NavParkash S. Sandhu

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.

Continuous Femoral Nerve Blocks: Varying Local Anesthetic Delivery Method (Bolus versus Basal) to Minimize Quadriceps Motor Block while Maintaining Sensory Block

Background: Whether the method of local anesthetic administration for continuous femoral nerve blocks—basal infusion versus repeated hourly bolus doses—influences block effects remains unknown. Methods: Bilateral femoral perineural catheters were inserted in volunteers (n = 11). Ropivacaine 0.1% was concurrently administered through both catheters: a 6-h continuous 5 ml/h basal infusion on one side and 6 hourly bolus doses on the contralateral side. The primary endpoint was the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle at hour 6. Secondary endpoints included quadriceps MVIC at other time points, hip adductor MVIC, and cutaneous sensation 2 cm medial to the distal quadriceps tendon in the 22 h after initiation of local anesthetic administration. Results: Quadriceps MVIC for limbs receiving 0.1% ropivacaine as a basal infusion declined by a mean (SD) of 84% (19) compared with 83% (24) for those receiving 0.1% ropivacaine as repeated bolus doses between baseline and hour 6 (paired t test P = 0.91). Intrasubject comparisons (left vs. right) also reflected a lack of difference: the mean basal-bolus difference in quadriceps MVIC at hour 6 was −1.1% (95% CI −22.0–19.8%). The similarity did not reach the a priori threshold for concluding equivalence, which was the 95% CI decreasing within ± 20%. There were similar minimal differences in the secondary endpoints during local anesthetic administration. Conclusions: This study did not find evidence to support the hypothesis that varying the method of local anesthetic administration—basal infusion versus repeated bolus doses—influences continuous femoral nerve block effects to a clinically significant degree.

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.

Sonographically guided infraclavicular brachial plexus block in adults: a retrospective analysis of 1146 cases.

Objective. The aim of this study was to analyze our experience in 1146 cases of sonographically guided infraclavicular brachial plexus block (ICBPB) performed over 32 months. Methods. Anesthetic records of 1146 cases of sonographically guided ICBPB performed by our staff were studied retrospectively with the use of a database created by an automated anesthesia record‐keeping system. The rates of successful blocks, failed blocks necessitating conversion to general anesthesia or requiring supplementation with local anesthetics, those requiring larger‐than‐usual doses of sedation, and complications were determined. Analysis included an attempt to determine the possible causes of inadequate blocks and complications. Results. In 1138 patients (99.3%), the block was successful. Six patients had incomplete blocks requiring general anesthesia, and another 2 patients needed local anesthetic supplementation by the surgeons. Ninety‐seven percent of the blocks were performed by residents directly supervised by an attending anesthesiologist who held the ultrasound probe. The mean age ± SD of the patients was 39 ± 15 years; the mean duration of surgery was 165 ± 114 minutes; and the male‐female ratio was 4:1. More than 50% of patients were obese. There were no reported cases of nerve injury, pneumothorax, or local anesthetic toxicity. Arterial punctures occurred in 8 (0.7%) patients, but all were inconsequential. Conclusions. The data from this retrospective study suggest that sonographic guidance provides a high success rate (99.3%) and improved safety for ICBPB. The increased operator team experience virtually eliminates failure and complications.

Feasibility of an Infraclavicular Block With a Reduced Volume of Lidocaine With Sonographic Guidance

Objective. A successful brachial plexus block requires a large volume of a local anesthetic. Sonography allows reliable deposition of the anesthetic around the cords of the brachial plexus, potentially lowering the anesthetic requirement. Methods. Fifteen sonographically guided infraclavicular blocks were performed in 14 patients with 2% carbonated lidocaine with epinephrine through a 17‐gauge Tuohy needle. The amount of lidocaine injected at several points around each cord was based on satisfactory spread observed sonographically. A 19‐gauge catheter was then placed with its tip between the posterior cord and axillary artery, and tip position was confirmed by observing the spread of 1 to 2 mL of injected air. Lidocaine was injected through the catheter if necessary to prolong the blocks. Results. Surgery was performed in all patients without general anesthesia, rescue blocks, or infiltration. A heroin user was given an additional 50 μg of fentanyl before the block. One patient required 5 mL of lidocaine through the catheter for an incomplete radial nerve block 5 minutes after initial injection. Seven patients received additional midazolam (mean, 2.5 mg) for alleviation of anxiety despite excellent blocks. The mean ± SD volume of lidocaine for the initial block was 16.1 ± 1.9 mL (4.2 ± 0.9 mg/kg). In 4 patients, additional lidocaine 1 hour after an initial successful block increased the total volume to 19.5 ± 7.1 mL (5 ± 1.9 mg/kg). The mean times to perform the block, onset of the block, and achieving surgical anesthesia and the duration of surgery were 10.8 ± 3.3, 2 ± 1.3, 5.9 ± 2.6, and 92.7 ± 54.4 minutes, respectively. Conclusions. A successful infraclavicular block in adults with 14 mL of lidocaine is feasible with the use of sonography. The reduced volume does not seem to affect the onset but shortens the duration of the block.

