Daily Anesthesiology Research Analysis
Three studies stood out today in anesthesiology and perioperative science: a preclinical Cell paper reveals a β-arrestin–biased NTSR1 allosteric modulator that provides potent, non-opioid analgesia with mechanistic depth; a randomized trial in JAMA Surgery shows cipepofol better preserves hemodynamics than propofol for induction in severe aortic stenosis; and a double-blind RCT in Annals of Surgery demonstrates hypovolemic phlebotomy expedites low-CVP achievement and reduces blood loss in open l
Summary
Three studies stood out today in anesthesiology and perioperative science: a preclinical Cell paper reveals a β-arrestin–biased NTSR1 allosteric modulator that provides potent, non-opioid analgesia with mechanistic depth; a randomized trial in JAMA Surgery shows cipepofol better preserves hemodynamics than propofol for induction in severe aortic stenosis; and a double-blind RCT in Annals of Surgery demonstrates hypovolemic phlebotomy expedites low-CVP achievement and reduces blood loss in open liver resection.
Research Themes
- Non-opioid analgesia via biased GPCR modulation
- Hemodynamic optimization during high-risk anesthesia induction
- Blood conservation strategies through low-CVP techniques
Selected Articles
1. Arrestin-biased allosteric modulator of neurotensin receptor 1 alleviates acute and chronic pain.
This preclinical study identifies SBI-810, a β-arrestin–biased NTSR1 positive allosteric modulator, as a potent analgesic across postoperative, inflammatory, and neuropathic pain models. Analgesia required NTSR1/β-arrestin-2, reduced excitatory signaling (NMDA/ERK), decreased Nav1.7 surface expression and neuronal firing, and attenuated C-fiber responses, while reducing opioid reward, constipation, and withdrawal behaviors.
Impact: Introduces a mechanistically distinct, non-opioid analgesic strategy with dual central and peripheral actions and favorable behavioral profile, addressing unmet needs in acute and chronic pain.
Clinical Implications: While preclinical, these findings support the development of biased NTSR1 modulators as non-addictive analgesics that could reduce reliance on opioids and mitigate opioid-related adverse effects.
Key Findings
- SBI-810 produced robust analgesia in postoperative, inflammatory, and neuropathic pain models via systemic and local routes.
- Analgesia required NTSR1 and β-arrestin-2, but not NTSR2 or β-arrestin-1, indicating mechanism specificity.
- SBI-810 suppressed NMDA/ERK signaling, reduced Nav1.7 surface expression and neuronal firing, and dampened C-fiber responses.
- Behaviorally, SBI-810 reduced opioid-induced conditioned place preference, constipation, and chronic opioid withdrawal symptoms.
Methodological Strengths
- Multi-model validation across acute and chronic pain paradigms with both systemic and local administration.
- Mechanistic depth linking receptor bias to synaptic, ion channel, and behavioral endpoints.
Limitations
- Preclinical rodent data without human pharmacokinetics, safety, or efficacy.
- Long-term safety, tolerance, and off-target effects remain uncharacterized.
Future Directions: Advance to IND-enabling studies including GLP toxicology and PK/PD, followed by phase 1 trials; explore indications beyond pain (e.g., pruritus) and combination with reduced-dose opioids.
G-protein-biased agonists have been shown to enhance opioid analgesia by circumventing β-arrestin-2 (βarr2) signaling. We previously reported that SBI-553, a neurotensin receptor 1 (NTSR1)-positive allosteric modulator biased toward βarr2 signaling, attenuates psychostimulant effects in mice. Here, we demonstrate that its analog, SBI-810, exhibits potent antinociceptive properties in rodent models of postoperative pain, inflammatory pain, and neuropathic pain via systemic and local administration. SBI-810's analgesic effects require NTSR1 and βarr2 but not NTSR2 or βarr1. Mechanistically, SBI-810 suppresses excitatory synaptic transmission, inhibits NMDA recepto
2. Hemodynamic Impact of Cipepofol vs Propofol During Anesthesia Induction in Patients With Severe Aortic Stenosis: A Randomized Clinical Trial.
In a single-center RCT of TAVR patients with severe aortic stenosis (n=122), cipepofol achieved significantly smaller MAP deficit AUC in the first 15 minutes postinduction versus propofol, lower hypotension incidence, and reduced norepinephrine requirements at matched anesthetic depth.
Impact: Addresses a high-risk induction scenario where hypotension is common and harmful; provides randomized evidence supporting an alternative induction agent with improved hemodynamic stability.
Clinical Implications: For severe aortic stenosis patients undergoing TAVR, cipepofol can be considered as an induction agent to mitigate postinduction hypotension, pending local availability and clinician familiarity.
Key Findings
- Primary endpoint: Smaller MAP AUC deficit with cipepofol vs propofol in first 15 minutes postinduction (P<.001).
- Lower postinduction hypotension with cipepofol (70.5% vs 88.5%; P=.01).
- Reduced norepinephrine requirements in the first 15 minutes (median 6.0 μg vs 10.0 μg; P=.006) at comparable BIS.
Methodological Strengths
- Randomized design with intention-to-treat analysis and trial registration.
- Equipotent dosing and comparable BIS ensure fair comparison of hemodynamic effects.
Limitations
- Single-center trial with short (15-minute) primary observation window.
- Clinical outcomes (e.g., myocardial injury, AKI) were not primary endpoints.
Future Directions: Multicenter trials powered for clinical outcomes and safety endpoints; dose-finding in broader cardiac risk populations; cost-effectiveness and implementation studies.
