Daily Anesthesiology Research Analysis
Three perioperative studies stand out today: a randomized trial shows transcutaneous auricular vagus nerve stimulation markedly reduces postpartum contraction pain after cesarean delivery; a meta-analysis links postoperative hypotension to higher mortality and myocardial injury; and a randomized trial supports opioid-sparing multimodal analgesia after craniotomy. Together they advance neuromodulation, hemodynamic vigilance, and ERAS-aligned pain strategies.
Summary
Three perioperative studies stand out today: a randomized trial shows transcutaneous auricular vagus nerve stimulation markedly reduces postpartum contraction pain after cesarean delivery; a meta-analysis links postoperative hypotension to higher mortality and myocardial injury; and a randomized trial supports opioid-sparing multimodal analgesia after craniotomy. Together they advance neuromodulation, hemodynamic vigilance, and ERAS-aligned pain strategies.
Research Themes
- Neuromodulation for perioperative analgesia
- Perioperative hemodynamic risk and outcomes
- Opioid-sparing multimodal strategies in neurosurgery
Selected Articles
1. Transcutaneous Auricular Vagus Nerve Stimulation for Postpartum Contraction Pain During Elective Cesarean Delivery: A Randomized Clinical Trial.
In a single-center randomized, sham-controlled trial of 156 women undergoing elective cesarean delivery under combined spinal-epidural anesthesia, taVNS reduced moderate-to-severe uterine contraction pain on postoperative day 3 (5.1% vs 28.2%; RR 0.18) and improved incision pain, depression, anxiety, recovery quality, and sleep. Analyses followed intention-to-treat.
Impact: This RCT introduces a nonpharmacologic, scalable neuromodulation approach that improves multiple patient-centered outcomes postpartum, potentially reducing opioid exposure and enhancing ERAS pathways in obstetric anesthesia.
Clinical Implications: taVNS could be incorporated as an adjunct to standard postoperative analgesia after cesarean delivery to reduce uterine contraction pain and improve recovery metrics, with minimal safety concerns. Implementation would require training and device availability.
Key Findings
- Incidence of moderate-to-severe uterine contraction pain on postoperative day 3: 5.1% with taVNS vs 28.2% with sham (RR 0.18, 95% CI 0.07-0.50; P < .001).
- Lower incision pain on day 3 (median VAS 2.20 vs 3.00) and improved sleep on day 2 (LSEQ 52.00 vs 47.50).
- Reduced depression (EPDS) and anxiety (PRAQ-R2) and higher recovery quality (ObsQoR-11 104 vs 99) with taVNS.
Methodological Strengths
- Randomized, sham-controlled design with intention-to-treat analyses
- Use of multiple validated patient-reported outcome measures across pain, mood, recovery, and sleep
Limitations
- Single-center study with short follow-up limited to early postoperative period
- Generalizability across diverse settings and long-term outcomes not assessed
Future Directions: Multicenter trials with longer follow-up should assess sustainability, safety, and opioid-sparing effects, and explore dosing parameters and subgroups (e.g., multiparity, breastfeeding).
