Daily Anesthesiology Research Analysis
Analyzed 37 papers and selected 3 impactful papers.
Summary
Three studies stood out today: a large prospective cohort found that epidural anesthesia maximizes external cephalic version success and vaginal delivery rates but increases maternal hypotension; a nationwide Danish analysis showed bystander-initiated CPR more than doubles OHCA survival, with no added survival benefit from community first-responders; and a prospective thoracic anesthesia study showed tidal volume challenge reliably predicts fluid responsiveness during one-lung ventilation.
Research Themes
- Optimization of obstetric anesthesia strategies for external cephalic version
- Prehospital resuscitation systems and survival outcomes
- Intraoperative hemodynamic assessment during one-lung ventilation
Selected Articles
1. Comparative effectiveness of intravenous remifentanil, epidural anesthesia and a two-step analgesic approach for external cephalic version: a large prospective single-center cohort study.
In a prospective single-center cohort (n=1963), epidural anesthesia produced the highest ECV success (70.0%) and vaginal delivery (72.2%) rates and the lowest maternal pain, compared with intravenous remifentanil or a stepwise approach. However, epidural anesthesia was associated with higher maternal hypotension (16.1%) and more fetal heart rate abnormalities.
Impact: This large, well-standardized cohort provides robust comparative effectiveness data directly informing anesthetic strategy selection for ECV, balancing procedural success, maternal comfort, and safety.
Clinical Implications: For patients prioritizing ECV success and lower pain, a single epidural attempt may be preferable with vigilant hypotension management; a stepwise strategy may suit those seeking to minimize neuraxial exposure. Shared decision-making should include discussion of hypotension and fetal heart rate risks.
Key Findings
- Epidural anesthesia achieved the highest ECV success rate (70.0%) versus remifentanil (52.2%) and stepwise approach (65.2%)
- Vaginal delivery rates were highest with epidural (72.2%) versus remifentanil (64.0%) and stepwise (66.1%)
- Maternal pain was lowest under epidural (78.3% reported none/minimal pain)
- Maternal hypotension occurred more with epidural (16.1%) and abnormal fetal heart rate patterns were more frequent than with remifentanil
- Procedure-related urgent cesareans were rare but higher with epidural (1.4%) than remifentanil (0.5%)
Methodological Strengths
- Large consecutive prospective cohort with standardized protocols and continuous anesthesiologist presence
- Direct comparative evaluation of three pragmatic analgesic strategies with clinically meaningful outcomes
Limitations
- Nonrandomized phased design introduces potential temporal and selection confounding
- Single-center setting may limit generalizability
Future Directions: Conduct multicenter randomized trials comparing epidural, remifentanil, and stepwise strategies, include cost-effectiveness analyses, and stratify by parity, BMI, and fetal factors.
BACKGROUND: Among the analgesic strategies used during external cephalic version, neuraxial anesthesia is the only approach that has consistently demonstrated higher vaginal delivery rates. However, neuraxial analgesia encompasses a heterogeneous range of techniques, and higher complication rates have been reported compared with other approaches. OBJECTIVES: This study aimed to compare the success of external cephalic version, modes of delivery, maternal pain, and complications using three strategies: intravenous analgesia with remifentanil, epidural anesthesia, and a stepwise approach in which epidural anesthesia was administered only if intravenous analgesia was unsuccessful. STUDY DESIGN: We conducted a single-center, consecutive three-phase cohort study including 1963 singleton pregnancies undergoing an external cephalic version: 558 with intravenous remifentanil (Group 1, 2012-2015), 665 with intravenous remifentanil followed by epidural anesthesia 2-3 days later if unsuccessful (Group 2, 2016-2019), and 730 under epidural anesthesia (Group 3, 2020-2024); yielding 2218 procedures, 1233 with intravenous remifentanil and 985 with epidural anesthesia. All procedures followed a standardized protocol, performed or supervised by experienced obstetricians, with