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

Medical University of South Carolina45 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Conditions

Arthroplasty, Replacement, Knee Nerve Block

Interventions

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Intravenous patient-controlled analgesia opioid consumption

Time frame: Cumulative IV-PCA use was recorded until femoral nerve catheter removed on postoperative day 2.

Visual analog pain scale score

Time frame: Preop; Immediately postoperatively in PACU; Postoperative day (POD) 0 at 8pm; POD 1 at 8am, 2pm & 8pm; POD 2 at 8am

Secondary Outcomes

Visual analog scale patient satisfaction scores

Time frame: POD 1 at 8am; POD 2 at 8am

Incidence of physician administered "rescue" boluses of the femoral nerve catheter

Hospital length of stay