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 Table of Contents  
Year : 2019  |  Volume : 5  |  Issue : 2  |  Page : 167-172

Femoral nerve block versus fentanyl & dexmedetomidine analgesia for positioning patients with fracture femur for administering subarachnoid block: A comparative study

1 Dept of Anaesthesiology & Critical Care Medicine, IGIMS, Patna, India
2 Dept. of Emergency Medicine, Max Hospital, New Delhi, India

Date of Submission14-Jan-2019
Date of Acceptance15-May-2019
Date of Web Publication12-Aug-2019

Correspondence Address:
Sanjeev Kumar
Professor, Dept. of Anaesthesiology, IGIMS, Patna
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Source of Support: None, Conflict of Interest: None

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Fracture of the femur is one of the common traumatic injuries encountered in the emergency departments. Satisfactory pain relief prior to subarachnoid block for surgical interferenceis desirable for patient’s co-operation. Such relief can be provided byuse of systemic analgesics, local anaesthesia, or femoral nerve blocks. This study was conducted on 60 patients after randomly allocation into two groups of 30 patients each. Group A has been received the femoral nerve block with 20 ml of 0.5% bupivacaine 15 minutes before the subarachnoid block while group B has been received intravenous fentanyl at 0.5^g/kg single shot & intravenous dexmedetomidine 1 ^g/kg over 15 minutes before the subarachnoid block and concluded that femoral nerve blocks produces a more intense analgesia with fewer side effects than systemic analgesic.

Keywords: Femoral nerve blocks (FNB), Fractured Neck of Femur (FNF), Sub-arachnoid Block, Single Shot Fentanyl, Dexmedetomidine

How to cite this article:
Lakhanpal M, Kumar R, Kumar S, Harshwardhan, Raghwendra K H. Femoral nerve block versus fentanyl & dexmedetomidine analgesia for positioning patients with fracture femur for administering subarachnoid block: A comparative study. J Indira Gandhi Inst Med Sci 2019;5:167-72

How to cite this URL:
Lakhanpal M, Kumar R, Kumar S, Harshwardhan, Raghwendra K H. Femoral nerve block versus fentanyl & dexmedetomidine analgesia for positioning patients with fracture femur for administering subarachnoid block: A comparative study. J Indira Gandhi Inst Med Sci [serial online] 2019 [cited 2023 Feb 5];5:167-72. Available from: http://www.jigims.co.in/text.asp?2019/5/2/167/301105

  Introduction : Top

Trauma is a leading cause of morbidity and mortality all over the world. Recently, major advancements have been evolved for managing trauma victims, which not only enhanced relieve of pain in trauma victims, but has also been shown lessen morbidity, early ambulation and improve long-term outcomes. Fracture of the femur is not an infrequent injury especially in elderly encountered to the emergency departments. Adequate pain relief before administrating subarachnoid block will increase patient’s co-operation. Analgesia can be provided in form of systemic analgesics, local anaesthesia, or femoral nerve blocks (FNB)[1],[2]. Fractured Neck of Femur (FNF) frequentlyneeds operative interfere like fixation with screw etc[3]. FNB produces a more intense analgesia with fewer side effects than systemic opiates[4] and NSAIDs. Spinal anaesthesia (Subarachnoid Block) is one of the techniques of regional anaesthesia for alleviating pain; it proffers the advantage of producing localized and very effective pain relief[5] and usually performed with the patient in the lateral decubitus position. Positioning the patient for this can be very painful; avoidance of this discomfort is a common and unsolved problem for Anaesthesiologists. Pain management in the elderly can be challenging due to the presence of co-morbidities. Before positioning a patient with FNF for Sub-arachnoid Block, FNB can provide excellent pain relief and is generally well tolerated[6],[7],[8],[9].

Ideally ultrasound-guidance for peripheral nerve blockade is intended to improve the block success rate and it is increasingly used around and for extending the duration of analgesia; continuous peripheral nerve block is usually provided by use of peri-neural catheter placement.

