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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 9  |  Issue : 3  |  Page : 233-239

Comparison of preemptive analgesia with bupivacaine versus bupivacaine-dexmedetomidine in femoral block for fracture femur


Department of Anaesthesiology, Dr. D. Y. Patil Medical College, Dr. D. Y. Patil University, Pimpri, Pune, Maharashtra, India

Date of Submission22-Feb-2020
Date of Decision16-Apr-2020
Date of Acceptance20-May-2020
Date of Web Publication28-Jul-2020

Correspondence Address:
Dr. Aparna Bagle
Department of Anaesthesiology, Dr. D. Y. Patil Medical College, Dr. D. Y. Patil University, Pimpri, Pune, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijhas.IJHAS_4_20

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  Abstract 


BACKGROUND: Patients with fracture femur experience very severe pain and anxiety. These patients require adequate analgesia to allow radiological, orthopedic, and other procedures. An ideal analgesic technique should provide pain relief without altering consciousness. Femoral nerve block (FNB) has been proved very effective in providing satisfactory analgesia in fracture femur patients. Dexmedetomidine has analgesic property when used as an adjuvant in regional anesthesia.
MATERIALS AND METHODS: This prospective, double-blind randomized comparative study was conducted on sixty American Society of Anesthesiologists I and II patients scheduled for elective fracture femur surgeries. They were divided into equal groups of thirty patients. FNB was given 15 min prior to spinal anesthesia. Group B received injection 0.25% bupivacaine 20 ml + 0.5 ml normal saline in FNB, while Group D received injection 0.25% bupivacaine 20 ml + injection. Dexmedetomidine 1 μg/kg, making a total volume of 0.5 ml. Hemodynamic variables, Visual Analog Score (VAS) score, and duration of analgesia were recorded from baseline till the end of surgery and 2 h postoperatively. Statistical analysis was done using SPSS version 20.0 (IBM software product, USA).
RESULTS: Duration of analgesia for Group B was 5.37 ± 0.56 h and for Group D was 6.63 ± 0.86 h. Duration of analgesia was prolonged in Group D. Fall in VAS was significantly higher in Group D after 10 min of femoral block compared to Group B. Although changes in heart rate, systolic blood pressure, and mean arterial pressure were statistically significant in both the groups, patients were hemodynamically stable.
CONCLUSION: Addition of dexmedetomidine in a dose of 1 μg/kg to bupivacaine 0.25% in FNB effectively reduces pain associated with positioning for spinal anaesthesia and prolong the duration of analgesia and without significant hemodynamic alteration.

Keywords: Bupivacaine, dexmedetomidine, femoral nerve block, fracture femur, preemptive analgesia


How to cite this article:
Bagle A, Solanki SP, Gulia T, Gaur S, Gaidhani C, Pujari S. Comparison of preemptive analgesia with bupivacaine versus bupivacaine-dexmedetomidine in femoral block for fracture femur. Int J Health Allied Sci 2020;9:233-9

How to cite this URL:
Bagle A, Solanki SP, Gulia T, Gaur S, Gaidhani C, Pujari S. Comparison of preemptive analgesia with bupivacaine versus bupivacaine-dexmedetomidine in femoral block for fracture femur. Int J Health Allied Sci [serial online] 2020 [cited 2020 Aug 6];9:233-9. Available from: http://www.ijhas.in/text.asp?2020/9/3/233/290719


  Introduction Top


The International Association for the Study of Pain has defined pain as “an unpleasant sensory and emotional experience, associated with actual or potential tissue damage or described in terms of such damage.”[1]

Effective pain control is vital for early mobilization and postoperative early discharge. Despite advances in the knowledge of pathophysiology of pain, pharmacology of analgesics, and development of effective techniques, many patients continue to experience considerable discomfort.[2] It is our responsibility to treat pain.

Premptive analgesia is defined as a treatment that is initiated before surgery in order to prevent the establishment of central sensitization evoked by the incisional and inflammatory injuries occurring during surgery and in the early postoperative period.[3] Owing to this protective effect on the nociceptive system, premptive analgesia has the potential to be more effective than a similar analgesic treatment. As a consequence, premptive analgesia prevents the development of chronic pain by decreasing the altered central sensory processing.