continuous presence of anesthesiologists. Ritodrine was administered for tocolysis, or atosiban when contraindicated. Outcomes included success of the external cephalic version, mode of delivery, maternal pain (0-10 numerical scale), any analgesia-related complications, and procedural-related obstetric complications including vaginal bleeding, abnormal fetal heart rate patterns, hospital admission or any event that led to a delivery. Chi-square test was used for comparison, with significance at p<0.05. RESULTS: Success rates were highest with epidural anesthesia (70.0%, 511/730), compared with intravenous remifentanil (52.2%, 291/558) and the stepwise approach (65.2%, 440/675; p < 0.001). This was reflected in vaginal delivery rates of 72.2% (526/730), 64.0% (342/534), and 66.1% (444/672), respectively (p = 0.005). Maternal pain was substantially lower under epidural, with 78.3% of women reporting no or minimal pain, whereas this proportion fell to 49.2% in the remifentanil group and to 36.2% in the two-step approach (p < 0.001). Adverse effects of anesthesia were generally uncommon and clinically mild, but higher with epidural anesthesia (p < 0.001). Maternal hypotension was the main complication under epidural anesthesia (16.1%, 159/985), followed by dizziness (3.7%, 36/985), neither associated with significant obstetric clinical consequences. Procedural complications were rare, but more common with epidural anesthesia, and overall, highest among patients undergoing the two-step approach (p = 0.264). Vaginal bleeding occurred in 3.6% (35/985) of epidural cases and 4.3% (53/1233) with remifentanil (p = 0.052). Abnormal fetal heart rate patterns were more frequent with epidural (3.6%, 35/985) than remifentanil (1%, 12/1233) (p < 0.001). Procedure-related hospital admissions were uncommon and similar (3.6%, 35/985, vs 3.6%, 45/1233). Procedure-related deliveries and urgent cesareans were rare, but higher with epidural (1.4%, 15/985) than with remifentanil (0.5%, 6/1233) (p = 0.021). CONCLUSION: In this study, a single attempt with epidural anesthesia was the most effective strategy for external cephalic version, achieving the highest success and vaginal delivery rates while providing superior maternal pain control, but with higher complications. These findings may help support more informed counseling and shared decision-making when discussing analgesic options for external cephalic version.
2. Community first-responders in cardiac arrest. Effect on survival? A comprehensive Danish study of 29,445 out-of-hospital cardiac arrests.
In a nationwide cohort (n=21,413 analyzed), bystander-initiated CPR before EMS arrival was associated with more than doubled survival at 30 and 365 days (OR 2.42 and 2.51). Initial resuscitation by community first-responders did not improve survival compared with resuscitation initiated by EMS upon arrival.
Impact: This large, comprehensive national analysis challenges assumptions about the added survival benefit of community first-responders and underscores bystander CPR as the primary driver of OHCA survival.
Clinical Implications: Invest in dispatcher-assisted bystander CPR training and rapid initiation strategies. Reassess the design, training, and dispatch criteria for community first-responder programs to ensure timely, high-quality CPR rather than reliance on CFR activation.
Key Findings
- Among 21,413 OHCA cases, bystander-initiated CPR before EMS arrival was associated with substantially higher 30-day (OR 2.42) and 365-day (OR 2.51) survival
- No significant survival difference when initial resuscitation was provided by community first-responders versus delayed until EMS arrival
- Initial resuscitation providers: bystanders (12,613), community first-responders (2,155), EMS (6,140); unclear in 505 cases
Methodological Strengths
- Nationwide manual review with large sample size and clear stratification by initial CPR provider
- Assessment of both 30-day and 365-day survival outcomes
Limitations
- Observational design with potential confounding (e.g., location, response times, patient mix)
- Initial CPR provider unclear in a subset of cases (n=505)
Future Directions: Prospective evaluations of community first-responder program components (response time, training quality) and dispatcher protocols; integration with smartphone alerts to shorten time-to-CPR.
