Low Tidal Volume Mechanical Ventilation Against No Ventilation During Cardiopulmonary Bypass in Heart Surgery (MECANO): A Randomized Controlled Trial.

BACKGROUND: Postoperative pulmonary complications are common after cardiac surgery and have been related to lung collapse during cardiopulmonary bypass (CPB). No consensus exists regarding the effects of maintaining mechanical ventilation during CPB to decrease these complications. RESEARCH QUESTION: To determine whether maintaining low-tidal ventilation (3 mL/kg 5 times/min, with positive end expiratory pressure of 5 cm H2O) during CPB (ventilation strategy) was superior to a resting-lung strategy with no ventilation (no ventilation strategy) regarding postoperative pulmonary complications, including mortality. STUDY DESIGN AND METHODS: In a randomized controlled trial, patients undergoing cardiac surgery at a single center from May 2017 through August 2019 were randomized to the ventilation or no ventilation strategy during CPB (1:1 ratio). Apart from the CPB phase, perioperative ventilation procedures were standardized. RESULTS: The study included 1,501 patients (mean age, 68.8 ± 10.3 years; 1,152 (76.7%) men; mean EuroSCORE II, 2.3 ± 2.7). Seven hundred fifty-six patients were in the ventilation strategy group, and no differences existed in baseline characteristics and types of procedures between the two groups. An intention-to-treat analysis yielded no significant difference between the ventilation and no ventilation groups regarding incidence of the primary composite outcome combining death, early respiratory failure, ventilation support beyond day 2, and reintubation, with 112 of 756 patients (14.8%) in the ventilation group vs 133 of 745 patients (17.9%) in the no ventilation group (OR, 0.80; 95% CI, 0.61-1.05; P = .11). Strict per-protocol analyses of 1,338 patients (89.1%) with equally distributed preoperative characteristics yielded similar results (OR, 0.81; 95% CI, 0.60-1.09; P = .16). Post hoc analysis of the subgroup who underwent isolated coronary artery bypass graft procedures (n = 725) showed that the ventilation strategy was superior to the no ventilation strategy regarding the primary outcome (OR, 0.56; 95% CI, 0.37-0.84; P = .005). INTERPRETATION: Among patients undergoing cardiac surgery with CPB, continuation of low tidal volume ventilation was not superior to no ventilation during CPB with respect to postoperative complications, including death, early respiratory failure, ventilation support beyond day 2, and reintubation. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT03098524; URL: www.clinicaltrials.gov.

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.

Closed-loop control of consciousness during lung transplantation: an observational study.

OBJECTIVE: To determine if propofol infusion can be steered automatically by using bispectral index (BIS) as a controller during lung transplantation. DESIGN: A prospective study of patients undergoing lung transplantation. SETTING: University hospital. PARTICIPANTS: Twenty consecutive patients scheduled for bilateral (n = 14) or single (n = 6) lung transplantation. INTERVENTIONS: The goal of the closed-loop administration of propofol was to maintain the BIS value between 40 and 60 during the maintenance phase. The remifentanil infusion was adjusted according to standard clinical practice. MEASUREMENTS AND MAIN RESULTS: The closed-loop system was able to provide anesthesia maintenance for all patients. Cardiopulmonary bypass was used in 5 patients, and 14 patients received a thoracic epidural catheter. The BIS value was maintained between 40 and 60 during 84% +/- 16% of the maintenance phase. Eleven patients were extubated in the operating room, and 1 patient needed reintubation. CONCLUSION: Closed-loop control of consciousness by a computer during lung transplantation is clinically feasible.

Low tidal volume mechanical ventilation against no ventilation during cardiopulmonary bypass heart surgery (MECANO): study protocol for a randomized controlled trial.

