Frailty and risk of systemic atherosclerosis: A bidirectional Mendelian randomization study.

BACKGROUND: Numerous observational studies have reported an association between frailty and atherosclerosis. However, the causal relationship between frailty and the occurrence of atherosclerosis in different anatomical sites remains unclear. we conducted a bidirectional Mendelian randomization (MR) study to evaluate the causal relationship between the frailty index (FI), and both systemic atherosclerosis and lipids. METHODS: We obtained summary statistics from large-scale genome-wide association studies (GWAS) of various phenotypes, including frailty (n = 175,226), coronary atherosclerosis (n = 56,685), cerebral atherosclerosis (n = 150,765), peripheral arterial disease (PAD) (n = 361,194), atherosclerosis at other sites (n = 17,832), LDL-C (n = 201,678), HDL-C (n = 77,409), and triglycerides (n = 78,700). The primary MR analysis employed the inverse variance weighted (IVW) method. Furthermore, to assess reverse causality, we employed inverse MR and multivariate MR analysis. RESULTS: Genetically predicted FI showed positive associations with the risk of coronary atherosclerosis (OR = 1.47, 95% CI 1.12-1.93) and cerebral atherosclerosis (OR = 1.99, 95% CI 1.05-3.78), with no significant association (p >0.05) applied to peripheral arterial disease and atherosclerosis at other sites. Genetically predicted FI was positively associated with the risk of triglycerides (OR = 1.31, 95% CI 1.08-1.59), negatively associated with the risk of LDL-C (OR = 0.87, 95% CI 0.78-0.97), and showed no significant association with the risk of HDL-C (p >0.05). Furthermore, both reverse MR and multivariate MR analyses demonstrated a correlation between systemic atherosclerosis, lipids, and increased FI. CONCLUSION: Our study elucidated that genetically predicted FI is associated with the risk of coronary atherosclerosis and cerebral atherosclerosis by the MR analysis method, and they have a bidirectional causal relationship. Moreover, genetically predicted FI was causally associated with triglyceride and LDL-C levels. Further understanding of this association is crucial for optimizing medical practice and care models specifically tailored to frail populations.

VO2 /MoO3 Heterojunctions Artificial Optoelectronic Synapse Devices for Near-Infrared Optical Communication.

Artificial optoelectronic synapses (OES) have attracted extensive attention in brain-inspired information processing and neuromorphic computing. However, OES at near-infrared wavelengths have rarely been reported, seriously limiting the application in modern optical communication. Herein, high-performance near-infrared OES devices based on VO2 /MoO3 heterojunctions are presented. The textured MoO3 films are deposited on the sputtered VO2 film by using the glancing-angle deposition technique to form a heterojunction device. Through tuning the oxygen defects in the VO2 film, the fabricated VO2 /MoO3 heterojunction exhibits versatile electrical synaptic functions. Benefiting from the highly efficient light harvesting and the unique interface effect, the photonic synaptic characteristics, mainly including the short/long-term plasticity and learning experience behavior are successfully realized at the O (1342 nm) and C (1550 nm) optical communication wavebands. Moreover, a single OES device can output messages accurately by converting light signals of the Morse code to distinct synaptic currents. More importantly, a 3 × 3 artificial OES array is constructed to demonstrate the impressive image perceiving and learning capabilities. This work not only indicates the feasibility of defect and interface engineering in modulating the synaptic plasticity of OES devices, but also provides effective strategies to develop advanced artificial neuromorphic visual systems for next-generation optical communication systems.

Epidemiology and Clinical Characteristics of Pediatric Sepsis in PICUs in Southwest China: A Prospective Multicenter Study.

