Daily Anesthesiology Research Analysis
Analyzed 115 papers and selected 3 impactful papers.
Summary
Three studies stand out today: a large meta-analysis shows that delivering higher enteral protein (1.2–2.0 g/kg/day) in critically ill adults offers no mortality or clinical benefit versus lower doses, with a signal of harm in acute kidney injury. A meta-analysis of randomized trials finds intranasal insulin substantially reduces postoperative delirium in elderly non-cardiac surgery without altering peripheral insulin resistance. A randomized non-inferiority trial demonstrates continuous erector spinae plane block provides analgesia comparable to thoracic epidural after thoracotomy, supporting a safer, simpler alternative.
Research Themes
- Critical care nutrition dosing and patient-centered outcomes
- Perioperative brain health and delirium prevention
- Regional anesthesia alternatives to epidural for thoracic surgery
Selected Articles
1. Optimal delivery of enteral protein in the critically ill: A systematic review and meta-analysis of randomised controlled trials.
Across 14 RCTs (n=6,553), delivering 1.2–2.0 g/kg/day of enteral protein versus <1.2 g/kg/day did not reduce mortality or improve clinical or muscle outcomes. Subgroup analyses suggested a potential increase in mortality among patients with acute kidney injury, with no consistent benefits observed across other subgroups.
Impact: This high-quality synthesis challenges the practice of targeting higher protein doses in ICU nutrition and highlights a possible harm signal in AKI, informing guideline updates and personalized nutrition strategies.
Clinical Implications: Avoid routine escalation to 1.2–2.0 g/kg/day enteral protein in unselected ICU patients; consider conservative targets and individualized dosing, particularly in those with or at risk for AKI, while prioritizing pragmatic outcomes.
Key Findings
- In 14 RCTs (n=6,553), greater protein (1.2–2.0 g/kg/day) did not reduce mortality versus lesser protein (<1.2 g/kg/day) (pooled RR 1.01, 95% CI 0.92–1.12).
- No consistent improvements were observed in clinical, patient-centered, or muscle outcomes with higher protein delivery.
- Subgroup analysis suggested increased mortality in patients with acute kidney injury receiving higher protein; heterogeneity across trials persisted.
Methodological Strengths
- Restricted to randomized controlled trials with predominantly enteral nutrition and comparable energy delivery
- Pre-specified subgroup analyses (exclusive EN, AKI, severity) and random-effects meta-analysis
Limitations
- Heterogeneity in protein targets, timing, and outcome definitions across trials
- Variable risk of bias and inclusion of a cluster crossover trial may affect precision
Future Directions: Prospective, biomarker-guided trials to define patient-specific protein thresholds, particularly in AKI, and to test functional recovery and long-term outcomes.
BACKGROUND AND AIM: Critically ill patients experience acute muscle wasting, associated with impaired clinical outcomes. It has been suggested that greater dietary protein delivery may attenuate muscle wasting and improve outcomes, but the optimal dose is unknown. The aim of this systematic review and meta-analysis was to evaluate the effect of enteral protein delivered to achieve doses recommended within international guidelines (1.2-2.0 g/kg bodyweight/day) compared to enteral protein delivered below international guidelines (<1.2 g/kg/day) on mortality and clinical, patient-centred, and muscle outcomes. METHODS: A systematic review of databases MEDLINE, EMBASE, CINAHL, and CENTRAL was performed from database inception through to 2 July 2025. Randomised controlled trials (RCTs) of adult critically ill patients comparing 'greater protein' delivery (1.2-2.0 g/kg/day) versus 'lesser protein' delivery (<1.2 g/kg/day) predominantly via enteral nutrition (EN), with similar energy delivery, were identified. Risk ratios were pooled for binary outcomes and mean differences or standardised mean differences for continuous outcomes using random-effects models. Subgroup analyses investigated the effect of exclusive EN; acute kidney injury (AKI) as defined within individual trials; and higher severity of illness (Sequential Organ Failure Assessment score ≥9) for the primary outcome (mortality). RESULTS: From a total of 10,414 citations, 14 RCTs were included, comprising n = 6553 patients (n = 3248 greater protein; n = 3305 lesser protein) from 13 individual patient RCTs and one cluster randomised cross-over trial. Greater protein delivery did not affect mortality (pooled RR 1.01, 95% CI 0.92, 1.12, p = 0.795; I
2. Efficacy of intranasal insulin in preventing postoperative delirium and its impact on insulin resistance in elderly non-cardiac surgical patients: a systematic review and meta-analysis.
In seven RCTs (n=778), intranasal insulin substantially reduced postoperative delirium in elderly non-cardiac surgery patients on day 1 (RR 0.33) and over 3–5 days cumulatively, without significant changes in HOMA-IR. The findings support a centrally mediated benefit independent of peripheral insulin resistance.
Impact: Demonstrates a noninvasive, inexpensive, and scalable intervention that significantly reduces postoperative delirium in a high-risk elderly population.
Clinical Implications: Consider intranasal insulin as part of multimodal delirium prevention in elderly non-cardiac surgery; implement glucose monitoring while focusing on CNS-targeted benefits rather than peripheral insulin resistance.
Key Findings
- POD incidence was significantly reduced on postoperative day 1 (RR 0.33; 95% CI 0.22–0.47).
- Cumulative POD incidence over 3 and 5 days was also reduced (RR 0.31 and 0.32, respectively).
- HOMA-IR changes did not differ between intranasal insulin and control groups (SMD −0.27; P=0.290), suggesting a central rather than peripheral mechanism.
