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

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.

Study Overview

• Status: Completed
• Conditions: Orthopedic Disorders
• Intervention / Treatment: Procedure: Apposition of needle bevel against femoral nerve

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 Needle tip withdrawn 1 mm from nerve.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 Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • New York
    • New York, New York, United States, 10025
      • St. Luke's-Roosevelt Hospital Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

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

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

Study Plan

How is the study designed?

Design Details

• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Intervention; A 22 GA 5 cm nerve block needle will be advanced to the following conditions: Needle tip slightly indenting the fascia iliaca; Needle tip advanced through fascia iliaca; Needle tip slightly indenting the anterior surface of the femoral nerve; 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.

Procedure: Apposition of needle bevel against femoral nerve; Indentation of femoral nerve and fascia iliaca by block needle and measurement of opening injection pressure during the controlled injection of 1 ml of dextrose (D5W) solution

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure	Time Frame
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
Incidence of paresthesias	1 week

Collaborators and Investigators

• Sponsor: St. Luke's-Roosevelt Hospital Center
• Investigators: Study Director: Malikah Latmore, MD, Mount Sinai St. Luke's Mount Sinai Roosevelt Hospitals

Study record dates

Study Major Dates

• Study Start: October 1, 2014
• Primary Completion (Actual): March 1, 2015
• Study Completion (Actual): March 1, 2015

Study Registration Dates

• First Submitted: March 3, 2015
• First Submitted That Met QC Criteria: May 19, 2015
• First Posted (Estimate): May 22, 2015

Study Record Updates

• Last Update Posted (Estimate): April 15, 2016
• Last Update Submitted That Met QC Criteria: April 13, 2016
• Last Verified: March 1, 2015

More Information

Terms related to this study

• Keywords: femoral nerve block; ultrasound guided nerve block; fascia iliaca; opening injection pressure
• Additional Relevant MeSH Terms: Musculoskeletal Diseases
• Other Study ID Numbers: StLukeNY