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Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block.

ABSTRACT: Whether the method of local anesthetic administration for continuous femoral nerve blocks--basal infusion versus repeated hourly bolus doses--influences block effects remains unknown.Bilateral femoral perineural catheters were inserted in volunteers (n = 11). Ropivacaine 0.1% was concurrently administered through both catheters: a 6-h continuous 5 ml/h basal infusion on one side and 6 hourly bolus doses on the contralateral side. The primary endpoint was the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle at hour 6. Secondary endpoints included quadriceps MVIC at other time points, hip adductor MVIC, and cutaneous sensation 2 cm medial to the distal quadriceps tendon in the 22 h after initiation of local anesthetic administration.Quadriceps MVIC for limbs receiving 0.1% ropivacaine as a basal infusion declined by a mean (SD) of 84% (19) compared with 83% (24) for those receiving 0.1% ropivacaine as repeated bolus doses between baseline and hour 6 (paired t test P = 0.91). Intrasubject comparisons (left vs. right) also reflected a lack of difference: the mean basal-bolus difference in quadriceps MVIC at hour 6 was -1.1% (95% CI -22.0-19.8%). The similarity did not reach the a priori threshold for concluding equivalence, which was the 95% CI decreasing within ± 20%. There were similar minimal differences in the secondary endpoints during local anesthetic administration.This study did not find evidence to support the hypothesis that varying the method of local anesthetic administration--basal infusion versus repeated bolus doses--influences continuous femoral nerve block effects to a clinically significant degree.

SUBMITTER: Charous MT

PROVIDER: S-EPMC3116995 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature

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Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block.

Charous Matthew T MT Madison Sarah J SJ Suresh Preetham J PJ Sandhu NavParkash S NS Loland Vanessa J VJ Mariano Edward R ER Donohue Michael C MC Dutton Pascual H PH Ferguson Eliza J EJ Ilfeld Brian M BM

Anesthesiology 20111001 4

<h4>Background</h4>Whether the method of local anesthetic administration for continuous femoral nerve blocks--basal infusion versus repeated hourly bolus doses--influences block effects remains unknown.<h4>Methods</h4>Bilateral femoral perineural catheters were inserted in volunteers (n = 11). Ropivacaine 0.1% was concurrently administered through both catheters: a 6-h continuous 5 ml/h basal infusion on one side and 6 hourly bolus doses on the contralateral side. The primary endpoint was the ma ...[more]

PMID: 21394001

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Project description:BackgroundIt remains unknown whether continuous or scheduled intermittent bolus local anesthetic administration is preferable for transversus abdominis plane (TAP) catheters. We therefore tested the hypothesis that when using TAP catheters, providing local anesthetic in repeated bolus doses increases the cephalad-caudad cutaneous effects compared with a basal-only infusion.MethodsBilateral TAP catheters (posterior approach) were inserted in 24 healthy volunteers followed by ropivacaine 2 mg/mL administration for a total of 6 hours. The right side was randomly assigned to either a basal infusion (8 mL/h) or bolus doses (24 mL administered every 3 hours for a total of 2 bolus doses) in a double-masked manner. The left side received the alternate treatment. The primary end point was the extent of sensory deficit as measured by cool roller along the axillary line at hour 6 (6 hours after the local anesthetic administration was initiated). Secondary end points included the extent of sensory deficit as measured by cool roller and Von Frey filaments along the axillary line and along a transverse line at the level of the anterior superior iliac spine at hours 0 to 6.ResultsAlthough there were statistically significant differences between treatments within the earlier part of the administration period, by hour 6 the difference in extent of sensory deficit to cold failed to reach statistical significance along the axillary line (mean = 0.9 cm; SD = 6.8; 95% confidence interval -2.0 to 3.8; P = .515) and transverse line (mean = 2.5 cm; SD = 10.1; 95% confidence interval -1.8 to 6.8; P = .244). Although the difference between treatments was statistically significant at various early time points for the horizontal, vertical, and estimated area measurements of both cold and mechanical pressure sensory deficits, no comparison remained statistically significant by hour 6.ConclusionsNo evidence was found in this study involving healthy volunteers to support the hypothesis that changing the local anesthetic administration technique (continuous basal versus hourly bolus) when using ropivacaine 0.2% and TAP catheters at 8 mL/h and 24 mL every 3 hours significantly influences the cutaneous effects after 6 hours of administration. Additional research is required to determine whether changing variables (eg, local anesthetic concentration, basal infusion rate, bolus dose volume, and/or interval) would provide different results.