  Review of Literature : Top

Peripheral neural blockade techniques of were developed near the beginning of the history of anaesthesia. The idea of injecting cocaine into nerve trunks is credited to William Halsted and Alfred Hall (1884). Carl Schleich introduced infiltration local anaesthesia in 1892 as an alternative to direct injection of nerve trunks. Further studies of peripheral nerve blocks were conducted by different researchers and which were introduced for pain relief as well as anaesthesia for peripheral limb surgeries. FNB has been used successfully in fracture femur patients who have unbearable pain, which reflects on their physiological and psychological aspects. It has also been used for analgesia in peri-hospital and emergency trauma units, thus avoiding systemic analgesics and their side effects. Multiple studies have been conducted for the same and few of them have been stated below. Haddad et al (1995)[6], Marhofer (1998)[10], Barriot et al. (1988)[11], Tam and Rainer (2005)[1], Mutty CE et al (2008)[12], E. Fiutek and ZFiutek (2008)[13] and lamaroon et al (2010)[14] had observed effects of femoral nerve block in various patient and was found to be effective at all levels of femur fracture site and concluded that femoral nerve blockade is a simple, safe and effective method of achieving the pain relief in fracture neck femur.

Szielard et al (2012)[15] carried out the study to investigate the analgesic efficacy of continuous femoral nerve block (CFNB) in patients with fractural neck of femur (FNF) and the study results suggested that CFNB periods was more effective perioperative analgesia. Tran et al. (2014)[16] conducted narrative review for the evidence to derive from randomized controlled trialspertaining to the efficacy of peripheral nerve blocks in non-operative settngs and suggested that peripheral nerve blocks can provide pain control for upper limb and lower limb trauma in non- operative settngs. Trivedi et al (2014)[17] conducted a study to evaluate the analgesic effect of Ropivacaine in comparison with Bupivacaine in femoral nerve block (FNB) for positioning of patient for subarachnoid block in patients with fracture femur and concluded that FNB provides effective analgesia in patients with fracture femur for positioning of patient before sub-arachnoid block.

  Materials and Methods : Top

The present clinical study was conducted to evaluate the efficacy of FNB with bupivacaine versus intravenous fentanyl in comparison with dexmedetomidine for analgesia to facilitate better positioning for spinal anaesthesia. The study was undertaken in the Indira Gandhi Institute of Medical Sciences, Patna during 2015-2016. For this study only those patients were considered which had age between 18-80 years, ASA physical status I-III and fracture femur undergoing surgery under sub- arachnoid block.

Those patients were excluded from study had haemorrhagic diathesis, peripheral neuropathy, psychiatric disorders, allergy to local anaesthetics, on opioid therapy/analgesics, polytrauma & head injury, refusal for procedure and morbid obesity.

Patients were randomized and allocated into two Groups of 30 patients each before spinal anaesthesia.

Group-A: Received the FNB with 20 ml of 0.5% bupivacaine 15 minutes before the subarachnoid block.

Group-B: Received i.v. Fentanyl at 0.5μg/kg single shot & i.v.

Dexmedetomidine 1 μg/kg over 15 minutes before the subarachnoid block.

Haemodynamic variables like heart rate, non-invasive blood pressure; saturation of oxygen, respiratory rate has been recorded before and during the procedures at two minute intervals. The quality of the sensory block was assessed by using the pinprick test in the central sensory region of each of the three nerves compared with the same stimulation on the contralateral leg. The rating was undertaken using a scale from 0 - No sensory sensation, 1 - Less sensory sensation and 2-Uncompromised sensibility.The analgesia provided by either of the modes was subjectively assessed by using Visual analogue scale scores before and after at 5 minutes and thereafter every 2 minutes up to 15 minutesthe procedures. Objective assessments were done by measuring the degree of hip flexion, before and after the procedure using goniometer The quality of patient positioning for administering spinal anaesthesia wa s also record ed by another anaesthesiologist blinded to the mode of analgesia with scores of 0-3 (0 - Not Satisfactory, 1 - Satisfactory, 2-Good and 3-Optimal).

Post operatively, patient analgesic requests in the first 24 hours were also assessed. Post-operative analgesia was standardized in all patients with i.v. Paracetamol 1gm QID (1st dose at skin closure), Intramuscular Tramadol 0.5- 0.7mg/kgor Diclofenac 75mg SOS.

  Statistical Analysis : Top

The data present in the electronic format was abstracted from the Microsoft Excel database and imported into SPSS statistical software’s and analyzed using different statistical methods. Descriptive data presented as mean ± Standard deviation (SD) and percentages. Continuous data were analyzed by using students independent Sample’t’ test. The p value of 0.05 or less than was considered for statistically significant.

