Daily Anesthesiology Research Analysis
Analyzed 49 papers and selected 3 impactful papers.
Summary
Three impactful anesthesiology-related studies stood out today: a novel semiparametric model (FLAME) shows that sustained intraoperative hypotension confers disproportionately higher AKI risk than fragmented episodes; a randomized, double-blind trial finds ciprofol non-inferior to propofol for rapid sequence induction with markedly less hypotension and no injection pain; and mechanistic work identifies microglial ACSS2 as a driver of neuropathic pain via autophagy disruption, revealing a potential analgesic target.
Research Themes
- Intraoperative hemodynamics and organ injury risk modeling
- Airway induction pharmacology and hemodynamic stability
- Neuroimmune mechanisms driving neuropathic pain
Selected Articles
1. FLAME: a model for duration-dependent risk accumulation in episodic temporal exposures.
This paper presents FLAME, a semiparametric episode-level model showing that duration, not just total time, drives risk accumulation. Applied to intraoperative hypotension, a single 60-minute episode yielded a 38% higher AKI probability than sixty 1-minute episodes of equal total duration, underscoring the need to avoid sustained hypotension.
Impact: Methodological innovation directly reframes how anesthesiologists should interpret and mitigate intraoperative hypotension exposure. Provides a ready-to-use R package for translation into perioperative analytics.
Clinical Implications: Prioritize prevention and rapid correction of sustained hypotensive episodes rather than focusing solely on cumulative hypotension minutes. Integrate episode-aware metrics into intraoperative decision support and quality dashboards.
Key Findings
- Introduces FLAME, an episode-level semiparametric model for duration-dependent risk accumulation.
- Applied to intraoperative hypotension: a single 60-min episode increased AKI probability to 0.33 vs 0.24 for sixty 1-min episodes (38% relative increase).
- Demonstrates that exposure pattern (sustained vs fragmented) matters beyond total duration.
- Provides an R package (flameRisk) to facilitate practical adoption.
Methodological Strengths
- Semiparametric modeling capturing episode-level duration effects rather than scalar summaries.
- Generalizable framework with open-source software for reproducibility and adoption.
Limitations
- Clinical application demonstrated in a single perioperative context; external validation across institutions and surgeries is needed.
- Observational application cannot exclude residual confounding in the exposure-outcome association.
Future Directions: Validate episode-aware thresholds for hypotension across surgeries, embed FLAME-derived metrics into real-time decision support, and extend to other episodic exposures (hypoxemia, tachyarrhythmias).
Emerging technologies enable continuous monitoring of temporal exposures to disease risk factors, leading to complex exposure processes characterized by subject-specific numbers and durations of exposure episodes. A key scientific question is how the number and duration of such episodes influence disease risk. Existing methods typically rely on scalar summaries or time-indexed representations and are not naturally suited to model duration-dependent risk accumulation at the episode level. We introduce the FLexible Accumulation ModEl (FLAME), a semiparametric model for risk accumulation at the level of individual exposure episodes, with duration as the primary driver of risk. FLAME is motivated by and applied to quantifying the association between the duration of intraoperative hypotension and acute kidney injury (AKI) following cardiac surgery. The estimated risk accumulation function reveals that, although 60 one-minute hypotensive episodes are associated with an AKI probability of 0.24, a single sustained 60-minute episode increases that probability to 0.33, representing a 38% increase despite identical total duration. These findings provide actionable insights for intraoperative hemodynamic management and demonstrate the importance of accounting for episodic exposure patterns. While motivated by cardiac surgery, FLAME is broadly applicable to other settings involving high-resolution temporal exposures. An R package, flameRisk, is provided to facilitate the application of the method in practice.
2. Comparison of the Efficacy of Ciprofol and Propofol for Rapid Sequence Induction and Intubation in Elective Non-Cardiac Surgery: A Prospective, Randomized, Non-Inferiority Trial.
Ciprofol achieved non-inferior excellent intubation conditions compared with propofol for RSI, while significantly reducing post-induction hypotension (15.3% vs 43.5%) and eliminating injection pain. Induction success and time to loss of consciousness were similar.
Impact: Provides high-quality randomized evidence for a newer induction agent that may enhance hemodynamic stability during RSI, a critical anesthetic moment.
Clinical Implications: Ciprofol may be considered as an alternative induction agent for RSI to reduce hypotension and injection pain in elective non-cardiac surgery; further data are needed in emergent and high-risk populations.
Key Findings
- Non-inferiority met for excellent intubation conditions: 96.5% (ciprofol) vs 95.3% (propofol).
- Significantly lower post-induction hypotension with ciprofol: 15.3% vs 43.5% (RR 0.35).
- Injection pain occurred in 68.2% with propofol but 0% with ciprofol.
- Similar induction success rates and time to loss of consciousness between groups.
Methodological Strengths
- Prospective, randomized, double-blind, non-inferiority design with prespecified margin.
- Both ITT and per-protocol analyses confirmed primary outcome.
Limitations
- Elective non-cardiac, adult population; generalizability to emergency and high-risk RSI is unknown.
- Single-country trial with modest sample size; hemodynamic outcomes beyond immediate induction were not detailed.
Future Directions: Evaluate ciprofol in emergency RSI, hemodynamically unstable and high-risk patients, and compare across different opioid and neuromuscular blocker regimens.
