Daily Anesthesiology Research Analysis

BACKGROUND: Chronic postsurgical pain (CPSP), defined as pain persisting beyond the normal healing period, is a significant surgical complication. This systematic review evaluated the effectiveness of dexmedetomidine in preventing CPSP. METHODS: A systematic search of PubMed/MEDLINE, the Cochrane Controlled Trials Register, Embase, and Wanfang Data was conducted following PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions until 17 January 2025. Randomized controlled trials (RCTs) comparing dexmedetomidine with a placebo for the prevention of CPSP were included. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline. Data were extracted independently by 2 researchers. A random-effects meta-analysis model was used to report pooled treatment effects and 95% CIs. The primary outcome was CPSP incidence post-surgery. Secondary outcome was CPSP intensity post-surgery. RESULTS: Twenty-three RCTs involving 1,979 patients were analysed. Compared to controls, perioperative dexmedetomidine administration appeared to reduce CPSP rates at 3 months (OR, 0.35; 95% CI, 0.23 - 0.54; P<0.00001) and 6 months (OR, 0.28; 95% CI, 0.18 - 0.42; P<0.00001), and 12 months (OR, 0.11; 95% CI, 0.03 - 0.43; P = 0.001). Both intravenous and perineural dexmedetomidine reduced CPSP occurrence at 3 months (intravenous administration, OR, 0.41; 95% CI, 0.25-0.67; P = 0.003; perineural administration, OR, 0.26; 95% CI, 0.11- 0.60; P = 0.001) and 6 months (intravenous administration, OR, 0.26; 95% CI, 0.16-0.41; P<0.00001; perineural administration, OR, 0.35; 95% CI, 0.14-0.90; P = 0.03). Intravenous dexmedetomidine reduced CPSP occurrence at 12 months (OR, 0.11; 95% CI, 0.03 - 0.43; P = 0.001). In addition, dexmedetomidine reduces chronic pain severity at 6 months (MD, - 0.91; 95% CI, - 1.17 to -0.64; P <0.00001). Perioperative dexmedetomidine use was associated with an increased incidence of bradycardia (OR: 3.35; 95% CI: 1.15 to 9.81; P = 0.03) but did not result in hypotension (OR: 1.37; 95% CI: 0.57 to 3.27; P = 0.48). CONCLUSIONS: This systematic review and network meta-analysis found that perioperative dexmedetomidine effectively reduces the occurrence of CPSP in surgical patients and serves as a valuable adjunct to standard analgesic regimens in surgery.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication following cardiac surgery involving cardiopulmonary bypass (CPB). This is partly attributable to crystalloid-based priming solutions causing both hemolysis and loss of oncotic pressure with tissue edema. While colloids like albumin and starches have not shown clear benefits, pilot studies using dextran-based priming reported improved oncotic pressure, reduced hemolysis, and lower levels of a renal injury marker, suggesting potential renal protective effects. OBJECTIVE: We hypothesized that a dextran-based priming solution can reduce the incidence of postoperative AKI in high-risk patients undergoing cardiac surgery with CPB. METHODS: In this randomized, controlled, double-blinded, multicenter trial, adult patients with a calculated postoperative AKI risk of ≥ 50% were assigned to receive either a dextran or a crystalloid-based CPB priming solution. The primary outcome was the incidence of AKI within 96 h postoperatively. Secondary outcomes included perioperative hemolysis, net fluid balance, and the need for postoperative renal replacement therapy. RESULTS: The trial was terminated early due to slow enrolment, with 101 of the planned 366 patients recruited. A total of 92 patients were included in the final analysis (43 in the dextran group, 49 in the control group). Postoperative AKI occurred in 81% and 53% of patients in the dextran and control groups, respectively (risk ratio 1.53, 95% confidence interval 1.15-2.06, p = 0.004). The dextran group demonstrated lower intraoperative hemolysis and a more favorable net fluid balance. Postoperative renal replacement therapy was required in 7% of the dextran group and 4% of the control group (p = 0.66). No significant differences in adverse events were observed between the groups. CONCLUSION: In high-risk patients undergoing cardiac surgery with CPB, the use of a dextran-based priming solution was associated with a significantly increased risk of postoperative AKI. EDITORIAL COMMENT: This randomized multicenter trial compared dextran to a crystalloid-based priming solution during cardiopulmonary bypass in participants with elevated risk of acute kidney injury. While the trial had to be terminated due to slow enrolment after about a third of planned cases were included, acute kidney injury was significantly more common in the dextran group, contrary to the primary hypothesis of the study. The study highlights the complexity and logistical challenges of conducting randomized treatment protocols for cardiopulmonary bypass, but at the same time highlights the importance of conducting such studies. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04293744.

