Rosalita C. Maldonado

Continuous Interscalene Brachial Plexus Block via an Ultrasound-Guided Posterior Approach: A Randomized, Triple-Masked, Placebo-Controlled Study

BACKGROUND: The posterior approach for placing continuous interscalene catheters has not been studied in a controlled investigation. In this randomized, triple-masked, placebo-controlled study, we tested the hypothesis that an ultrasound-guided continuous posterior interscalene block provides superior postoperative analgesia compared to a single-injection ropivacaine interscalene block after moderately painful shoulder surgery. METHODS: Preoperatively, subjects received a stimulating interscalene catheter using an ultrasound-guided, in-plane posterior approach. All subjects received an initial bolus of ropivacaine. Postoperatively, subjects were discharged with oral analgesics and a portable infusion device containing either ropivacaine 0.2% or normal saline programmed to deliver a perineural infusion over 2 days. The primary outcome was average pain on postoperative day (POD) 1 (scale: 0–10). Secondary outcomes included least and worst pain scores, oral opioid requirements, sleep disturbances, patient satisfaction, and incidence of complications. RESULTS: Of the 32 subjects enrolled, 30 perineural catheters were placed per protocol. Continuous ropivacaine perineural infusion (n = 15) produced a statistically and clinically significant reduction in average pain (median [10th–90th percentile]) on POD 1 compared with saline infusion (n = 15) after initial ropivacaine bolus (0.0 [0.0–5.0] versus 3.0 [0.0–6.0], respectively; P < 0.001). Median oral opioid consumption (oxycodone) was lower in the ropivacaine group than in the placebo group on POD 1 (P = 0.002) and POD 2 (P = 0.002). Subjects who received a ropivacaine infusion suffered fewer sleep disturbances than those in the placebo group (P = 0.005 on POD 0 and 1 nights) and rated their satisfaction with analgesia higher than subjects who received normal saline (P < 0.001). CONCLUSIONS: Compared to a single-injection interscalene block, a 2-day continuous posterior interscalene block provides greater pain relief, minimizes supplemental opioid requirements, greatly improves sleep quality, and increases patient satisfaction after moderate-to-severe painful outpatient shoulder surgery.

Electrical stimulation versus ultrasound guidance for popliteal-sciatic perineural catheter insertion: a randomized controlled trial.

Background: Sciatic perineural catheters via a popliteal fossa approach and subsequent local anesthetic infusion provide potent analgesia and other benefits after foot and ankle surgery. Electrical stimulation (ES) and, more recently, ultrasound (US)-guided placement techniques have been described. However, because these techniques have not been compared in a randomized fashion, the optimal method remains undetermined. Therefore, we tested the hypotheses that popliteal-sciatic perineural catheters placed via US guidance require less time for placement and produce equivalent results, as compared with catheters placed using ES. Methods: Preoperatively, subjects receiving a popliteal-sciatic perineural catheter for foot and/or ankle surgery were randomly assigned to either the ES with a stimulating catheter or US-guided technique with a nonstimulating catheter. The primary end point was catheter insertion duration (in minutes) starting when the US transducer (US group) or catheter-placement needle (ES group) first touched the patient and ending when the catheter-placement needle was removed after catheter insertion. Results: All US-guided catheters were placed per protocol (n = 20), whereas only 80% of stimulation-guided catheters could be placed per protocol (n = 20, P = 0.106). All catheters placed per protocol in both groups resulted in a successful surgical block. Perineural catheters placed by US took a median (10th-90th percentile) of 5.0 min (3.9-11.1 min) compared with 10.0 min (2.0-15.0 min) for stimulation (P = 0.034). Subjects in the US group experienced less pain during catheter placement, scoring discomfort a median of 0 (0.0-2.1) compared with 2.0 (0.0-5.0) for the stimulation group (P = 0.005) on a numeric rating scale of 0 to 10. Conclusions: Placement of popliteal-sciatic perineural catheters takes less time and produces less procedure-related discomfort when using US guidance compared with ES.

