Femoral shaft fractures result from high-impact injuries and require definitive surgery to correct the deformity. Neuraxial blockade is the preferred mode of anaesthetic technique compared to General Anaesthesia. [1] Automobile accidents are more prevalent in the younger population, while ground-level falls are more common in the elderly population, which is attributed to osteoporosis.[2] To obtain satisfactory patient comfort for positioning while providing spinal anaesthesia, various analgesic modalities such as midazolam, opioids, and ketamine were used.[3]t They have their own side effects. Femoral nerve block (FNB) offers an excellent alternative for pain management during the perioperative period. [4] Femoral nerve block is recommended both in emergency care settings and during surgeries as an adjunct to neuraxial or general anaesthesia. Block provides targeted pain relief effectively and immediately thus potentially reducing the reliance on systemic opioids and improving overall patient outcomes. [5] Dexmedetomidine is a newer α2 adrenergic agonist with anxiolytic, sedative, and analgesic properties with cardiovascular stability. Dexmedetomidine up to 2 μg.kg−1 has been used in FNB for prolonging the duration of analgesia.[1] However, there are very few studies regarding the efficacy of Dexmedetomidine 1 μg.kg−as an adjuvant to 0.25% Bupivacaine in FNB for ease of positioning for subarachnoid block (SAB) and for postoperative analgesia in patients undergoing femur fracture surgery. Therefore, we conducted this study to evaluate the analgesic effect of Dexmedetomidine as an Adjuvant to Bupivacaine in Ultrasound Guided Femoral Nerve Block in Patients undergoing elective surgery for femur fracture shaft of femur. The objective was to study and compare FNB with bupivacaine and bupivacaine with dexmedetomidine in fracture femur under spinal anaesthesia with regard to NRS < 3 after block for Positioning of patient during spinal anesthesia , duration of postoperative analgesia by using NRS scores, total tramadol consumption in 24 hours, patient satisfaction score at the end of the study and to assess any side effects and complications such as hypotension, bradycardia, sedation ,nausea vomiting and quadricep weakness

After Institutional Ethical Committee approval and registration in clinical trial registry India (CTRI) (CTRI no. CTRI/2023/10/058940) this Prospective, Randomized, Comparative, Interventional, double blinded study was conducted in a tertiary care centre. Based on the study by Vinod M and Malashree G[1], a sample size of 41 cases in each group was required at 80% study power and alpha error 0.05 assuming standard deviations of 97 minute. It was further enhanced to 45 patients in each group expecting 10% drop outs or attrition. After obtaining written and informed consent, a total of 90 adult patients (20–70 years) of either sex classified as American Society of Anesthesiologists (ASA) Physical Status 1, 2, and 3, unable to sit due to pain with NRS > 7, and scheduled for elective surgery for shaft of femur fracture, were allocated randomly into two study groups using computerized random number table. We identified and excluded patients with a history of psychiatric illness, on anticoagulant therapy, agitated, suspected compartment syndrome in the lower limbs, block site infection, allergic to local anesthetics, multiple traumas, presence of peripheral sensorineural deficit, and on analgesics within 8 h before performing nerve block. Patients in whom the block procedure was unsuccessful (if NRS score is not < 3 within 20 min of performing peripheral nerve block) were also excluded from the study. In all enrolled patients detailed pre-anaesthetic evaluation and relevant investigations done. Drugs and instruments required to administer general anaesthesia, an emergency resuscitation kit, and ultrasound equipment for performing the peripheral nerve block were prepared and kept ready beforehand. On patient arrival, IV line was secured and monitors were attached, preoperative NRS score was assessed and noted. Zero was interpreted as no pain and 10 was the worst possible pain. Patient was positioned supine. The upper thigh just inferior to inguinal ligament was painted and draped in a sterile manner first with 5% povidone iodine solution followed by surgical spirit. A linear 6-12 MHz ultrasound probe was utilized and placed transversely on the femoral crease. The femoral artery was identified, the probe was moved slightly lateral to visualize the femoral nerve under the fascia iliaca. The nerve appears as a hyperechoic, triangular to oval shaped structure enveloped with the two layers of the fascia iliaca. In USG guided femoral nerve block