OBJECTIVES: To describe the epidemiological characteristics of pediatric sepsis in Southwest China PICUs. DESIGN: A prospective, multicenter, and observational study. SETTING: Twelve PICUs in Southwest China. PATIENTS: The patients admitted to the PICU from April 1, 2022, to March 31, 2023. The age ranged from 28 days to 18 years. All patients met the criteria of severe sepsis or septic shock. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 31 PICUs invited to participate, 12 PICUs (capacity of 292 beds) enrolled patients in the study. During the study period, 11,238 children were admitted to the participating PICUs, 367 (3.3%) of whom met the diagnosis of severe sepsis or septic shock. The most prevalent sites of infection were the respiratory system (55%) and the digestive system (15%). The primary treatments administered to these patients included antibiotics (100%), albumin (61.3%), invasive mechanical ventilation (58.7%), glucocorticoids (55.6%), blood products (51%), gammaglobulin (51%), and vasoactive medications (46.6%). Sepsis-related mortality in the PICU was 11.2% (41/367). Nearly half of the sepsis deaths occurred within the first 3 days of PICU admission (22/41, 53.7%). The mortality rate of septic shock (32/167, 19.2%) was significantly higher than that of severe sepsis (9/200, 4.5%; p < 0.001). The outcomes of a multivariate logistic regression analysis suggested that a higher pediatric Sequential Organ Failure Assessment score, and the use of invasive mechanical ventilation and vasoactive medications were independently associated with PICU mortality in children with sepsis. CONCLUSIONS: This report updates the epidemiological data of pediatric sepsis in PICUs in Southwest China. Sepsis is still a life-threatening disease in children.

Efficient and rapid adsorption of methylene blue dyes by novel metal-organic frameworks and organic/inorganic hybrid alginate-based dual network gel composites.

To address the limitations of gel-based adsorbents, such as inadequate mechanical strength, low adsorption capacity, and limited reusability, this study presents an innovative approach employing a dual network gel. The dual network consists of calcium alginate (CA) ionic crosslinked organic networks, and vinyl silica-based nanoparticles (VSNP) as crosslinking agents in acrylic acid (AA) free radical polymerization networks (denoted as P (AA-co-VSNP), abbreviated as PAV). After freeze-drying, ultimately yielding an organic/inorganic hybrid dual network gel (referred to as CA/P(AA-co-VSNP), abbreviated as CPAV), enriched with abundant functional groups, thereby enhancing material reusability. To further enhance the adsorption capacity, CPAV undergoes hydrothermal reactions to obtain metal-organic frameworks (MOFs) composite dual network gel adsorbent (UiO-66@CPAV). UiO-66@CPAV exhibited a density of 0.165 g/cm3 and showcased a unique pore structure with nested macropores and mesopores, featuring a uniform distribution of pore holes. Notably, the specific surface area was measured at 96.3 m2/g, and an average pore diameter was 17.9 nm. Most impressively, the actual maximum adsorption capacity reached 841.7 mg/g, and even after 10 cycles of use, the adsorption capacity remained 91.9 % of its initial value. Overall, this research introduced a novel methodology for the development of dual network MOFs@gel adsorbents, showcasing promising advancements in the field.

PVA/sodium alginate multi-network aerogel fibers, incorporated with PEG and ZnO, exhibit enhanced temperature regulation, antibacterial, thermal conductivity, and thermal stability.

This paper presents a novel approach for the fabrication of polyvinyl alcohol (PVA)/sodium alginate (SA) aerogel fibers with a multilayered network structure using wet spinning and freeze-thaw cycling techniques. The multiple cross-linking networks regulate the pore structure, leading to the formation of stable and tunable multilevel pore architectures. PEG and nano-ZnO were successfully loaded onto the PVA/SA modified aerogel fibers (MAFs) using vacuum impregnation. MAFs exhibited excellent thermal stability at 70 °C without leakage after 24 h of heating. Furthermore, MAFs demonstrated excellent temperature regulation performance, with a latent heat of 121.4 J/g, which accounts for approximately 83 % of PEG. After modification, the thermal conductivity of MAFs was significantly improved, and they exhibited excellent antibacterial properties. Therefore, MAFs are expected to be widely used in intelligent temperature-regulating textiles.

One-Step Bulk-Suspension Polymerization of Polyethylene Glycol-Based Copolymer Microspheres for Phase Change Textiles.