Project description:Background:Peripheral nerve blocks, particularly femoral nerve blocks (FNBs), are commonly performed for anterior cruciate ligament (ACL) reconstruction. However, associated quadriceps muscle weakness after FNBs is well described and may occur for up to 6 months postoperatively. The adductor canal block (ACB) has emerged as a viable alternative to the FNB, theoretically causing less quadriceps weakness during the immediate postoperative period, as it bypasses the majority of the motor fibers of the femoral nerve that branch off proximal to the adductor canal. Purpose/Hypothesis:This study sought to identify if a difference in quadriceps strength exists after an ACB or FNB for ACL reconstruction beyond the immediate postoperative period. Beyond the immediate postoperative period, we anticipated no difference in quadriceps strength between patients who received ACBs or FNBs for ACL reconstruction. Study Design:Randomized controlled trial; Level of evidence, 1. Methods:A total of 102 patients undergoing primary ACL reconstruction using a variety of graft types were enrolled between November 2015 and April 2016. All patients were randomized to receive an ACB or FNB before surgery, and the surgeon was blinded to the block type. All patients underwent aggressive rehabilitation without functional bracing postoperatively. The time to the first straight-leg raise was reported by the patient. Isokinetic strength testing was performed at 3 and 6 months postoperatively. Results:Data for 73 patients were analyzed. There was no significant difference in patient demographics of age, body mass index, sex, or tourniquet time between the FNB (n = 35) and ACB (n = 38) groups. The mean time to the first straight-leg raise was similar, at 13.1 ± 1.0 hours for the FNB group and 15.5 ± 1.2 hours for the ACB group (P = .134). The mean extension torque at 60 deg/s increased significantly for both the ACB (53.7% ± 3.4% to 68.3% ± 2.9%; P = .008) and the FNB (53.3% ± 3.3% to 68.5% ± 4.1%; P = .006) groups from 3 to 6 months postoperatively. There was also no significant difference in mean extension torque at 60 deg/s or 180 deg/s between the FNB and ACB groups at 3 and 6 months. There were no significant differences in postoperative complications (infection, arthrofibrosis, retear) between groups. Conclusion:Although prior studies have shown immediate postoperative benefits of ACBs compared with FNBs, with a faster return of quadriceps strength, in the current study there was no statistically or clinically significant difference in quadriceps strength at 3 and 6 months postoperatively in patients who received ACBs or FNBs for ACL reconstruction.

Project description:BACKGROUND:Traumatic injury of the femur resulting in femoral fracture may result in significant postoperative pain. As with other causes of acute pain, regional anesthesia may offer a benefit over conventional therapy with intravenous opioids. This study prospectively assesses the effects of femoral nerve blockade with a lateral femoral cutaneous nerve block (FN-LFCN) on intraoperative anesthetic requirements, postoperative pain scores, and opioid requirements. MATERIALS AND METHODS:Seventeen pediatric patients (age 2-18 years) undergoing surgical repair of a traumatic femur fracture fulfilled the study criteria and were randomly assigned to general anesthesia with either an FN-LFCN block (n = 10) or intravenous opioids (n = 7). All patients received a general anesthetic with isoflurane for maintenance anesthesia during the surgical repair of the femur fracture. Patients randomized to the FN-LFCN block group received ultrasound-guided nerve blockade using ropivacaine (0.2%/0.5% based on patient weight). At the conclusion of surgery, the airway device was removed once tracheal extubation criteria were achieved, and patients were transported to the post-anesthesia care unit (PACU) for recovery and assessment of pain by a blinded study nurse. RESULTS:The final study cohort included 17 patients (n = 10 for FN-LFCN block group; n = 7 for the intravenous opioid group). Although the median of the maximum postoperative pain scores in the regional group was 0, this did not reach statistical significance when compared to the median pain score of 3 in the intravenous opioid group. Likewise, no difference between the two groups was noted when comparing intraoperative anesthetic requirements, opioid requirements (intraoperative, in the post-anesthesia recovery room, and in the inpatient ward), and the time to first opioid requirement postoperatively in the inpatient ward. CONCLUSION:This prospective, randomized, double-blinded study failed to demonstrate a clear benefit of regional anesthesia over intravenous opioids intraoperatively and postoperatively during repair of femoral shaft fractures in the pediatric population.