Fracture femur is a common injury, which causes severe pain and distress. Fracture femur is a particularly painful bone injury as the periosteal tissue is highly supplied by nerve fibers from femoral nerve, and the periosteum exhibits the lowest pain threshold of all deep somatic structures. It causes moderate-to-severe pain, which requires effective analgesia both preoperatively and postoperatively. Thus, adequate pain management before surgical preparation for any positioning, transforming, and immobilization of patients is crucial for management.[4] Fracture femur may involve the femoral neck or femoral shaft or distal femur. The repair most commonly involves either internal fixation of the fracture or replacement of the femoral head with arthroplasty surgically.

Subarachnoid block was used commonly than general anesthesia for femoral fracture surgery. However, any kind of movement of the patient leads to intense pain.[5] Adequate pain relief in these patients not only increases comfort in these patients, but has also been shown to improve positioning for spinal anesthesia. Multimodal analgesics or femoral nerve block (FNB) are often given to such patients to help them tolerate positioning.

Multimodal analgesic regimens which include nonsteroidal anti-inflammatory drugs (NSAIDs), opioids and various regional analgesic techniques, for example, peripheral nerve blocks such as the FNB, 3 in 1 block, and the fascia iliaca block, have been used in femur surgeries so far. NSAIDs even in moderate dose cause adverse effects, especially in the elderly population. Although opioids are potent analgesics, they are associated with serious adverse effects such as drowsiness, nausea, respiratory depression, and constipation, limiting their use.

Femoral nerve blockade is widely practiced by physicians in a variety of circumstances, i.e., analgesia for femur fractures in pre-hospital medicine, in the accident and emergency departments and in the clinical setting of perioperative care.[6] Femoral nerve blockade is likely to be the most widely performed lower limb block. FNB was first administered as per the technique described by Winnie et al. Femoral block increases comfort and also been shown to improve positioning for a spinal anesthesia in fracture femur patients. To improve the quality of peripheral nerve blocks, many adjuvants to local anesthetics have been investigated over the years.[7] One such agent is dexmedetomidine; it is a potent as well as highly selective alpha-2 adrenergic agonist having a sedative, sympatholytic, and analgesic effect and have been described as a safe and effective additive in many anesthetic applications and analgesic techniques. The physiological response resulting from the stimulation of alpha-2 adrenergic receptors varies and depends on their location, in the nervous system their stimulation decreases calcium entry in the nerve terminals resulting in an inhibitory effect on the neurotransmitter release, thus facilitating analgesia.[8] It has an alpha-2/alpha-1 selectivity ratio of 1600:1, which is eight times more potent than clonidine (200:1).

We tried to evaluate the effect of addition of dexmedetomidine with bupivacaine on analgesic efficacy, hemodynamic effects, side effects, and duration of analgesia in FNB.


  Materials and Methods Top


After obtaining approval from the Institutional Ethics Committee and written informed consent from all the patients, sixty American Society of Anesthesiologists (ASA) physical status I-II patients of 18–70 years scheduled for fracture femur surgery under spinal anesthesia were included in this prospective, randomized, double-blind, comparative study. ASA Grade 3 and more, patient not willing to be a part of the study, patients with known sensitivity to any drugs under study were excluded from the study. By keeping the significance level of 5%, power of study at 80%, the sample size was calculated by WinPepi Statistical Package, Winpepi Version 11.3 (Abramson JH).

The cases were selected after a thorough preanesthetic assessment, including detailed history, clinical evaluation, and relevant lab investigations (complete blood count, urine examination, bleeding time, and clotting time). Preanesthetic evaluation was carried out in all patients. A day prior, patients were counseled with regard to femoral block, spinal anesthesia, as well as the operative procedure. The visual analog scale (Visual Analog Score [VAS] 0 – no pain and 10 – maximum pain) was explained to the patient during the preoperative visit.

Patients were fasted 6 h before the procedure; clear fluids were allowed up to 3 h. Tablet alprazolam 0.25 mg night before surgery was given. In the preoperative room, multiparamonitor (electrocardiogram, pulsox, noninvasive blood pressure) was attached. Intravenous access was secured with 18G intracath and preloading with lactated Ringer's solution 10 ml/kg was done. Oxygen was given via face mask to all the patients. Patients received femoral block guided by a peripheral nerve stimulator. Under all aseptic precaution, the procedure was carried out by placing the patient supine. After identifying the anterior superior iliac spine and the pubic symphysis, a line was drawn between these two landmarks. This line represented the inguinal ligament. Then, palpation of the femoral pulse was done and marked in the inguinal crease. The point of needle entry was directly lateral (1–1.5 cm) to the femoral artery in the inguinal crease. At this landmark, the femoral nerve is maximally wide and superficial. The needle was directed cephalad toward the center of the inguinal ligament line. The nerve stimulator was initially set at 1.0–1.2 mA. Then needle was directed cephalad at approximately 30°–45° angle. A brisk “patellar snap” with the current of 0.5 mA or less was indicative of successful localization of the needle near the femoral nerve. The nerve being superficial lies within 3 cm from the skin and lateral to the femoral artery. Already prepared study drug was given according to patient's allocation to the either study group.