The paper presents a feasible strategy through one-step bulk-suspension polymerization, grafting PEG onto an in situ synthesized copolymer. In more detail, PEG was grafted onto a homemade polystyrene/maleic anhydride copolymer (SMA) via bulk-suspension polymerization with poly(vinyl alcohol) as a suspending agent. According to the optimal reaction conditions, the grafting rate of PEG was 56.2% through chemical titration experiments. At the same time, the quantitative relationship between the grafting rate and enthalpy was demonstrated for the first time in a PEG-based solid-solid phase change material (S-SPCM). Morphology observation revealed that the obtained S-SPCM is made up of white microspheres of approximately 100-150 µm. The powdery product polystyrene/maleic anhydride grafted polyethylene glycol (SMA-g-PEG) obtained through bulk-suspension polymerization endowed that the whole product could be used directly as a phase change material without postprocessing. The melting enthalpy and crystallization enthalpy of SMA-g-PEG were 79.3 J/g and 76.9 J/g, respectively. Based on the effective fixed load of PEG, the macrostructure of SMA-g-PEG was almost unchanged at 70 °C compared with the macrostructures at 20 °C, and the latent heat of SMA-g-PEG was decreased slightly after 1000 thermal cycles. Overall, the obtained SMA-g-PEG can be used as a filler in insulation materials and composited with fibers to obtain phase change thermoregulated smart textiles.

[Establishment of a 3-dimentional finite element system simulating En masse retraction implemented by customized lingual appliances].

PURPOSE: This study was designed to establish a 3-dimentional finite element system to simulate the clinical scenario where labial segment was retracted with sliding mechanism in extraction cases treated by individualized lingual orthodontics. METHODS: A typical clinical case was selected. The subject was diagnosed with Class I malocclusion with alveolar protrusion and treated with extraction of 4 first premolars. The subject was under the treatment stage of frontal retraction by eBrace system, an individualized lingual appliance. The subject was also taken cone-beam CT (CBCT) based on which digital 3D reconstruction of dentition structures was formed with Mimics software. With the aid of software platform Pro/E 4.0, the important anatomical structures were defined, and relevant lingual devices, including lingual brackets, arch-wires, mini-screws and other accessories were formed. With the aids of software platform Geomagic Studio 13.0, the 3-dimentional structural mode, featuring maxillary alveolar, upper dentition, periodontal ligament, miniscrew and lingual applicance, were constructed. With the assistance of Ansys Workbench 15.0, 3D model for finite element system was finalised by conducting model meshing and defining the mechanical properties and the interface relations of the selected materials. RESULTS: Based on the digital information drawn from CBCT image, a 3-dimentional finite element system was successfully created, featuring all the elements mimicking the clinical scenario for En masse retraction. This system enabled an insight study on the effects of various retraction modes controlling the incisal torque and maintaining the dental arch integrity. CONCLUSIONS: The creation of a finite element system in this study is based on the digital data from the CBCT image of a real patient diagnosed with prognathic malocclusion and treated by lingual appliance. The clinical scenario of labial segment retraction via sliding mechanism is simulated in this finite element model.

[Expression of TNFAIP6 in oral verrucous carcinoma and oral squamous cell carcinoma and its relationship with clinicopathology].

PURPOSE: This study was designed to establish a 3-dimentional finite element system to simulate the clinical scenario where labial segment was retracted with sliding mechanism in extraction cases treated by individualized lingual orthodontics. METHODS: A typical clinical case was selected. The subject was diagnosed with Class I malocclusion with alveolar protrusion and treated with extraction of 4 first premolars. The subject was under the treatment stage of frontal retraction by eBrace system, an individualized lingual appliance. The subject was also taken cone-beam CT (CBCT) based on which digital 3D reconstruction of dentition structures was formed with Mimics software. With the aid of software platform Pro/E 4.0, the important anatomical structures were defined, and relevant lingual devices, including lingual brackets, arch-wires, mini-screws and other accessories were formed. With the aids of software platform Geomagic Studio 13.0, the 3-dimentional structural mode, featuring maxillary alveolar, upper dentition, periodontal ligament, miniscrew and lingual applicance, were constructed. With the assistance of Ansys Workbench 15.0, 3D model for finite element system was finalised by conducting model meshing and defining the mechanical properties and the interface relations of the selected materials. RESULTS: Based on the digital information drawn from CBCT image, a 3-dimentional finite element system was successfully created, featuring all the elements mimicking the clinical scenario for En masse retraction. This system enabled an insight study on the effects of various retraction modes controlling the incisal torque and maintaining the dental arch integrity. CONCLUSIONS: The creation of a finite element system in this study is based on the digital data from the CBCT image of a real patient diagnosed with prognathic malocclusion and treated by lingual appliance. The clinical scenario of labial segment retraction via sliding mechanism is simulated in this finite element model.

Glycemic Variability Is Independently Associated With Poor Prognosis in Five Pediatric ICU Centers in Southwest China.

