Daily ReportSep 11, 2026
Anesthesiology, September 11 edition
We read 46 papers and selected 3.
Summary
Today’s most impactful studies identify anesthesia-related mechanisms and practices that may improve experimental validity, perioperative safety, and patient-centered care. Particularly notable are the demonstration that isoflurane substantially remodels metabolism in vivo, randomized evidence that dexamethasone increases perioperative glycemic variability in older adults with diabetes, and new data clarifying the clinical meaning of perioperative code-status decisions.
Research Themes
- Anesthesia-induced physiological and metabolic confounding
- Precision perioperative monitoring and risk management
- Ethical and patient-centered perioperative decision-making
Selected Articles
1. A simple, anesthesia-free infusion technique for in vivo metabolic tracing.
This mechanistic study demonstrates that isoflurane anesthesia profoundly alters circulating and tissue metabolite profiles, including tissue-specific remodeling in the brain and pancreas. The authors developed a minimally invasive tail-vein catheterization method that permits multihour tracer infusion in awake, freely moving mice, reducing anesthesia-related metabolic confounding.
Impact: The paper challenges a common assumption in preclinical metabolism research: that anesthesia is a neutral procedural condition. Its awake-animal infusion approach may improve reproducibility and validity across metabolic, pharmacologic, and disease-model studies.
Clinical Implications: The findings primarily affect basic and translational research rather than immediate clinical care. Investigators performing metabolic flux studies should consider anesthesia as a major experimental confounder and use awake infusion methods when scientifically and ethically appropriate.
Key Findings
- Isoflurane broadly decreased serum acylcarnitines and fatty acids while increasing selected amino acid metabolites and nucleotide species.
- Isoflurane induced coordinated but tissue-specific metabolic remodeling, including glycolytic changes in the brain and amino acid accumulation in the pancreas.
- A brief-anesthesia tail-vein catheterization technique enabled multihour tracer infusion in awake, freely moving mice.
Methodological Strengths
- Direct comparison of anesthetized and awake metabolic conditions across serum and multiple organs.
- Development of a practical, nonsurgical catheterization technique compatible with prolonged in vivo tracer infusion.
Limitations
- The abstract does not report the number of animals or provide complete quantitative effect estimates.
- The method was evaluated in mice, so its applicability to other species and to human metabolic studies remains uncertain.
Future Directions: Future studies should define the reproducibility of the awake infusion technique across strains, disease models, sexes, and tracer classes, and determine which anesthesia-related metabolic changes are reversible. Standardized reporting of anesthesia conditions should become routine in preclinical metabolic research.
Accurate metabolic flux analysis requires tracer delivery that preserves physiological metabolism. Current methods may distort metabolism through isoflurane anesthesia, surgical stress, or complex procedures. We demonstrate that isoflurane anesthesia profoundly alters serum and tissue metabolism across multiple pathways. In serum, acylcarnitines and fatty acids were broadly decreased, whereas amino acid metabolites and select nucleotide species were increased. Across multiple organs, isoflurane induced coordinated metabolic remodeling and distinct tissue-specific responses, including glycolytic remodeling in the brain and amino acid accumulation in the pancreas.
2. Single-dose dexamethasone increases perioperative glycemic variability in older patients with diabetes undergoing lung surgery: a continuous glucose monitoring-based randomized controlled trial.
In this randomized controlled trial of 72 older adults with type 2 diabetes undergoing thoracoscopic lung resection, a single 8 mg dose of dexamethasone increased the maximum intraoperative glucose change and continuous glucose monitoring-derived glycemic variability. The findings identify transient glucose instability that may be underestimated by conventional intermittent glucose measurements.
Impact: Dexamethasone is widely used for postoperative nausea and vomiting prophylaxis and other perioperative indications, yet its dynamic glycemic effects in older patients with diabetes are incompletely characterized. The trial provides clinically actionable negative or cautionary evidence using a more sensitive monitoring method.
Clinical Implications: In older patients with diabetes undergoing thoracic surgery, clinicians should balance the antiemetic and anti-inflammatory benefits of dexamethasone against increased glycemic variability. Continuous or more frequent glucose monitoring may be appropriate for high-risk patients, particularly when dexamethasone is administered.
Key Findings
- Intraoperative dexamethasone increased the maximum change in blood glucose compared with placebo.
- Continuous glucose monitoring showed greater perioperative glycemic variability after dexamethasone, including changes in standard deviation, coefficient of variation, and instability measures.