Ultrasound guidance versus electrical stimulation for femoral perineural catheter insertion

Objective. Continuous femoral nerve blocks provide potent analgesia and other benefits after knee surgery. Perineural catheter placement techniques using ultrasound guidance and electrical stimulation (ES) have been described, but the optimal method remains undetermined. We tested the hypothesis that ultrasound guidance alone requires less time for femoral perineural catheter insertion and produces equivalent results compared with ES alone. Methods. Preoperatively, patients receiving a femoral perineural catheter for knee surgery were randomly assigned to either ultrasound guidance with a nonstimulating catheter or ES with a stimulating catheter. The primary outcome was the catheter placement procedure time (minutes) starting when the ultrasound transducer (ultrasound group) or catheter insertion needle (ES group) first touched the patient and ending when the catheter insertion needle was removed after catheter insertion. Results. Perineural catheters placed with ultrasound guidance (n = 20) took a median (10th–90th percentiles) of 5.0 (3.9–10.0) minutes compared with 8.5 (4.8–30.0) minutes for ES (n = 20; P = .012). All ultrasound‐guided catheters were placed according to the protocol (n = 20) versus 85% of ES‐guided catheters (n = 20; P = .086). Patients in the ultrasound group had a median procedure‐related discomfort score of 0.5 (0.0–3.1) compared with 2.5 (0.0–7.6) for the ES group (P = .015). There were no vascular punctures with ultrasound guidance versus 4 in the ES group (P = .039). Conclusions. Placement of femoral perineural catheters takes less time with ultrasound guidance compared with ES. In addition, ultrasound guidance produces less procedure‐related pain and prevents inadvertent vascular puncture.

Ultrasound Guidance Versus Electrical Stimulation for Infraclavicular Brachial Plexus Perineural Catheter Insertion

Objective. Electrical stimulation (ES)‐ and ultrasound‐guided placement techniques have been described for infraclavicular brachial plexus perineural catheters but to our knowledge have never been previously compared in a randomized fashion, leaving the optimal method undetermined. We tested the hypothesis that infraclavicular catheters placed via ultrasound guidance alone require less time for placement and produce equivalent results compared with catheters placed solely via ES. Methods. Preoperatively, patients receiving an infraclavicular perineural catheter for distal upper extremity surgery were randomly assigned to either ES with a stimulating catheter or ultrasound guidance with a nonstimulating catheter. The primary outcome was the catheter insertion duration (minutes) starting when the ultrasound transducer (ultrasound group) or catheter placement needle (stimulation group) first touched the patient and ending when the catheter placement needle was removed after catheter insertion. Results. Perineural catheters placed with ultrasound guidance took a median (10th–90th percentile) of 9.0 (6.0–13.2) minutes compared with 15.0 (4.9–30.0) minutes for stimulation (P < .01). All ultrasound‐guided catheters were successfully placed according to the protocol (n = 20) versus 70% in the stimulation group (n = 20; P < .01). All ultrasound‐guided catheters resulted in a successful surgical block, whereas 2 catheters placed by stimulation failed to result in surgical anesthesia. Six catheters (30%) placed via stimulation resulted in vascular punctures compared with none in the ultrasound group (P < .01). Procedure‐related pain scores were similar between groups (P = .34). Conclusions. Placement of infraclavicular perineural catheters takes less time, is more often successful, and results in fewer inadvertent vascular punctures when using ultrasound guidance compared with ES.

