Daily Anesthesiology Research Analysis
Three perioperative studies likely to influence anesthesiology practice emerged today: a meta-analysis shows perioperative dexmedetomidine reduces chronic postsurgical pain up to 12 months; a multicenter RCT found dextran cardiopulmonary bypass priming increases acute kidney injury in high-risk cardiac surgery; and a randomized trial indicates ephedrine preserves blood pressure and cardiac output better than phenylephrine or norepinephrine when given as a prophylactic bolus at induction.
Summary
Three perioperative studies likely to influence anesthesiology practice emerged today: a meta-analysis shows perioperative dexmedetomidine reduces chronic postsurgical pain up to 12 months; a multicenter RCT found dextran cardiopulmonary bypass priming increases acute kidney injury in high-risk cardiac surgery; and a randomized trial indicates ephedrine preserves blood pressure and cardiac output better than phenylephrine or norepinephrine when given as a prophylactic bolus at induction.
Research Themes
- Prevention of chronic postsurgical pain using alpha-2 agonists
- Renal safety of cardiopulmonary bypass priming strategies
- Optimal vasopressor choice for anesthetic induction hemodynamic stability
Selected Articles
1. Dexmedetomidine for the prevention of chronic postsurgical pain: a systematic review and meta-analysis.
Across 23 RCTs (n=1,979), perioperative dexmedetomidine reduced chronic postsurgical pain at 3, 6, and 12 months, with consistent benefits for both intravenous and perineural administration and reduced chronic pain intensity at 6 months. Bradycardia risk increased, while hypotension did not.
Impact: This synthesis quantifies a long-term preventive effect of dexmedetomidine on CPSP, a hard outcome with major quality-of-life impact, supporting protocolized use in high-risk surgeries. It balances efficacy with a clear adverse-event signal (bradycardia).
Clinical Implications: Consider dexmedetomidine (IV infusion or perineural adjunct) as part of multimodal analgesia to prevent CPSP, with monitoring for bradycardia and individualized dosing. Integration into ERAS pathways may be reasonable for surgeries with high CPSP risk.
Key Findings
- Reduced CPSP incidence at 3 months (OR 0.35, 95% CI 0.23–0.54), 6 months (OR 0.28, 95% CI 0.18–0.42), and 12 months (OR 0.11, 95% CI 0.03–0.43).
- Both IV and perineural dexmedetomidine were effective at 3 and 6 months; IV route remained effective at 12 months.
- Chronic pain severity at 6 months decreased (MD −0.91, 95% CI −1.17 to −0.64).
- Bradycardia increased (OR 3.35), whereas hypotension did not (OR 1.37).
Methodological Strengths
- PRISMA-compliant systematic search with duplicate independent data extraction.
- Random-effects meta-analysis with route-specific subgroup analyses.
Limitations
- Heterogeneity across surgeries, dosing regimens, and CPSP definitions.
- Adverse event reporting varied; potential publication bias cannot be excluded.
Future Directions: Define optimal dosing, timing, and patient selection (e.g., phenotyping) for CPSP prevention, and evaluate cost-effectiveness and long-term functional outcomes.
2. Dextran vs. Crystalloid Priming Solution in Cardiac Surgery: A Randomized Trial on Acute Kidney Injury.
In high-risk CPB patients (n=92 analyzed), dextran priming increased AKI incidence (81% vs 53%; RR 1.53) despite reduced hemolysis and better net fluid balance. Renal replacement therapy rates and adverse events were similar; the trial was terminated early for slow enrollment.
Impact: A rigorous multicenter, double-blind RCT provides practice-changing evidence against dextran priming in high-risk cardiac surgery, overturning prior pilot signals of renal protection.
Clinical Implications: Avoid dextran-based priming in high-risk CPB patients pending further evidence; crystalloid priming remains preferable. Hemolysis reduction with dextran did not translate to renal benefit and may be harmful.
Key Findings
- AKI within 96 hours: 81% (dextran) vs 53% (crystalloid), RR 1.53 (95% CI 1.15–2.06), p=0.004.
- Lower intraoperative hemolysis and more favorable net fluid balance with dextran priming.
- No significant difference in postoperative renal replacement therapy (7% vs 4%; p=0.66) or adverse events.
- Trial stopped early for slow enrollment; 92 patients analyzed (of planned 366).
Methodological Strengths
- Randomized, double-blind, multicenter design targeting a high-risk population.
- Pre-specified primary endpoint (AKI within 96 h) with objective assessment.
Limitations
- Early termination and limited sample size reduce precision and generalizability.
- Not powered for secondary outcomes; details of dextran formulation/dose standardization may limit external applicability.
Future Directions: Mechanistic studies to explain AKI signal with dextran priming; adequately powered trials across risk strata and alternative colloid/crystalloid strategies.
3. Haemodynamic Changes After Prophylactic Doses of Ephedrine, Phenylephrine, Norepinephrine Versus Placebo During Induction of General Anaesthesia: A Randomised Trial.
In healthy women undergoing TCI propofol–remifentanil induction, prophylactic ephedrine (0.1 mg/kg) limited SAP drop (−27 mmHg) and best preserved cardiac output (−22%), whereas phenylephrine and norepinephrine led to larger SAP declines (~−40 mmHg) and greater CO reductions (−38% to −42%). By 5 minutes, SAP with phenylephrine/norepinephrine resembled placebo.
Impact: Head-to-head, double-blind physiologic comparisons provide actionable guidance on vasopressor choice for induction, highlighting ephedrine’s CO-sparing profile over alpha-agonists when used as a single prophylactic bolus.
Clinical Implications: If choosing a prophylactic bolus vasopressor at induction with propofol–remifentanil, ephedrine is preferable to phenylephrine or norepinephrine to preserve CO and mitigate hypotension; alpha-agonists may require alternative dosing (e.g., infusion) or patient-specific use.
Key Findings
- Maximal SAP decrease: ephedrine −27±8.9 mmHg vs phenylephrine −40±11, norepinephrine −41±13, placebo −42±10.
- Cardiac output decrease: ephedrine −22%±11% vs phenylephrine −38%±7.8% and norepinephrine −42%±9.8%.
- SVR increased most with norepinephrine, intermediate with phenylephrine, least with ephedrine.
- At 5 minutes, SAP with phenylephrine/norepinephrine approximated placebo, indicating short duration of effect.
Methodological Strengths
- Randomized, double-blind, dose-controlled design with beat-to-beat LiDCOplus monitoring.
- Standardized TCI propofol–remifentanil induction protocol; ClinicalTrials.gov registration (NCT03864094).
Limitations
- Single-center; participants were healthy women undergoing gynecologic surgery, limiting generalizability.
- Short observation window (first 5 minutes) without downstream clinical outcomes.
Future Directions: Evaluate different dosing strategies (e.g., infusions), mixed-sex/older cohorts, and impact on clinically relevant outcomes (hypotension episodes, rescue vasopressors, organ injury).