Daily Anesthesiology Research Analysis
Analyzed 67 papers and selected 3 impactful papers.
Summary
Three impactful anesthesiology-related studies stood out: a single-blind RCT in Anesthesiology found that extending goal-directed fluid therapy with individualized mean arterial pressure targets into the postoperative period did not reduce complications after esophagectomy. A mechanistic study identified a dorsal raphe–basolateral amygdala serotonergic pathway (via 5-HT1A) that accelerates emergence from sevoflurane. A randomized non-inferiority trial showed an infraspinatus–teres minor interfascial plane block provides noninferior analgesia to superior trunk block for shoulder arthroscopy with less hemidiaphragmatic paralysis.
Research Themes
- Individualized perioperative hemodynamic management
- Neural circuit mechanisms of anesthetic emergence
- Diaphragm-sparing regional anesthesia for shoulder surgery
Selected Articles
1. Individualised Perioperative Blood Pressure and Fluid Therapy in Oesophagectomy a prospective, single-blind randomised controlled trial.
In 100 esophagectomy patients, extending goal-directed fluid therapy with an individualized mean arterial pressure threshold (night-time baseline) through the first postoperative night increased fluid balance and norepinephrine use and modestly raised MAP, but did not reduce 30-day morbidity (Comprehensive Complication Index). The trial demonstrates that protocolled treatment differences did not translate into improved outcomes.
Impact: This rigorously designed RCT challenges the assumption that individualized and extended hemodynamic protocols improve outcomes in high-risk esophagectomy.
Clinical Implications: Avoid routine extension of individualized GDFT with night-time MAP targets into the postoperative period for esophagectomy; prioritize protocol simplicity and resource stewardship unless future multicenter data show benefit.
Key Findings
- Extended individualized GDFT increased fluid balance by 516 mL (95% CI 57–974; p=0.028).
- Norepinephrine use was higher in the intervention group (median 7,894 μg vs 4,611 μg; p<0.001).
- Mean arterial pressure increased by 3 mmHg (95% CI 1–5; p=0.011).
- No difference in 30-day Comprehensive Complication Index (39.0 vs 39.2; p=0.95).
Methodological Strengths
- Prospective, single-blind randomized controlled design with predefined primary endpoint (CCI at day 30).
- Objective individualized MAP threshold (night-time baseline) and protocol spanning intra- to postoperative period.
Limitations
- Single-center trial with modest sample size (n=100) may limit generalizability and power for rare complications.
- Intervention increased vasopressor and fluid exposure, potentially confounding organ-specific outcomes not captured by CCI.
Future Directions: Multicenter trials to test individualized MAP targets versus simplified strategies, evaluate organ-specific outcomes, and explore patient phenotypes who may benefit.
BACKGROUND: Oesophagectomy is a key treatment for oesophageal cancer but carries a high risk of postoperative complications, some potentially preventable through optimised haemodynamic management. Goal-directed fluid therapy individualises cardiac output targets but often applies fixed blood pressure thresholds and is discontinued before major postoperative fluid shifts occur. Extending goal-directed fluid therapy into the postoperative period with individualised blood pressure thresholds may address these limitations. METHODS: In this single-centre, prospective, blinded, randomised controlled trial, patients undergoing oesophagectomy were randomised 1:1 to either extended goal-directed fluid therapy or standard care. In the extended goal-directed fluid therapy group, cardiac output was optimised and mean arterial pressure threshold was the individual patient's night-time baseline. The protocol continued from tracheal intubation through to 07:00 the following morning. The primary outcome was total postoperative morbidity, measured by the Comprehensive Complication Index at day 30. RESULTS: Of 100 patients (49 extended goal-directed fluid therapy group, 51 standard group), extended goal-directed fluid therapy was associated with a higher fluid balance (2,517 ± 1,194 mL vs 2,001 ± 1,114 mL, mean difference: 516 mL, 95% CI: 57 - 974, p = 0.028), increased norepinephrine use (median: 7,894 μg [IQR: 3,946-13,793] vs 4,611 μg [IQR: 2,138-7,296], p < 0.001), and higher mean arterial pressure (mean difference: 3 mmHg, 95% CI: 1-5, p = 0.011). At day 30, mean Comprehensive Complication Index did not differ between groups (39.0 ± 20.0 vs 39.2 ± 21.0; mean difference: -0.2; 95% CI: -8.6 to 8.1; p = 0.95). CONCLUSION: Despite achieving protocol-driven treatment differences, extended and individualised goal-directed fluid therapy did not reduce postoperative complications following oesophagectomy.
2. Dorsal raphe serotonergic neurons facilitate arousal from sevoflurane anesthesia by heterogeneously modulating neuronal activity in the basolateral amygdala.
Using fiber photometry, optogenetics, pharmacology, and in vivo electrophysiology, the study shows that DRN serotonergic inputs to the BLA decrease during sevoflurane anesthesia. Activation of these terminals or 5-HT1A receptor agonism within the BLA accelerates emergence, via inhibition of GABAergic neurons and excitation of glutamatergic neurons.
Impact: Identifies a discrete serotonergic circuit and receptor mechanism (BLA 5-HT1A) for accelerating emergence from sevoflurane, opening avenues for targeted pro-emergence strategies.
Clinical Implications: Although preclinical, the BLA 5-HT1A pathway suggests testable targets (e.g., 5-HT1A agonists or neuromodulation) to hasten emergence and reduce delayed recovery; translation requires human validation.
Key Findings
- DRN serotonergic afferent activity in BLA decreases during sevoflurane anesthesia relative to wakefulness.
- Optogenetic activation of DRN→BLA serotonergic terminals accelerates EEG and behavioral emergence.
- BLA microinjection of a 5-HT1A agonist, but not 5-HT2A/5-HT2C agonists, promotes emergence.