Patients were randomly assigned to Group B and Group D depending on the drug injected in FNB. Randomization was done by computer-generated random number table. Group B (n = 30) received 0.25% injection bupivacaine 20 ml +0.5 ml normal saline and Group D (n = 30) received 0.25% injection bupivacaine 20 ml + dexmedetomidine 1 μg/kg making volume 0.5 ml in femoral block.

Anesthesiologists who administered the drug and the observer were blinded to the study. Sterile syringes containing equal volumes of study drugs depending on group allocation were loaded by another anesthesiologist not concerned or participating in the study. Perioperative monitoring was done by the same anesthesiologist who administered the drug, but unaware of the content of the syringes.

After performing FNB, quantitative relief of pain using VAS was assessed at interval of 3 min, 5 min, 10 min, and 15 min. Then, the patients were shifted to operating room. Spinal anesthesia was performed in sitting position while checking VAS during positioning. After confirming the appropriate interspace (L3–L4 or L4–L5), 2% lignocaine 2 cc was injected, the subarachnoid block was performed using 25G Quinckes needle and 3 ml of 0.5% bupivacaine (H) was injected after obtaining a clear flow of cerebrospinal fluid. Time to perform spinal anesthesia was recorded. The time of onset, maximum level, and duration of sensory block were recorded. After completion of the surgery, patients were shifted to recovery room and observed in recovery for 4 h and after recording motor blockade, hemodynamic parameters shifted to ward. VAS was noted postoperatively half hourly for first 2 h. If VAS >5, rescue analgesia was given with injection diclofenac 75 mg intramuscular and duration of analgesia was noted from the time of femoral block to VAS >5.


  Results Top


The pulse rate among both the study groups was studied at baseline and after femoral block and postoperatively. There was no significant difference found in the pulse rate between the two groups.

The mean arterial blood pressure was comparable in both the groups and at 5, 10, 15, 30, 45, and 60 min after femoral block [Graph 1].



The mean arterial blood pressure was differed significantly between both the study groups at 3 min, 90 min, and 120 min after femoral block, which was clinically insignificant and not required vasopressure [Graph 2].



The mean VAS score preoperatively differed significantly between both the study groups at 10 min after femoral block, and postoperatively VAS score differed significantly between both the study groups after 60, 90, and 120 min of surgery The VAS score was significantly higher in the Group B than the Group D. While the score differed nonsignificantly at baseline, during positioning (after 15 min of FNB), and at 3, 5, and 15 min after femoral block and 30 min of postoperative. The mean ± standard deviation (SD) values of patients mean preoperative VAS score in both the groups are depicted in [Graph 3].



The mean duration of analgesia between the groups of patients consuming only bupivacaine (Group B) was significantly lower as compared to the patients who were given bupivacaine with dexmedetomidine (Group D). The mean ± SD values of duration of analgesia in both the groups are shown in [Table 2].

The most common side effects of bupivacaine and bupivacaine with dexmedetomidine were hypotension, bradycardia, nausea, sedation, pruritis, and neuropathy. The incidences of these side effects were recorded among the study groups. Hypotension was recorded in two and four patients in Groups B and D, respectively. Bradycardia was seen only in two patients in Group D, while there was no incidence reported of other side effects of these drugs. The results are presented in [Graph 4] [Table 1] and [Table 2].
Table 1: Pulse rate (bpm) at baseline, after femoral block and postoperative

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Table 2: Comparison of mean duration of analgesia between Group B and Group D

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  Discussion Top


In the present era of trauma, it has been observed that femur fracture patients suffer from severe pain and anxiety. Patients with femur fracture require a continuum of pain management from the time of prehospital admission till final rehabilitation. Pain causes spasm of the thigh muscles, which leads to displacement of the broken bone ends and therefore a vicious cycle of more pain and consequent spasm follows. This pain arises from periosteum which is the most sensitive structure in the body. The nerve supply for periosteum of superficial bone is derived from the nerves to the overlying skin and the deeper bone by motor branches to the nearby muscle. These patients require surgical correction and therefore needs anesthesia to perform the surgical procedures.

