The Efficacy of Automated Intermittent Boluses for Continuous Femoral Nerve Block: a Prospective, Randomized Comparison to Continuous Infusions

Study Overview
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Brief Summary
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The optimal infusion technique (continuous rate vs. intermittent bolus) for peripheral nerve blocks has not been established. To our knowledge, this is the first study to compare the efficacy of an automated intermittent bolus technique to a continuous rate of infusion of local anesthetic in femoral nerve catheters. We hypothesized that the intermittent bolus technique would provide enhanced analgesia compared to a continuous infusion rate as assessed by intravenous patient-controlled analgesia (IV-PCA) hydromorphone consumption and visual analog scale (VAS) pain scores.

Official Title
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The Efficacy of Automated Intermittent Boluses for Continuous Femoral Nerve Block: a Prospective, Randomized Comparison to Continuous Infusions

Conditions
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Arthroplasty, Replacement, Knee, Nerve Block

Intervention / Treatment
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* Other: Automated intermittent bolus


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists (ASA) physical status 1 through 3 elective, primary, unilateral TKA Exclusion Criteria: patient refusal pregnancy diabetic neuropathy or any other neurologic or neuromuscular disease rheumatoid arthritis current coagulopathy skin infection at needle insertion site for the femoral or sciatic blocks significant renal or hepatic impairment unsuccessful femoral or sciatic block or femoral catheter placement femoral catheter dislodgement after placement inability to understand VAS pain scales inability to use an IV-PCA pump

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Continuous infusion rate<br>Patients received a continuous infusion of 0.2% ropivacaine at 10.1 mL/hr via their femoral nerve catheter. | Other: Automated intermittent bolus<br>* Automated intermittent bolus delivery method of 0.2% ropivacaine at 5 mL every 30 minutes with a basal infusion of 0.1 mL/hr.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intravenous patient-controlled analgesia opioid consumption |  | Cumulative IV-PCA use was recorded until femoral nerve catheter removed on postoperative day 2. | 
| Visual analog pain scale score |  | Preop; Immediately postoperatively in PACU; Postoperative day (POD) 0 at 8pm; POD 1 at 8am, 2pm & 8pm; POD 2 at 8am | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual analog scale patient satisfaction scores |  | POD 1 at 8am; POD 2 at 8am | 
| Incidence of physician administered rescue boluses of the femoral nerve catheter |  |  | 
| Hospital length of stay |  |  |