Daily Anesthesiology Research Analysis
Analyzed 14 papers and selected 3 impactful papers.
Summary
Today's strongest studies address modifiable peri-anesthetic risks and recovery outcomes. Randomized evidence indicates that avoiding routine 100% oxygen before pediatric extubation may reduce postoperative atelectasis, while remimazolam-esketamine may lower sedation-related adverse events during ERCP in older adults. A prospective translational cohort also links gut microbiota, indole-3-propionic acid, and plasma Tau to postoperative delirium vulnerability.
Research Themes
- Lung-protective oxygen management during pediatric emergence
- Safer procedural sedation in older adults
- Gut-brain mechanisms and biomarkers of postoperative delirium
Selected Articles
1. Impact of high fraction of inspired oxygen before extubation on incidence of postoperative atelectasis in children: a randomized controlled trial.
This randomized controlled trial found that administering 100% inspired oxygen for 10–20 minutes before extubation significantly increased the incidence and severity of postoperative atelectasis in children compared with 50% oxygen. The findings identify extubation as an important and previously under-studied window for oxygen-induced lung injury and support lower oxygen concentrations when clinically safe.
Impact: The study directly challenges the routine use of 100% oxygen during emergence and provides randomized pediatric evidence supporting a lung-protective extubation strategy. Its result is immediately testable in practice and could influence perioperative oxygen protocols.
Clinical Implications: For children undergoing general anesthesia, 50% inspired oxygen before extubation may be considered when adequate oxygenation is maintained, rather than automatically using 100%. Clinicians should balance this approach against individual hypoxemia risk and continue objective oxygenation monitoring.
Key Findings
- 100% FiO₂ for 10–20 minutes before extubation significantly increased postoperative atelectasis compared with 50% FiO₂.
- The high-oxygen strategy increased both the incidence and severity of postoperative atelectasis.
- The trial identifies the extubation period as a critical target for lung-protective anesthesia practice.
Methodological Strengths
- Randomized controlled design directly compared two pre-extubation oxygen concentrations.
- Lung ultrasound was used to assess postoperative atelectasis, providing a bedside and clinically relevant outcome measure.
Limitations
- The provided abstract does not report the sample size, allocation details, or blinding procedures.
- The postoperative assessment duration and the generalizability across different pediatric age groups and surgical populations are not established in the provided information.
Future Directions: Multicenter trials should confirm the finding across pediatric age groups and procedures, define oxygenation thresholds for safely using lower FiO₂, and evaluate whether reduced atelectasis translates into fewer pulmonary complications and shorter recovery.
BACKGROUND: High fraction of inspired oxygen (FiO₂) before extubation may promote postoperative atelectasis. METHOD: To compare the atelectasis formation in pediatric patients receiving different FiO₂ concentrations before extubation. RESULTS: A statistically significant difference in incidence of postoperative atelectasis was found between low and high FiO₂ groups. CONCLUSION: 100% FiO₂ before extubation increased postoperative atelectasis compared with 50% FiO₂. IMPACT: This study is the first randomized controlled trial in children to evaluate the effect of pre-extubation inspired oxygen concentration on post-extubation atelectasis, using lung ultrasound. Even short-term administration of 100% FiO₂ (10-20 min) before extubation significantly increases the incidence and severity of postoperative atelectasis in children.
2. Safety and Efficacy of Remimazolam Combined with Esketamine for Anesthesia in Elderly Patients Undergoing ERCP: A Randomized Controlled Trial.
In this single-center randomized trial of 160 adults aged 60–80 years undergoing ERCP, remimazolam-esketamine reduced composite sedation-related adverse events from 35.0% with propofol-fentanyl to 17.5%. Anesthetic regimen success was similar between groups, although induction was modestly longer and tachycardia, hypertension, and psychotomimetic symptoms were numerically more frequent with remimazolam-esketamine.
Impact: The trial isolates the effect of the anesthetic regimen while standardizing airway support, oxygen delivery, capnography, and rescue procedures. The 50% relative reduction in composite adverse events supports further evaluation of remimazolam-esketamine for procedural anesthesia in older adults.
Clinical Implications: Remimazolam-esketamine may be considered a potential alternative to propofol-fentanyl for selected older patients undergoing ERCP, particularly when respiratory or circulatory instability is a concern. Careful monitoring for tachycardia, hypertension, and psychotomimetic symptoms remains necessary.
Key Findings
- Composite sedation-related adverse events occurred in 17.5% of the remimazolam-esketamine group versus 35.0% of the propofol-fentanyl group.
