Daily Anesthesiology Research Analysis
Analyzed 119 papers and selected 3 impactful papers.
Summary
Three perioperative studies stand out today: a pre-planned subgroup analysis from the POISE-3 randomized trial shows tranexamic acid reduces major bleeding in urologic surgery without increasing thrombotic events; a large liver transplantation cohort links moderate-to-severe intraoperative hypotension (defined by MAP-depth and duration) to higher 1-year mortality; and a multicenter review finds frequent early heparinization after neuraxial anesthesia with no observed spinal hematomas, challenging conservative timing norms.
Research Themes
- Perioperative hemostasis and antifibrinolytic therapy
- Neuraxial anesthesia safety and anticoagulation timing
- Intraoperative hemodynamic thresholds and long-term outcomes
Selected Articles
1. Safety and Efficacy of Tranexamic Acid in Urologic Surgery: Results from the International, Randomized, Placebo-Controlled POISE-3 Trial.
In a pre-planned subgroup of POISE-3 (n=1124 urologic surgeries), tranexamic acid reduced major bleeding (6.1% vs 9.5%; HR 0.63, 95% CI 0.41-0.97) without increasing the 30-day thrombosis composite (HR 1.12, 95% CI 0.79-1.58). Effects were consistent across surgical approaches, cancer status, and antithrombotic use.
Impact: This provides randomized, perioperative evidence specific to urologic surgery supporting TXA to reduce major bleeding without apparent thrombotic harm.
Clinical Implications: Consider TXA (1 g at incision and closure) for urologic procedures with moderate-to-high bleeding risk; routine thrombosis surveillance remains prudent given limited power for rare events.
Key Findings
- Major bleeding was reduced with TXA vs placebo: 6.1% vs 9.5% (HR 0.63, 95% CI 0.41-0.97).
- The 30-day bleeding composite trended lower with TXA: 8.1% vs 10.9% (HR 0.73, 95% CI 0.50-1.07).
- No increase in the 30-day thrombosis composite with TXA (HR 1.12, 95% CI 0.79-1.58); MINS 62 vs 58, stroke 2 vs 2, VTE 3 vs 3.
- No effect modification by surgical approach (open, minimally invasive, transurethral), cancer status, or recent antithrombotic therapy.
Methodological Strengths
- International randomized, placebo-controlled design with pre-planned urologic subgroup.
- Clinically meaningful, adjudicated composite bleeding and thrombosis outcomes.
Limitations
- Subgroup analysis limits certainty compared with primary trial analyses.
- Few thrombotic events reduce precision for stroke and VTE risk estimates.
Future Directions: Larger, procedure-specific RCTs should refine TXA dosing/timing and quantify thrombotic risk in high-risk subgroups (e.g., active cancer, prior VTE).
BACKGROUND AND OBJECTIVE: Perioperative bleeding is common. Evidence for tranexamic acid (TXA) in urology remains limited and conflicting, and major urologic guidelines provide no recommendations. In an a priori planned analysis, we evaluated TXA among patients undergoing urologic surgery in POISE-3. METHODS: POISE-3 was an international randomized trial of patients undergoing surgery with bleeding and cardiovascular risk factors. Participants received TXA (1 g intravenous bolus at surgery start and end) or placebo. The primary efficacy outcome was a 30-day bleeding composite (life-threatening/major/critical organ), and the primary safety outcome was a 30-day thrombosis composite (myocardial injury after noncardiac surgery [MINS], nonhemorrhagic stroke, peripheral arterial thrombosis, or symptomatic proximal venous thromboembolism [VTE]). KEY FINDINGS AND LIMITATIONS: Among 1124 urologic participants (556 TXA and 568 placebo), 489 had laparoscopic/robotic, 360 open, 244 transurethral, and 31 percutaneous surgery. The composite bleeding outcome occurred in 45 (8.1%) with TXA and in 62 (10.9%) with placebo (hazard ratio [HR] = 0.73, 95% confidence interval [CI] = 0.50-1.07). Major bleeding occurred in 34 (6.1%) with TXA and in 54 (9.5%) with placebo (HR = 0.63, 95% CI = 0.41-0.97). The composite safety outcome occurred in 67 (12.1%) with TXA and in 62 (10.9%) with placebo (HR = 1.12, 95% CI = 0.79-1.58; MINS: 62 vs 58; strokes: 2 vs 2; VTEs: 3 vs 3). We identified no interactions by surgical approach, cancer status, or recent antithrombotic usage. Patient-important thrombotic events were few, limiting precision for stroke and VTE estimates. CONCLUSIONS AND CLINICAL IMPLICATIONS: TXA reduced major bleeding and supports perioperative use in urologic surgery, especially when the bleeding risk is high.
2. Intraoperative hypotension during liver transplantation is associated with long-term mortality.
In 1,063 liver transplants, only moderate-to-severe intraoperative hypotension—quantified by deeper MAP thresholds and specific exposure durations—independently predicted higher 1-year mortality. Shallower thresholds (<65 or <60 mmHg) were not associated after adjustment, emphasizing depth×time interactions.
Impact: Provides actionable MAP-depth and duration thresholds linking IOH to long-term mortality in a high-risk surgery, informing target-setting and alarms in liver transplantation anesthesia.
Clinical Implications: Prioritize avoiding MAP <55 mmHg for prolonged periods and especially <45–40 mmHg even briefly; implement threshold-duration aware monitoring and early vasopressor strategies.
Key Findings
- 1-year mortality was 7.1% following liver transplantation.
- Independent associations with mortality: MAP <55 mmHg for ≥43 min (HR 2.48), <50 mmHg for ≥14 min (HR 2.60), <45 mmHg for ≥13 min (HR 4.98), and <40 mmHg for ≥5 min (HR 6.72).