Universally accepted and preferred technique of anesthesia for surgery of fracture femur is spinal anesthesia. The advantages of spinal anesthesia over general anesthesia are early mobility, less chances of deep-vein thrombosis, and mortatility.[9] In fracture femur, patients the major problem encountered for spinal anesthesia is pain associated with patient positioning for the same. For such surgical procedures, the problems are further heightened if the patients are obese.

Sandby-Thomas et al. reported that the most frequently used agents to allow for positioning of trauma patients for regional anesthesia have been midazolam, ketamine, and propofol. Alternative agents such as fentanyl, remifentanil, morphine, nitrous oxide, and sevoflurane have also been used, whereas nerve blocks were used infrequently. To produce analgesia of the lower limb, femoral block and sciatic block was described by Crile G as early as 1902,[10] but it gained popularity after Fenwick who introduced the method at the Sydney Hospital in 1957.[11] It provides adequate analgesia in patients with fracture femur.

The advantages of FNB are adequate pain relief, minimizes muscle spasm within a short time, decreases pain during radiological procedures which necessitates patient movement, and the fracture can be reduced and splinted without the need for general anesthesia in the acute phase. As the block is unilateral, there is no risk of hemodynamic alterations. It is quick and easy to perform with minimum equipment. Different techniques to perform FNB are: using peripheral nerve stimulator, ultrasound guided technique or by loss of resistance technique. In present study, we used peripheral nerve stimulator technique.

For pain relief in fracture femur various researches have been conducted FNB with local anesthetic agents with good results, but the duration of analgesia and patient acceptance is still not sufficient to avoid the use of another modality of analgesia. To prolong the duration of analgesia, local anesthetics along with various adjuvant drugs such as epinephrine, opioids, midazolam, ketamine, and neostigmine have been evaluated, but they were found to be either ineffective or produced an unacceptably high incidence of adverse effects. Therefore, an ideal adjuvant drug should have rapid onset of action, be safe, easily administrable providing prolong duration of analgesia.

In regional anesthesia, alpha-2 adrenergic agonists when used as an adjuvant have analgesic and sedative property. These agents are very effective as an adjuvant in regional anesthesia as they have faster onset of action, rapid establishment of both sensory and motor blockades, prolonged duration of analgesia and stable cardiovascular parameters.

The proposed mechanism for the action of alpha-2 adrenoceptor agonist in peripheral nerve blockades are centrally mediated analgesia, alpha-2 adrenoceptor mediated vasoconstrictive effects, attenuation of the inflammatory response, and direct action on a peripheral nerve.

Dexmedetomidine has been used clinically for sedation and anxiolysis in the intensive care unit and procedural sedation and has also been used preoperatively for premedication to decrease emergence delirium, to attenuate the stress response of anesthesia and surgery and treatment of postoperative pain.[12] The idea of perineural administration of dexmedetomidine was conceived in the last decade, following the successful use of clonidine in nerve blocks. The perineural action of clonidine is mediated through the inhibition of hyperpolarization-activated cation current (I [H]) rather than through alpha-2-mediated mechanism.[13]

Dexmedetomidine is a newer alpha-2 adrenergic agonist. As compared to clonidine, dexmedetomidine has high affinity for binding to the alpha 2/alpha 1 receptors with 1600:1 ratio whereas for clonidine it is 220:1 ratio. Dexmedetomidine has also been proposed to act by inhibiting hyperpolarization-activated cation current like clonidine.

The initial animal studies carried out by Brummett et al. showed a significant increase in the duration of analgesia achieved by perineural dexmedetomidine, without significant neurotoxicity. This was followed by the studies of perineural dexmedetomidine on healthy human volunteers [14] and on surgical patients, most of which consistently demonstrated a prolong analgesic effect without significant adverse effects.

In the current study, we have used and compared the effectiveness of bupivacaine 0.25% 20 ml alone and mixture of bupivacaine with dexmedetomidine (1 μg/kg).

Demographic profile

The patients in both the groups were comparable in terms of their age, gender, weight, duration of surgery, and ASA grading (P > 0.05).

Hemodynamic parameters

Baseline parameters

In our study, baseline values (before administrating any drug) of heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were comparable in both the Groups B and D.

We observed statistically significant fall but no clinically significance in the mean HR, SBP, DBP, and MAP levels as compared to their basal value in both the groups, and the fall was much more in Group D than in Group B. This might be due to systemic absorption of dexmedetomidine from the site of drug administration, which inhibits sympathetic activity and provides better analgesia and sedation.

