Efficacy of parasternal block to decrease intraoperative opioid use in coronary artery bypass surgery via sternotomy: a randomized controlled trial.

OBJECTIVE: This study aims to assess the effect of a preoperative parasternal plane block (PSB) on opioid consumption required to maintain hemodynamic stability during sternotomy for coronary artery bypass graft surgery. METHODS: This double-blind, randomized, placebo-controlled trial prospectively enrolled 35 patients scheduled for coronary artery bypass graft surgery under general anesthesia with propofol and remifentanil. Patients were randomized to receive preoperative PSB using either ropivacaine (PSB group) or saline solution (placebo group) (1:1 ratio). The primary endpoint was the maximal effect-site concentration of remifentanil required to maintain heart rate and blood pressure within the recommended ranges during sternotomy. RESULTS: Median maximum concentration of remifentanil necessary to maintain adequate hemodynamic status during sternotomy was significantly reduced in PSB group (4.2 (2.5-6.0) ng/mL) compared with placebo group (7.0 (5.2-8.0) ng/mL) (p=0.02). Mean maximum concentration of propofol used to control depth of anesthesia was also reduced (3.9±1.1 µg/mL vs 5.0±1.5 µg/mL, PSB vs placebo, respectively; p=0.02). This reduction in propofol consumption during sternotomy enabled a more adequate level of sedation to be maintained in patients (minimum patient state index was 11.7±8.7 in placebo group and 18.3±6.8 in PSB group; p=0.02). PSB reduced postoperative inflammatory response by limiting concentrations of proinflammatory cytokines IL-8, IL-18, IL-23, IL-33 and MCP-1 measured in the first 7-day after surgery (p<0.05). CONCLUSIONS: Preoperative PSB reduced the maximum concentrations of remifentanil and propofol required to maintain hemodynamic stability and depth of anesthesia during sternotomy. TRIAL REGISTRATION NUMBER: NCT03734159.Sébastien Bloc, M.D.1,2; Brieuc P. Pérot, Ph.D.3; Hadrien Gibert, M.D.1; Jean-Dominique Law Koune, M.D.1; Yannick Burg, M.D.1; Didier Leclerc, M.D.1; Anne-Sophie Vuitton, M.D.1; Christophe De La Jonquière, M.D.1; Marine Luka, L.S.3; Thierry Waldmann, M.D.4; Nicolas Vistarini, M.D.4; Stéphane Aubert, M.D.4; Mickaël M. Ménager, Ph.D.3; Messaouda Merzoug, Ph.D.2; Cécile Naudin, Ph.D.2; Pierre Squara, M.D.2,5.

Elastomeric pump reliability in postoperative regional anesthesia: a survey of 430 consecutive devices.

BACKGROUND: Postoperative analgesia via continuous perineural infusion of local anesthetics compares favorably with systemic analgesia. Elastomeric pumps increase patient satisfaction compared with electronic models. In in vitro investigations, infusions remained within 15% of their designated set rates. We assessed in vivo the infusion rate of elastomeric pumps in regional analgesia after orthopedic surgery. METHODS: All consecutive elastomeric pumps were retrospectively studied during a 10-mo period. Perineural catheters were inserted preoperatively and connected postoperatively to elastomeric pumps filled with ropivacaine 0.2%. Before infusion, elastomeric pumps and ropivacaine were stored at room temperature. Two models of pumps were randomly used: Infusor LV5 (Baxter, France) or Easypump (Braun, Germany), both set at 5 mL/h. Nurses weighed the devices at the bedside using a portable electronic scale several times a day until catheter removal. Weights over time allowed accurate deflation profile assessment and flow rate calculation. An unchanged weight over time indicated either an obstructed catheter or an ineffective device. RESULTS: After connection to the catheter, 88 devices did not deflate (80 Easypump of 300 and 8 Infusor of 130, P < 0.0001). One Easypump was impossible to deflate, even after disconnection from its catheter. In two cases, catheters were obstructed. In 21 cases, catheters were removed 11 to 72 h later without being tested for patency. In 24 cases, pumps correctly deflated after catheters were injected without difficulty with a local anesthetic bolus. The remaining 40 devices spontaneously started to deflate 6 to 43 h after their connection. These 88 elastomeric pumps were associated with higher maximal visual analog scale scores during the first postoperative night than devices showing immediate deflation after connection (34 +/- 21 mm vs 26 +/- 19 mm, P = 0.006). Flow rates were calculated over a mean period of 54 +/- 18 h (Easypump) and 49 +/- 19 h (Infusor). The flow rates differed from those set by manufacturers (5 mL/h +/- 15%) in 47% of Easypump and in 34% of Infusor devices (P = 0.01). CONCLUSIONS: In vivo reliability of elastomeric pumps is different than in vitro. In the event of early insufficient postoperative perineural analgesia, an absence of deflation of the elastomeric pump must be considered. We recommend weighing these devices every 3 h during the first 24 h of infusion.