Clinical trial NCT02451813: The Relationship Between Needle Position and Injection Pressure During Femoral Nerve Block
Official title: The Relationship Between Needle Position and Injection Pressure During Femoral Nerve Block
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Orthopedic Disorders
Keywords: opening injection pressure
femoral nerve block
fascia iliaca
ultrasound guided nerve block
Lead sponsor: St. Luke's-Roosevelt Hospital Center
Sponsor class: OTHER
First posted: 2015-05-22
Enrollment: 20
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP

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 Needle tip withdrawn 1 mm from nerve.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.

Eligibility criteria: 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

Primary outcomes:
measure: Incidence of high opening injection pressure (15 psi or greater) when needle tip in contact with nerve
timeFrame: 1 minute
Secondary outcomes:
measure: Incidence of high opening injection pressure (15 psi or greater) at other needle locations
timeFrame: 1 minute
measure: Minimum threshold current to elicit a motor response with needle-nerve contact and needle disengagement
timeFrame: 1 minute
measure: Incidence of paresthesias
timeFrame: 1 week
Other outcomes:
Locations:
city: New York
country: United States
facility: St. Luke's-Roosevelt Hospital Center
state: New York
Study officials:
affiliation: Mount Sinai St. Luke's Mount Sinai Roosevelt Hospitals
name: Malikah Latmore, MD
role: STUDY_DIRECTOR
References: