The Relationship Between Needle Position and Injection Pressure During Femoral Nerve Block

Not Applicable

Completed

• Conditions: Orthopedic Disorders
• Interventions: Procedure: Apposition of needle bevel against femoral nerve

• Registration Number: NCT02451813
• Lead Sponsor: St. Luke's-Roosevelt Hospital Center

Brief Summary

Recent evidence suggests that injection pressure monitoring may be able to predict needle nerve contact in the brachial plexus nerve block model, but little is known about multifascicular nerves. The investigators hypothesize that injection pressure monitoring can reliably predict needle-nerve contact during femoral nerve block.

Detailed Description

Single center, observational study. Patients scheduled for elective lower limb surgery with femoral nerve block will be recruited. Femoral nerve will be identified using a linear ultrasound transducer. A 22 GA 5 cm nerve block needle will be inserted with bevel downward and advanced to the following conditions:

1. Needle tip slightly indenting the fascia iliaca lateral to the femoral nerve

2. Needle tip advanced through fascia iliaca

3. Needle tip slightly indenting the anterior surface of the femoral nerve

4. Needle tip withdrawn 1 mm from nerve.

At each of these conditions, 1 ml of dextrose solution will be injected via an automated pump at 10 ml/min and the spread of injectate observed sonographically. Simultaneously, a blinded observer will measure opening injection pressure using both an electronic and a mechanical transducer. If opening pressure reaches 15 psi, this investigator will halt the injection. In addition, minimum threshold current required to elicit a motor response will be recorded for conditions 3 and 4. Patients will be contacted at 7 days and asked about any adverse effects.

Study Timeline

• Study Start: 2014-10
• Status Verified: 2015-03
• Primary Completion: 2015-03
• Study Completion: 2015-03
• Study First Submitted: 2015-03-03
• Study First Submitted QC: 2015-05-19
• Study First Posted: 2015-05-22
• Last Update Submitted: 2016-04-13
• Last Update Posted: 2016-04-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Age 18-65
• ASA physical status I-III
• scheduled for lower limb surgery where femoral block is part of intended analgesic plan

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Exclusion Criteria

• Contraindication to femoral nerve block (e.g. infection)
• BMI > 35 kg/m2
• inability to communicate postoperative symptoms
• pre-existing neurologic deficits in the operative extremity
• allergy to local anesthetics
• history of opioid dependence

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Intervention	Apposition of needle bevel against femoral nerve	A 22 GA 5 cm nerve block needle will be advanced to the following conditions: 1. Needle tip slightly indenting the fascia iliaca 2. Needle tip advanced through fascia iliaca 3. Needle tip slightly indenting the anterior surface of the femoral nerve 4. Needle tip withdrawn 1 mm from nerve. At each of these conditions, 1 ml of dextrose solution will be injected and spread of injectate observed sonographically. A blinded observer will measure injection pressure. If opening pressure reaches 15 psi, this investigator will halt the injection. In addition, minimum threshold current required to elicit a motor response will be recorded for conditions 3 and 4.

Primary Outcome Measures

Name	Time	Method
Incidence of high opening injection pressure (15 psi or greater) when needle tip in contact with nerve	1 minute

Secondary Outcome Measures

Name	Time	Method
Incidence of paresthesias	1 week
Incidence of high opening injection pressure (15 psi or greater) at other needle locations	1 minute
Minimum threshold current to elicit a motor response with needle-nerve contact and needle disengagement	1 minute

Trial Locations

Locations (1)

St. Luke's-Roosevelt Hospital Center; 🇺🇸 New York, New York, United States