a 20 G needle was inserted using an in-plane technique, from the lateral end of the transducer. On successful placement of the needle tip close to the nerve and after confirming negative aspiration for blood, a small volume of local anaesthetic was injected. The remaining drug was injected after confirming adequate drug spread and distribution NRS Score was recorded before the block and immediately after the block at every 1 min interval up to 20 min until NRS is <3. The time taken to achieve NRS<3 was noted. When NRS Score<3 was achieved, under all aseptic precautions SAB was given in sitting position in L3-L4 space using 25 G Quincke’s needle and 0.5% hyperbaric Bupivacaine 12.5mg +25mcg of fentanyl was injected. When adequate sensory and motor blockade was achieved, surgery was started. Intraoperative parameters such as Heart Rate, SBP, DBP, MAP and SpO2 were monitored. After the completion of surgery, patient was shifted to PACU. NRS Score was assessed at hourly interval for first 6 hours, 2 hourly intervals for 12hours, and 4 hourly intervals for 24 hrs. Inj. Tramadol 100 mg was administered as a rescue analgesic when NRS was >3 and this time was noted. This time was calculated from NRS<3 after the block to request of first rescue analgesia by patient at NRS>3. Total dose of Tramadol required in 24hrs was noted, Patient’s satisfaction score was assessed and Side effects were noted. Statistical analysis was performed with the SPSS (Statistical Package for the Social science), version 21 for Windows statistical software package (SPSS inc., Chicago, II USA). Continuous data was expressed as mean± standard deviation. These data were compared in two groups and differences in means was inferred by student t test. Categorical data was presented as proportions. These data were compared in two groups and the difference in the proportions was inferred by chi-square test. The level of significance was kept 95% for all statistical analysis. p value < 0.05 was considered as significant for both types of data.

Demographic profile (Age, Gender, ASA grade, and Duration of surgery) in both the study groups were comparable. (p value<0.05) (Table no.1) The baseline NRS in Group A was 8.16 ± 0.7, while in Group B was 8±0.7. The mean time to achieve NRS < 3 was higher in Group A 4.51 ± 0.51 minutes compared to Group B 2.60 ± 0.50 minutes, with p<0.001.(Table no. 2). The mean of total duration of analgesia in Group A was 328.6 ± 29.3 minutes and in Group B was 482.2 ± 19.4 minutes, with p<0.001.(Table no. 3) The mean total dose of tramadol consumption was higher in Group A (297.8±14.91 mg) compared to Group B (275.6 ± 43.46 mg), with p=0.002. The mean value of postoperative NRS was less in group B as compared to group A at all time intervals. (Figure 2) The mean value of Baseline, intraoperative and postoperative haemodynamic parameters between both the study groups were comparable. side effects in both the groups were comparable. (Figure 1) Table 1: Demographic Profile of both Study Groups Demographic profile Group A Group B P Value Mean Age(years) 44.44±16.98 43.58±19.14 0.821 Gender (Male/Female) 37/8 30/15 0.147 ASA grade I/II/III 13/25/7 10/21/14 0.215 Mean Duration of surgery. (minutes) 110.2±19 103.3±14.1 0.054 Table 2: Comparison of time to achieve NRS<3 in study groups Group n Mean time to NRS<3 (in minutes) P value Group A 45 4.51 ± 0.51 <0.001 (S) Group B 45 2.60 ± 0.50 Table 3: Comparison of total duration of analgesia of study groups Group n Total duration of analgesia (in minutes) P value Group A 45 328.6 ± 29.3 <0.001 (S) Group B 45 482.2 ± 19.4

Central neuraxial blockade is preferred anaesthetic technique used for repair of femur fractures. Patient positioning for spinal anaesthesia in such patients may cause severe pain due to the slight sliding of fracture ends over each other. This leads to severe distress, pain, tachycardia, hypertension, and increased cardiac work load due to sympathetic hyperactivity. Effective management of perioperative pain decreases the length of hospital stay and risk of thromboembolic events. The analgesic strategies used in such patients include intravenous opioids, epidural analgesia and peripheral nerve blocks. The usage of systemic opioids has various drawbacks like pruritis, nausea, vomiting, constipation, dependence, and respiratory depression. Patients who receive epidural analgesia are prone to hypotension, and urinary retention. The administration of peripheral nerve blocks in such patients is recommended and is regarded as the gold standard analgesic strategy for pain management. FNB and FICB have been successfully used for this purpose. We have planned this study to evaluate the analgesic efficacy of