IMPORTANCE: Postpartum uterine contraction pain manifests as a severe, intermittent lower abdominal discomfort caused by uterine contraction during the early puerperium. Transcutaneous auricular vagus nerve stimulation (taVNS) has demonstrated promising effects in managing both acute and chronic pain conditions; however, there remains a paucity of studies regarding the use of taVNS for alleviating postpartum uterine contraction pain. OBJECTIVE: To investigate the effect of taVNS in alleviating postpartum uterine contraction pain among women receiving combined spinal-epidural anesthesia for elective cesarean delivery. DESIGN, SETTING, AND PARTICIPANTS: This randomized clinical trial was conducted from April 6 to August 31, 2024, at the Affiliated Hospital of Xuzhou Medical University, Xuzhou, China. Participants were aged 18 years or older and scheduled for elective cesarean delivery. Statistical analysis was performed in September 2024. All analyses were conducted according to the intention-to-treat principle. INTERVENTIONS: Participants were randomly allocated 1:1 to either the active taVNS group or the sham taVNS group. Both groups received the stimulation for 30 minutes each time, once a day, on the day of surgery and postoperative days 1 and 2. MAIN OUTCOMES AND MEASURES: The primary outcome was the incidence of moderate to severe postpartum uterine contraction pain on the third postoperative day, evaluated using a visual analogue scale (uterine contraction pain was classified as moderate to severe if the score was ≥4). Secondary outcomes included peak uterine contraction pain and incision pain, postpartum anxiety, postpartum depression, postpartum recovery quality, and sleep quality. RESULTS: A total of 156 women were recruited and randomized to the active taVNS group (78 patients; mean [SD] age, 31.5 [4.3] years) or the sham taVNS group (78 patients; mean [SD] age, 31.3 [4.5] years). The incidence of moderate to severe uterine contraction pain in the active taVNS group was 5.1% (4 of 78) compared with 28.2% (22 of 78) in the sham taVNS group on the third postoperative day (relative risk, 0.18 [95% CI, 0.07-0.50]; P < .001) The active taVNS group had lower median scores on the third postoperative day for incisional pain (visual analogue score: 2.20 [IQR, 2.00-2.50] vs 3.00 [IQR, 2.60-3.33]), depression (EPDS: 3.00 [IQR, 2.00-4.00] vs 5.00 [IQR, 3.00-6.00]), and anxiety (PRAQ-R2: 13.50 [IQR, 12.00-15.00] vs 15.00 [IQR, 13.75-17.00]), as well as significantly higher scores for recovery quality on the third postoperative day (ObsQoR-11: 104 [IQR, 103-105] vs 99 [IQR, 96-101]) and sleep quality on the second postoperative day (LSEQ: 52.00 [IQR, 50.00-55.00] vs 47.50 [IQR, 43.00-52.00]) compared with the sham taVNS group. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, taVNS significantly reduced uterine contraction pain, incisional pain, depression, and anxiety, and improved recovery quality and sleep quality compared with sham taVNS. These findings suggest that taVNS represents a novel and safe strategy for alleviating postpartum uterine contraction pain among women undergoing cesarean delivery and for promoting postoperative recovery. TRIAL REGISTRATION: Chinese Clinical Trial Register Identifier: ChiCTR2400082716.
2. The effect of postoperative hypotension on surgical patients' adverse clinical outcomes: A systematic review and meta-analysis.
Across 23 studies (262,435 patients), postoperative hypotension was associated with increased mortality (OR 2.51) and myocardial injury (OR 2.52). Associations with AKI and stroke were less robust due to publication bias and sensitivity to single-study removal. Heterogeneity stemmed largely from variable POH thresholds.
Impact: This synthesis strengthens the prognostic significance of postoperative hypotension beyond intraoperative events, prioritizing postoperative blood pressure monitoring as a critical patient safety target.
Clinical Implications: Implement continuous or frequent postoperative blood pressure surveillance and define actionable thresholds and durations to mitigate mortality and myocardial injury risk. Protocols should integrate POH detection into PACU/ward early warning systems.
Key Findings
- POH associated with higher mortality (OR 2.51, 95% CI 1.86-3.38).
- POH associated with myocardial injury (OR 2.52, 95% CI 1.71-3.69).
- AKI association (OR 1.72) affected by publication bias; stroke association (OR 1.82) was unstable in leave-one-out analyses.
- Heterogeneity primarily due to inconsistent POH thresholds across studies.
Methodological Strengths
- Large pooled sample size with comprehensive meta-analytic techniques
- Bias assessment (Egger's, trim-and-fill) and sensitivity/subgroup analyses
Limitations
- Predominantly observational data with residual confounding risk
- Heterogeneity in POH definitions and measurement methods across studies
Future Directions: Prospective studies to standardize POH definitions, quantify depth and duration thresholds, and test interventions targeting postoperative blood pressure management.