Ultrasound-guided transversus abdominis plane catheters and ambulatory perineural infusions for outpatient inguinal hernia repair.

Background and Objectives: Transversus abdominis plane (TAP) blocks anesthetize the lower abdominal wall, and TAP catheters have been used to provide prolonged postoperative analgesia after laparotomy. The use of TAP catheters on an outpatient basis has not yet been described. We present our experience with ultrasound-guided TAP perineural catheter insertion and subsequent management of ambulatory TAP local anesthetic infusions after inguinal hernia repair. Methods: Three patients scheduled for unilateral open inguinal hernia repair underwent preoperative posterior TAP catheter placement for postoperative pain management using a technique employing ultrasound guidance alone. A bolus of local anesthetic solution was injected via the catheter in divided doses, and block onset was confirmed before surgery. Postoperatively, a continuous infusion of ropivacaine 0.2% was delivered using a portable infusion pump, and patients were discharged with a prescription for oral analgesics for breakthrough pain and perineural infusion instructions. Patients were followed up daily by telephone. Results: All patients underwent successful TAP catheter insertion and maintained their catheters until postoperative day 2. All patients reported minimal pain for the duration of infusion without the need for any supplemental opioid analgesics, high satisfaction with postoperative analgesia, and no infusion-related complications. Conclusions: An ultrasound-guided TAP catheter and ambulatory local anesthetic perineural infusion are a promising option for prolonged postoperative analgesia after outpatient inguinal hernia repair. A posterior insertion permits preoperative placement by keeping the catheter away from the planned surgical field.

Transpectoral ultrasound-guided catheterization of the axillary vein: An alternative to standard catheterization of the subclavian vein

Subclavian vein catheterization is associated with failure and complications because of injury to the nearby lung and subclavian artery. Its position, sandwiched between the clavicle and the first rib, makes sonographic imaging difficult. The medially pointed sonography probe makes it difficult to align the needle as well as image the entire needle. The axillary vein lies outside of the thoracic cage and can be easily imaged in its longitudinal view along with the entire needle, guidewire, dilator, and catheter in real-time. All described techniques of venous access using sonography have used transverse images of veins, and the needle is not completely visualized. Five cases of axillary vein catheterization using longitudinal section images of the vein, and following the needle, guidewire, and line with real-time sonography, are described. The use of longer puncture needles and introducer sheaths is suggested. A larger study is required to assess the potential of this technique.

A randomized comparison of infraclavicular and supraclavicular continuous peripheral nerve blocks for postoperative analgesia.

Background: Although the efficacy of single-injection supraclavicular nerve blocks is well established, no controlled study of continuous supraclavicular blocks is available, and their relative risks and benefits remain unknown. In contrast, the analgesia provided by continuous infraclavicular nerve blocks has been validated in randomized controlled trials. We therefore compared supraclavicular with infraclavicular perineural local anesthetic infusion following distal upper-extremity surgery. Methods: Preoperatively, subjects were randomly assigned to receive a brachial plexus perineural catheter in either the infraclavicular or supraclavicular location using an ultrasound-guided nonstimulating catheter technique. Postoperatively, subjects were discharged home with a portable pump (400-mL reservoir) infusing 0.2% ropivacaine (basal rate of 8 mL/hr; 4-mL bolus dose; 30-min lockout interval). Subjects were followed up by telephone on an outpatient basis. The primary outcome was the average pain score on the day after surgery. Results: Sixty subjects were enrolled, with 31 and 29 randomized to receive an infraclavicular and supraclavicular catheter, respectively. All perineural catheters were successfully placed per protocol. Because of protocol violations and missing data, an intention-to-treat analysis was not used; rather, only subjects with catheters in situ and whom we were able to contact were included in the analyses. The day after surgery, subjects in the infraclavicular group reported average pain as median of 2.0 (10th-90th percentiles, 0.5-6.0) compared with 4.0 (10th-90th percentiles, 0.6-7.7) in the supraclavicular group (P = 0.025). Similarly, least pain scores (numeric rating scale) on postoperative day 1 were lower in the infraclavicular group compared with the supraclavicular group (0.5 [10th-90th percentiles, 0.0-3.5] vs 2.0 [10th-90th percentiles, 0.0-4.7], respectively; P = 0.040). Subjects in the infraclavicular group required less rescue oral analgesic (oxycodone, in milligrams) for breakthrough pain in the 18 to 24 hrs after surgery compared with the supraclavicular group (0.0 [10th-90th percentiles, 0.0-5.0] vs 5.0 [10th-90th percentiles, 0.0-15.0], respectively; P = 0.048). There were no statistically significant differences in other secondary outcomes. Conclusions: A local anesthetic infusion via an infraclavicular perineural catheter provides superior analgesia compared with a supraclavicular perineural catheter.