The impact of deep versus standard neuromuscular block on intraoperative safety during laparoscopic surgery: an international multicenter randomized controlled double-blind strategy trial - EURO-RELAX TRIAL.

BACKGROUND: Muscle relaxants are routinely used during anesthesia to facilitate endotracheal intubation and to optimize surgical conditions. However, controversy remains about the required depth of neuromuscular block (NMB) needed for optimal surgical working conditions and how this relates to other outcomes. For instance, a deep neuromuscular block yields superior surgical working conditions compared to a standard NMB in laparoscopic surgery, however, a robust association to other (safety) outcomes has not yet been established. METHODS: Trial design: an international multicenter randomized controlled double-blind strategy trial. Trial population: 922 patients planned for elective, laparoscopic or robotic, abdominal surgery. INTERVENTION: Patients will be randomized to a deep NMB (post-tetanic count 1-2 twitches) or standard care (single-dose muscle relaxant administration at induction and repeated only if warranted by surgical team). Main trial endpoints: Primary endpoint is the difference in incidence of intraoperative adverse events during laparoscopic surgery graded according to ClassIntra® classification (i.e., ClassIntra® grade ≥ 2) between both groups. Secondary endpoints include the surgical working conditions, 30-day postoperative complications, and patients' quality of recovery. DISCUSSION: This trial was designed to analyze the effect of deep neuromuscular block compared to standard neuromuscular block on intra- and postoperative adverse events in patients undergoing laparoscopic surgery. TRIAL REGISTRATION: ClinicalTrials.gov NCT04124757 (EURO-RELAX); registration URL: https://clinicaltrials.gov/ct2/show/NCT04124757 , registered on October 11th, 2019.

Nociception-guided versus Standard Care during Remifentanil-Propofol Anesthesia: A Randomized Controlled Trial.

BACKGROUND: The multidimensional index of nociception, the nociception level, outperforms blood pressure and heart rate in detection of nociceptive events during anesthesia. We hypothesized that nociception level-guided analgesia reduces opioid consumption and suboptimal anesthesia events such as low blood pressure and use of vasoactive medication. METHODS: In this single-blinded randomized study, 80 American Society of Anesthesiologists class I-III adult patients of either sex, scheduled for major abdominal procedures under remifentanil/propofol anesthesia by target-controlled infusion, were included. During the procedure nociception level, noninvasive blood pressure, and heart rate were monitored. Patients were randomized to receive standard clinical care or nociception level-guided analgesia. In the nociception level-guided group, remifentanil concentration was reduced when index values were less than 10 or increased when values were above 25 for at least 1 min, in steps of 0.5 to 1.0 ng/ml. Propofol was titrated to bispectral index values between 45 and 55. The primary outcomes of the study were remifentanil and propofol consumption and inadequate anesthesia events. RESULTS: Compared with standard care, remifentanil administration was reduced in nociception level-guided patients from (mean ± SD) 0.119 ± 0.033 to 0.086 ± 0.032 µg · kg · min (mean difference, 0.039 µg · kg · min; 95% CI, 0.025-0.052 µg · kg · min; P < 0.001). Among nociception level-guided patients, 2 of 40 (5%) experienced a hypotensive event (mean arterial pressure values less than 55 mm Hg) versus 11 of 40 (28%) patients in the control group (relative risk, 0.271; 95% CI, 0.08-0.77; P = 0.006). In the nociception level-guided group, 16 of 40 (40%) patients received vasoactive medication versus 25 of 40 (63%) patients in the standard care group (relative risk, 0.64; 95% CI, 0.40-0.99; P = 0.044). CONCLUSIONS: Nociception level-guided analgesia during major abdominal surgery resulted in 30% less remifentanil consumption.

Frequent respiratory events in postoperative patients aged 60 years and above.

There is limited information on the occurrence of respiratory events in postoperative patients after discharge from the postanesthesia care unit. We studied the respiratory rate (RR) of 68 patients aged 60 years and above during the first 6 hours following elective surgery under general anesthesia to assess the frequency of respiratory events in the care unit and on the ward. RR was derived from the continuous RR counter RespiR8, measuring RR by quantifying the humidity of exhaled air. One-minute-averaged RRs were collected and analyzed to assess the frequency of postoperative bradypnea (RR 1-6 breaths/minute) and apnea (cessation of inspiratory flow ≥60 seconds). Values were median (interquartile range) or mean (SD). The median RR was 13 (10-15) breaths/minute. In the 6-hour postoperative period, 78% and 57% of patients experienced at least one bradypnea or apnea event, respectively. A median of ten (3.5-24) bradypnea and three (1-11) apnea events were detected per patient. The occurrence of respiratory events in the postanesthesia care unit (PACU) was a predictor of events on the ward (bradypnea, r2=0.4, P<0.001; apnea, r2=0.2, P<0.001). Morphine consumption correlated weakly with respiratory events in the PACU, but not on the ward. Patients with apnea had significantly larger neck circumference than patients without (39.6 [0.7] versus 37.4 [0.8] cm, P<0.05). Bradypneic or apneic respiratory events are frequent in postoperative elderly patients and even occur relatively late after surgery. Continuous respiratory monitoring on the ward, especially in patients with risk factors, such as early occurrence of events, opioid use, and larger neck circumference, is likely warranted.