BACKGROUND: Postoperative pulmonary complications are a leading cause of morbidity and mortality after cardiac surgery. There are no recommendations on mechanical ventilation associated with cardiopulmonary bypass (CPB) during surgery and anesthesiologists perform either no ventilation (noV) at all during CPB or maintain low tidal volume (LTV) ventilation. Indirect evidence points towards better pulmonary outcomes when LTV is performed but no large-scale prospective trial has yet been published in cardiac surgery. DESIGN: The MECANO trial is a single-center, double-blind, randomized, controlled trial comparing two mechanical ventilation strategies, noV and LTV, during cardiac surgery with CPB. In total, 1500 patients are expected to be included, without any restrictions. They will be randomized between noV and LTV on a 1:1 ratio. The noV group will receive no ventilation during CPB. The LTV group will receive 5 breaths/minute with a tidal volume of 3 mL/kg and positive end-expiratory pressure of 5 cmH2O. The primary endpoint will be a composite of all-cause mortality, early respiratory failure defined as a ratio of partial pressure of oxygen/fraction of inspired oxygen <200 mmHg at 1 hour after arrival in the ICU, heavy oxygenation support (defined as a patient requiring either non-invasive ventilation, mechanical ventilation or high-flow oxygen) at 2 days after arrival in the ICU or ventilator-acquired pneumonia defined by the Center of Disease Control. Lung recruitment maneuvers will be performed in the noV and LTV groups at the end of surgery and at arrival in ICU with an insufflation at +30 cmH20 for 5 seconds. Secondary endpoints are those composing the primary endpoint with the addition of pneumothorax, CPB duration, quantity of postoperative bleeding, red blood cell transfusions, revision surgery requirements, length of stay in the ICU and in the hospital and total hospitalization costs. Patients will be followed until hospital discharge. DISCUSSION: The MECANO trial is the first of its kind to compare in a double-blind design, a no-ventilation to a low-tidal volume strategy for mechanical ventilation during cardiac surgery with CPB, with a primary composite outcome including death, respiratory failure and postoperative pneumonia. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03098524 . Registered on 27 February 2017.

Scalp infiltration with bupivacaine plus epinephrine or plain ropivacaine reduces postoperative pain after supratentorial craniotomy.

Local anesthetic infiltration has been proposed to decrease postoperative pain. The aim of this study was to determine whether scalp infiltration with bupivacaine or ropivacaine would improve analgesia after supratentorial craniotomy for tumor resection. Eighty patients were recruited into a randomized double-blind study. Infiltration was performed after skin closure with 20 mL of saline 0.9% (placebo group, n = 40), of 0.375% bupivacaine with epinephrine 1:200,000 (bupivacaine group, n = 20), or of 0.75% ropivacaine (ropivacaine group, n = 20). Postoperative analgesia was provided with patient-controlled morphine IV analgesia (PCA). The study was continued until PACU discharge, which occurred early in the morning following surgery. Results are reported on 37 patients in the placebo group, 20 in the bupivacaine group, and 19 in the ropivacaine group because 4 patients experienced postoperative complications and were excluded from the study. Morphine titration at arrival in the postanesthesia care unit was necessary more often in the placebo group (62% of the patients) than in the 2 treated groups (19% in each, P = 0.02). The median quantity of morphine administered during the first 2 postoperative hours, including initial titration administered by a nurse and PCA-administered morphine, was lower in each treated group than in the placebo group (P < 0.01). The median morphine consumption up to the 16th postoperative hour was not significantly different among the 3 groups. There was no difference in the visual analogue scale scores among the 3 groups at any time. Scalp infiltration with either bupivacaine or ropivacaine had a statistically significant effect on morphine consumption during the first 2 postoperative hours.

Using the intubating laryngeal mask airway for ventilation and endotracheal intubation in anesthetized and unparalyzed acromegalic patients.

Airway management may be difficult in acromegalic patients. The purpose of the study was to evaluate the intubating laryngeal mask airway (ILMA) as a primary tool for ventilation and intubation in acromegalic patients. Twenty-three consenting consecutive adult acromegalic patients presenting for transsphenoidal resection of pituitary adenoma were enrolled in the study. Anesthesia was induced using propofol (1.5 mg/kg followed by 0.5-mg/kg increments); the ILMA was inserted when the bispectral index fell below 50. The ILMA was successful as a primary airway for oxygenation and ventilation at the first attempt for 21 (91%) patients, while 2 (9%) patients required a second attempt. Patient movement was noticed in five (21.7%) of the patients during ILMA insertion. An attempt at tracheal intubation through the ILMA was performed following administration of a mean 395 +/- 168-mg dose of propofol. Overall success rates for tracheal intubation were 82% (19 patients). The first-attempt success rate for tracheal intubation was 52.6% (10 patients), second- and third-attempt success rates were 42.1% (8 patients) and 5.3% (1 patient), respectively. Coughing or movement during intubation was observed in 12 (63.2%) of the patients. Direct laryngoscopy permitted intubation in three cases and blind intubation using a bougie in the fourth case. ILMA can be used as a primary airway for oxygenation in acromegalic patients (manual bag ventilation), but the rate of failed blind intubation through the ILMA precludes its use as a first choice for elective airway management.

Sevoflurane-remifentanil versus propofol-remifentanil anesthesia at a similar bispectral level for off-pump coronary artery surgery: no evidence of reduced myocardial ischemia.