IMPORTANCE: Postinduction hemodynamic instability is a frequent complication among patients with severe aortic stenosis (AS). Using cipepofol as the anesthesia agent may reduce the incidence and severity of hemodynamic instability. OBJECTIVE: To assess whether cipepofol outperforms propofol in maintaining postinduction hemodynamic stability in patients with AS. DESIGN, SETTING, AND PARTICIPANTS: This single-center, randomized clinical trial was conducted from June 29, 2023, to July 8, 2024, at the Second Affiliated Hospital of Zhejiang University School of Medicine in China. Patients with AS scheduled for transcatheter aortic valve replacement (TAVR) were eligible for inclusion. INTERVENTIONS: Participants were randomized 1:1 to receive either cipepofol or propofol as anesthesia induction agents at equipotent doses. MAIN OUTCOMES AND MEASURES: The primary outcome was the area under the curve (AUC) of the mean arterial pressure (MAP) difference from baseline during the initial 15 minutes postinduction. RESULTS: A total of 124 patients with AS scheduled for TAVR were randomized into either the cipepofol group (n = 62) or the propofol group (n = 62). Of 124 patients randomized, 1 patient from each group was excluded due to ineligibility for the TAVR procedure, and data were analyzed for 122 patients (61 patients per group) based on the intention-to-treat principle. Among 122 total patients, mean (SD) age was 72.2 (5.0) years, and 53 patients (43.4%) were female. The cipepofol group exhibited a significantly smaller median (IQR) AUC (-8505.0 mm Hg · s [-12 402.8 to -5130.0]) compared with the propofol group (-13 189.0 mm Hg · s [-17 006.7 to -7593.3]; P < .001). Moreover, compared with the propofol group, the cipepofol group demonstrated a significantly lower incidence of postinduction hypotension (70.5% vs 88.5%; P = .01) and required a smaller median (IQR) dose of norepinephrine during the first 15 minutes postinduction (6.0 μg [0.0-10.0] vs 10.0 μg [5.0-20.0]; P = .006). Additionally, the 2 groups' bispectral indices were comparable. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, cipepofol provided superior hemodynamic stability as an induction agent compared to propofol at equipotent doses and similar anesthesia depths for patients with AS. Therefore, cipepofol could serve as an alternative induction agent to propofol for patients at high cardiovascular risk. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05881291.
3. Impact of Hypovolemic Phlebotomy with Low Central Venous Pressure on Intraoperative Blood Loss in Open Liver Resection: A Double-Blind Randomized Controlled Trial.
In a double-blind RCT (n=100), hypovolemic phlebotomy to target low CVP reduced parenchymal transection blood loss by ~150 mL, shortened time to low CVP by ~75 minutes, and improved bleeding scores without increasing transfusions or complications.
Impact: Provides randomized evidence for a pragmatic, implementable blood conservation strategy in open liver surgery, aligning anesthetic hemodynamic targets with surgical field optimization.
Clinical Implications: Protocols incorporating controlled phlebotomy to expedite low-CVP states may be adopted to reduce blood loss during transection in open hepatectomy, with careful monitoring and team coordination.
Key Findings
- Reduced blood loss during parenchymal transection with HP (median 300 vs 500 mL; P=0.02).
- Faster achievement of low CVP with HP (median 50 vs 107.5 minutes; P=0.01).
- Lower surgical bleeding scores with HP and similar transfusion rates and postoperative complications.
- HP independently protected against >500 mL blood loss (AOR 0.19; P=0.02).
Methodological Strengths
- Double-blind randomized controlled design with prespecified primary endpoint.
- Objective intraoperative measures and adjusted analyses supporting causal inference.
Limitations
- Single-center study; sample size modest for rare adverse events.
- Transfusion rates did not differ, limiting conclusions on allogeneic exposure reduction.
Future Directions: Multicenter validation with standardized low-CVP protocols; integration with enhanced coagulation management and goal-directed fluid therapy; cost-effectiveness and recovery outcomes.
OBJECTIVE: To assess the efficacy and safety of hypovolemic phlebotomy (HP) versus conventional management (control group) in achieving low central venous pressure (CVP) to reduce blood loss during open liver resections. BACKGROUND: Excessive blood loss increases perioperative complications and worsen patient outcomes. HP is used to reduce blood loss and the need for allogenic transfusions. This study compares intraoperative blood loss between HP and conventional techniques in liver resection. METHODS: This prospective, randomized controlled trial, conducted between 2020 and 2024, evaluated intraoperative blood loss as the primary endpoint, with secondary endpoints of allogenic transfusion and postoperative outcomes. RESULTS: One hundred participants were randomized to either HP or control groups, with similar baseline characteristics. The HP group had significantly lower blood loss during parenchymal transection (300 (250-500) vs. 500 (300-750) mL, difference = 150, 95% CI [50, 275]; P = 0.02), shorter time to achieve low CVP (50 (30-100) vs. 107.5 (45-150) minutes, difference = -75.0, 95% CI [-95.0, -56.0]; P = 0.01), and a lower surgical bleeding score (2 (1-3) vs. 2 (2-4), difference = -1.0, 95% CI [-1.0, -0.5]; P = 0.01). Transfusion rates and postoperative complications were similar. HP was an independent protective against blood loss > 500 mL (AOR = 0.19, 95% CI [0.04-0.80]; P = 0.02). CONCLUSIONS: HP significantly reduces intraoperative blood loss and enhances bleeding control by achieving low CVP more quickly. It is an effective technique for minimizing blood loss and improving outcomes in open liver resections.