative analgesic requirement. Methodology: After institutional ethics committee approval and obtaining written informed consent from the parents, hundred children of age 1-12years, posted for elective upper limb orthopedic surgery, were randomly allocated into two groups of 50 each. All the children were premedicated with ketamine (4mg/kg) and glycopyrolate (0.2mg) IM 15 minutes prior to shifting inside the operation theatre. The children received 0.25%bupivacaine (1ml/kg) along with either 1ml saline (control group) or 1µg/kg of dexmedetomidine (study group) as per their group and brachial plexus block was given using classical supraclavicular approach. Heart rate, blood pressure and peripheral oxygen saturation were noted every 5min for first 30 minutes and then every 15minutes till the end of the procedure. Results: Demographic data and hemodynamic parameters were comparable between the groups. However there was significant statistical difference in the duration of analgesia in the study group (p value < 0.001) and also required less intraoperative sedation and less postoperative analgesia ( p value < 0.001) than the control group. Congenital anomalies like syndactyly, radial and ulnar club hand, constriction band syndrome are common in pediatric population.

Key Word: supraclavicular brachial plexus block.

 

INTRODUCTION

Brachial plexus block is a well-accepted technique in children for upper limb procedures. Several adult human studies have concluded the superiority of dexmedetomidine as an adjuvant to local anesthetic during brachial plexus block. But similar evidence is lacking in pediatric population. Thus we conducted this prospective, randomized, double blind clinical efficacy study to evaluate the effectiveness of adding dexmedetomidine to bupivacaine in supraclavicular brachial plexus block in children, in terms of duration of analgesia, intraoperative sedation and postoperative analgesic requirement.

 

METHODOLOGY

This prospective, randomized, double blinded clinical efficacy study was conducted to evaluate the effectiveness of adding dexmedetomidine to bupivacaine in supraclavicular brachial plexus block in children, in terms of duration of analgesia, intraoperative sedation and postoperative analgesic requirement. After obtaining institutional ethics committee approval, written informed consent was obtained from the parents, after explaining about the procedure, its benefits and complications. Hundred children of aged 1-12years, belonging to ASA PS1,2, posted for elective upper limb orthopedic surgery of duration less than 2hours were included in the study. Parents who did not give consent and any patient with history of coagulation abnormalities were excluded from the study.  All the children were kept fasting for 6hours for solids and 2hours for clear liquids, breast feeding was allowed up to 4hours before surgery. These children were randomly allocated into two groups of 50 each. children <6years of age were premedicated with ketamine (4mg/kg) and glycopyrolate (0.2mg) IM 15 minutes prior to shifting inside the operation theatre. Once they were sedated, they were shifted to operation theatre, monitors like saturation probe, noninvasive blood pressure monitor, and electrocardiogram were connected and Intravenous cannula was secured. For older kids, EMLA cream was applied on the dorsum of the hand or the foot in the preoperative area 30 minutes before shifting to operation theatre. After shifting to the operation theatre, monitors were connected and intravenous cannula was secured. Inj.ketamine 1-2mg/kg and glycopyrolate 0.2mg iv was given. Oxygen was given through facemask at 4l/min for all the children. Resuscitation equipments like laryngeal mask airway, tracheal tubes, and drugs required to convert the anesthetic technique to general anesthesia like propofol, neuromuscular blocking agents were loaded and kept ready. All the blocks were given by senior anesthesiology consultant in the operation theatre, who was blinded to the drug given. Supraclavicular block was performed using anatomical landmark approach; child was positioned in supine, with head ring and shoulder roll. Ipsilateral shoulder was pulled towards the feet to keep the clavicle horizontal. Area was painted with 2%betadine and draped. Under sterile aseptic precautions, midpoint of clavicle and transverse process of C6 tubercle (chassaignac’s tubercle) {if not identified, then line from the cricoid cartilage to the posterior border of sternocleidomastoid} were identified. A 23G, 2.5cm hypodermic needle with syringe attached was used. Point of needle insertion was the junction of middle and lateral third of clavicle’s midpoint and chassaignac’s tubercle. Skin weal was raised and the needle was directed downwards, backwards and medially until contact was made with the first rib. No conscious effort was made to elicit paraesthesia. Needle was withdrawn by a millimetre, and then the drug was injected after negative aspiration for blood and air, thereby ruling out the accidental injection into blood vessel or pleural puncture.  The children received 0.25%bupivacaine (1ml/kg) along with either 1mL saline (control group- group A) or 1µg/kg of dexmedetomidine diluted to 1mL (study group – group B) as per their group.  Heart rate, blood pressure and peripheral oxygen saturation were noted every 5min for first 30minutes and then every 15minutes till the end of the procedure. Sensory loss was assessed using needle in the areas supplied by ulnar, median, radial and musculocutaneous nerves. Motor block was assessed based on the inability to move the limb during the pneumatic tourniquet inflation and during surgical incision and the block was considered successful if there was no pain or movement during the same. General anesthesia was administered if the child started moving vigorously or complained of pain during tourniquet inflation or surgical incision and the child was excluded from the study. Midazolam 1mg IV bolus was used to sedate the child in the intraoperative period, aimed at maintaining Ramsay sedation score of 3-4. Total dose of midazolam given during intraoperative period was noted. Child was observed for any complications like bradycardia, hypotension, pneumothorax and haematoma formation and was treated accordingly. Once the surgery was over, then the child was shifted to postoperative unit and observed for 12hours.  In the postoperative period, pain and sedation was assessed using CHEOPS scale. Rescue analgesia with inj.fentanyl 1µg/kg was given when CHEOPS scale was more than 6 and the total dose required in the first 12hours of postoperative period was also noted ^20,21. Oral liquids were started 3hrs after receiving in the postoperative period. After starting oral food, a combination syrup of paracatemol and ibugesic (each 5ml of suspension has 100mg of ibuprofen and 162.5mg of paracatemol in a flavored syrup base, dose based on the child’s age)was started every 8^th hourly. Duration of block was defined by the time between the block given and the time during which child had a CHEOPS score of more than 6 for the first time.