- Intermittent glucose testing may miss clinically relevant transient glycemic excursions in this vulnerable population.
Methodological Strengths
- Randomized placebo-controlled design with prospective registration.
- Continuous glucose monitoring captured dynamic glycemic variability beyond single glucose measurements.
Limitations
- The sample size was modest and limited to older patients with type 2 diabetes undergoing thoracoscopic lung resection.
- The study did not establish whether increased glycemic variability translated into more infections, longer hospitalization, or other patient-centered adverse outcomes.
Future Directions: Larger pragmatic trials should evaluate dexamethasone dose reduction, alternative antiemetic strategies, and glucose-monitoring protocols in patients with diabetes. Studies should also determine whether continuous glucose monitoring-guided treatment improves clinical outcomes rather than merely detecting glycemic excursions.
OBJECTIVES: To investigate whether a single intraoperative dose of dexamethasone alters perioperative glycemic dynamics in older patients with type 2 diabetes undergoing thoracoscopic lung resection. Glycemic dynamics were captured using continuous glucose monitoring (CGM). METHODS: 72 patients aged ≥ 60 years with type 2 diabetes who underwent elective thoracoscopic lung resection were randomly assigned to receive either 8 mg of dexamethasone or placebo (0.9% saline) intravenously during anesthesia induction. The primary outcome was the maximum change in intraoperative blood glucose from preoperative baseline. Key secondary outcomes included CGM-derived glycemic variability (GV) metrics, including standard deviation (SD), coefficient of variation (CV), blood glucose instability index (GLI) and time-in-range measures, assessed throughout the perioperative period.
3. Perioperative Continuation of Code-status Limitations and Early Postoperative Mortality: A Retrospective Cohort Study.
This five-hospital retrospective cohort study included 2,833 adults presenting for anesthesia with a preexisting limitation on resuscitation. Three-day mortality was higher among patients whose non-full-code status was maintained than among those whose status was reversed to full code, but most early deaths followed transition to comfort-focused care, suggesting that the association reflects goals-of-care trajectories rather than missed perioperative rescue.
Impact: The study addresses a common but ethically sensitive perioperative practice: how do-not-resuscitate decisions are handled around anesthesia and surgery. Its results caution against interpreting postoperative mortality as evidence that maintaining code-status limitations causes inadequate rescue, while supporting more transparent shared decision-making.
Clinical Implications: Perioperative teams should explicitly document patient preferences, clarify whether code-status limitations are procedure-specific or temporarily modified, and distinguish treatment limitation from failure to provide rescue. Postoperative mortality analyses should account for transitions to comfort-focused care and evolving goals of care.
Key Findings
- Among 2,833 patients, 82% reversed to full code perioperatively and 18% remained not full code.
- Three-day mortality was 2.9% among patients who remained not full code versus 1.2% among those who reversed to full code; adjusted odds ratio was 2.18.
- Among early deaths with continued hospitalization, 81% occurred after transition to comfort-focused care.
Methodological Strengths
- Large multisite cohort with complete inclusion of 2,833 eligible patients and multivariable adjustment for important clinical factors.
- The study examined postoperative code-status trajectories, adding clinical context beyond a simple mortality comparison.
Limitations
- The retrospective observational design cannot establish that perioperative code-status continuation causes higher mortality.
- The study was conducted within one academic health system, which may limit generalizability to other institutions and healthcare systems.
Future Directions: Prospective multicenter studies should evaluate standardized perioperative code-status conversations, documentation quality, patient and family understanding, and outcomes after surgery. Research should focus on whether structured shared decision-making reduces unwanted interventions while preserving access to appropriate perioperative rescue.
OBJECTIVE: The objective of this study was to determine whether perioperative continuation of code status limitations is associated with early postoperative mortality and to characterize postoperative code-status trajectories preceding early deaths. SUMMARY BACKGROUND DATA: Decisions about perioperative management of do-not-resuscitate (DNR) orders are common, yet their relationship to early postoperative outcomes remains poorly understood. METHODS: This was a retrospective cohort study conducted from March 2024 to June 2025 across 5 hospitals within a single academic health system. We included adults aged 18 years or older who presented for a procedure under anesthesia with a code status other than full code. The exposure was perioperative code status (reversal to full code vs. not full code). The primary outcome was all-cause mortality within 3 days of the procedure.