Total knee arthroplasty under quadruple nerve block with ropivacaine 0.32%: effect of addition of intravenous dexmedetomidine to intravenous dexamethasone on analgesic duration.

BACKGROUND AND OBJECTIVES: Peripheral nerve blocks reduce postoperative pain and enhance recovery after total knee arthroplasty (TKA). This study aims to assess the benefits of addition of intravenous dexmedetomidine (DexM) to intravenous dexamethasone on the analgesic duration of quadruple nerve blocks. METHODS: This double-blind, randomized, controlled trial prospectively enrolled 90 patients scheduled for TKA under quadruple nerve blocks (sciatic, femoral, obturator, and lateral femoral cutaneous nerves blocks) with 70 mL, 0.32% ropivacaine. All patients received systemic dexamethasone 10 mg. Patients were randomized to receive DexM (2 µg/kg, intravenous) or placebo (1:1 ratio). The primary endpoint was the duration of analgesia defined as the time to first request for rescue analgesia (oxycodone). RESULTS: Kaplan-Meier curves for the first analgesic request were similar between groups (log-rank test; p=0.27). Median (IQR) duration of analgesia was similar between placebo (1575 min (1211-1952)) and DexM (1470 min (1263-1700)) groups (p=0.56). Cumulative consumption of oxycodone at the 48th hour was 20 mg (10-30) and 30 mg (20-40) in placebo and DexM groups, respectively (p=0.14). The day after surgery, 93% and 89% of patients were able to walk in placebo and DexM groups, respectively (p=0.46). Intravenous DexM was associated with bradycardia, hypotension and longer recovery room stay (p<0.05 for all comparisons). CONCLUSIONS: In a multimodal analgesic regimen, addition of systemic DexM (2 µg/kg) to systemic dexamethasone does not prolong the analgesic duration of quadruple nerve block with ropivacaine 0.32% after TKA. TRIAL REGISTRATION NUMBER: NCT03834129.

Perineural Versus Systemic Dexamethasone in Front-Foot Surgery Under Ankle Block: A Randomized Double-Blind Study.

BACKGROUND AND OBJECTIVES: Among the different adjuvants, dexamethasone is one of the most accepted to prolong the effect of local anesthetics. This study aims to determine the superiority of perineural over systemic dexamethasone administration after a single-shot ankle block in metatarsal osteotomy. METHODS: We performed a prospective, double-blind, randomized study. A total of 100 patients presenting for metatarsal osteotomy with an ankle block were randomized into 2 groups: 30 mL ropivacaine 0.375% + perineural dexamethasone 4 mg (1 mL) + 2.5 mL of systemic saline solution (PNDex group, n = 50) and 30 mL ropivacaine 0.375% + 1 mL of perineural saline solution + intravenous dexamethasone 10 mg (2.5 mL) (IVDex group, n = 50). The primary end point was the duration of analgesia defined as the time between the performance of the ankle block and the first administration of rescue analgesia with tramadol. RESULTS: Time period to first rescue analgesia with tramadol was similar in the IVDex group and the PNDex group. Data are expressed as mean (SD) or median (range). Duration of analgesia was 23.2 (9.5) hours in the IVDex group and 19 (8.2) hours in the PNDex group (P = 0.4). Consumption of tramadol during the first 48 hours was 0 mg (0-150 mg) in the IVDex group versus 0 mg (0-250 mg) in the PNDex group (P = 0.59). Four (8%) and 12 (24%) patients reported nausea or vomiting in the IVDex group and the PNDex group, respectively (P = 0.03). CONCLUSIONS: In front-foot surgery, perineural and systemic administrations of dexamethasone are equivalent for postoperative pain relief when used as an adjuvant to ropivacaine ankle block. CLINICAL TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov, identifier NCT02904538.

Diaphragmatic paralysis in obese patients in arthroscopic shoulder surgery: consequences and causes.

PURPOSE: Ambulatory process in arthroscopic shoulder surgery has boomed over past decades. Some anesthetic techniques such as interscalene block (ISB) and its surrogates are associated with diaphragmatic paralysis and might compromise outpatient procedure. HYPOTHESIS: This study aims to assess consequences of diaphragmatic paralysis in obese patients. METHODS: This prospective observational study screened patients with body mass index (BMI) ≥ 30 kg/m2 undergoing acromioplasty or supraspinatus tendon repair. Surgery was performed using brachial plexus block, and the method of brachial plexus block was left at the discretion of attending anesthesiologists. Post-operative hemidiaphragmatic paralysis was evaluated using M-mode ultrasonography and its consequences on patient ventilation were assessed: occurrence of hypoxic episode defined as oxygen saturation less than 90% (by pulse oximeter) in room air, dyspnea and failure of ambulatory procedure. Causes of diaphragmatic paralysis were also analyzed. RESULTS: Ninety-one patients were screened, 82 patients were included in this study and 37 patients (45%) presented diaphragmatic paralysis. Compared to patients without diaphragmatic paralysis, diaphragmatic paralysis was associated with dyspnea [10 (27%) versus 1 (2%); p = 0.0019], occurrence of patients presenting at least one hypoxic episode [6 (16%) versus 1 (2%); p = 0.02] and failure of ambulatory process [10 (27%) versus 1 (2%); p = 0.009]. The combination of axillary and suprascapular nerve blocks, but also low volume ISB, was found to be protective against diaphragmatic paralysis when compared to high volume ISB [Odds ratios 0.0019 (0.001-0.026) and 0.0482 (0.008-0.27), respectively; p < 0.001]. CONCLUSION: In patients with BMI ≥ 30 kg/m2 undergoing arthroscopic shoulder surgery, diaphragmatic paralysis is associated with dyspnea, occurrence of hypoxic episodes and failure of ambulatory procedure. High volume ISB and also, to a lesser extent, low volume ISB were found to be responsible for diaphragmatic paralysis. TRIAL REGISTRY NUMBER: Registration n° 2014-202.