Background: Glucose variability (GV) is a common complication of dysglycemia in critically ill patients. However, there are few studies on the role of GV in the prognosis of pediatric patients, and there is no consensus on the appropriate method for GV measurement. The objective of this study was to determine the "optimal" index of GV in non-diabetic critically ill children in a prospective multicenter cohort observational study. Also, we aimed to confirm the potential association between GV and unfavorable outcomes and whether this association persists after controlling for hypoglycemia or hyperglycemia. Materials and Methods: Blood glucose values were recorded for the first 72 h and were used to calculate the GV for each participant. Four different metrics [SD, glycemic lability index (GLI), mean absolute glucose (MAG), and absolute change of percentage (ACACP)] were considered and compared to identify the "best" GV index associated with poor prognosis in non-diabetic critically ill children. Among the four metrics, the SD was most commonly used in previous studies, while GLI- and MAG-integrated temporal information, that is the rate and magnitude of change and the time interval between glucose measurements. The fourth metric, the average consecutive ACACP, was introduced in our study, which can be used in real-time clinical decisions. The primary outcome of this study was the 28-day mortality. The receiver operating characteristic (ROC) curve analysis was conducted to compare the predictive power of different metrics of GV for the primary outcome. The GV index with the largest area under ROC curve (AUC) was chosen for subsequent multivariate analyses. Multivariate Cox regression analysis was performed to identify the potential predictors of the outcome. To compare the contribution in 28-day mortality prognosis between glycemic variability and hyper- or hypoglycemia, performance metrics were calculated, which included AUC, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Results: Among 780 participants, 12.4% (n = 97) died within 28 days after admission to the pediatric intensive care unit (PICU). Statistically significant differences were found between survivors and non-survivors in terms of four GV metrics (SD, GLI, MAG, and ACACP), in which MAG (AUC: 0.762, 95% CI: 0.705-0.819, p < 0.001) achieved the largest AUC and showed a strong independent association with ICU mortality. Subsequent addition of MAG to the multivariate Cox model for hyperglycemia resulted in further quantitative evolution of the model statistics (AUC = 0.651-0.681, p = 0.001; IDI: 0.017, p = 0.044; NRI: 0.224, p = 0.186). The impact of hyperglycemia (adjusted hazard ratio [aHR]: 1.419, 95% CI: 0.815-2.471, p = 0.216) on outcome was attenuated and no longer statistically relevant after adjustment for MAG (aHR: 2.455, 95% CI: 1.411-4.270, p = 0.001). Conclusions: GV is strongly associated with poor prognosis independent of mean glucose level, demonstrating more predictive power compared with hypoglycemia and hyperglycemia after adjusting for confounding factors. GV metrics that contain information, such as time and rate of change, are the focus of future research; thus, the MAG may be a good choice. The findings of this study emphasize the crucial role of GVs in children in the PICU. Clinicians should pay more attention to GV for clinical glucose management.

Epidemiology of Pediatric Severe Sepsis in Main PICU Centers in Southwest China.

OBJECTIVES: To estimate the prevalence, management, and outcomes of pediatric severe sepsis in the main PICUs in Southwest China. DESIGN: A prospective, observational, and multicenter study. SETTING: Eight PICUs in Southwest China with 19 (13-24) beds and 1,322 (1,066-1,452) annual admissions each. PATIENTS: A total of 10,598 patients (29 d to 18 yr old) were consecutively admitted between September 1, 2016, and August 31, 2017. All patients were screened and evaluated for severe sepsis or septic shock. Of them, 10,353 patients were excluded due to incomplete data or not meeting the consensus criteria for severe sepsis or septic shock; 245 patients were included with complete data. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Finally, 245 patients who were diagnosed with severe sepsis or septic shock were included in the study, with an incidence rate of 2.3%. Of them, 64.0% of the enrolled patients were male with 80.8% being less than 5 years old and 60.8% being from rural areas. The respiratory system was the most common organ system in which dysfunction was observed (76.7%) as well as the most frequently infected site (37.6%). The primary therapies were antibiotics (99.0%), immunoglobulin (88.3%), mechanical ventilation (78.4%), vasoactive infusions (59.6%), and corticosteroids (46.1%). Among the 188 patients who had respiratory dysfunction, 173(92%) required mechanical ventilation and 39 (20.7%) met the criteria for pediatric acute respiratory distress syndrome. Seven of the patients with pediatric acute respiratory distress syndrome died (7/39, 17.9%). The median durations for mechanical ventilation and vasoactive medications were 123.5 hours (35.25-226.00 hr) and 2 days (1-5 d), respectively. Eighty-six percent of patients had multiple organ dysfunction syndrome at the point at which severe sepsis was recognized, and 31% had underlying conditions. The hospital mortality rate was 18.8%. CONCLUSIONS: This report is the first to present the prevalence, treatment, and outcomes of pediatric severe sepsis in the main PICU centers in Southwest China. The mortality rate remains high; therefore, improved clinical management and implementation of large-scale clinical trials are necessary to improve early diagnoses and treatment.