Dexmedetomidine as an Adjuvant to 0.25% Bupivacaine in Ultrasound Guided Femoral Nerve Block. The mean time to achieve NRS < 3 after block was faster in Group B (2.60 ± 0.50 minutes), as compared to group A (4.51 ± 0.51 minutes) this difference was found to be statistically significant (p<0.001) so addition of dexmedetomidine in a dose of 1ug/kg results in faster onset of block. Similar results have been observed by Kumar H et al, they compared ropivacaine plus 1ug/kg dexmedetomidine to ropivacaine alone and observed that onset of analgesia was earlier in group D 3.77±0.84 as compared group R 4.6±1.1. (p<0.005) which corelate with our study. In our study the total duration of analgesia was longer in group B in which we have used 1ug/kg dexmedetomidine as an adjuvant to bupivacaine. In a similar dose comparison study, [9] authors performed femoral nerve block for knee arthroscopies using 25, 50, and 75 μg of dexmedetomidine with bupivacaine. They found a significant prolongation in duration of analgesia, especially at 50 and 75 μg doses. Helal SM et al [7] who compared 0.5% bupivacaine alone to 0.5% bupivacaine plus 100ug dexmedetomidine also found that duration of analgesia was longer in group BD by 75% than in group (P<0.01). Packiasabapathy SK et al [8] compared 1 µg.kg−1 and 2 µg.kg−1 of Dexmedetomidine to plain 0.25%Bupivacaine. They found a significantly prolonged duration of analgesia in group with 2 µg.kg−1 Dexmedetomidine as compared to the group with 1 µg.kg−1 Dexmedetomidine and plain Buivacaine group without any significant side effects. Experimental studies on dexmedetomidine as an adjuvant for nerve blocks have shown that duration of analgesia is prolonged by blocking the hyperpolarisation-activated cation current (Ih current) . Blocking the Ih current results in prolonged hyperpolarisation of the nerve, which seems to be more pronounced in unmyelinated C fibres (pain) than in Aa fibres (motor) . Blocking the Ih current may therefore have a more pronounced effect on pain than motor response It also has central effects from systemic absorption, contributing to analgesia and sedation by activating alpha-2 adrenoceptors in the brainstem. In the present study the mean total dose of tramadol consumption was lower in Group B (275.6 ± 43.46 mg) as compared to Group A (297.8 ± 14.91 mg), and this difference was found to be statistically significant (p=0.002). In a study author [9] observed that total 24 hours postoperative morphine consumption was significantly less with 75 μg dexmedetomidine (1.8 ± 2.6 mg), followed by 50 μg dexmedetomidine (3.9 ± 3.4 mg), 25 μg dexmedetomidine (6.5 ± 3.5 mg), as compared to bupivacaine alone (7.6 ± 5.1 mg). Packiasabapathy SK et al[8] also found that postoperative mean morphine consumption was significantly lower in dexmedetomidine group. In our study hemodynamic parameters such as heart rate, systolic BP, diastolic BP, mean arterial pressure, and SpO2 were comparable in both the groups and statistically not significant. Packiasabapathy SK et al [8] compared 1 µg.kg−1 and 2 µg.kg−1 of Dexmedetomidine to plain 0.25%Bupivacaine, they haven’t observed any significant side effects like bradycardia and hypotension in any group. In our study patients were more sedated in group B as compared to group A upto 5 hrs postoperatively but patients were arousable. The sedative effect of perineural dexmedetomidine is dose-dependent and peaks at 60–90 min. In a study authors[10] observed that mean Ramsay Sedation Scale score in Group A (dexmedetomidine group) was 2.2 ± 0.5 and in Group B (only bupivacaine group) it was 2 ± 0.4. This difference in mean Ramsay Sedation Scale score between two groups was not statistically significant. Regarding the side effects, the incidence of nausea and parasthesia was higher in Group A as compared to Group B, these differences were however not found to be statistically significant (p=1.000). Authors[8] also observed that there was no significant difference in adverse effects between the groups, supporting findings of our study. In our study all the patients were satisfied with quality of block in both the groups and they were very comfortable in sitting position and none of the patient developed quadriceps weakness. There are some limitations in our study as it was conducted using sample size of 90 which is a small sample size. Larger, multi centric trials are required to reproduce the results and hence providing the efficacy of the blocks. No postoperative differentiation between static and dynamic pain was done. Assessment of NRS score is a subjective variable and was a limitation that can vary with the level of communication and understanding between patient and anaesthesiologist.

