Interscalene Block with and without Intraoperative Local Infiltration with Liposomal Bupivacaine in Shoulder Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Interscalene brachial plexus blockade (ISBPB) is an effective anesthetic technique for shoulder arthroplasty; however, "rebound pain" can increase the patient's postoperative pain experience and narcotic usage. Exparel (liposomal bupivacaine) injected into the soft tissues at the surgical site has theoretical efficacy for up to 72 hours after administration. The purpose of this study was to evaluate postoperative pain scores and narcotic consumption following shoulder arthroplasty performed with either ISBPB alone or ISBPB and intraoperative Exparel. METHODS: Seventy-eight patients undergoing primary shoulder arthroplasty were randomized to receive an ISBPB with Exparel (39 patients) or without Exparel (39 patients). The primary outcome variable was morphine equivalent units (MEUs) consumed over the first 24 hours after surgery. Secondary outcomes included intraoperative narcotic administration and visual analog scale (VAS) scores for pain (at 0, 8, 16, 24, 48, and 72 hours after surgery). RESULTS: There were no significant demographic differences between the ISBPB and ISBPB + Exparel groups. Total narcotic consumption over the first 24 hours after surgery was significantly lower in the ISBPB group compared with the ISBPB + Exparel group (mean and standard deviation, 18.9 ± 25.6 MEU versus 35.3 ± 36.7 MEU, p = 0.009). VAS pain scores did not differ significantly between groups at any time point during the first 72 hours after surgery. CONCLUSIONS: Patients treated with Exparel required significantly more postoperative narcotics and demonstrated no significant reduction in pain scores over the first 72 hours after primary shoulder arthroplasty. Exparel does not appear to have substantial value when added to a pain protocol that includes an ISBPB. LEVEL OF EVIDENCE: Therapeutic Level l. See Instructions for Authors for a complete description of levels of evidence.

Randomized Controlled Trial of Interscalene Block Compared with Injectable Liposomal Bupivacaine in Shoulder Arthroplasty.

BACKGROUND: Shortcomings of interscalene brachial plexus blockade include technical failure and rebound pain. Bupivacaine liposome injectable suspension, a sustained release preparation, is used for surgical-site administration. The purpose of this study was to evaluate these 2 postoperative pain management strategies in patients undergoing shoulder arthroplasty. METHODS: In a non-blinded, randomized controlled trial of participants undergoing primary shoulder arthroplasty, patients were randomized to interscalene brachial plexus blockade or intraoperative soft-tissue infiltration of bupivacaine liposome injectable suspension. The primary outcome variable was morphine equivalent units consumed over the first 24 hours postoperatively. Secondary outcomes included morphine equivalent units consumed intraoperatively and a visual analog scale (VAS) for pain at 0, 8, 16, and 24 hours. RESULTS: Seventy-eight patients were randomized to interscalene brachial plexus blockade treatment (the blockade group) and 78 patients were randomized to bupivacaine liposome injectable suspension treatment (the suspension group). The mean total postoperative narcotic consumption (and standard deviation) over 24 hours after the surgical procedure was 14.8 ± 11.3 morphine equivalent units in the blockade group compared with 14.4 ± 16.8 morphine equivalent units in the suspension group (p = 0.849). Intraoperative narcotics were significantly lower (p < 0.001) in the blockade group (8.9 ± 4.1 morphine equivalent units) compared with the suspension group (16.2 ± 7.0 morphine equivalent units). The mean VAS pain score was significantly lower in the blockade group than in the suspension group at 0 hours postoperatively (0.8 ± 2.2 compared with 3.3 ± 2.7 points; p < 0.001) and at 8 hours postoperatively (1.4 ± 2.4 compared with 3.2 ± 2.2 points; p < 0.001), but it was not significantly different at 16 hours postoperatively (4.3 ± 2.8 compared with 3.8 ± 2.4 points; p = 0.348). The VAS pain scores were significantly higher (p = 0.021) in the blockade group (4.9 ± 2.7 points) compared with the suspension group (3.9 ± 2.3 points) at 24 hours postoperatively. CONCLUSIONS: Patients treated with bupivacaine liposome injectable suspension required an equivalent amount of postoperative narcotics and greater intraoperative narcotics compared with patients treated with interscalene brachial plexus blockade. Although interscalene brachial plexus blockade provided improved pain scores for the first 8 hours after the surgical procedure, pain scores were worse at 24 hours. The optimal postoperative pain regimen for shoulder arthroplasty and the cost-effectiveness of analgesic techniques require further investigation. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Ultrasound measurement of inferior vena cava collapse predicts propofol-induced hypotension.

STUDY OBJECTIVES: Hypotension is a common side effect of propofol, but there are no reliable methods to determine which patients are at risk for significant propofol-induced hypotension (PIH). Ultrasound has been used to estimate volume status by visualization of inferior vena cava (IVC) collapse. This study explores whether IVC assessment by ultrasound can assist in predicting which patients may experience significant hypotension. METHODS: This was a prospective observational study conducted in the operating suite of an urban community hospital. A convenience sample of consenting adults planned to receive propofol for induction of anesthesia during scheduled surgical procedures were enrolled. Bedside ultrasound was used to measure maximum (IVCmax) and minimum (IVCmin) IVC diameters. IVC-CI was calculated as [(IVCmax-IVCmin)/IVCmax × 100%]. The primary outcome was significant hypotension defined as systolic blood pressure (BP) below 90mmHg and/or administration of a vasopressor to increase BP during surgery. RESULTS: The study sample comprised 40 patients who met inclusion criteria. Mean age was 55years, (95%CI, 49-60) with 53% female. 55% of patients had significant hypotension after propofol administration. 76% of patients with IVC-CI≥50% had significant hypotension compared to 39% with IVC-CI<50%, P=.02. IVC-CI≥50% had a specificity of 77.27% (95%CI, 64.29%-90.26%) and sensitivity of 66.67% (95%CI, 52.06%-81.28%) in predicting PIH. The odds ratio for PIH in patients with IVC-CI≥50% was 6.9 (95%CI, 1.7-27.5). CONCLUSION: Patients with IVC-CI≥50% were more likely to develop significant hypotension from propofol. IVC ultrasound may be a useful tool to predict which patients are at increased risk for PIH.