[Retrospective analysis of 39 child cases of paragonimiasis].

Clinical data of 39 children with paragonimiasis treated in Chongqing Three Gorges Central Hospital during 2008-2010 were retrospectively analyzed. The cases aged from 3 to 10 years old, with 25 cases of polyserositis (64.1%), 14 cases of cerebral paragonimiasis (35.9%). Among the cases of polyserositis, all showed dyspnea,tachypnea and diminished respiration (100%). Other symptoms or signs included purulent pleurisy, orthopnea, restricted activity, distant heart sounds, purulent pericarditis, abdominal distension, and hepatomegaly. In the 14 cases of cerebral paragonimiasis, 10 cases (71.4%) complained headache, 8 cases (57.1%) with vomiting, and other symptoms such as seizures, limb rigidity associated with conscious disturbance. Eight patients were treated with surgery and praziquantel, while others with praziquantel alone. After treatment 25 cases (64.1%) were cured, 13 cases (33.3%) improved, and 1 case (2.6%) showed no change.

[Effect of remifentanil on propofol pharmacokinetics with target controlled infusion in elderly patients].

OBJECTIVE: To investigate the effects of remifentanil administered by target-controlled infusion (TCI) with different plasma concentration and time on pharmacokinetics of propofol in elderly patients. METHODS: Thirty-two ASA I-II patients (65-82 years old) undergoing elective lower abdominal operations were divided into 4 groups randomly: TCI propofol combined with epidural block (group A, n=8); TCI remifentanil with plasma concentration 4 µg/L and propofol (group B, n=8); TCI remifentanil with plasma concentration 7 µg/L and propofol (group C, n=8); and TCI propofol and remifentanil (plasma concentration 4 µg/L) with infusion time longer than 4 hours (group D, n=8). Propofol was infused by target-controlled infusion with plasma concentration 3 mg/L in the 4 groups. bispetral index (BIS), heart rate (HR), blood pressure (BP) were recorded during operation. Blood samples were collection from radial arterial catheter. Samples of 2 mL of arterial blood were taken at 0, 1, 3, 5, 10, 15, 30 min and then every 30 min after the start of the infusion of propofol, and at 0, 2, 4, 6, 8, 10, 15, 30, 45, 60, 120, 240, 360, 480, 720, 1440 min after the termination of the infusion of propofol. Propofol concentrations in blood were measured by reversed-phase high-performance liquid chromatography (HPLC). The pharmacokinetics analyses were performed using the nonlinear mixed-effects model approach implemented in NONMEM computer program. After obtaining the best NONMEM model with covariates, the influence of coadministered remifentanil on the model was examined. RESULTS: In all the patients, the depth of anesthesia was enough (BIS value=40-60), and the circulatory system function was stable during operation. The final model of propofol pharmacokinetics in the three groups (A+B, A+C, and A+D groups) was best described by a three-compartment mammillary model. The values of objective function (OFV) were -810.1, -714.4, and -896.4. Addition of remifentanil covariate effects to the final model resulted in no improvement in the objective function. CONCLUSION: target-controlled infusion of propofol combined with different plasma concentration of remifentanil or remifentanil infusing more than 4 hours had no effect on pharmacokinetics of propofol in elderly patients.

Two-stage analysis of pharmacokinetics of sufentanil administered by target-controlled infusion in Chinese patients.