- DRN serotonergic inputs inhibit BLA GABAergic neurons while exciting glutamatergic neurons across states.
Methodological Strengths
- Multimodal in vivo approach combining fiber photometry, optogenetics, pharmacology, and electrophysiology.
- Cell-type–specific mechanistic resolution (GABAergic vs glutamatergic targets) within a defined circuit.
Limitations
- Preclinical animal study; human generalizability and safety of targeting BLA 5-HT1A are unknown.
- Findings centered on sevoflurane; applicability to other anesthetics remains to be determined.
Future Directions: Translational studies to assess 5-HT1A modulation on emergence in humans; comparative work across anesthetic classes; exploration of neuromodulatory strategies.
BACKGROUND: Although the dorsal raphe nucleus (DRN) serotonergic neurons-which play a key role in consciousness-send dense projections to the basolateral amygdala (BLA), the electrophysiological mechanisms underlying their role in general anesthesia regulation remain elusive. METHODS: Fiber photometry was used to monitor DRN serotonergic activity changes in the BLA during sevoflurane anesthesia and arousal process. Optogenetics and neuropharmacology were taken advantage to study the effects and receptor mechanisms. Additionally, in vivo electrophysiology was applied to elucidate the neurophysiological mechanisms underlying DRN serotonergic modulating BLA during sevoflurane anesthesia and arousal process. RESULTS: DRN serotonergic afferents in the BLA exhibited decreased activity during sevoflurane anesthesia compared to wakefulness. Optogenetic activation of DRN serotonergic terminals in BLA accelerated arousal from sevoflurane anesthesia, as evidenced by electroencephalographic (EEG) signatures and behavioral recovery. Microinjection of 5-hydroxytryptamine (5-HT)1A receptors agonist (but not 5-HT2A or 5-HT2C agonists) into the BLA similarly promoted anesthetic emergence. Mechanistically, DRN serotonergic input inhibited GABAergic neurons while exciting glutamatergic neurons in the BLA, with these effects persisting across both wakefulness and anesthetic states. CONCLUSIONS: Our findings establish a functional role for the DRN serotonergic-BLA neural pathway in promoting arousal from sevoflurane general anesthesia. These results provide novel mechanistic insights into the neural circuitry underlying consciousness recovery.
3. Comparison between infraspinatus-Teres minor (ITM) Interfascial block and superior trunk block in shoulder arthroscopy: A randomized non-inferiority trial.
In 100 patients undergoing shoulder arthroscopy, the ITM interfascial plane block was noninferior to the superior trunk block for maximal 24-hour resting pain. Importantly, ITM significantly reduced hemidiaphragmatic paralysis compared with STB, supporting a diaphragm-sparing analgesic approach.
Impact: Provides randomized evidence for a diaphragm-sparing alternative to STB, addressing a key safety concern (HDP) in shoulder surgery regional anesthesia.
Clinical Implications: Consider ITM interfascial block when reducing risk of hemidiaphragmatic paralysis is prioritized (e.g., patients with limited respiratory reserve), while maintaining analgesic efficacy comparable to STB.
Key Findings
- ITM block met non-inferiority versus STB for maximal 24-hour resting pain (median difference 0; 95% CI −1 to 0; P<0.01 for non-inferiority).
- ITM significantly reduced hemidiaphragmatic paralysis compared to STB.
- Secondary measures (QoR-15, OBAS, rescue analgesic use) were comparable while favoring diaphragm function with ITM.
Methodological Strengths
- Prospective randomized non-inferiority design with predefined margin and ultrasound-guided standardized techniques.
- Clinically relevant safety endpoint (hemidiaphragmatic paralysis) assessed alongside analgesia.
Limitations
- Single-center study with moderate sample size; generalizability may be limited.
- Different local anesthetic volumes between groups (15 mL STB vs 25 mL ITM) may influence spread and outcomes.
Future Directions: Multicenter trials to validate reduced HDP with ITM, optimize dosing/volumes, and assess outcomes in patients with pulmonary comorbidities.
STUDY OBJECTIVE: To evaluate whether there are differences in postoperative pain scores and the incidence of hemidiaphragmatic paralysis (HDP) between ultrasound-guided superior trunk block (STB) and infraspinatus teres minor fascial plane block (ITM). DESIGN: Prospective, randomized controlled non-inferiority trial. SETTING: A tertiary hospital. PATIENTS: A total of 100 patients aged 18 to 65 years scheduled for elective arthroscopic surgery were enrolled. INTERVENTIONS: Following sterile skin preparation, patients in the STB group received 15 mL of 0.375 % ropivacaine, while those in the ITM group received 25 mL of 0.375 % ropivacaine. MEASUREMENTS: The primary outcome was the highest resting pain score during the first 24 h postoperatively. Secondary outcomes included resting pain scores at six predefined time points (1, 3, 6, 9, 12,and 24 h), the incidence and severity of hemidiaphragmatic paralysis (HDP), block performance time, sensory block onset time, duration of analgesia, postoperative rescue analgesic consumption, grip strength, patient satisfaction scores, 24-h Quality of Recovery-15 (QoR-15) assessments, and Overall Benefit of Analgesia Scores (OBAS). MAIN RESULTS: Within 24 h postoperation, the highest pain score was 3 [2.0-4.0] in the STB group and 3 [2.8 to 4.3] in the ITM group, with a median difference of 0 (95 % CI, -1 to 0). The upper limit of the 95 % CI was below the prespecified non-inferiority margin of 1″. (non-inferiority P < 0.01). CONCLUSIONS: For maximal postoperative pain control within 24 h after shoulder arthroscopy, the ITM block was noninferior to STB, with significantly reduced diaphragmatic paralysis rates.