Methodological Strengths
- Systematic search across multiple international and Chinese databases; RCT-only inclusion
- Pooled risk estimates with precision; evaluation of dosing regimens and mechanistic surrogate (HOMA-IR)
Limitations
- Moderate total sample size and heterogeneity in dosing and assessment windows
- Limited reporting on adverse events and long-term cognitive outcomes
Future Directions: Large, multicenter RCTs to define optimal dosing, timing, safety, and cost-effectiveness, with standardized delirium assessments and long-term cognitive follow-up.
BACKGROUND: Postoperative delirium (POD) is a common and serious complication in elderly patients and has been established to be associated with insulin resistance (IR), a key marker of dysregulated glucose metabolism. Therefore, this study aims to systematically evaluate the efficacy of intranasal insulin in preventing POD in elderly non-cardiac surgery patients and to further investigate whether its mechanism of action is related to the improvement of IR. METHODS: A systematic literature search was conducted in PubMed, Embase, the Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wan Fang Database, Chinese Scientific Journals Database and Chinese Biomedical Literature Database from inception to October 19, 2025, to identify randomized controlled trials that compared elderly patients who were administered intranasal insulin during the perioperative period with those who were not. The primary outcomes of this study were the incidence of POD and the efficacy of different insulin dosing regimens. The secondary outcome was the change in the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) values before and after surgery. Data from eligible trials were pooled to calculate the combined risk ratio (RR) or standardized mean difference (SMD). RESULTS: Analysis of seven trials involving 778 elderly patients showed that, compared to placebo, intranasal insulin significantly reduced POD incidence on day one (RR: 0.33; 95%CI: 0.22 to 0.47; P<0.001) and its cumulative incidence over three days (RR: 0.31; 95%CI: 0.22 to 0.44; P<0.001) and five days (RR: 0.32; 95%CI 0.18 to 0.56; P<0.001). In contrast, the change in HOMA-IR across the surgery period did not differ significantly between the two groups (SMD: -0.27; 95%CI: -0.77 to 0.23; P=0.290). CONCLUSIONS: Intranasal insulin is effective in reducing the incidence of POD. This benefit is likely mediated through central nervous system glucose metabolism, rather than by reversing peripheral IR, a premise that requires validation in future trials.
3. Continuous Erector Spinae Plane Block versus Thoracic Epidural Analgesia After Thoracotomy: A Randomized Controlled Assessor-Blinded Non-Inferiority Trial.
In an assessor-blinded randomized non-inferiority trial (mITT n=44), continuous ESPB achieved non-inferior resting pain scores on POD1 compared with TEA after thoracotomy, with comparable opioid use, recovery quality, and 3–6 month chronic pain. No major complications were reported.
Impact: Supports a safer, technically simpler alternative to thoracic epidural for thoracotomy analgesia, potentially expanding access and reducing complications.
Clinical Implications: Consider continuous ESPB as an alternative to TEA in thoracic surgery, especially when epidural is contraindicated or high-risk, while implementing standardized dosing and monitoring protocols.
Key Findings
- Primary non-inferiority met: POD1 resting NRS difference −0.59 (95% CI −1.72 to 0.54) within a 2-point margin.
- Secondary outcomes (opioid consumption, QoR-15, pain on POD2–3, chronic pain at 3 and 6 months) were comparable.
- No major complications occurred in either group.
Methodological Strengths
- Randomized, assessor-blinded, predefined non-inferiority margin with modified intention-to-treat analysis
- Standardized catheter placement techniques and local anesthetic protocols
Limitations
- Single-center study with modest sample size (mITT n=44) may limit generalizability
- Non-inferiority margin (2 NRS points) and analgesic regimen may not reflect all practice settings
Future Directions: Larger multicenter trials comparing ESPB to TEA with standardized outcomes (including respiratory complications and mobilization) and health-economic analyses.
PURPOSE: Thoracic epidural analgesia (TEA) remains the current gold standard for postoperative pain control after thoracotomy, but is associated with significant complications and contraindications. This study evaluated whether continuous erector spinae plane block (ESPB) provides non-inferior analgesia to TEA. PATIENTS AND METHODS: Adult patients scheduled for elective thoracotomy were randomized 1:1 to receive continuous TEA or ESPB. Outcome assessors were blinded to group allocation. In the TEA group, an epidural catheter was inserted at T6-7 under fluoroscopic guidance with tip confirmation at T5. In the ESPB group, a catheter was placed under ultrasound guidance at the T5 transverse process. Both groups received 0.2% ropivacaine boluses before incision, followed by patient-controlled analgesia for three days. The primary endpoint was resting numeric rating scale pain score on postoperative day 1 with a 2-point non-inferiority margin. Secondary endpoints included pain scores on days 2-3, opioid consumption, QoR-15K scores, and chronic pain assessments at 3 and 6 months. RESULTS: Fifty-three patients were enrolled; 44 were included in the modified intention-to-treat analysis (ESPB n=23; TEA n=21). Mean resting NRS scores on postoperative day 1 were 4.22±1.93 (ESPB) versus 4.81±1.78 (TEA). The between-group difference was -0.59 (95% CI, -1.72-0.54; P=0.296), meeting the predefined non-inferiority margin. Secondary outcomes, including pain scores, opioid consumption, Quality of Recovery-15 scores, and chronic pain assessments at 3 and 6 months, were comparable between groups. No major complications occurred. CONCLUSION: Continuous ESPB demonstrated analgesic efficacy comparable to TEA for postoperative pain control after thoracotomy. Combined with its superior safety profile and technical simplicity, ESPB may serve as an effective alternative to TEA in thoracic surgery.