 

RESULTS

Figure 1: changes in the heart rate between the groups.

 

Mean systolic (figure 2), diastolic blood pressure (figure 3), at baseline, 5min, 10min, 15min, 30min, 45min, 60min, 75min, 90min, 105min and 120min were comparable between the groups (p>0.05).

Figure 2: changes in mean systolic blood pressure between the groups

 

Figure 3: Changes in mean diastolic blood pressure

 

Duration of the surgery and oxygen saturation level was comparable between the groups. Duration of analgesia was higher in study group (group B) 419.20 ± 192.230 (mean ± SD) than the control group (group A) 304.84± 132.563 ( mean ± SD ) with p value < 0.001,which is statistically very significant (figure 4).

Figure 4: duration of analgesia              Figure 5:  sedation dose in the intraoperative period and total analgesic dose used in the postoperative period                             

Sedation dose used in the intraoperative period was lesser in the study group (group A) .22± .507 than the control group 1.62± 1.905 (mean ± SD) with p value less than 0.001. Total analgesic dose used in the first 12hours of postoperative period was lesser in study group 26 ± .664 than the control group 64± .66 (mean ± SD) with p value less than 0.001, which is statistically very significant (figure 5).

No adverse effects like bradycardia, hypotension were noted in both the groups. One patient in group A and two patients in group B had failed block, were converted to general anesthesia with laryngeal mask airway and were excluded from the study.

 

