Daily Anesthesiology Research Analysis
Three large-scale perioperative studies stand out today: a statewide analysis shows opioid-free discharge after bariatric surgery rose fourfold without worsening outcomes; a single-center cohort of 1,555 liver transplants supports the safety of early extubation with very low reintubation rates; and a multicenter machine-learning model accurately predicts postoperative pulmonary complications after neurosurgery, outperforming existing risk scores.
Summary
Three large-scale perioperative studies stand out today: a statewide analysis shows opioid-free discharge after bariatric surgery rose fourfold without worsening outcomes; a single-center cohort of 1,555 liver transplants supports the safety of early extubation with very low reintubation rates; and a multicenter machine-learning model accurately predicts postoperative pulmonary complications after neurosurgery, outperforming existing risk scores.
Research Themes
- Opioid stewardship and enhanced recovery after surgery
- Early extubation strategies in transplant anesthesia
- Machine-learning risk prediction for postoperative pulmonary complications
Selected Articles
1. Variation in opioid-free discharge after metabolic surgery from 2018 to 2023: a state-wide analysis from the Michigan Bariatric Surgery Collaborative.
In a statewide registry of 54,276 metabolic-bariatric operations, opioid-free discharge rose from 7.7% to 32.1% with only 0.4% filling opioids within 30 days. This strategy did not increase complications and was associated with fewer ED visits, suggesting safety and effectiveness of opioid stewardship at discharge.
Impact: This large-scale, real-world analysis demonstrates that opioid-free discharge after bariatric surgery is scalable and safe, with measurable reductions in ED utilization. It provides compelling evidence to shift postoperative prescribing norms.
Clinical Implications: Programs can implement opioid-free discharge pathways with monitoring, patient education, and non-opioid analgesia, expecting comparable complication rates and potentially fewer ED visits.
Key Findings
- Opioid-free discharge increased from 7.7% (2018) to 32.1% (2023).
- Only 0.4% of opioid-free patients filled an opioid prescription within 30 days.
- Opioid-free discharge was associated with fewer ED visits (7.7% vs 8.2%) with similar 30-day complication rates (7.6% vs 7.3%).
Methodological Strengths
- Very large, statewide, procedure-specific registry with risk-adjusted 30-day outcomes
- Contemporary multi-year trend analysis with surgeon-level comparisons
Limitations
- Observational design may suffer residual confounding (e.g., pain severity, patient preference not fully captured)
- Generalizability outside the collaborative and to other procedures uncertain
Future Directions: Prospective implementation trials integrating patient-reported pain outcomes and tailored non-opioid protocols; exploration of scalability to other surgeries and diverse health systems.
2. Development and multicenter validation of machine learning models for predicting postoperative pulmonary complications after neurosurgery.
Using 7,533 development cases with temporal (n=2,824) and external (n=2,300) validation, a DNN model and an 11-feature LR nomogram predicted PPCs within 7 days after neurosurgery (AUC ~0.83). The LR nomogram outperformed ARISCAT and LAS VEGAS scores, indicating potential for clinical decision support.
Impact: Provides validated, parsimonious and full-feature ML tools tailored to neurosurgery, outperforming widely used generic scores and enabling targeted perioperative prevention.
Clinical Implications: Integrate the nomogram into preoperative assessment to identify high-risk patients for lung-protective ventilation, early mobilization, and respiratory therapy; monitor model drift with ongoing calibration.
Key Findings
- PPC incidence ~9–9.5% across development, temporal, and external datasets.
- DNN achieved AUC 0.835 (Brier 0.069) in temporal validation; LR/XGBoost performed closely.
- An 11-feature LR nomogram outperformed ARISCAT (AUC 0.672) and LAS (0.663) with AUC 0.824.
Methodological Strengths
- Temporal and external validation across multiple centers with standardized PPC definitions (EPCO)
- Comparison of six ML algorithms with both full and LASSO-selected feature sets
Limitations
- Retrospective data extraction; unmeasured confounders and practice variability may persist
- Feature importance inconsistency between LR-SHAP and multivariable analyses
Future Directions: Prospective implementation with clinician-in-the-loop decision support; assess impact on PPC reduction and cost; periodic recalibration across institutions.
3. Safety and Feasibility of Early Extubation in Liver Transplantation: Experience in 1555 Patients.
In 1,555 adult liver transplants, 62% underwent early extubation with only 3.2% requiring ventilation within 48 hours and no increase in postoperative pneumonia. Notably, even in the highest quartiles of MELD-Na and blood loss, one-third of patients were safely extubated early.
Impact: Provides strong real-world evidence that early extubation is feasible and safe in liver transplantation, including select high-risk subgroups, supporting broader protocol adoption.
Clinical Implications: Transplant anesthesia teams can adopt early extubation pathways with defined selection criteria and rescue plans, potentially reducing ICU utilization without increasing pulmonary complications.
Key Findings
- Early extubation was achieved in 62% (969/1555) of liver transplants.
- Only 3.2% required ventilation within 48 h postoperatively (1.1% reintubation for respiratory failure; 2.1% continued intubation after reoperation).
- No significant difference in postoperative pneumonia; 34% of highest-risk quartile (MELD-Na >34 and EBL >5 L) were extubated early.
Methodological Strengths
- Large single-center cohort over a decade with pre-specified primary outcome
- Stratified analyses by MELD-Na and blood loss quartiles including high-risk subgroups
Limitations
- Retrospective, single-center design with potential selection bias
- Limited detail on standardized extubation criteria across providers
Future Directions: Prospective multicenter protocols to test standardized early extubation criteria and evaluate ICU length of stay, costs, and long-term outcomes.