The Effects of Local Anesthetic Concentration and Dose on Continuous Infraclavicular Nerve Blocks: A Multicenter, Randomized, Observer-Masked, Controlled Study

BACKGROUND: It remains unclear whether local anesthetic concentration or total drug dose is the primary determinant of continuous peripheral nerve block effects. The only previous investigation, involving continuous popliteal-sciatic nerve blocks, specifically addressing this issue reported that insensate limbs were far more common with higher volumes of relatively dilute ropivacaine compared with lower volumes of relatively concentrated ropivacaine. However, it remains unknown if this relationship is specific to the sciatic nerve in the popliteal fossa or whether it varies depending on anatomic location. We therefore tested the null hypothesis that providing ropivacaine at different concentrations and rates, but at an equal total basal dose, produces comparable effects when used in a continuous infraclavicular brachial plexus block. METHODS: Preoperatively, an infraclavicular catheter was inserted using the coracoid approach in patients undergoing moderately painful orthopedic surgery distal to the elbow. Patients were randomly assigned to receive a postoperative perineural ropivacaine infusion of either 0.2% (basal 8 mL/h, bolus 4 mL) or 0.4% (basal 4 mL/h, bolus 2 mL) through the second postoperative day. Both groups, therefore, received 16 mg of ropivacaine each hour with a possible addition of 8 mg every 30 min via a patient-controlled bolus dose. Our primary end point was the incidence of an insensate limb during the 24-h period beginning the morning after surgery. Secondary end points included analgesia and patient satisfaction. RESULTS: Patients given 0.4% ropivacaine (n = 27) experienced an insensate limb, a mean (sd) of 1.8 (1.6) times, compared with 0.6 (0.9) times for subjects receiving 0.2% ropivacaine (n = 23; estimated difference = 1.2 episodes, 95% confidence interval, 0.5–1.9 episodes; P = 0.001). Satisfaction with postoperative analgesia (scale 0–10, 10 = highest) was scored a median (25th–75th percentiles) of 10.0 (8.0–10.0) in Group 0.2% and 7.0 (5.3–8.9) in Group 0.4% (P = 0.018). Analgesia was similar in each group. CONCLUSIONS: For continuous infraclavicular nerve blocks, local anesthetic concentration and volume influence perineural infusion effects in addition to the total mass of local anesthetic administered. Insensate limbs were far more common with smaller volumes of relatively concentrated ropivacaine. This is the opposite of the relationship previously reported for continuous popliteal-sciatic nerve blocks. The interaction between local anesthetic concentration and volume is thus complex and varies among catheter locations.

The Effects of Varying Local Anesthetic Concentration and Volume on Continuous Popliteal Sciatic Nerve Blocks: A Dual-Center, Randomized, Controlled Study

BACKGROUND: It remains unknown whether local anesthetic concentration, or simply total drug dose, is the primary determinant of continuous peripheral nerve block effects. We therefore tested the null hypothesis that providing different concentrations and rates of ropivacaine, but at equal total doses, produces comparable effects when used in a continuous sciatic nerve block in the popliteal fossa. METHODS: Preoperatively, a perineural catheter was inserted adjacent to the sciatic nerve using a posterior popliteal approach in patients undergoing moderately painful orthopedic surgery at or distal to the ankle. Postoperatively, patients were randomly assigned to receive a perineural ropivacaine infusion of either 0.2% (basal 8 mL/h, bolus 4 mL) or 0.4% (basal 4 mL/h, bolus 2 mL) through the second postoperative day. Therefore, both groups received 16 mg of ropivacaine each hour with a possible addition of 8 mg every 30 min via a patient-controlled bolus dose. The primary end point was the incidence of an insensate limb, considered undesirable, during the 24-h period beginning the morning after surgery. Secondary end points included analgesia and patient satisfaction. RESULTS: Patients given 0.2% ropivacaine (n = 25) experienced an insensate limb with a mean (sd) of 1.8 (1.8) times, compared with 0.6 (1.1) times for subjects receiving 0.4% ropivacaine (n = 25; estimated difference = 1.2 episodes, 95% confidence interval, 0.3–2.0 episodes; P = 0.009). In contrast, analgesia and satisfaction were similar in each group. CONCLUSIONS: For continuous popliteal-sciatic nerve blocks, local anesthetic concentration and volume influence block characteristics. Insensate limbs were far more common with larger volumes of relatively dilute ropivacaine. During continuous sciatic nerve block in the popliteal fossa, a relatively concentrated solution in smaller volume thus appears preferable.