AIM: Since 2018, Denmark has implemented a national community first-responder system, activated by the emergency dispatch centre, to supplement local first-responder programs. The responders are dispatched to all out-of-hospital cardiac arrests (OHCA). This study aimed to investigate the effect of community first-responders on survival following OHCA. METHODS: A manual review of prehospital medical records for all 29,445 OHCA cases in Denmark from 2018 through 2023. The type of responder who initiated resuscitative efforts was stratified into three main groups: bystanders present at the incident, community first-responders, or ambulance personnel. The primary outcome was survival at 30 days and 365 days. RESULTS: After exclusions, 21,413 patients were analysed, of which initial resuscitation efforts were provided by on-scene bystanders (12,613), community first-responders (2,155), or emergency medical service (EMS) personnel (6,140). In 505 cases, the provider of the initial CPR was unclear. Provision of initial resuscitative efforts by on-scene bystanders before ambulance arrival was associated with odds ratios of 2.42 for 30-day survival and 2.51 for 365-day survival, compared with patients whose first resuscitation was not initiated before EMS arrival. There was no significant difference in outcome when first resuscitation efforts were provided by community first responders or delayed until EMS arrival. CONCLUSION: In OHCA, basic life support initiated by bystanders was associated with a survival rate more than twice that of OHCA patients whose first resuscitation was provided by community first-responders or ambulance personnel. Our findings support early resuscitation, but we found no evidence to support dispatching community first-responders to OHCA.
3. The predictive value of tidal volume challenge-induced hemodynamic changes for fluid responsiveness in patients undergoing thoracoscopic surgery with one-lung ventilation: a prospective observational study.
In 60 VATS patients under lung-protective OLV, TVC-induced changes in SVV and PPV predicted fluid responsiveness with AUCs of 0.83 and 0.86 at cutoffs >2% (ΔSVV_TVC) and >3% (ΔPPV_TVC), respectively. Predictive performance was unaffected by left vs right lateral decubitus positioning, though gray zones encompassed 22–38% of patients.
Impact: Addresses a common intraoperative challenge—predicting fluid responsiveness during lung-protective OLV—by providing actionable thresholds for TVC-derived indices.
Clinical Implications: TVC with monitoring of ΔSVV and ΔPPV can augment decision-making for fluid management during OLV, using cutoffs >2% and >3% respectively, while acknowledging gray zones and integrating with clinical context.
Key Findings
- Among 60 patients, 26 (43%) were fluid responders
- ΔSVV_TVC predicted responsiveness with AUC 0.83; optimal cutoff >2% (77% sensitivity, 76% specificity)
- ΔPPV_TVC predicted responsiveness with AUC 0.86; optimal cutoff >3% (85% sensitivity, 80% specificity)
- Gray zones: ΔSVV_TVC 1–3% (38% of patients); ΔPPV_TVC 2–4% (22% of patients)
- Predictive performance did not differ by left vs right lateral decubitus position
Methodological Strengths
- Prospective protocol with standardized timepoints and advanced hemodynamic monitoring (LiDCO)
- Trial registration and predefined indices (ΔSVV_TVC, ΔPPV_TVC) with ROC analysis
Limitations
- Single-center study with a modest sample size
- Gray zones encompass a notable proportion of patients, limiting decisiveness for some cases
Future Directions: Multicenter validation and assessment of whether TVC-guided fluid therapy improves patient-centered outcomes (e.g., complications, length of stay).
BACKGROUND: Video-assisted thoracic surgery (VATS) relies on one-lung ventilation (OLV) to achieve optimal surgical conditions. However, the lung protective ventilation strategies commonly employed during OLV diminish the accuracy of traditional dynamic parameters in predicting fluid responsiveness. The tidal volume challenge (TVC) has been proposed to overcome this limitation, yet its effectiveness in OLV patients remains to be validated. In this study, we used LiDCO to evaluate TVC-induced changes in SVV(ΔSVV_TVC) and PPV(ΔPPV_TVC), and assessed their ability to predict fluid responsiveness in patients receiving lung-protective OLV during VATS. METHODS: All patients received OLV in lateral position after general anesthesia induction. Upon achieving hemodynamic stability, the study protocol was initiated. Hemodynamic and respiratory parameters, including heart rate, mean arterial pressure, stroke volume variation (SVV), pulse pressure variation (PPV), stroke volume index (SVI), cardiac index, peak inspiratory pressure, and dynamic lung compliance were recorded at four time points: before TVC (T