BACKGROUND: Ephedrine, phenylephrine, and norepinephrine are commonly used to manage hypotension during the induction of anaesthesia. The objective of this study was to evaluate whether prophylactic administration of assumed equipotent doses of these vasopressors could maintain systolic arterial blood pressure (SAP) and heart rate (HR) within 80% of baseline for the first 5 min following induction of anaesthesia. METHODS: This randomised, double-blind, dose-controlled study was conducted at the Day Surgery Unit of Haugesund Hospital, Norway. One hundred and twenty-eight healthy women scheduled for gynaecological surgery were randomly allocated in a 1:1:1:1 ratio to receive prophylactic administration of ephedrine (0.1 mg/kg), phenylephrine (1 μg/kg), norepinephrine (0.1 mg/kg), or placebo (sodium chloride 9 mg/mL) at a volume of 0.1 mL/kg. Anaesthesia was induced using target-controlled infusion (TCI) of propofol and remifentanil. The initial 2.5 min constituted a sedation phase, after which the targets of propofol and remifentanil were increased, and the assigned vasopressor was administered. Beat-to-beat haemodynamic monitoring was performed using the LiDCOplus system. The primary outcome variables were the maximal decrease in SAP and HR within 5 min following bolus administration. Secondary outcome measures included changes in stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR). RESULTS: The absolute changes in SAP (mean ± standard deviation) following vasopressor administration were -27 ± 8.9 (ephedrine), -40 ± 11 (phenylephrine), -41 ± 13 (norepinephrine), and -42 ± 10 (placebo) mmHg. The differences (95% confidence interval [CI]) in the maximal SAP change between placebo and the vasopressors were as follows: ephedrine, -15 (-22, -9.9) mmHg; phenylephrine, -2.3 (-8.8, 4.2) mmHg; and norepinephrine, -1.7 (-8.3, 4.9) mmHg. Relative reductions in SAP from baseline to minimum values were -20% for ephedrine, -30% for phenylephrine, -30% for norepinephrine, and -32% for placebo. The absolute changes (median, interquartile range) in HR with ephedrine, phenylephrine, norepinephrine, and placebo were -10 (-6.2 to -18), -19 (-17 to -26), -23 (-20 to -33), and -15 (-9.5 to -21) bpm, respectively. Relative changes from baseline to minimum values in HR were -17% for ephedrine, -30% for phenylephrine, -37% for norepinephrine, and -22% for placebo. The differences in SV change between groups were small. CO was best preserved with ephedrine (-22% ± 11%), while phenylephrine and norepinephrine were associated with greater reductions (-38% ± 7.8% and -42% ± 9.8%, respectively). SVR increased most markedly in the norepinephrine group, followed by phenylephrine, with the smallest increase observed in the ephedrine group. CONCLUSION: Prophylactic administration of ephedrine effectively maintained SAP, HR, and CO within the first 5 min following bolus injection at induction with propofol and remifentanil. In contrast, bolus administration of norepinephrine and phenylephrine demonstrated a short duration of action, with SAP comparable to placebo at 5 min. Based on these findings, prophylactic administration of a bolus ephedrine is recommended, whereas prophylactic phenylephrine or norepinephrine injections may not be clinically preferable for bolus use in this context. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03864094, March 6, 2019 This trial assessed circulatory responses to three different commonly used vasoactive support (vasopressor) drugs given as a single bolus together anesthetic induction propofol and remifentanil, and this in a cardiovascularly healthy adult surgical cohort. Results demonstrated that pharmacodynamic patterns with the three different test drugs, along with a no-prophylactic vasopressor comparitor. Findings showed a favorable profile for ephedrine compared to phenylephrine or noradrenaline if choosing to give a vasopressor in this way.