  Results : Top

Demographics of patients according to age height, weight and sex were not significantly different between the treatment Groups (p value > 0.05).

The mean score of pin prick test for Group-A was lower than that of Group-B from 2 minutes to 15 minutes. The results of t-test reveal that there is no significant difference between mean score of pin prick test for the treatment groups except the mean score at 8 minutes [Table 1]. This implies that only mean score at 8 min was significantly different from Group-A and Group-B (p value < 0.05).
Table 1: Results of Pin Prick Test

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[Table 2] shows the descriptive statistics of Heart rate. The mean heart rate of patients from Group-A was slightly higher than that of Group-B for all the time period. The results of t-test reveal that there is no significant difference between mean heart rate for the treatment Groups (p value >0.05).
Table 2: Descriptive statistics of Heart rate

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The mean systolic blood pressure of patients from Group-A was slightly higher than that of Group-B form baseline to 15 minutes. The results of t-test reveal that there is no significant difference between mean systolic blood pressure for the treatment Groups (p value >0.05)[Table 3]. The same was observed in mean diastolic blood pressure [Table 4].
Table 3: Descriptive statistics of Systolic Blood Pressure

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Table 4: Descriptive statistics of Diastolic Blood Pressure

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The mean respiratory rate of patients from Group-A was slightly higher than that of Group-B form baseline to 15 minutes. The results of t-test reveal that there is no significant difference between mean respiratory rate for the treatment Groups (p value >0.05) [Figure 1].
Figure 1: Mean Respiratory Rate

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The range of the mean SPO2 is 99-100% for the treatment Groups. The mean SPO2 of patients from Group-A and Group-B was almost similar. The results of t-test reveal that there is no significant difference between mean SPO2 for the treatment Groups (p value >0.05) [Table 5].
Table 5: Descriptive statistics of SPO2

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Patients in Group-A reported smaller pain scores (VAS) as compared to Group-B at each time point upto 15 minutes [Figure 2]. The results of t-test reveal that there is significant difference between mean VAS score for the treatment Groups at 9 minutes, 11 minutes and 15 minute s (p value <0.05).
Figure 2: VAS Score for the study Groups

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Postoperative Paracetamol consumption within 24 hours was same in both the groups, whereas consumption of Diclofenac and Tramadol was more in group B as compared to group A [Figure 3], [Figure 4], [Figure 5].
Figure 3: Postoperative Paracetamol consumption within 24 hours

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Figure 4: Postoperative total Diclofenac consumption within 24 hours

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Figure 5: Postoperative total Tramadol consumption within 24 hours

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  Discussion : Top

Trauma can produce significant pain especially in the long bone fractures prior to its proper stabilization. This is because of presence of significant number of nerve endings located in the periosteum and mineralized bone[18]. Regional anaesthesia for lower extremity fractures, including femur and hip fractures, has been extensively studied in the literature. Meta-analyses suggest that regional anaesthesia, specifically central neuraxial anesthesia, reduces the incidence of deep venous thrombosis (DVT) and pulmonary embolism as well as the incidence of postoperative confusion, as well to reducing the risk of postoperative pneumonia in patients who require surgical stabilization[19],[20].

A study suggests that under-used technique of FNB is simple, effective, and cheap method of analgesia if used in emergency department[21]. Another study showed that FNB effectively decreases pain, anxiety, and heart rate after femoral trauma[22]. A study also suggest that it is effective in relieving pain and muscle spasm cause by fractured bone and help for positioning during conduct of regional anaesthesia, even when patients’ legs are placed in traction[23].

Subarachnoid block is routinely used for definitive treatment of femur fracture at our institution. Even a slight movement and sittng position to perform a subarachnoid blockade results in overriding of the fracture ends and is extremely painful, almost always requires analgesics[23] may be in form of peripheral nerve block or systemic analgesics. As the patients of femur fractures are elderly, it is better to avoid systemic analgesics which are having more complications compared to peripheral nerve block. The techniques like ultrasound guided nerve blocks and nerve locator assisted blocks offer the advantage of being more objective as the nerves can be identified more accurately and avoid possible injury to the nerve and surrounding structures. A peripheral nerve locator is relatively simple to use while ultrasonography needs availability, experience and expertise in the field. In the present study peripheral nerve locator is used to perform femoral nerve block with bupivacaine in a series of such patients and compared the findings with those of a control Group.

