Daily Anesthesiology Research Analysis
Analyzed 71 papers and selected 3 impactful papers.
Summary
Three impactful studies in anesthesiology and perioperative medicine stood out today: a prospective study showing that the preoperative caval–aortic (IVC:Ao) ultrasound index accurately predicts postinduction hypotension; a large, externally validated obstetric anesthesia model estimating the risk of labor epidural catheter replacement or conversion; and functional characterization of six RYR1 variants refining malignant hyperthermia risk classification.
Research Themes
- Perioperative hemodynamic risk stratification
- Obstetric anesthesia risk prediction and triage
- Pharmacogenetics and malignant hyperthermia pathophysiology
Selected Articles
1. Preoperative Ultrasonographic Assessment of Caval-Aortic Index and Inferior Vena Cava Collapsibility Index for Predicting Postinduction Hypotension During General Anesthesia: A Prospective Observational Study.
In a prospective cohort of 100 surgical patients, the preoperative caval–aortic (IVC:Ao) index predicted postinduction hypotension with excellent accuracy (AUC 0.971), outperforming the inferior vena cava collapsibility index. A threshold of IVC:Ao ≤1.1 achieved 94% sensitivity and 94% specificity with a markedly smaller gray zone than IVC-CI.
Impact: Provides a practical, high-performing ultrasound metric for real-time risk stratification of postinduction hypotension, a frequent perioperative hazard linked to organ injury.
Clinical Implications: Incorporating IVC:Ao scanning into preinduction checks could guide fluid/vasopressor readiness and induction strategies (agent choice, dosing), particularly when IVC-CI is equivocal.
Key Findings
- IVC:Ao predicted postinduction hypotension with AUC 0.971 (95% CI 0.916–0.994), outperforming IVC-CI (AUC 0.846; p=0.025).
- An IVC:Ao cutoff ≤1.1 yielded sensitivity 94.1% and specificity 93.8%, with a narrow gray zone (10% vs 53% for IVC-CI).
- Each 0.1-unit decrease in IVC:Ao increased odds of hypotension nearly fivefold (OR 4.95; p<0.001).
Methodological Strengths
- Prospective design with standardized preinduction ultrasound measurements and blinded outcome capture.
- Multivariable modeling quantified independent predictive contributions and provided actionable cutoffs with gray-zone analysis.
Limitations
- Single-center study with modest sample size (N=100), requiring external validation.
- Short monitoring window (10 minutes postinduction) limits assessment of downstream clinical outcomes.
Future Directions: Validate IVC:Ao thresholds across diverse populations and induction protocols; test protocolized interventions triggered by IVC:Ao to reduce hypotension-related organ injury.
OBJECTIVES: This study aimed to compare the predictive performance of the inferior vena cava collapsibility index (IVC-CI) and the caval-aortic (IVC:Ao) index for postinduction hypotension. DESIGN: Prospective observational study. SETTING: Tertiary care university hospital. PARTICIPANTS: One hundred adult patients scheduled for elective surgery under general anesthesia. INTERVENTIONS: Before anesthetic induction, ultrasonographic measurements of the inferior vena cava and abdominal aorta were obtained in the supine position. The IVC-CI and IVC:Ao index were calculated using standard definitions. Mean arterial pressures were recorded every 2 minutes for 10 minutes following induction of anesthesia. MEASUREMENTS AND MAIN RESULTS: Postinduction hypotension occurred in 68 patients (68%). The IVC:Ao index demonstrated excellent discriminative performance (area under the curve [AUC], 0.971; 95% confidence interval [CI], 0.916-0.994) and significantly outperformed the IVC-CI (AUC, 0.846; 95% CI, 0.760-0.910; p = 0.025). An IVC:Ao index cutoff value ≤1.1 yielded a sensitivity of 94.1% and a specificity of 93.8%, with a narrow gray zone (values yielding both sensitivity and specificity <90%) including 10% of patients, compared with 53% for the IVC-CI. In multivariable analyses, each 0.1-unit decrease in the IVC:Ao index was associated with increased odds of hypotension (odds ratio, 4.95; 95% CI, 2.43-10.09; p < 0.001). Similarly, each 10-point increase in the IVC-CI was independently associated with hypotension (odds ratio, 6.17; 95% CI, 2.66-14.31; p < 0.001). CONCLUSIONS: Preoperative ultrasonographic assessment of the IVC:Ao index provides superior predictive performance and a substantially narrower gray zone compared with the IVC-CI for identifying patients at risk of postinduction hypotension.
2. Functional analysis and classification of six RYR1 variants in Japanese patients with malignant hyperthermia.
Six previously uncharacterized RYR1 variants from Japanese MH patients were functionally assessed in HEK-293 cells and all exhibited hypersensitive Ca2+ release to caffeine and 4-CmC. Based on functional data, p.Pro2366Arg was classified as pathogenic/likely pathogenic, while several others were considered likely pathogenic but remained VUS under formal criteria.
Impact: Directly advances malignant hyperthermia pharmacogenetics by functionally validating specific RYR1 variants, strengthening presymptomatic risk classification.
Clinical Implications: Functional evidence supports MH susceptibility assessment for carriers of p.Pro2366Arg and informs perioperative avoidance of triggering agents and family counseling.
Key Findings
- All six RYR1 variants showed hypersensitive Ca2+ release to caffeine and 4-CmC versus WT in HEK-293 cells.
