Ultrasound guidance of needle tip position for femoral nerve blockade: An observational study

Generic versus reference listed ropivacaine for peripheral nerve blockade: A randomised, triple-blinded, crossover, equivalence study in volunteers

BACKGROUND

Generic drug preparations do not require the same degree of scrutiny as the originally licensed preparation before they can be approved for clinical use. The permitted tolerance limits for bioequivalent preparations might be associated with clinically relevant differences for drugs with a narrow therapeutic index, such as local anaesthetics.

OBJECTIVE

We compared pharmacokinetic and pharmacodynamic characteristics of generic and reference listed or original preparations of ropivacaine.

DESIGN

The current healthy volunteer study used a randomised, triple-blinded, cross-over equivalence design.

SETTING

Tertiary university hospital, Medical University of Vienna.

SUBJECTS

Healthy male volunteers (N=18) aged 18 to 60 years.

INTERVENTIONS

A series of three ultrasound-guided ulnar nerve blocks separated by at least 6 days were carried out on each volunteer. Reference listed ropivacaine (NaropinTM) was used for two blocks and a generic preparation of ropivacaine was used for the other block. Sensory block onset and duration were evaluated using loss of pinprick sensation.

MAIN OUTCOME MEASURES

Duration of sensory block was the primary outcome. Secondary outcomes included time-to-onset of sensory block, ropivacaine pharmacokinetics from venous blood samples and pH of the preparations. Equivalence was evaluated using the ratios of means and 90% confidence intervals (CIs) of log transformed data.

RESULTS

Equivalence was demonstrated for the primary outcome measure, the duration of sensory block [original : generic ratio 1.01 (90% CI 0.87 to 1.16); P < 0.007] and all pharmacokinetic variables. Equivalence could not be concluded for time-to-onset of sensory block [reference : generic ratio 0.80 (90% CI 0.63 to 1.03); P = 0.27], although reproducibility of this variable using our experimental model was lower than for other variables. The generic preparation was significantly more alkaline [difference 0.06 pH units (95% CI 0.04 to 0.07); P < 0.0001].

CONCLUSION

Our finding of equivalence for sensory block duration and key pharmacokinetic variables between a generic and original preparation of ropivacaine is reassuring. The significant, but small, difference in pH is not clinically important.

TRIAL REGISTRATION

EudraCT 2019-003148-61, German Clinical Trials Register (DRKS 00017750).

Femoral nerve excursion with knee and neck movements in supine, sitting and side-lying slump: An in vivo study using ultrasound imaging

BACKGROUND

Neurodynamic assessment and management are advocated for femoral nerve pathology. Contrary to neurodynamic techniques for other nerves, there is limited research that quantifies femoral nerve biomechanics.

OBJECTIVES

To quantify longitudinal and transverse excursion of the femoral nerve during knee and neck movements.

DESIGN

Single-group, experimental study, with within-participant comparisons.

METHODS

High-resolution ultrasound recordings of the femoral nerve were made in the proximal thigh/groin region in 30 asymptomatic participants. Scans were made during knee flexion in supine and a semi-seated position, and during neck flexion in side-lying slump (Slump _FEMORAL). Healthy participants were assessed to reveal normal nerve biomechanics, not influenced by pathology. Data were analysed with one-sample and paired t-tests. Reliability was assessed with intraclass correlation coefficients (ICC).

RESULTS

Longitudinal and transverse excursion measurements were reliable (ICC≥0.87). With knee flexion, longitudinal femoral nerve excursion was significant and larger in supine than in sitting (supine (mean (SD)): 3.6 (2.0) mm; p < 0.001; sitting: 1.1 (1.6) mm; p = 0.001; comparison: p = 0.001). There was also excursion in a medial direction (supine: 1.4 (0.3) mm; p < 0.001; sitting: 0.7 (0.6) mm; p < 0.001) and anterior direction (supine: 0.2 (0.2) mm; p < 0.001; sitting: 0.1 (0.2) mm; p = 0.06). Neck flexion in Slump _FEMORAL did not result in longitudinal (0.0 (0.3) mm; p = 0.55) or anteroposterior (0.0 (0.1) mm; p = 0.10) excursion, but resulted in medial excursion (1.1 (0.5) mm; p < 0.001).

CONCLUSION

Although the femoral nerve terminates proximal to the knee, femoral nerve excursion in the proximal thigh occurred with knee flexion; Neck flexion in Slump _FEMORAL resulted in medial excursion.

Intravenous analgesia with opioids versus femoral nerve block with 0.2% ropivacaine as preemptive analgesic for fracture femur: A randomized comparative study

BACKGROUND AND OBJECTIVE

Femoral fractures are extremely painful and pain invariably worsens on any movement. Anesthesia for fracture femur surgery is usually provided by spinal block. This study was undertaken to compare the analgesic effects of femoral nerve block (FNB) using nerve stimulator with 0.2% ropivacaine (15 ml) and intravenous (I.V.) fentanyl before patient positioning for fracture femur surgery under spinal anesthesia.

MATERIALS AND METHODS

A prospective, randomized, double-blind, comparative study was conducted on 60 American Society of Anesthesiologists I and II patients (18-60 years) scheduled for femur surgery under combined spinal epidural anesthesia. Patients in Group I (n = 30), were administered FNB using nerve stimulator with 0.2% ropivacaine (15 ml) and in Group II patients (n = 30), I.V. fentanyl 0.5 μg/kg was given as preemptive analgesia. Parameters observed included time to spinal anesthesia, intra-operative and postoperative visual analog scale (VAS) for any pain and postoperative epidural top-ups dosages.

RESULTS

Demographic profile was comparable in both the groups. VAS at 2 min in Group I was 5.63 and in Group II it was 8.00. Satisfaction score was better in Group I as compared to Group II patients. Time to administer subarachnoid block was 17.80 min in patients of Group I as compared to 25.03 min in Group II patients. Postoperatively, VAS scores were lower in Group I than Group II patients. The frequency of epidural top-ups was higher in Group II than in Group I patients.

CONCLUSIONS

FNB is comparatively better in comparison to I.V. fentanyl when used as preemptive and postoperative analgesic in patients being operated for fracture femur.