Partial hepatectomy (PH) may increase the risk of myocardial injury after non-cardiac surgery (MINS), a complication associated with substantial perioperat

Evidence remains limited on how specialty-specific competency scores change month by month during the transition of newly recruited nurses into anesthesia

Background: Intraoperative blood pressure variability (BPV) is associated with adverse perioperative outcomes, although the prognostic meaning of variability itself, once blood pressure level is accounted for, remains uncertain. Preoperative metabolic indicators have not been examined in relation to intraoperative BPV. The triglyceride-glucose (TyG) index, a surrogate marker of insulin resistance, is associated with arterial stiffness in community populations. We examined whether the preoperative TyG index is associated with intraoperative BPV in surgical patients, and whether an estimated pulse wave velocity (ePWV) surrogate statistically accounts for part of this association. Methods: This single-center retrospective cohort study included 7081 adults who underwent elective major abdominal surgery under general anesthesia for at least 120 min at Beijing Tsinghua Changgung Hospital between January 2016 and December 2022. The primary outcome was the coefficient of variation of intraoperative mean arterial pressure (CV-MAP). ePWV was calculated from age and preoperative mean arterial pressure (MAP) and is therefore a surrogate rather than a direct measure of arterial stiffness. Multivariable linear regression assessed the TyG-CV-MAP association; models excluding and including age are reported as co-primary analyses. Exploratory mediation analysis using the Baron-Kenny framework with 5000 bootstrap iterations estimated the proportion of the association statistically accounted for by ePWV. Subgroup analyses tested age as an effect modifier, and a sensitivity model additionally adjusted for antihypertensive and antidiabetic medication use. Results: After adjustment for sex, body mass index, comorbidities, surgical duration, American Society of Anesthesiologists physical status, and surgery type, each unit increase in the TyG index was associated with a 0.0128-unit increase in CV-MAP (95% confidence interval [CI], 0.0097 to 0.0158; p < 0.001); with age additionally included, the estimate was 0.0086 (95% CI, 0.0056 to 0.0117; p < 0.001). In absolute terms, each unit increase in TyG corresponded to a 1.074 mmHg higher standard deviation of intraoperative MAP (MAP-SD; 95% CI, 0.842 to 1.305), against a cohort mean MAP-SD of 12.0 mmHg. ePWV statistically accounted for approximately one quarter to one third of the total effect (indirect effect, 0.0038; bootstrap 95% CI, 0.0030 to 0.0046). The association was present in patients younger than 65 years (β = 0.0132, p < 0.001), with no evidence of an association in those aged 65 years or older (β = 0.0008, 95% CI, −0.0054 to 0.0071; p = 0.79; interaction β = −0.0124, 95% CI, −0.0187 to −0.0061; p < 0.001). Sensitivity analyses supported the robustness of these findings, including a model adjusted for antihypertensive and antidiabetic medication use (β = 0.0128, 95% CI, 0.0098 to 0.0159; p < 0.001). Conclusions: The preoperative TyG index was independently associated with greater intraoperative BPV in major abdominal surgery, with the association present in patients younger than 65 years but not in older patients. An ePWV-based surrogate statistically accounted for approximately one quarter to one third of this association; because ePWV is derived from age and blood pressure rather than measured directly, this proportion may reflect the structure of the surrogate rather than a causal arterial-stiffness pathway. The clinical significance remains uncertain given the modest incremental predictive contribution and the absence of clinically anchored endpoints; prospective validation with directly measured pulse wave velocity is required.

Infra-hepatic inferior vena cava (IVC) balloon occlusion is an effective strategy for reducing intraoperative bleeding during precision liver surgery, yet rapid balloon inflation can produce abrupt transient deviations in downstream venous pressure that are not yet quantitatively characterized. Current practice relies on operator experience, with no quantitative framework to balance occlusion efficacy against downstream pressure safety. A computational fluid dynamics (CFD) model of the balloon-occluded IVC was developed in ANSYS 2025 R2 with two-way fluid–structure interaction (FSI), Carreau–Yasuda blood rheology, and a balloon described by an Ogden hyperelastic model; the flow regime was laminar (Re ≈ 254). Reduced-order ARX models of four input–output subsystems were identified from CFD-generated data, and a model predictive control (MPC) strategy was formulated to penalize downstream pressure overshoot through a weighted cost function. The identified models achieved training normalized root-mean-square errors of 0.0363 to 0.1164 and out-of-sample validation errors of 0.1224 to 0.2381. Conventional sigmoid inflation induced a 45.82% overshoot in downstream pressure (P_aft); the optimal input signal (q = [0, 1, 0, 0], λ = 0.1) reduced this to 6.05%, a reduction of 39.77 percentage points, while preserving >90% flow occlusion at U_F = 3 × 10⁴ Pa. The proposed framework offers a quantitative basis for balloon-occlusion device design that limits downstream pressure overshoot, motivating subsequent benchtop, ex vivo, and in vivo validation.