OBJECTIVE: Sevoflurane could decrease myocardial ischemic injury in patients undergoing off-pump coronary artery bypass surgery. This study was designed to compare postoperative troponin I (cTnI) concentrations after sevoflurane-remifentanil versus propofol-remifentanil anesthesia. DESIGN: Prospective, randomized single-blind clinical study. SETTING: University hospital. PARTICIPANTS: Eighteen patients. INTERVENTIONS: General anesthesia was conducted with sevoflurane-remifentanil (n = 9) or propofol-remifentanil (n = 9). Administration of sevoflurane and propofol was adjusted to maintain the bispectral index (BIS) between 40 and 60. MEASUREMENTS AND MAIN RESULTS: Groups were comparable regarding the patients' characteristics. The objective of BIS was maintained in both groups except during the period of coronary artery grafts (p < 0.001) when the BIS number in the propofol group fell below 40 and was significantly lower than in the sevoflurane group. Intraoperative hemodynamic variables were similar between groups. No patient required cardiopulmonary bypass. Need for inotropic and vasoactive support during the first graft was not necessary in the propofol group and occurred in 4 patients in the sevoflurane group (not significant). During the second graft, 2 patients in the propofol group and 3 in the sevoflurane group needed hemodynamic support. Postoperative hemodynamic variables were comparable between groups. Areas under the curve of postoperative increases in cTnI were 27.0 +/- 38.6 and 17.4 +/- 14.6 ng/mL/hour in the sevoflurane and propofol groups, respectively (not significant). CONCLUSION: This study does not support cardioprotective effects of sevoflurane. The particularly short total cumulative duration of ischemia and the relatively low administered end-tidal sevoflurane concentrations may explain this result.

The influence of a muscle relaxant bolus on bispectral and datex-ohmeda entropy values during propofol-remifentanil induced loss of consciousness.

Studies investigating the influence of muscle relaxants on the bispectral index have yielded contradictory results. In our prospective, randomized, double-blind experiments, patients received a fixed target concentration of remifentanil along with a target-controlled infusion of propofol, titrated until loss of consciousness. Two minutes after loss of consciousness, the study group received a bolus injection of atracurium, whereas the control group received a placebo. The following variables were recorded: bispectral index, spectral edge frequency, electromyographic activity, state entropy, and response entropy provided by the Datex-Ohmeda Entropy monitor. Similar values were obtained in both groups at loss of consciousness. Placebo administration induced a decrease in bispectral index (P < 0.002), spectral edge frequency (P < 0.05), electromyographic activity (P < 0.02), state entropy (P < 0.05), and response entropy (P < 0.01) compared with the values measured at loss of consciousness. Atracurium administration induced a decrease in bispectral index (P < 0.0001), spectral edge frequency (P < 0.01), electromyographic activity (P < 0.0001), state entropy (P < 0.0001), and response entropy (P < 0.0001) values. Decreases in bispectral index (P < 0.05), electromyographic activity (P < 0.0001), and response entropy (P < 0.01) were larger after atracurium than placebo injection. In lightly anesthetized patients, myorelaxant administration decreases bispectral index and response entropy, but not state entropy values.

Treatment of hypoxemia during one-lung ventilation using intravenous almitrine.

UNLABELLED: We performed this prospective randomized double-blinded study to assess the ability of almitrine to treat hypoxemia during one-lung ventilation (OLV). Twenty-eight patients were anesthetized with propofol, sufentanil, and atracurium; lung separation was achieved with a double-lumen tube. A transesophageal Doppler probe was inserted to evaluate cardiac index. If SpO(2) was equal to or decreased to <95% during OLV (inspired fraction of oxygen of 0.6), patients were included in the study and received a placebo or almitrine (12 microg x kg(-1) x min(-1) for 10 min followed by 4 microg x kg(-1) x min(-1)) infusion until SpO(2) reached 90% or decreased to <90% (exclusion from the study). Eighteen of the 28 patients were included and received either almitrine (n = 9) or a placebo (n = 9). Treatment was discontinued in 1 patient in the almitrine group and 6 in the placebo group (P < 0.05). Treatment was successful (SpO(2) remaining >or=95% during OLV) in 8 patients in the almitrine group and 1 in the placebo group (P < 0.01). Heart rate, arterial blood pressure, and cardiac index did not change throughout the study, but we could obtain an adequate aortic blood flow signal in only half of the patients. Almitrine could be used to treat hypoxemia during OLV. IMPLICATIONS: IV almitrine improves oxygenation during one-lung ventilation without hemodynamic modification. Such treatment could be used when conventional ventilatory strategy fails to treat hypoxemia or cannot be used.