BACKGROUND: Rapid sequence induction and intubation (RSII) requires an agent that provides excellent intubating conditions with minimal hemodynamic disturbance. Propofol is standard but often causes hypotension. We compared the novel agent ciprofol with propofol for RSII in adult patients scheduled for elective non-cardiac surgery. METHODS: In this prospective, randomized, double-blind, non-inferiority trial, 170 adult patients scheduled for elective non-cardiac surgery were allocated to receive intravenous ciprofol (0.4 mg/kg, n = 85) or propofol (2.0 mg/kg, n = 85) for induction, with remifentanil and rocuronium. The non-inferiority margin was set at -10% for the primary outcome. The primary outcome was the proportion of patients with excellent intubation conditions (Viby-Mogensen scale). Secondary outcomes included incidence of hypotension, induction success rate, time to loss of consciousness (LOC), bispectral index (BIS) values, and pain on injection. RESULTS: Excellent intubation conditions were achieved in 96.5% (82/85) of the ciprofol group and 95.3% (81/85) of the propofol group (difference 1.2%, 95% CI: -4.4% to 6.7%). The lower limit of the 95% CI exceeded the prespecified non-inferiority margin of -10%. The per-protocol analysis confirmed non-inferiority (difference 1.2%, 95% CI -4.2% to 6.7%). The incidence of post-induction hypotension was significantly lower in the ciprofol group (15.3% vs 43.5%; RR 0.35, 95% CI 0.20 to 0.61; P < 0.001). No patient reported injection pain with ciprofol, compared to 68.2% with propofol (P < 0.001). Time to LOC and induction success rates were similar between groups. CONCLUSION: In adult patients undergoing elective non-cardiac surgery under a standardized RSI protocol, ciprofol 0.4 mg/kg provided intubating conditions non-inferior to propofol 2.0 mg/kg and was associated with less post-induction hypotension and injection pain. Further studies are needed in emergency, critically ill, and high-risk RSI populations. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2500095742).
3. Peripheral nerve injury-induced upregulation of acyl-CoA synthetase 2 contributes to neuropathic pain via mediating microglial autophagy disruption in the spinal dorsal horn.
Peripheral nerve injury upregulated ACSS2 in spinal microglia, increasing H3K27ac and raptor/mTORC1–TFEB signaling and disrupting autophagy, thereby promoting neuropathic pain. Pharmacologic inhibition and microglia-targeted genetic suppression of ACSS2 alleviated pain hypersensitivity and normalized autophagy and inflammatory cytokines.
Impact: Reveals a previously unrecognized epigenetic-metabolic axis (ACSS2–H3K27ac–raptor/mTORC1–TFEB) in microglia driving neuropathic pain, highlighting ACSS2 as a tractable analgesic target.
Clinical Implications: Although preclinical, targeting ACSS2 or its downstream autophagy pathway could inform development of non-opioid analgesics for neuropathic pain relevant to perioperative and chronic pain practice.
Key Findings
- SNL increased ACSS2 predominantly in spinal dorsal horn microglia, with elevated H3K27ac and raptor expression and activated mTORC1/TFEB signaling.
- Autophagy was disrupted (↑p62, ↓LC3II/LC3I); ACSS2 inhibition or microglial ACSS2 knockdown/knockout alleviated pain hypersensitivity and restored autophagy signaling.
- Microglial ACSS2 suppression reduced SP1 binding and H3K27ac at the raptor promoter and reversed increases in IL-1β and TNF-α.
Methodological Strengths
- Convergent pharmacological, viral shRNA, and genetic knockout approaches with cellular specificity.
- Mechanistic linkage from epigenetic modification to autophagy pathway and behavioral pain outcomes.
Limitations
- Preclinical rodent model; human translatability and safety of ACSS2 inhibition remain untested.
- Potential off-target effects of ACSS2 inhibitors require clarification.
Future Directions: Assess ACSS2 modulation in human tissues and pain cohorts, develop CNS-penetrant selective inhibitors, and evaluate efficacy in translational models and early-phase clinical trials.
Acyl-CoA synthetase 2 (ACSS2), by producing acetyl-coenzyme A from acetate in the nucleus, facilitates histone acetylation and regulates gene expression. However, the role of ACSS2 in neuropathic pain remains unclear. Herein, we found that lumbar 5 spinal nerve ligation (SNL) increased ACSS2 expression predominately in microglia of the spinal dorsal horn. This increase was accompanied by elevated histone H3K27 acetylation (H3K27ac), enhanced raptor expression, activated mTORC1/TFEB signaling, raised p62, and reduced LC3II/LC3I ratio. Repeated intrathecal or intravenous injections of ACSS2 inhibitor (ACSS2i) partially prevented development of, and reversed established, neuropathic pain in male and female rats. Microglia-specific AAV-F4/80-ACSS2 shRNA injection into L5 spinal dorsal horn alleviated SNL-induced pain hypersensitivity, counteracted the increase in H3K27ac and rescued mTORC1/TFEB signaling-mediated autophagy impairment. SNL-enhanced binding of SP1, a transcriptional regulator of raptor, and the elevation of H3K27ac at the raptor promoter were inhibited by AAV-F4/80-ACSS2 shRNA. The increases of IL-1β and TNF-α production after SNL were also reversed by these interventions. Microglia-specific Acss2 knockout (Acss2