Daily Anesthesiology Research Analysis
A single-center randomized trial found that tourniquet use during total knee arthroplasty in older adults increased postoperative delirium and was associated with biomarker changes suggesting hypoxia/oxidative stress. A simulation and applied re-analysis study identified multistate models as the optimal approach to analyze ventilator-free days in critical care trials. A meta-analysis of cesarean spinal anesthesia showed low-dose hypobaric local anesthetics reduce hypotension but may compromise a
Summary
A single-center randomized trial found that tourniquet use during total knee arthroplasty in older adults increased postoperative delirium and was associated with biomarker changes suggesting hypoxia/oxidative stress. A simulation and applied re-analysis study identified multistate models as the optimal approach to analyze ventilator-free days in critical care trials. A meta-analysis of cesarean spinal anesthesia showed low-dose hypobaric local anesthetics reduce hypotension but may compromise analgesic efficacy unless combined with intrathecal opioids.
Research Themes
- Perioperative neurocognitive disorders and modifiable surgical factors
- Methodological advances in ICU outcome analysis (ventilator-free days)
- Optimization of obstetric spinal anesthesia dosing and side-effect trade-offs
Selected Articles
1. Impact of tourniquet application on postoperative delirium in elderly patients undergoing total knee arthroplasty: a randomized clinical trial.
In 313 older adults undergoing TKA, tourniquet use nearly doubled postoperative delirium within 7 days (19.1% vs 9.6%). Biomarker changes (increased HIF-1α at 30 min and 24 h; decreased SOD at 24 h) suggest hypoxia/oxidative stress pathways. Postoperative complications and adverse events were similar between groups.
Impact: This randomized trial provides actionable evidence that a common intraoperative practice (tourniquet use) increases postoperative delirium in older adults and links it to plausible biological pathways.
Clinical Implications: Consider minimizing or avoiding tourniquet use in elderly TKA when feasible, intensifying delirium prevention, and monitoring oxidative stress-related biomarkers. Protocols targeting hypoxia/oxidative stress (e.g., optimizing oxygen delivery, antioxidant strategies) merit evaluation.
Key Findings
- Postoperative delirium incidence was higher with tourniquet (19.1%) vs no tourniquet (9.6%), RR 1.12 (95% CI 1.02–1.23), P=0.018.
- HIF-1α increased at 30 minutes and 24 hours postoperatively with tourniquet; SOD decreased at 24 hours.
- Postoperative complications and adverse events were comparable between groups.
Methodological Strengths
- Prospective randomized design with a sizable sample (n=313).
- Concurrent measurement of mechanistic biomarkers (HIF-1α, SOD, S100β) to support biological plausibility.
Limitations
- Single-center trial; generalizability may be limited.
- Blinding of clinicians/patients is unclear; potential performance/detection bias.
Future Directions: Multicenter RCTs comparing standardized tourniquet protocols (duration/pressure) and testing targeted interventions (e.g., HIF-1α modulation, antioxidant strategies) to prevent delirium.
2. What is the optimal approach to analyse ventilator-free days? A simulation study.
Across simulations and four applied RCT datasets, multistate models outperformed alternatives for analyzing ventilator-free days and offered interpretable effect sizes. Zero-inflated/hurdle count models and cause-specific Cox for death showed poor Type I error control, whereas time-to-event approaches, the Mann–Whitney test, proportional odds models, and the win ratio generally performed well.
Impact: This work provides a rigorous, comparative roadmap for analyzing a widely used ICU endpoint, enabling more robust and comparable evidence across trials.
Clinical Implications: Adopting multistate models for ventilator-free days can improve inference and comparability in critical care trials, informing regulatory and guideline-level analyses.
Key Findings
- Multistate models achieved superior performance and interpretability for VFD analysis in simulations and applied RCT datasets.
- Zero-inflated and hurdle Poisson/negative binomial models and cause-specific Cox for death exhibited poor Type I error control.
- Time-to-event approaches, Mann–Whitney test, proportional odds model, and win ratio generally showed good performance.
Methodological Strengths
- Comprehensive simulations with varied scenarios (16 datasets) and evaluation of 12 statistical methods.
- External application to four landmark RCT datasets with sensitivity analyses.
Limitations
- Simulated scenarios cannot encompass all clinical complexities and endpoint definitions.
- Recommendations are methodological; no direct patient-level intervention tested.
Future Directions: Develop consensus guidelines and provide user-friendly tools for multistate modeling of VFDs; extend evaluations to other composite ICU endpoints.
3. Efficacy of low-dose hypobaric anesthetics in spinal anesthesia for cesarean delivery: systematic review and meta-analysis.
Across 17 RCTs (n=1,280), low-dose hypobaric spinal local anesthetics reduced maternal hypotension (RR 0.56) but increased the need for analgesic supplementation (RR 3.13). When low-dose anesthetic was combined with intrathecal opioids, analgesic efficacy was comparable to conventional-dose local anesthetic without opioid.
Impact: This synthesis clarifies dose–side effect trade-offs in obstetric spinal anesthesia and supports opioid adjuvants to maintain efficacy while minimizing hypotension.
Clinical Implications: For cesarean spinal anesthesia, consider low-dose hypobaric local anesthetic with intrathecal opioid to reduce hypotension without sacrificing analgesic efficacy, while individualizing dosing and monitoring.
Key Findings
- Low-dose hypobaric local anesthetics reduced maternal hypotension (RR 0.56; 95% CI 0.43–0.73).
- Analgesic supplementation was more frequent with low-dose regimens (RR 3.13; 95% CI 2.14–5.59).
- With intrathecal opioid adjuvants, low-dose anesthetic achieved similar efficacy to conventional-dose without opioid (RR 1.32; 95% CI 0.58–3.00).
Methodological Strengths
- Systematic review and meta-analysis of 17 RCTs with protocol registered on PROSPERO.
- Subgroup analyses addressing the role of intrathecal opioid adjuvants and multiple secondary outcomes.
Limitations
- Evidence grades for key outcomes were low to moderate; heterogeneity in dosing and anesthetic agents.
- Potential variability in definitions and reporting of hypotension and analgesic supplementation across trials.
Future Directions: Head-to-head, standardized RCTs comparing low-dose plus opioid vs conventional-dose regimens, with patient-centered outcomes and neonatal safety.