Visual analog score

VAS differed significantly between both the groups at 10 min after femoral block and 60, 90, and 120 min postoperatively. The VAS score was significantly higher in the Group B with than the Group D (P < 0.0001).

Similarly in 2018, Hemant et al.[15] in their study of the efficacy of dexmedetomidine added to ropivacaine in FNB for pain relief in patients with fracture of femur found that the VAS score at 5 min after the block was significantly decreased to 3.63 ± 1.04 in Group D compared to 4.56 ± 1.33 in Group R.

In 2007, Schiferer et al.[16] conducted a randomized controlled trial of femoral nerve blockade administered preclinically for pain relief in femoral trauma and concluded that in patients receiving the femoral nerve blockade, pain values decreased by half from VAS 86 ± 6 mm at the site of the accident to VAS 41 ± 15 mm during transport. Anxiety decreased by half from VAS 84 ± 11 mm to VAS 39 ± 14 mm.

In 2015, Somvanshi et al.[17] studied FNB for acute pain relief in fracture shaft femur in emergency ward and found VAS scores decreased significantly from 9.12 ± 0.9, preblock VAS score to 1.84 ± 1.25, and VAS score at 10 min after the block (P < 0.001).

However, the addition of dexmedetomidine to bupivacaine results in more significant fall in VAS scores because of its analgesic action.

Duration of analgesia

The average duration of analgesia for Group B patients was 5.37 ± 0.56 h and Group D patients was 6.63 ± 0.86 h.

Statistically, the difference between two groups was highly significant (P < 0.05). Similar prolongation of analgesia was seen in different studies.

In 2018, Hemant et al.[15] studied the efficacy of dexmedetomidine added to ropivacaine in FNB for pain relief in patients with fracture of femur and showed that the mean duration of analgesia was prolonged in group with dexmedetomidine (744.33 ± 179.6 min) than that in group with ropivacaine (263 ± 67 min).

In 2017, Packiasabapathy et al.[18] compared bupivacaine alone and dexmedetomidine 1 and 2 ug/kg with bupivacaine in FNB for perioperative analgesia in patients undergoing total knee replacement (TKR) arthroplasty. They showed that the mean duration of analgesia was significantly longer with higher dosage (2 μg/kg) of dexmedetomidine (6.66 h) compared to its lower dosage (5.70 h) and bupivacaine alone (4.55 h).

In 2016, Bhawana et al.[19] showed that addition of dexmedetomidine as adjuvant to ropivacaine in FNB in adult patients undergoing unilateral TKR under spinal anaesthesia, prolongs the duration and enhance the quality of analgesia. The mean pain scores were significantly low till 2 h postoperatively with dexmedetomidine. Time to first demand rescue analgesia was statistically prolonged with dexmedetomidine with mean duration of 346.8 ± 240 min, compared to 150 ± 115.2 min with ropivacaine (P = 0.001).

In 2016, Helal et al.[20] studied the effect of perineural administration of dexmedetomidine in combination with bupivacaine in a femoral-sciatic nerve block. They showed that sensory and motor blockade durations were longer in bupivacaine with dexmedetomidine (+45%) as compared to bupivacaine alone.

Side effects

Only two patients out of thirty developed hypotension among the Group B and four patients out of thirty developed hypotension in Group D. Bradycardia was only seen in two patients out of thirty in Group D. There was no incidence reported of any other side effect.

There are mixed reports on the incidence of systemic adverse effects with perineural dexmedetomidine. A few of the above-mentioned studies have observed significant bradycardia and hypotension after dexmedetomidine use,[20] which we did not noticed in our study. Considering the low incidence of systemic adverse effects associated with perineural dexmedetomidine, our study was not powered to find any significant difference in the incidence of adverse effects between the groups. A large, adequately powered study might be required to demonstrate the same.


  Conclusion Top


Addition of dexmedetomidine in a dose of 1ug/kg to bupivacaine 0.25% in FNB effectively reduces pain associated with positioning for spinal anaesthesia and prolongs the duration of analgesia and without significant hemodynamic alteration.

Limitation

There were some limitations of the study. First, our study was conducted on ASA Grades I and II patients. Hence, further studies on elderly patients and those with compromised cardiac function are required to recommend its use in such group of high-risk patients; second, absence of ultrasound to perform FNB. As ultrasound-guided nerve blocks are reported to be safe with minimum failure rate, they provide better localization of nerve and minimum requirement of drug volume. We have used peripheral nerve stimulation (PNS) guided femoral block as we are not having ultrasound in our setup. In spite of the use of PNS guided FNB we did not observed any failed block or injury to the nerve in our study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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