Project description:PurposeTo evaluate the effect of the single-shot quadratus lumborum (QL) block versus femoral nerve and fascia iliacus (F/FI) blocks performed preoperatively on perioperative opioid requirements, subjective pain scores, and time to discharge.MethodsPatients who underwent hip arthroscopy for femoroacetabular impingement and had a preoperative nerve block between January 2017 and August 2019 at our institution were identified. Patients were separated into 2 groups: those who either received a preoperative single-shot QL block or a preoperative single-shot F/FI block. All patients received general anesthesia. Intraoperative, postanesthesia care unit (PACU), and total morphine equivalents were analyzed using unpaired t test. Secondary outcome measures including total time in PACU and block-related complications were recorded and analyzed as well.ResultsOne hundred one patients were retrospectively reviewed. Forty-three patients received preoperative QL blocks, and 58 patients received preoperative F/FI blocks. Demographics and operative characteristics were similar between the 2 groups. Patients receiving a QL block required significantly lower total morphine equivalents (63.1 vs 87.0, P < .001). Patients receiving a QL block also had shorter PACU stays (116 vs 148 minutes, P < .001) and lower subjective pain scores at the time of discharge (3.27 vs 4.98, P < .001) compared with the F/FI block group. There were also significant decreases in the number of intraoperative opioids (42.1 vs 58.4, P < .001) and PACU opioids (20.7 vs 28.7, P = .03) used when analyzed separately. Two patients in the femoral nerve block group had noted a fall postoperatively while the block was in effect. No patients in the QL block group had a block-related complication.ConclusionsPatients receiving a preoperative QL block for hip arthroscopy demonstrated lower total opioid requirements, shorter PACU stay, and lower pain scores at discharge than patients receiving preoperative F/FI blocks with no reported adverse events.Level of evidenceLevel III, retrospective comparative trial.

Project description:Fractured neck of femur generally requires operative fixation and is a common cause of admission to hospital. The combination of femoral nerve block and spinal anesthesia is a common anesthetic technique used to facilitate the surgical procedure. The optimal disposition of local anesthetic (LA) relative the femoral nerve (FN) has not been defined. Our hypothesis was: that the deposition of LA relative to the FN influences the quality of analgesia for positioning of the patient for performance of spinal anesthesia. The primary outcome was verbal rating (VRS) pain scores 0-10 assessed immediately after positioning the patient to perform spinal anesthesia.With Institutional ethical approval and having obtained written informed consent from each, 52 patients were studied. The study was registered with ClinicalTrials.gov (NCT01527812). Patients were randomly allocated to undergo to one of three groups namely: intention to deposit lidocaine 2% (15 ml) i. above (Group A), ii. below (Group B), iii. circumferential (Group C) to the FN. A blinded observer assessed i. the sensory nerve block (cold) in the areas of the terminal branches of the FN and ii. VRS pain scores on passive movement from block completion at 5 minutes intervals for 30 minutes. Immediately after positioning the patient for spinal anesthesia, VRS pain scores were recorded.Pain VRS scores during positioning were similar in the three groups [Above group/Below group/Circumferential group: 2(0-9)/0(0-10)/3(0-10), median(range), p:0.32]. The block was deemed to have failed in 20%, 47% and 12% in the Above group, Below group and Circumferential group respectively. The median number of needle passes was greater in the Circumferential group compared with the Above group (p:0.009). Patient satisfaction was greatest in the Circumferential group [mean satisfaction scores were 83.5(19.8)/88.1(20.5)/93.8(12.3), [mean(SD), p=0.04] in the Above, Below and Circumferential groups respectively.We conclude that there is no clinical advantage to attempting to deposit LA circumferential to the femoral nerve (relative to depositing LA either above or below the nerve), during femoral nerve block in this setting.

Dataset Information

Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block.

Publications

Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block.

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