DISCUSSION

Regional anesthetic techniques, especially supraclavicular brachial plexus block is well documented technique in children undergoing upper limb surgeries^16-18. Drugs like clonidine, dexamethasone, and dexmedetomidine have been used as adjuncts to local anesthetics in peripheral nerve blockade^6-11. Among all these drugs, dexmedetomidine, which is often used for procedural sedation and in ICU⁹, is gaining popularity as an adjunct to local anesthetic, because of its selective alpha2 blockade^12,14. Several studies in adult population have concluded the superiority of dexmedetomidine as an adjunct to local anesthetic in peripheral nerve blockade. But there is not much literature regarding the use of dexmedetomidine as an additive in brachial plexus blockade in children. Thus we had conducted a prospective, randomized, double blinded study to study the effect of adding dexmedetomidine to bupivacaine in supraclavicular block on the duration of analgesia, intraoperative sedation requirement and need of rescue analgesia in the postoperative period. Regional techniques in children⁴ are often considered as a challenge to anesthesiologists for two main reasons: 1. Younger children need sedation to let the anesthesiologists to perform a block, which itself might interfere in assessing the sensory and motor blockade in sedated children. Till now there is no standard technique to assess the efficacy of block in sedated children. 2. Older children who might cooperate to an anesthesiologist to give a block, but most of the times they may not cooperate in eliciting paresthesia, which often might result in mental trauma to the children in the postoperative period. In this study, we did not make an effort to elicit paresthesia. Instead we stick to the classical anatomical landmarks approach, we had deposited over the first rib and the success rate of the block in our study > 97 %. We attribute the success to the distribution of local anesthetic to the compact brachial plexus sheath over the first rib. As there is no standard technique to assess the motor and sensory blockade in sedated children, general anesthesia was induced if the patient started moving vigorously on tourniquet inflation or during the skin incision. Various techniques of brachial plexus block through axillary and interscalene approach have been suggested for upper limb procedures ²³. We followed supraclavicular method because of our familiarity with the technique, and its ability to produce dense blockade with less complications.^22,26,27 Interscalene approach has its own complications like cervical plexus block, phrenic nerve blockade ^24,25, and musculocutaneous nerve can get spared in axillary approach²³. Pande et al ¹⁵ used supraclvicular block technique as a sole anesthetic technique in 200 children, undergoing closed reduction of arm fractures. They had used 1.5% lignocaine with epinephrine as the block drug and have found that classical supraclavicular brachial plexus block as an acceptable, effective method with good success rate. We have used 0.25% bupivacaine with dexmedetomidine as the surgery proposed is of longer duration around 2hours. Sandhya et al ⁸ have used dexmedetomidine in the dose of 100µg as an additive with 0.325% bupivacaine in supraclavicular brachial plexus block in adult population. They have concluded that dexmedetomidine shortens the onset and prolongs the duration of block with adequate sedation. In our study, we have used dexmedetomidine in the dose of 1µg/Kg as an additive with 0.25% bupivacaine and we have found that it increases the duration of analgesia, reduces the sedation requirement in the intraoperative period and analgesic requirement in the postoperative period. We did not observe any bradycardia or hypotension in the perioperative period.

 

CONCLUSION

Dexmedetomidine as an additive to bupivacaine in supraclavicular block in pediatric population prolongs the duration of analgesia with adequate intraoperative sedation and with lesser need of rescue analgesics in the postoperative period.

 

