Daily Anesthesiology Research Analysis
Three anesthesiology-relevant studies stood out today: a double-blind randomized trial showed intraoperative dexmedetomidine improved postoperative microcirculation and markedly reduced acute kidney injury after cardiac surgery; a systematic review/meta-analysis found perioperative hypnosis reduces pain, anxiety, and postoperative nausea/vomiting; and a randomized EEG-guided titration trial demonstrated that maximizing alpha power subtly altered intraoperative drug dosing without reducing PACU d
Summary
Three anesthesiology-relevant studies stood out today: a double-blind randomized trial showed intraoperative dexmedetomidine improved postoperative microcirculation and markedly reduced acute kidney injury after cardiac surgery; a systematic review/meta-analysis found perioperative hypnosis reduces pain, anxiety, and postoperative nausea/vomiting; and a randomized EEG-guided titration trial demonstrated that maximizing alpha power subtly altered intraoperative drug dosing without reducing PACU delirium.
Research Themes
- Organ protection and microcirculation in cardiac anesthesia
- Nonpharmacologic adjuncts (hypnosis) for perioperative outcomes
- EEG-guided anesthetic titration and postoperative delirium
Selected Articles
1. Intraoperative Dexmedetomidine Enhances Postoperative Microcirculation and Reduces Acute Kidney Injury in Cardiac Surgery: A Double-Blind Randomized Trial.
In a double-blind RCT of 68 cardiac/aortic surgery patients, intraoperative dexmedetomidine improved sublingual microcirculation (higher perfused vessel density at 48 h), increased intraoperative urine output, and substantially reduced postoperative AKI (11.8% vs 50%). The dosing began at induction and continued until the end of surgery.
Impact: This RCT links microcirculatory preservation with a large, clinically meaningful reduction in AKI—a major driver of morbidity after CPB—suggesting an actionable anesthetic strategy for organ protection.
Clinical Implications: Consider dexmedetomidine infusion during CPB-era cardiac/aortic surgery to improve microcirculation and reduce AKI risk, while monitoring for alpha-2 agonist adverse effects. Replication and multicenter validation are warranted before guideline changes.
Key Findings
- Higher postoperative perfused vessel density at 48 h with dexmedetomidine (17.0 vs 15.6 mm/mm²; P=0.041).
- Greater intraoperative urine output with dexmedetomidine (950 vs 605 mL; P=0.002).
- Marked reduction in postoperative AKI incidence (11.8% vs 50%; P=0.001).
- Alpha-2 agonist dosing: 0.5 mcg/kg loading, then 0.5 mcg/kg/h until end of surgery.
Methodological Strengths
- Randomized, double-blind design with standardized measurement of sublingual microcirculation at multiple time points.
- Clinically relevant endpoints including AKI incidence alongside physiologic microcirculatory metrics.
Limitations
- Single-center study with modest sample size may overestimate effect sizes.
- Microcirculation measured sublingually may not fully represent renal microvascular physiology.
Future Directions: Multicenter, adequately powered RCTs to confirm AKI reduction, dose–response studies, and mechanistic work bridging sublingual and renal microcirculation.
2. Hypnosis for anaesthetists: a systematic review and meta-analyses.
Across 142 studies (n=9,238), pre-procedural hypnosis reduced postoperative pain (VAS MD −0.88 cm) and anxiety, while per-procedural hypnosis reduced intra-procedural pain (MD −1.14 cm), decreased postoperative anxiety, and lowered PONV risk (RR 0.43). Evidence on post-procedural hypnosis or other endpoints remains limited.
Impact: Provides the most comprehensive synthesis to date for anesthesia-relevant hypnosis, clarifying benefits on pain, anxiety, and PONV and informing nonpharmacologic adjunct use.
Clinical Implications: Hypnosis delivered before or during procedures can be considered to reduce anxiety, intra-procedural pain, and PONV, especially in high-anxiety patients or settings aiming to minimize antiemetics/opioids. Standardized protocols and trained practitioners are key.
Key Findings
- Pre-intervention hypnosis reduced postoperative VAS pain (MD −0.88 cm; 95% CI −1.72 to −0.05).
- Per-intervention hypnosis reduced intra-procedural pain (MD −1.14 cm) and postoperative anxiety (SMD −0.44).
- Per-intervention hypnosis lowered PONV risk (RR 0.43; 95% CI 0.25–0.74).
- Adding nonrandomized data did not materially alter estimates; evidence for post-intervention hypnosis was lacking.
Methodological Strengths
- Large-scale systematic review with stratified random-effects meta-analyses by timing.
- Sensitivity analyses including nonrandomized controlled studies to test robustness.
Limitations
- Heterogeneity across study designs and hypnosis protocols; variable study quality.
- Primary outcome (hypnotic/opioid use) effects were not consistently reported; limited data on post-intervention hypnosis.
Future Directions: High-quality, CONSORT-compliant RCTs using standardized hypnosis protocols focusing on medication-sparing effects, patient selection, and cost-effectiveness.
3. EEG alpha power and delirium in the postanaesthesia care unit in older adults: the AlphaMax trial part 1 - effect of desflurane and fentanyl titration during maintenance.
In older adults (n=200), EEG-guided titration to maximize alpha power increased fentanyl and reduced desflurane, producing an early but unsustained alpha-power increase after incision. PACU delirium rates were similar between groups (37% vs 33%), indicating no clinical benefit despite EEG modulation.
Impact: Provides high-quality, negative evidence that alpha-power–targeted titration does not reduce immediate postoperative delirium, refining EEG-guided anesthesia strategies.
Clinical Implications: Do not rely on alpha-power targeting alone to prevent PACU delirium. Focus on multifactorial delirium prevention (hemodynamics, analgesia, anticholinergic burden, sleep, mobilization) and consider EEG metrics as adjunctive physiologic markers rather than standalone targets.
Key Findings
- EEG-guided titration increased fentanyl dosing (median 650 μg vs 500 μg) and reduced desflurane ET concentration (3.9% vs 4.4%).
- Early post-incision alpha power was modestly higher (+0.8 dB) with titration but not sustained thereafter.
- No reduction in PACU delirium (37% vs 33%; P=0.553).
- Desflurane–alpha correlation was abolished by titration, suggesting altered EEG–dose relationship.
Methodological Strengths
- Randomized design with standardized desflurane–fentanyl technique and blinded PACU delirium assessment.
- Prospective EEG-guided intervention targeting a predefined physiologic biomarker (alpha power).
Limitations
- Underpowered for PACU delirium after feasibility-driven sample size reduction.
- Alpha-power increase was transient, limiting physiologic exposure to the targeted state.
Future Directions: Evaluate multimodal EEG-guided strategies (avoiding burst suppression, optimizing delta/alpha dynamics) within comprehensive delirium prevention bundles.