We conclude that addition of perineural Dexmedetomidine at a dose of 1µg/kg as an adjuvant to Bupivacaine provided significant reduction in pain and prolonged the duration of analgesia, thereby reducing the need for post operative analgesics.

1. Vinod M, Malashree G, Goud ES, Ravikumar K. Dexmedetomidine as an adjuvant to 0.25% bupivacaine in ultrasound guided femoral nerve block for preoperative positioning and postoperative analgesia in patients undergoing elective surgery for fracture shaft of femur. Anesth Essays Res 2022;16:98-103 2. Singer BR, McLauchlan GJ, Robinson CM, Christie J. Epidemiology of fractures in 15,000 adults: the influence of age and gender. J Bone Joint Surg Br. 1998 Mar;80(2):243-8 3. Jadon A, Kedia SK, Dixit S, Chakraborty S. Comparative evaluation of femoral nerve block and intravenous fentanyl for positioning during spinal anaesthesia in surgery of femur fracture. Indian J Anaesth 2014;58:705-8 4. Natarajan P, Srinivasan KS, Dhanasekaran C, Sekaran KKN. Comparison of 0.2% bupivacaine with 0.2% ropivacaine in femoral nerve block for preoperative positioning and postoperative analgesia in femur fractures. Int J Adv Sci Res 2016;2:169-72. 5. Griffiths R, Babu S, Dixon P, et al. Guideline for the management of hip fractures 2020: Guideline by the Association of Anaesthetists. Anaesthesia. 2021;76:225-237. 6. Kumar H, Tripathi A, Somvanshi M. Efficacy of dexmedetomidine as an adjuvant to ropivacaine in femoral nerve block for acute pain relief in patients with fracture of femoral shaft and neck. Indian J Pain 2018;32:86-90. 7. Helal SM, Eskandr AM, Gaballah KM, Gaarour IS. Effects of perineural administration of dexmedetomidine in combination with bupivacaine in a femoral-sciatic nerve block. Saudi J Anaesth. 2016 Jan-Mar;10(1):18-24. doi: 10.4103/1658-354X.169469. PMID: 26955305; PMCID: PMC4760035. 8. Packiasabapathy SK, Kashyap L, Arora MK, Batra RK, Mohan VK, Prasad G, et al. Effect of dexmedetomidine as an adjuvant to bupivacaine in femoral nerve block for perioperative analgesia in patients undergoing total knee replacement arthroplasty: A dose-response study. Saudi J Anaesth 2017;11:293-8. 9. Abdulatif M, Fawzy M, Nassar H, Hasanin A, Ollaek M, Mohamed H. The effects of perineural dexmedetomidine on the pharmacodynamic profile of femoral nerve block: a dose-finding randomised, controlled, double-blind study. Anaesthesia. 2016 Oct;71(10):1177-85. doi: 10.1111/anae.13603. PMID: 27611039. 10. Gopal ND, Krishnamurthy D: A Clinical Comparative Study of Fascia Iliaca Compartment Block with Bupivacaine and Bupivacaine with Dexmedetomidine for Positioning and Duration of Postoperative Analgesia in Fracture Femur under Spinal Anesthesia.