Health-related quality of life after tricompartment knee arthroplasty with and without an extended-duration continuous femoral nerve block: A prospective, 1-year follow-up of a randomized, triple-masked, placebo-controlled study

BACKGROUND: We previously provided evidence that extending an overnight continuous femoral nerve block to 4 days after tricompartment knee arthroplasty (TKA) provides clear benefits during the perineural infusion in the immediate postoperative period. However, it remains unknown if the extended infusion improves subsequent health-related quality of life between 7 days and 12 mo. METHODS: Patients undergoing TKA received a femoral perineural infusion of ropivacaine 0.2% from surgery until the following morning, at which time patients were randomized to either continue perineural ropivacaine (n = 25) or normal saline (n = 25) in a double-masked fashion. Patients were discharged with their catheter and a portable infusion pump, and catheters were removed on postoperative day 4. Health-related quality of life was measured using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index preoperatively and then at 7 days, as well as 1, 2, 3, 6, and 12 mo after surgery. The WOMAC evaluates three dimensions of health-related quality of life: pain, stiffness, and physical functional disability. For inclusion in the analysis, we required a minimum of 4 of the 6 time points, including day 7 and at least 2 of mo 3, 6, and 12. RESULTS: The two treatment groups had similar WOMAC scores for the mean area under the curve calculations (point estimate for the difference in mean area under the curve for the two groups [overnight infusion group−extended infusion group] = 1.2, 95% confidence interval: −5.6 to +8.0; P = 0.72) and at all individual time points (P > 0.05). CONCLUSIONS: We found no evidence that extending an overnight continuous femoral nerve block to 4 days improves (or worsens) subsequent health-related quality of life between 7 days and 12 mo after TKA. (ClinicalTrials.gov number, NCT00135889.)

Health-Related Quality of Life After Hip Arthroplasty With and Without an Extended-Duration Continuous Posterior Lumbar Plexus Nerve Block: A Prospective, 1-Year Follow-Up of a Randomized, Triple-Masked, Placebo-Controlled Study

BACKGROUND: We previously reported that extending an overnight continuous posterior lumbar plexus nerve block to 4 days after hip arthroplasty provides clear benefits during the perineural infusion in the immediate postoperative period. However, it remains unknown whether the extended infusion improves subsequent health-related quality of life. METHODS: Patients undergoing hip arthroplasty received a posterior lumbar plexus perineural infusion of ropivacaine 0.2% from surgery until the following morning, at which time patients were randomized to continue either perineural ropivacaine (n = 24) or normal saline (n = 23) in a double-masked fashion. Patients were discharged with their catheter and a portable infusion pump, and catheters were removed on postoperative Day 4. Health-related quality of life was measured using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index preoperatively and then at 7 days and 1, 2, 3, 6, and 12 mo after surgery. The WOMAC evaluates three dimensions of health-related quality of life, such as pain, stiffness, and physical functional disability (global score of 0–96, lower scores indicate lower levels of symptoms or physical disability). For inclusion in the primary analysis, we required a minimum of three of the six timepoints, including Day 7 and at least two of Months 3, 6, and 12. RESULTS: The two treatment groups had similar global WOMAC scores for the mean area under the curve calculations (point estimate for the difference in mean area under the curve for the two groups [extended infusion group—overnight infusion group] = 0.8, 95% confidence interval: −5.3 to + 6.8 [−5.5% to + 7.1%]; P = 0.80) and at all individual timepoints (P > 0.05). CONCLUSIONS: This investigation found no evidence that extending an overnight continuous posterior lumbar plexus nerve block to 4 days improves (or worsens) subsequent health-related quality of life between 7 days and 12 mo after hip arthroplasty.