Daily Anesthesiology Research Analysis
Across anesthesiology and critical care, a multicenter randomized trial showed transvenous diaphragm neurostimulation increased ventilator weaning success but with more serious adverse events. A meta-analysis identified diaphragm-sparing regional anesthesia techniques that substantially reduce hemidiaphragmatic paralysis versus conventional interscalene block. A 40,004-patient international cohort produced a validated model to predict clinically important postoperative hypotension.
Summary
Across anesthesiology and critical care, a multicenter randomized trial showed transvenous diaphragm neurostimulation increased ventilator weaning success but with more serious adverse events. A meta-analysis identified diaphragm-sparing regional anesthesia techniques that substantially reduce hemidiaphragmatic paralysis versus conventional interscalene block. A 40,004-patient international cohort produced a validated model to predict clinically important postoperative hypotension.
Research Themes
- Device-enabled liberation from mechanical ventilation
- Diaphragm-sparing regional anesthesia strategies
- Perioperative hemodynamic risk prediction
Selected Articles
1. Temporary Transvenous Diaphragm Neurostimulation for Weaning from Mechanical Ventilation (RESCUE-3).
In an international RCT halted early for slow enrollment (mITT n=216), transvenous diaphragm neurostimulation increased 30-day weaning success (70% vs 61%; adjusted HR 1.34; 95% credible interval 1.01–1.78; posterior probability 97.9%) and likely reduced ventilation duration (-2.5 days; 95% CrI -5.0 to 0.1). Serious adverse events were more frequent in the treatment arm (36% vs 24%), while 30-day mortality was similar.
Impact: First adequately powered multicenter RCT to test a neurostimulation strategy to facilitate ventilator weaning, demonstrating probabilistic benefit despite early termination.
Clinical Implications: Diaphragm neurostimulation may be considered for difficult-to-wean patients, with careful monitoring for adverse events and patient selection. Findings justify larger confirmatory trials and inform discussions on device-enabled weaning protocols.
Key Findings
- 30-day ventilator weaning success improved: 70% (treatment) vs 61% (control); adjusted HR 1.34 (95% CrI 1.01–1.78), posterior probability 97.9%
- Ventilation duration likely reduced by 2.5 days (95% CrI -5.0 to 0.1); posterior probability 97.1%
- Serious adverse events higher with neurostimulation (36% vs 24%); 30-day mortality similar (9.8% vs 10.5%)
Methodological Strengths
- International, multicenter randomized design with Bayesian primary analysis
- Pre-specified borrowing of prior evidence and modified intent-to-treat population
Limitations
- Open-label design and early termination at interim due to slow enrollment
- Increased serious adverse events signal; device and operator dependence
Future Directions: Conduct larger, blinded or pragmatic confirmatory trials to refine patient selection, quantify safety, and evaluate cost-effectiveness and long-term outcomes.
2. Hemidiaphragmatic paralysis after ultrasound-guided brachial plexus blocks for shoulder surgery: A systematic review and meta-analysis of randomized clinical trials.
Among 28 RCTs (n=1,737), low-volume ISB significantly reduced hemidiaphragmatic paralysis versus conventional ISB (RR 0.62; ARD -0.30). Evidence synthesis indicated high-level certainty for the extrafascial technique, moderate for lower-concentration, and low for supraclavicular approaches. Several other comparisons were inconclusive.
Impact: Provides consolidated, methodologically rigorous evidence guiding diaphragm-sparing anesthesia choices for shoulder surgery with direct implications for respiratory safety.
Clinical Implications: Prefer extrafascial and low-concentration ISB or consider supraclavicular approaches when respiratory reserve is limited or phrenic-sparing is desired; balance analgesia with diaphragmatic function.
Key Findings
- Low-volume ISB reduced hemidiaphragmatic paralysis vs conventional ISB (risk ratio 0.62; absolute risk difference -0.30)
- Extrafascial technique supported by high-level certainty; lower concentration by moderate; supraclavicular blockade by low-level certainty (GRADE/TSA-informed)
- Other diaphragm-sparing techniques showed non-definitive results
Methodological Strengths
- Comprehensive synthesis using meta-regression, trial sequential analysis, and GRADE
- Exclusive inclusion of RCTs with predefined protocol (PROSPERO)
Limitations
- Heterogeneity across techniques, volumes, and outcome assessments
- Some comparisons lacked sufficient trials for conclusive estimates
Future Directions: Head-to-head RCTs comparing suprascapular/superior trunk blocks and standardized low-volume/extrafascial ISB on both analgesia and respiratory outcomes.
3. Derivation and internal-external validation of clinical prediction model for postoperative clinically important hypotension in patients undergoing noncardiac surgery: an international prospective cohort study.
Using 40,004 patients across 28 centers, a 41-variable prediction model for clinically important postoperative hypotension achieved C-statistics of 0.73 (derivation, bias-corrected) and 0.72 (validation). A simplified four-element model also performed reasonably (C-statistic 0.68), enabling preoperative risk estimation.
Impact: Delivers a validated, generalizable risk tool from a large international cohort to identify patients at high risk for postoperative hypotension, a key modifiable perioperative hazard.
Clinical Implications: Enable targeted monitoring, early vasopressor strategies, and postoperative blood pressure protocols in high-risk patients, and support shared decision-making and resource allocation.
Key Findings
- Incidence of clinically important postoperative hypotension was 12.4% (4,959/40,004) across centers
- 41-variable model: C-statistic 0.73 (bias-corrected) in derivation and 0.72 in validation cohorts
- Simplified four-element model achieved C-statistic 0.68, enabling pragmatic implementation
Methodological Strengths
- Large, multinational prospective cohort with internal-external validation
- Comprehensive variable set and assessment of calibration and discrimination
Limitations
- Observational design with potential unmeasured confounding and site-level practice variability
- Outcome based on SBP threshold plus clinician intervention may introduce ascertainment bias
Future Directions: Prospective impact analyses to test whether model-guided care reduces hypotension-related organ injury, and external validation in ambulatory and high-risk subspecialty populations.