- The relative risk was 0.50, with P=0.016; the adjusted relative risk was 0.49 with P=0.003.
- Anesthetic regimen success was similar, at 97.5% versus 98.8%, while induction was modestly longer with remimazolam-esketamine.
Methodological Strengths
- Prospective randomized parallel-group design with intention-to-treat analysis.
- Both groups received identical airway, oxygenation, capnography, and rescue-management protocols, reducing confounding from respiratory support.
Limitations
- The study was single-center and included a selected population of adults aged 60–80 years with American Society of Anesthesiologists physical status I–III.
- Event counts for tachycardia, hypertension, and psychotomimetic symptoms were small, and the abstract does not establish long-term outcomes or broad generalizability.
Future Directions: Multicenter randomized trials should assess diverse ERCP populations, compare dose strategies, evaluate clinically important individual respiratory and cardiovascular outcomes, and determine whether the regimen improves recovery and resource use.
OBJECTIVE: Older adults undergoing ERCP are particularly susceptible to sedation-related respiratory and circulatory adverse events. This trial compared the safety and efficacy of remimazolam-esketamine with propofol-fentanyl, with identical standardized nasopharyngeal airway-assisted respiratory management in both groups. PATIENTS AND METHODS: This single-center, prospective, randomized, parallel-group superiority trial enrolled 160 patients aged 60-80 years with American Society of Anesthesiologists physical status I-III who were scheduled for elective ERCP. Participants were randomly assigned 1:1 to remimazolam-esketamine (RE group; n=80) or propofol-fentanyl (PF group; n=80). Both groups received identical nasopharyngeal airway placement, oxygen delivery, capnography, and rescue algorithms; the randomized intervention was the anesthetic drug regimen.
3. Gut microbiota and blood biomarkers as correlating factors in patients with postoperative delirium: analysis of three prospective observational studies.
Across three prospective observational datasets, interactions among gut microbiota, indole-3-propionic acid, and plasma Tau were observed specifically in patients who developed postoperative delirium. Network analyses showed altered microbial relationships, and microbiome-based machine-learning classifiers demonstrated potential discriminatory ability, supporting a gut-blood-brain axis as a candidate mechanism and therapeutic target.
Impact: The study integrates microbiome ecology, a neurodegenerative biomarker, and a microbial metabolite to propose a biologically coherent mechanism for postoperative delirium. It advances the field beyond association with single biomarkers toward interacting pathways that could support prevention or targeted treatment.
Clinical Implications: The findings may eventually support perioperative risk stratification using microbiome and blood biomarkers and motivate trials of microbiota- or metabolite-directed interventions. They are hypothesis-generating and should not yet be used alone for clinical diagnosis or treatment selection.
Key Findings
- Ten percent of the screened participants developed postoperative delirium.
- Significant associations among gut microbiota, indole-3-propionic acid, and plasma Tau were observed only in participants with postoperative delirium.
- Co-occurrence network structures differed between delirium and non-delirium groups, and three machine-learning classifiers showed potential discriminatory performance.
Methodological Strengths
- Prospective observational design across three studies with prespecified clinical and biological assessments.
- Integration of microbial network analysis, plasma biomarkers, microbial metabolites, and machine-learning classification.
Limitations
- Although 491 participants were screened, final analyses included only 139 participants with blood biomarker data and 86 with gut microbiota data.
- The observational associations and machine-learning findings do not establish causality, and the reported classifier performance was limited and requires external validation.
Future Directions: Larger multicenter longitudinal studies should validate the microbiota–Tau–metabolite relationships, test temporal changes before and after surgery, and determine whether microbiota or indole-3-propionic acid modulation can prevent or mitigate postoperative delirium.
Postoperative delirium is associated with both gut microbiota alterations and Tau phosphorylation; however, how these factors interact and jointly contribute to postoperative delirium remains poorly understood. This prospective observational cohort study screened 491 patients aged ≥65 years undergoing elective laminectomy or hip or knee replacement under general or spinal anesthesia at Massachusetts General Hospital (2016-2020). The study aimed to assess the correlation between plasma Tau protein levels, specific gut microbiota, and the gut microbiota-derived metabolite indole-3-propionic acid (IPA) in participants with and without postoperative delirium. Exclusion criteria included major neurological disease, smoking history, sensory impairment, and recent antibiotic use. Delirium was assessed 24-48 h postoperatively. Out of 491 screened participants, 139 had blood biomarker data, and 86 had gut microbiota data included in the final analysis.