Abstract and Introduction
Background: No previous study investigated the dexmedetomidine-based opioid-free anesthesia (OFA) protocol in cardiac surgery. The main objective of this study was to evaluate the feasibility and the postoperative opioid-sparing effect of dexmedetomidine-based OFA in adult cardiac surgery patients.
Methods: We conducted a single-centre and retrospective study including 80 patients above 18 years old who underwent on-pump cardiac surgery between November 2018 and February 2020. Patients were divided into two groups: OFA (lidocaine, ketamine, dexmedetomidine, MgSO4) or opioid-based anaesthesia (remifentanil and anti-hyperalgesic medications such as ketamine and/or MgSO4 and/or lidocaine at the discretion of the anesthesiologist). The primary endpoint was the total amount of opioid consumed in its equivalent of intravenous morphine during the first 48 postoperative hours. Secondary outcomes included perioperative hemodynamics, post-operative maximal pain at rest and during coughing and adverse outcomes. Data are expressed as median [interquartile range].
Results: Patients in the OFA-group had a higher EuroSCORE II, with more diabetes, more dyslipidemia and more non-elective surgery but fewer smoking history. In the OFA group, the median loading dose of dexmedetomidine was 0.6 [0.4–0.6] μg.kg− 1 while the median maintenance dose was 0.11 μg.kg− 1.h− 1 [0.05–0.20]. In 10 (25%) patients, dexmedetomidine was discontinued for a drop of mean arterial pressure below 55 mmHg. The median total amount of opioid consumed in its equivalent of intravenous morphine during the first 48 postoperative hours was lower in the OFA group (15.0 mg [8.5–23.5] versus 30.0 mg [17.3–44.3], p < 0.001). While no differences were seen with rest pain (2.0 [0.0–3.0] versus 0.5 [0.0–5.0], p = 0.60), the maximal pain score during coughing was lower in OFA group (3.5 [2.0–5.0] versus 5.5 [3.0–7.0], p = 0.04). In OFA group the incidence of atrial fibrillation (18% versus 40%, p = 0.03) and non-invasive ventilation use (25% versus 48%, p = 0.04) were lower. The incidence of bradycardia and the intraoperative use of norepinephrine were similar between both groups.
Conclusion: Dexmedetomidine-based OFA in cardiac surgery patients is feasible and could be associated with a lower postoperative morphine consumption and better postoperative outcomes. Further randomized studies are required to confirm these promising results and determine the optimal associations, dosages, and infusion protocols during cardiac surgery.
As early as the 1990's fast-track protocols have been implemented successfully lowering opioid doses and allowing rapid extubation after cardiac surgery using a balanced opioid anesthetic.[1–3] However, balanced opioid anesthesia may be responsible for hyperalgesia and acute tolerance which could lead to both an increase in opioid prescription and postoperative chronic pain (nearly 20% 1 y after sternotomy). Recently nonopioid interventions including the intraoperative use of dexmedetomidine have been proposed to reduce opioid consumption during the perioperative period of cardiac surgery patients.[6,7] Better pain control and lower opioid consumption seems to be crucial to enable the implementation of postoperative enhanced recovery elements such as early mobilization and early nutrition.
A milestone that could help reducing even further perioperative opioid consumption for cardiac surgery patients might be the integration of opioid-free anesthesia (OFA) protocol. In OFA for non-cardiac surgery, sympathetic nervous system control is obtained administrating a combination of several drugs studied the last 30 years such as intravenous lidocaine, ketamine, dexmedetomidine which is a highly selective alpha-2 agonist and magnesium sulphate. This multimodal analgesic approach has an important opioid sparing effect that has been shown to limit opioid-related side effects such as respiratory depression and, thus prolonged duration of mechanical ventilation, delirium, urinary retention, nausea, ileus and vomiting. Few data on OFA in cardiac surgery demonstrating its feasibility are available.[13,14] One retrospective study compared an OFA (protocol combining propofol-lidocaine-ketamine-dexamethasone) to an opioid-based anaesthesia (OBA) with sufentanil and regional anaesthesia. Recent data suggest that dexmedetomidine added to a balanced anaesthesia protocol in cardiac surgical patients could reduce opioid consumption, postoperative pain and duration of mechanical ventilation.[16,17] Interestingly, dexmedetomidine administration through this approach may also reduce postoperative myocardial injury, incidence of new onset of arrythmias and even postoperative mortality up to 1 year after cardiac surgery.
The main objective of the present retrospective study was to evaluate the feasibility and the postoperative opioid-sparing effect of dexmedetomidine-based OFA in adult cardiac surgery patients. We tested the hypothesis that dexmedetomidine-based OFA could significantly reduce morphine consumption during the first 48 h following on-pump cardiac surgery.
BMC Anesthesiol. 2021;21(166) © 2021 BioMed Central, Ltd.