INTRODUCTION: Postoperative hypotension (POH) represents an independent predictor of multiorgan morbidity. Emerging evidence indicates its risks exceed those associated with intraoperative hypotension (IOH). Considering the ubiquitous presence of this pathophysiological disturbance across surgical settings, our meta-analysis evaluates associations between POH and major adverse outcomes. METHODS: We systematically searched PubMed, Web of Science, Cochrane Library, and Embase for clinical studies investigating POH and adverse outcomes, with literature coverage through 7 February 2025. Mortality during follow-up was designated as the primary outcome. Secondary outcomes included acute kidney injury (AKI), myocardial injury, delirium, stroke, and postoperative length of stay (LOS). Publication bias was assessed using Egger's test and trim-and-fill analysis; sensitivity analyses employed the leave-one-out method; and subgroup analysis was performed to explore heterogeneity. RESULTS: This meta-analysis incorporated 23 studies involving 262,435 patients. Significant associations were identified between POH and adverse outcomes, including mortality (OR = 2.51, 95 % confidence interval [CI] 1.86-3.38), AKI (OR = 1.72, 95 % CI 1.25-2.36), myocardial injury (OR = 2.52, 95 % CI 1.71-3.69), and stroke (OR = 1.82, 95 % CI 1.09-3.05). However, publication bias detected by the trim-and-fill method compromised the robustness of AKI findings, while the stroke association demonstrated instability in leave-one-out sensitivity analyses. Subgroup analyses identified multiple POH thresholds as the primary source of heterogeneity. CONCLUSION: These findings establish POH as a clinically significant correlate of postoperative mortality and myocardial injury. However, POH associations with AKI and stroke exhibit limited robustness, requiring further investigation. Future studies must delineate the impact of POH depth, duration, and measurement method.
3. Opioid-sparing multimodal analgesia for post-craniotomy pain: a randomized, double-blind, placebo-controlled trial.
In a randomized, double-blind, placebo-controlled trial of 60 adults after elective supratentorial craniotomy, an opioid-sparing multimodal analgesia regimen reduced early postoperative VAS scores (1–4 h) and adverse effects versus conventional opioid-based care. Findings support ERAS-consistent pain pathways in neurosurgical patients.
Impact: Demonstrates practical benefits of multimodal, opioid-sparing analgesia in a population where opioid side effects hinder neuroassessment, offering an implementable ERAS-aligned pathway.
Clinical Implications: Adopt multimodal, opioid-sparing regimens after craniotomy to improve early pain control and reduce opioid-related adverse effects, facilitating earlier and clearer neurological assessments.
Key Findings
- Opioid-sparing multimodal analgesia reduced early postoperative VAS scores at 1, 2, and 4 hours compared with conventional opioid-based care.
- Fewer adverse effects were observed in the multimodal group.
- Trial was prospectively registered (NCT05474040), supporting methodological rigor.
Methodological Strengths
- Randomized, double-blind, placebo-controlled design
- Prospective registration and standardized early postoperative pain assessments
Limitations
- Single-center study with modest sample size limits generalizability
- Outcomes focused on early postoperative window; longer-term pain and functional outcomes not reported
Future Directions: Larger multicenter RCTs should evaluate sustained analgesic benefits, cognitive outcomes, and opioid-sparing magnitude, and delineate optimal multimodal components in neurosurgical ERAS pathways.
BACKGROUND: Postoperative pain control in neurosurgical patients particularly after elective craniotomy remains clinically challenging due to the need for early neurological assessment and the adverse effects associated with opioid use. This study aimed to compare the efficacy and safety of an opioid-sparing multimodal analgesia (MMA) protocol versus a conventional opioid-based regimen for managing post-craniotomy pain. METHODOLOGY: This prospective, randomized controlled trial was conducted over 12 months at Zagazig University Hospitals and included 60 adult patients (aged 18–65 years, American Society of Anesthesiologists )ASA( physical status I–II) scheduled for elective supratentorial craniotomy with planned postoperative intensive care unit (ICU) admission. Patients were randomly assigned in a 1:1 ratio to either a multimodal opioid-sparing analgesia group (Group M, RESULTS: VAS scores were significantly lower in Group M at 1, 2, and 4 h postoperatively ( CONCLUSION: In this randomized controlled trial, opioid-sparing MMA provided superior postoperative pain control after elective craniotomy, with fewer adverse effects compared to conventional opioid-based regimens. These results support the incorporation of MMA into standard postoperative protocols and align with the principles of Enhanced Recovery After Surgery (ERAS) in neurosurgical care. TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov under the identifier NCT05474040, with the initial registration on 26 July 2022, and retrospective registration available at ClinicalTrials.gov. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12871-025-03306-5.