The foremost conclusion of our study was that FNB offered better-quality analgesia for positioning patients with fracture femur for administering subarachnoid block. In addition, FNB it was associated with greater patient satisfaction. Most of the other studies have described the successful use of FNB as analgesia in the emergency department[6],[24]. Parker et al stated that nerve blocks reduced pain score and analgesic requirements[25]. However, some of the studies have investigated FNB to facilitate positioning during conduct of regional anaesthesia. The patients included in our study were ASA grade I-III. Szucs et al 2012 also reported that most of the patients have ASA grade I and II.5.Results of the present study also supported the same as the study finding depicts the similar figures i.e in Group-A exactly 50% were grade II patients and 11(36.67%) were grade I patients and also the same was observed in Group B.

In treatment group almost 40% patient’s quality of positioning had satisfactory and around 30% patients had not satisfactory and good respectively and around 10% patients had optimal.

After spinal anaesthesia it is essential to determine the adequacy of the block. This determination is usually performed with the use of a needle pinprick test[26],[27]. A needle pinprick test is performed by lightly poking the skin, starting at the groin and moving cephalad at 1-2inch intervals until the patient verifies the intensity of the pinprick is the same as an unanesthetized area[28]. Our findings of the pinprick test reveals that mean score of pinprick test were not equal when assessing after receiving the femoral nerve block and receiving intravenous fentanyl. This was also proved statistically. The results also showed that the sensory block was high in Group-A as compared to Group-B.

We found the heart rate, blood pressure and respiratory rate of patients in Group-A was slightly higher than that of Group-B. We also found there was no significant difference between the mean heart rate, blood pressure and respiratory rate between two Groups. The same was reported by Marhofer et al (2000)29.The findings of the reveals that range of the mean SPO2 is 99-100% for the treatment Groups and almost similar. This was also proved statistically.

Gosavi et al evaluated pain during change of position from supine to sittng after FNB with lidocaine and VAS scores were 2.7 ± 1.130 VAS values during placement in the sittng position were lower in the FNB Group as compared to i.v. Fentanyl i.e. 0.5 ± 0.5 versus 3.3 ± 1.4 respectively9. Mosaffa et al compared i.v. Fentanyl with fascia iliaca block using Lidocaine. VAS values during placement in the lateral decubitus position were lower in the fascia iliaca block Group i.e 0.5 (0-1) versus 4 (2-6) for fascia iliaca block and i.v.Fentanyl respectively[31].ln our study, the results revealed that the post-operative pain was less in Group-A and it was higher in the Group- B. This finding is supported by the requirement of post-operative analgesia consumption within 24 hours.

The data related to consumption of analgesia showed that, there was a requirement of Paracetamol in major of the study subjects and few for Diclofenac during 24 hours of post-operative period, whereas in Group-B, there was request of all the three types of analgesia (Paracetamol, Diclofenac and Tremadol) in most of the study population. This is because of intravenous fentanyl had a shorter extent of analgesia and needed more top ups in postoperatively compare to FNB. This can be explained because fentanyl acts at the central level and has a shorter duration of action of 2-4 hours[32]. FNB reduces the time to perform spinal anesthesia, increases the postoperative duration of analgesia and reduces analgesic requirements postoperatively. This study also revealed that there was no complication induced by FNB technique in either group.

  Conclusion : Top

Pain relief is awfully important in the management of fracture of lower limb. Proper analgesia in the early stages of care will promote comfort and confidence; and later on, if pain is poorly controlled, early mobilization will be delayed; bringing with it the usual complications of prolonged bed rest and increase the risks of postoperative delirium. Although major lacuna in using this technique is due to lack of confidence and expertise in taping the Femoral Nerve and also lack of facility for USG guided FNB in many small healthcare setups across India, but these issues need to be met by continuous training and also providing funds to the small healthcare setups from the Government and other stake holders. This study recommends the clinicians for FNB to be considered in femoral fractures pain management even though further researches are warranted to detect smaller difference in terms of pain or analgesic consumption or with different dose or concentration of the local anaesthetic, which may have beneficial effect.

  References Top

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


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