- p.Pro2366Arg was classified as pathogenic/likely pathogenic based on functional data and criteria.
- Variants p.Ile2358Thr, p.Asp2431His, and p.Arg2454Gly were likely pathogenic yet remained VUS; p.Asp2431Glu and p.Glu2545Asp remained VUS.
Methodological Strengths
- Use of full-length RYR1 expression with standardized agonist (caffeine, 4-CmC) dose–response assays.
- Confirmation of protein expression by immunoblotting to support functional readouts.
Limitations
- Heterologous HEK-293 system may not fully recapitulate skeletal muscle context.
- Formal classification constrained by criteria, leaving several variants as VUS despite functional abnormalities.
Future Directions: Corroborate findings in patient-derived myotubes or in vivo models and integrate functional data into consensus variant classification frameworks for MH.
BACKGROUND: Malignant hyperthermia (MH) is a life-threatening pharmacogenetic disorder triggered by volatile anaesthetics or depolarising neuromuscular blockers, characterised by dysregulated calcium homeostasis in skeletal muscle. Dysfunction of ryanodine receptor type 1 (RYR1) because of genetic variants plays a central role in MH. Functional evaluation of newly identified RYR1 variants is essential for accurate presymptomatic diagnosis of MH susceptibility. This study aimed to assess the function of novel RYR1 variants detected in Japanese patients. METHODS: Six previously uncharacterised RYR1 variants were introduced into full-length rabbit RYR1 cDNA and expressed in human embryonic kidney (HEK-293) cells. Calcium release in response to caffeine and 4-chloro-m-cresol (4-CmC) was measured using Fura-2 AM. Expression of variants and wild-type (WT) RYR1 was confirmed by immunoblotting. Concentration-response curves (EC RESULTS: All six variants (p.Ile2358Thr, p.Asp2431His, p.Asp2431Glu, p.Pro2366Arg, p.Arg2454Gly, p.Glu2545Asp) showed hypersensitivity to caffeine and 4-CmC. Best-fit EC CONCLUSIONS: The RYR1 variant p.Pro2366Arg was classified as pathogenic or likely pathogenic, whereas p.Ile2358Thr, p.Asp2431His and p.Arg2454Gly remained as variants of uncertain significance but as likely pathogenic, and p.Asp2431Glu and p.Glu2545Asp remained variants of uncertain significance.
3. Predictive modeling of labor epidural catheter replacement or conversion to spinal or general anesthesia: a multicenter retrospective cohort study (2017-2024).
Using 82,823 labor epidural cases across a multihospital system, the REACT-OB model predicted epidural replacement or conversion to spinal/general anesthesia with externally validated AUROC of 0.67. Key predictors included prior within-encounter replacement/conversion, late-pregnancy BMI, pre-placement pain, prior cesarean, parity, and delivery hospital.
Impact: Introduces a scalable, externally validated risk tool to anticipate epidural failure or conversion in obstetric anesthesia, supporting triage and resource allocation.
Clinical Implications: REACT-OB may guide early anesthesiologist involvement, catheter technique selection, and OR readiness in patients at higher risk, pending prospective validation.
Key Findings
- Multicenter cohort of 82,823 epidural placements with 6.0% composite outcome of replacement or conversion.
- Externally validated AUROC ~0.67 for both logistic regression and XGBoost.
- Key predictors: prior within-encounter replacement/conversion, end-of-pregnancy BMI, pre-placement pain score, prior cesarean, parity, and delivery hospital.
Methodological Strengths
- Large, system-wide dataset with external validation at a held-out hospital.
- Use of both statistical and machine-learning approaches with decision-curve and simulation analyses.
Limitations
- Retrospective EHR-based design subject to unmeasured confounding and documentation bias.
- Moderate discrimination (AUROC 0.67) requires prospective refinement for bedside use.
Future Directions: Prospectively integrate REACT-OB into labor units for real-time triage and test whether targeted interventions reduce conversion or replacement rates.
BACKGROUND: Labor epidural analgesia may be inadequate during labor or for cesarean delivery anesthesia. No prediction model identifies cases of labor epidural analgesia with increased risk for epidural catheter replacement or conversion to spinal or general anesthesia. METHODS: We conducted a retrospective cohort study of patients receiving labor epidural analgesia initiated with standard epidural or dural puncture epidural technique in a large, multihospital healthcare system between 2017 and 2024. Demographic, comorbidity, vital-sign, and procedural data were extracted from the electronic health record. The composite outcome was epidural catheter replacement, subsequent spinal anesthesia, or advanced airway placement indicating general anesthesia for cesarean delivery within the same anesthesia encounter. Statistical and machine-learning models were developed; one hospital was held out for external validation. RESULTS: The cohort included 82,823 cases of epidural catheter placement among 65,419 unique patients; 5010 cases (6.0%) met the composite outcome. Logistic regression and XGBoost performed similarly on external validation (area under the receiver operating characteristic curve, 0.67). Important predictors included prior replacement or conversion during the same encounter, end-of-pregnancy body mass index, pre-placement pain score, prior cesarean delivery, parity, and delivery hospital. Decision-curve analysis and Monte Carlo simulation suggested possible utility for screening and triage when anesthesia staffing is limited. CONCLUSIONS: We developed and externally validated Risk Estimation for Anesthesia Catheter Technique replacement or conversion in Obstetrics (REACT-OB) to estimate the risk of this outcome. Prospective validation is required before clinical use.