A randomized comparison of loss of resistance versus loss of resistance plus electrical stimulation: effect on success of thoracic epidural placement.

BACKGROUND: Loss of resistance (LOR) for epidural catheter placement has been utilized for almost a century. LOR is a subjective endpoint associated with a high failure rate. Nerve stimulation (NS) has been described as an objective method for confirming placement of an epidural catheter. We hypothesized that the addition of NS to LOR would improve the success of epidural catheter placement. METHODS: One-hundred patients were randomized to thoracic epidural analgesia (TEA) utilizing LOR-alone or loss of resistance plus nerve stimulation (LOR + NS). The primary endpoint was rate of success, defined as loss of sensation following test dose. Secondary endpoints included performance time. An intention-to-treat analysis was planned, but a per-protocol analysis was performed to investigate the success rate when stimulation was achieved. RESULTS: In the intention-to-treat analysis there was no difference in success rates (90% vs 82% [LOR + NS vs LOR-alone]; P = 0.39). The procedural time increased in the LOR + NS group (33.9 ± 12.8 vs 24.0 ± 8.0 min; P < 0.001). The per-protocol analysis found a statistically higher success rate for the LOR + NS group compared to the LOR-alone group (98% vs. 82%; P = 0.017) when only patients in whom stimulation was achieved were included. CONCLUSIONS: Addition of NS technique did not statistically improve the success rate for epidural placement when analyzed in an intention-to-treat format and was associated with a longer procedural time. In a per-protocol analysis a statistically higher success rate for patients in whom stimulation was obtained highlights the potential benefit of adding NS to LOR. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03087604 on 3/22/2017; Institutional Review Board Wake Forest School of Medicine IRB00039522, Food and Drug Administration Investigational Device Exemption: G160273.

Transversus abdominis plane block as the primary anesthetic for peritoneal dialysis catheter surgery.

STUDY OBJECTIVE: The primary goal of this study was to determine whether transversus abdominis plane (TAP) blocks were effective as the primary anesthetic technique for insertion and/or removal of peritoneal dialysis catheters. DESIGN: This study is a descriptive case series investigation. SETTING: Operating rooms at a tertiary care academic medical center. PATIENTS: Twenty-four patients, American Society of Anesthesiologists (ASA) physical status 3 and 4, were included in this study. INTERVENTIONS: Patients who had received a TAP block preoperatively for open surgical insertion or removal of a peritoneal dialysis catheter over a 26-month period with the intent of the block to serve as the primary anesthetic were included in this study. MEASUREMENTS: Preoperative and intraoperative sedative medications and local anesthetic medications were analyzed. The primary outcome of the study was the ability of the TAP block to provide surgical anesthesia as determined by a lack of need to convert to general anesthesia (defined by placement of an airway device, use of volatile anesthetics, intraoperative propofol infusion dose equal to or greater than 100 µg kg(-1) min(-1)). Secondary outcomes included analysis of any complications from the higher concentrations of local anesthetics required for surgical block. MANI RESULTS: Of 24 patients, 21 underwent the procedure without conversion to general anesthesia as defined above. No complications related to local anesthetics were found. CONCLUSION: Transversus abdominis plane blockade can be successful at serving as the primary anesthetic modality for the insertion and/or removal of a peritoneal dialysis catheter by open-surgical approach. There were no systemic toxic effects or other complications recorded.

An Evaluation of Ultrasound-Guided Adductor Canal Blockade for Postoperative Analgesia After Medial Unicondylar Knee Arthroplasty.

BACKGROUND: Unicondylar knee arthroplasty (UKA) is a commonly performed procedure with significant expected postoperative pain. Peripheral nerve blocks are 1 analgesic option, but some approaches may decrease quadriceps motor strength and interfere with early ambulation. In this study, we compared the analgesia provided by an adductor canal block (ACB) and a psoas compartment block (PCB) after UKA. We hypothesized that the ACB would provide equivalent analgesia, defined as a difference of <2 points on the pain scale (0-10 numeric rating scale [NRS]), at rest and with movement 6 hours after block placement. METHODS: One hundred fifty patients undergoing medial UKA were randomly assigned to receive either an ACB or a PCB with 0.25% bupivacaine, 5 µg/mL epinephrine, and 1.67 µg/mL clonidine. All patients received multimodal analgesics, sham blockade at the alternate site, and a posterior capsule injection during surgery. Patients and observers were blinded to treatment groups. The primary end points were NRS pain scores with rest and movement at 6 hours. Secondary end points included quadriceps muscle strength at 6 hours (0-5 [5 being full strength]; Medical Research Council scale) as well as NRS pain scores, opioid consumption, and opioid-related side effects over 24 hours. RESULTS: One hundred forty-seven patients were analyzed. Pain scores were equivalent at 6 hours with rest (ACB 1.0 ± 2 vs PCB 1.1 ± 2.2 [mean NRS ± SD]; 95% confidence interval of mean difference, -0.8 to 0.6; P < 0.0001) and with movement (ACB 1.6 ± 2.6 vs PCB 1.5 ± 2.8; 95% confidence interval of mean difference, -0.8 to 0.9; P < 0.0001). In addition, pain scores at rest and with movement at 12, 18, and 24 hours were equivalent. Quadriceps motor strength was significantly increased in the ACB group (Medical Research Council scale score, 4.0 ± 1.1 vs 2.5 ± 1.3 [mean ± SD]; P < 0.0001). No significant differences were found between groups for time to first analgesic or for cumulative opioid consumption at 6, 12, 18, or 24 hours. Other than an increase in the incidence of pruritus in the ACB group at 6 hours, there were no differences in opioid-related side effects. CONCLUSIONS: An ACB provides equivalent analgesia after medial UKA when compared with a PCB. In addition, the ACB caused significantly less motor weakness. An ACB should be considered for postoperative analgesia after medial UKA.