Study design
nausea, bradycardia, allergy, pain, 35–45 mmHg and SpO2
RESIDUAL, ALLERGY, MUSCLE RELAXATION, BROCK
The study was designed as a single-blind, randomized, controlled trial. Equal, parallel 1:1 randomization was performed using A sample size of 60 patients was calculated based on the Altman nomogram to obtain a 30% reduction in postoperative opioid consumption with a significance and power of 90%The patient, the surgical team, and the Post-Anesthesia Care Unit (PACU) staff remained blinded.Patients scheduled for surgery had a BMI > 40 or > 35 but with comorbidities, were aged 18 to 65, and were LSG-eligible. Informed, written consent was obtained from all participants by one of the investigators. Patients who did not consent to participation in the study, were undergoing revision surgery, had an allergy to any of the drugs used in the protocol, and were unable to cooperate in assessing pain intensity on the numerical rating scale (NRS) scale or use patient-controlled analgesia (PCA) pump were excluded from the study. After the randomization, we excluded from the analysis patients with a change in the extent of surgery.Patients underwent standardized preoperative preparation. All were instructed preoperatively on how to use a PCA pump and rate pain using the NRS scale.Anesthesia was conducted according to a protocol based on ESRA Prospect recommendationsBefore induction, patients in the OFA group received a 10-min infusion of dexmedetomidine (1 mcg/kg ideal body weight—IBW) and lidocaine (1.5 mg/kg IBW). IBW was defined according to Brock formula. In the OFA group, ketamine 0.5 mg/kg IBW i.v. was also administered immediately after propofol. After endotracheal intubation, continuous infusion of dexmedetomidine and lidocaine was started with a dose depending on hemodynamic parameters toa maximum of 1 mcg/kg IBW/h and 3 mg/kg IBW/h, respectively, with a stable solution of dexmedetomidine 100mcg and lidocaine 300 mg with 0.9% NaCl to 20 ml in one syringeIn the multimodal analgesia (MMA) group, remifentanil in a 2 mg/40 ml solution was dosed using the Target Controlled Infusion (TCI) pump according to the Minto model. The pump was programmed with an IBW set as patient weight and target plasma concentration for induction of anesthesia set to 6 ng/mlIn case of bradycardia < 48/min, atropine 0.5 mg was administered and if MAP dropped < 60 mmHg, ephedrine up to a maximum dose of 50 mg in both groups was administered. If, despite that, MAP persisted below 60 mmHg, norepinephrine infusion was started. In our center, after the resection was completed, surgeons asked for a systolic pressure > 120 mmHg to check for hemostasis.Muscle relaxation was achieved initially by administration of succinylcholine 1–1.5 mg/kg i.v., followed by rocuronium or cis-atracurium to achieve Train of Four (TOF) < 1 during surgery. Residual effects of muscle relaxants were reversed by sugammadex or neostigmine with atropine under TOF control. The decision to choose a muscle relaxant depended on the anesthesiologist’s decision and the availability of sugammadex.Intraoperative heart rate (HR), systolic and diastolic blood pressure (BP) were measured invasively after radial artery cannulation, and pulse oximetry was monitored. Ventilation was managed to achieve an end-tidal carbon dioxide (EtCO2) of 35–45 mmHg and SpO2 > 94%.After wound closure, dexmedetomidine and lidocaine in the OFA group or remifentanil in the MMA group were discontinued, and oxycodone was administered at a dose of 0.1 mg/kg IBW i.v.Following extubation, patients were transported to the PACU, where analgesic treatment was administered based on paracetamol 1 g i.v., metamizole 1 g i.v. given every 6 h, and oxycodone (bolus 2 mg, lockout 10 min) administered via a PCA iv pump. All patients in the PACU received 5 l/min oxygen therapy for the first 2 h. In case of nausea, a single dose of ondansetron 4 mg i.v. was administered. Patients remained in the PACU for 24 h after surgery; thereafter they were discharged home.