- Extended exposure at MAP <65 or <60 mmHg was not independently associated with mortality after adjustment.
- Both lower MAP and longer exposure increased predicted mortality in threshold-duration models.
Methodological Strengths
- Large single-center cohort with granular MAP threshold–duration analysis.
- Multivariable adjustment to mitigate confounding.
Limitations
- Retrospective single-center design susceptible to residual confounding and information bias.
- Causality cannot be inferred; MAP measurement frequency/accuracy may vary across phases of LT.
Future Directions: Prospective, protocolized trials testing MAP threshold-duration targets and vasopressor strategies during liver transplantation are warranted.
BACKGROUND: Intraoperative hypotension (IOH) is common during liver transplantation (LT); however, its impact on long-term mortality remains unclear. We investigated the association between IOH and 1-year mortality using various mean arterial pressure (MAP) thresholds and exposure durations. METHODS: This retrospective observational cohort study included 1063 patients who underwent LT. We defined IOH as an MAP < 65 mmHg and examined each threshold in 5 mmHg increments to < 40 mmHg. Our primary outcome was 1-year mortality after LT. Multivariate logistic regression was used to control for confounding variables while assessing the association between IOH and 1-year mortality. RESULTS: The 1-year mortality after LT was 7.1%. Only moderate-to-severe IOH showed independent associations with 1-year mortality: MAP < 55 mmHg for ≥ 43 minutes (hazard ratio [HR] 2.48, 95% CI: 1.05-5.86; P = 0.038), MAP < 50 mmHg for ≥ 14 min (HR 2.60, 95% CI: 1.01-6.65; P = 0.047), MAP < 45 mmHg for ≥ 13 min (HR 4.98, 95% CI: 1.18-21.0; P = 0.029), and MAP < 40 mmHg for ≥ 5 min (HR 6.72, 95% CI: 1.56-28.9; P = 0.010), whereas longer exposure durations at MAP < 65 or < 60 mmHg were not independently associated with increased mortality. Furthermore, both a lower MAP and longer exposure duration for each threshold increased the predicted probability of 1-year mortality. CONCLUSIONS: Moderate-to-severe hypotension was independently associated with increased 1-year mortality after LT. These findings underscore the importance of intraoperative blood pressure management in LT recipients.
3. Systemic Heparinization After Neuraxial Anesthesia in Vascular Surgery: A Multicenter Retrospective Analysis.
Across 877 vascular surgery cases with neuraxial anesthesia, 41.2% received systemic heparin within 60 minutes (26.3% within 45 minutes) despite guideline recommendations. No spinal hematomas were observed; estimated upper bounds for risk were ≤0.8–1.3% (frequentist) and ≤0.3–0.34% (Bayesian).
Impact: Real-world multicenter data challenge conservative timing norms by showing frequent early heparinization without observed spinal hematoma, informing risk-benefit discussions and institutional protocols.
Clinical Implications: Institutions may revisit rigid 1-hour rules, implement standardized documentation and monitoring, and tailor heparin timing to procedural risk while maintaining vigilance for neuraxial hematoma.
Key Findings
- 41.2% received intravenous heparin within 60 minutes after neuraxial anesthesia; 26.3% within 45 minutes.
- Substantial inter-institutional and procedure-specific variability; EVAR showed the shortest intervals.
- No clinically significant spinal hematomas were observed across 877 cases.
- Upper risk bounds for spinal hematoma were low (≤0.8–1.3% frequentist; ≤0.3–0.34% Bayesian).
Methodological Strengths
- Multicenter real-world cohort with large sample size.
- Use of both frequentist and Bayesian methods to bound rare-event risk.
Limitations
- Retrospective design with potential documentation inaccuracies in timing.
- Zero-event analysis limits precision; residual confounding cannot be excluded.
Future Directions: Prospective registries and pragmatic trials should define safe heparin timing windows stratified by neuraxial technique and vascular procedure risk.
OBJECTIVES: Societal guidelines recommend initiating systemic heparinization >1 hour after neuraxial anesthesia (NA) to reduce the risk of spinal hematoma (SH) formation. This study was designed to assess anesthesiologists' adherence to these guidelines in the context of vascular surgeries and compare compliance among Canadian tertiary hospitals. The incidence of SH within the studied period was also evaluated (secondary outcome). DESIGN: Retrospective chart review between April 2012 and April 2023. SETTING: Canadian academic tertiary centers. PARTICIPANTS: Vascular surgery patients (>18 years old) undergoing femoral-femoral bypass, femoral-tibial bypass, and endovascular aneurysm repair surgeries under NA. INTERVENTIONS: NA with subsequent systemic heparinization. MEASUREMENTS AND MAIN RESULTS: In total, 877 patients were analyzed. Among them, 41.2% received intravenous heparin <60 minutes and 26.3% <45 minutes after NA. There was significant variability in guideline compliance between participating institutions. Compliance also varied with the type of surgical procedure. The interval was shortest at all centers for endovascular aneurysm repairs, with 63.3% of patients receiving heparin <60 minutes and 41.2% <45 minutes after NA. No cases of clinically significant SH were reported. Given the zero numerator, the risk of SH was estimated at ≤0.8% and ≤1.3% (frequentist method) or ≤0.3% and ≤0.34% (Bayesian approach), stated with 95% and 99% confidence or credibility, respectively. CONCLUSIONS: Despite significant variability among participating institutions, anesthesiologists at all centers often overlooked societal guidelines and administered systemic heparin before the 1-hour recommendation following NA. Guideline compliance also varied across the surgical procedures studied. No cases of SH were reported.