REFERENCES

1. Tobias JD. Brachial plexus anaesthesia in children. Paed Anaesth 2001; 11: 265.
2. Clayton ML, Turner DA. Upper arm block anesthesia in children with fractures. Journal of the American Medical Association 1959; 169: 99.
3. Small GA. Brachial plexus block anesthesia in children. Journal of the American Medical Association 1951; 147: 1648±51.
4.  Leak WD, Wichell SW. Regional anesthesia in paediatric patients: review of clinical experience. Regional Anesthesia 1982; 7: 64.
5. Brown DL. Brachial plexus anesthesia: an analysis of options. Yale Journal of Biology and Medicine 1993; 66: 415±31.
6. Singelyn FJ, Dangoisse M, Bartholomee S, Gouverneur JM. Adding clonidine to mepivacaine prolongs the duration of anaesthesia and anaesthesia after brachial plexus block. Reg Anesth 1992;17:148-50. 
7. Duma A, Urbanek B, Sitzwohl C, Kreiger A, Zimpfer M, Kapral S. Clonidine as an adjuvant to local anaesthetic axillary brachial plexus block: A randomized, controlled study. Br J Anaesth 2005;94:112-6.
8. Sandhya Agarwal, Ritu Aggarwal, Praveen. Dexmedetomidine prolongs the effect of bupivacaine in supraclavicular brachial plexus block . Journal of Anaesthesiology Clinical Pharmacology | January-March 2014 | Vol 30 | Issue 1
9. Shukry M, Miller JA. Update on dexmedetomidine: Use in nonintubated patients requiring sedation for surgical procedures. Ther Clin Risk Manag 2010;6:111-21.
10. Esmaoglu A, Yegenoglu F, Akin A, Turk CY. Dexmedetomidine added to levobupivacaine prolongs axillary brachial plexus block.. Anaesth Analg 2010;111:1548-51.
11. Swami SS, Keniya VM, Ladi SD, Rao R. Comparison of dexmedetomidine and clonidine (a2 agonist drugs) as an adjuvant to local anaesthesia in supraclvicular brachial plexus block: A randomized double-blind prospective study. Indian J Anaesth 2012;56:243-9.
12. Hall JE, Uhrich TD, Barney JA, Arain SA, Ebert TJ. Sedative, amnestic, and analgesic properties of small-dose dexmedetomidine infusions. Anesth Analg 2000;90:699-705.
13. Yoshitomi T, Kohjitani A, Maeda S, Higuchi H, Shimada M, Miyawaki T. Dexmedetomidine enhances the local anesthetic action of lidocaine via an alpha-2A adrenoceptor. Anesth Analg 2008;107:96-101.
14. Masuki S, Dinenno FA, Joyner MJ, Eisenarch JH. Selective alpha2- adrenergic properties of dexmedetomidine over clonidine in the human forearm. J Appl Physiol 2005;99:587-92.
15. R. Pande, M. Pande, U. Bhadani, C. K. Pandey and A.Bhattacharya. Supraclavicular brachial plexus block as a sole anaesthetic technique in children: an analysis of 200 cases. Anaesthesia, 2000, 55, pages 798-810.
16. Fung BK, Gislefoss AJ. Evaluation of supraclavicular brachial plexus block in upper extremity surgery. Ma Tsui Hsueh Tsa Chi 1993; 31: 87-90.
17. Korbon GA, Carron H, Lander J. First rib palpation: a safer, easier technique for supraclavicular brachial plexus block. Anesthesia and Analgesia 1989; 68: 682-5.
18. Yamano Y. Safe method of supraclavicular brachial plexus anesthesia. Archives of Orthopedic and Trauma Surgery 1983; 102, 92-4.
19. Dalens B, Vanneuville G, Tanguy A. A new parascalene approach to the brachial plexus block in children: comparison with supraclavicular approach. Anesthesia and Analgesia 1987; 66: 1264-71.
20. Hannallah RS, Rosales JK. Experience with parents' presence during anaesthesia induction in children. Canadian Anaesthetists' Society Journal 1983; 30: 286-9.
21. Li L, Liu X, Herr K (2007) Postoperative pain intensity assessment: a comparison of four scales in Chinese adults. Pain Med 8(3):223–234
22. Brown DL, Cahill DR, Bridenbaugh LD. Supraclavicular nerve block: anatomic analysis of a method to prevent pneumothorax. Anesthesia and Analgesia 1993; 76: 530-4.
23. Lanz E, Theiss D, Jankovic D. The extent of blockade following various techniques of brachial plexus block. Anesthesia and Analgesia 1983; 62: 55-8.
24. Kayerker UM, Dick MM. Phrenic nerve paralysis following interscalene brachial plexus block. Anesthesia and Analgesia 1983; 62: 536-7.
25. Bashein G, Robertson HT, Kennedy WF Jr. Persistent phrenic nerve paresis following interscalene brachial plexus block. Anesthesiology 1985; 63: 102-4.
26. Ortells Polo MA, Garcia Guiral M, Garcia Amigueti FJ, Carral Olondris JN, Garcia Godino T, Aguiar Mojarro JA. Brachial plexus anesthesia: results of a modified perivascular supraclavicular technique. Revista Espanola Anestesiologia Reanimacion 1996; 43: 94-8.
27. Pham Dang C, Gunst JP, Gouin F, et al. A novel supraclavicular approach to brachial plexus block. Anesthesia and Analgesia 1997; 85: 111-16.

Policy for Articles with Open Access Authors who publish with MedPulse International Journal of Anesthesiology (Print ISSN:2579-0900) (Online ISSN: 2636-4654) agree to the following terms: Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal. Authors are permitted and encouraged to post links to their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.