A Comparison of Different Remifentanil Effect-Site Concentrations to Allow for Early Extubation After Cardiac Surgery

Postoperative pain after different doses of remifentanil infusion during anaesthesia: a meta-analysis

BACKGROUND

This meta-analysis aimed to explore the correlation between the different doses of remifentanil-based anaesthesia and postoperative pain in randomised trials.

METHODS

The electronic databases including PubMed, Cochrane, clinical trial registries, and Google Scholar were searched up to November 2022 for randomised controlled trials (RCTs) that assessed the dose dependent efficacy of remifentanil for postoperative pain intensity and hyperalgesia.

RESULTS

31 studies involving 2019 patients were included for analysis. Compared with the high remifentanil dose administration, patients in low doses showed less postoperative pain intensity at 1-2 h (weighted mean differences (WMD): 0.60, 95% CI, 0.05 to 1.15), 3-8 h (WMD: 0.38, 95% CI, 0.00 to 0.75), 24 h (WMD: 0.26, 95% CI, 0.04 to 0.48) and 48 h (WMD: 0.32, 95% CI, 0.09 to 0.55). Remifentanil-free regimen failed to decrease the pain score at 24 h (WMD: 0.10, 95% CI, -0.10 to 0.30) and 48 h (WMD: 0.15, 95% CI, -0.22 to 0.52) in comparison with remifentanil-based anaesthesia. After excluding trials with high heterogeneity, the dose of the remifentanil regimen was closely correlated with the postoperative pain score (P=0.03). In addition, the dose of the remifentanil regimen was not associated with the incidence of postoperative nausea and vomiting (PONV) (P=0.37).

CONCLUSIONS

Our meta-analysis reveals that the low dose of remifentanil infusion is recommendable for general anaesthesia maintenance. No evidence suggests that remifentanil-free regimen has superiority in reducing postoperative pain. Moreover, remifentanil doesn't have a dose dependent effect in initiating PONV.

TRIAL REGISTRATION

The protocol of present study was registered with PROSPERO (CRD42022378360).

Effects of norepinephrine infusion during cardiopulmonary bypass on perioperative changes in lactic acid level (Norcal)

INTRODUCTION

Hyperlactatemia, a problem reported in up to 30% of cardiac surgery patients, results from excessive production of or decreased clearance of lactate. It is typically a symptom of tissue hypoperfusion and may be associated with the prevalence of postoperative acute mesenteric ischemia and renal failure, or prolonged intensive care unit (ICU) and hospital stay, and increased 30-day mortality.

METHODS AND MEASUREMENTS

Eighty cardiac surgery patients using cardiopulmonary bypass (CPB) were randomly assigned into either a placebo (n = 39) or norepinephrine 0.05-0.2 µg/kg/min (n = 41) as well as norepinephrine boluses during CPB to maintain mean arterial blood pressure (MAP) at 65 to 80 mm Hg. Patient assignments were done after receiving ethical approval to proceed. The primary result was the perioperative changes in lactic acid level. Secondary findings were also recorded, including hemodynamic variables, the incidence of vasoplegia, intraoperative hypotension, myocardial ischemia, the need for vasopressor support, postoperative complications, and mortality.

RESULTS

The peak levels and perioperative changes in blood lactate during the first 24 postoperative hours, the number of patients who experienced early hyperlactatemia on admission to the ICU (Placebo: 46.2%, Norepinephrine: 51.2%, p = .650), vasoplegia, hemodynamic changes, incidences of intraoperative hypotension, myocardial ischemia, postoperative complications, and mortality rates were similar in the two groups. Patients in the norepinephrine group received lower intraoperative rescue norepinephrine boluses to maintain the target MAP (p = .039) and had higher MAP values during the CPB and intraoperative blood loss [mean difference [95% confidence interval]; 177 [20.9-334.3] ml, p = .027].

CONCLUSION

norepinephrine and placebo infusions during the CPB with the maintenance of MAP from 65 to 80 mmHg had comparative effects on the changes in blood lactate and incidence of vasoplegia after cardiac surgery. Norepinephrine infusion maintained higher MAP values during the CPB.