BACKGROUND: Sufentanil is a suitable choice for target-controlled infusion (TCI) because of its shorter context-sensitive half-time. The current study was to estimate the pharmacokinetics of sufentanil TCI in Chinese patients using the two-stage analysis. METHODS: Twelve adult patients with American Society of Anesthesiologists (ASA) physical status I or II undergoing elective surgery under general anesthesia were included. Anesthesia was induced with propofol, rocuronium and sufentanil administered by TCI lasting for 30 minutes, with target effect-site concentration of sufentanil 4 or 6 ng/ml. Frequent arterial blood samples (1.5 ml) were taken during and up to 24 hours after sufentanil TCI. Before the end of surgery, another arterial blood sample (1.0 ml) was drawn for the blood-gas analysis. Plasma sufentanil concentrations were determined by liquid chromatography-tandem mass spectrometry (limit of quantitation was 5 pg/ml). The data were analyzed with the two-stage approach, linear regression and correlation analysis. RESULTS: The pharmacokinetics of sufentanil TCI were adequately described by a three-compartment model. The variables were derived as follows: the volume of central compartment (V(1)) was 5.4 L, volume of distribution at steady-state (Vdss) was 222.6 L, metabolic clearance (Cl(1)) was 0.84 L/min and elimination half-life (t(1/2Y)) was 389 minutes. Patients' age, gender and PaCO2 correlated significantly with the pharmacokinetic parameters. The Vdss, volume of slowly equilibrating compartment (V(3)) and t(1/2Y) increased, and rapid distribution clearance (Cl(2)) decreased with increasing patient age. Male patients had larger values of Vdss, volume of rapidly equilibrating compartment (V(2)) and V(3) than female patients. The Vdss and V(3) increased with higher PaCO2 values. There were no significant correlations between the pharmacokinetic variables and body weight, height, lean body mass, plasma albumin, sufentanil dose, duration of surgery, pH or base excess of blood (BE-B). CONCLUSIONS: The pharmacokinetics of sufentanil TCI in Chinese patients can be optimally described by a three-compartment model. The pharmacokinetic analysis technique may affect the pharmacokinetic parameters and correlations.

Clinical evaluation of target controlled infusion system for sufentanil administration.

BACKGROUND: Sufentanil target controlled infusion (TCI) provides stable analgesia, better hemodynamic control than a bolus injection of intravenous anesthetics, anticipated recovery and improved quality of anesthesia during perioperative period. This study evaluated the accuracy and feasibility of TCI system for sufentanil at high concentrations in Chinese surgical patients. METHODS: Twelve low risk adult patients undergoing elective surgery under general anesthesia were included in this study. Sufentanil was administered with a specific TCI system incorporating the population pharmacokinetic data of sufentanil previously reported, using a target effect-site concentration of sufentanil 4 or 6 ng/ml. Sufentanil TCI duration was 30 minutes. Frequent arterial blood samples were taken during and up to 24 hours after sufentanil TCI for determination of plasma sufentanil concentrations by liquid chromatography-mass spectrometry/mass spectrometry. The changes of circulatory system function during the procedure, recovery profile and adverse effects were recorded. Measured plasma sufentanil concentrations were compared with the values predicted by the TCI system. The bias (median performance error, MDPE), precision (median absolute performance error, MDAPE) and wobble (variability of performance error) of the sufentanil TCI system were determined. RESULTS: All patients had stable cardiovascular variables during induction and maintenance of anesthesia. Time to eye opening and extubation were (5.6 + or - 1.7) minutes when TCI set to 4 ng/ml and (7.2 + or - 2.3) minutes when set to 6 ng/ml. There was no episode of agitation, muscle rigidity or intraoperative awareness. The bias (MDPE), precision (MDAPE) and wobble of the sufentanil TCI system were -3.7%, 18.9% and 19.6% respectively during TCI, and the MDPE, MDAPE and wobble were -29.1%, 31.7% and 15.0% respectively after TCI (up to 8 hours). CONCLUSIONS: The TCI system programmed for sufentanil at 4 or 6 ng/ml was considered acceptable for clinical use in low risk Chinese surgical patients. But the relatively larger MDPE and MDAPE after TCI suggest improvements of the pharmacokinetic model are needed.

[Target-controlled infusions of remifentanil and propofol in elderly patients].

OBJECTIVE: To investigate the clinical reliability and feasibility of target-controlled infusion (TCI) with different plasma concentration remifentanil and propofol. METHODS: Thirty ASA I-II patients, > or =65 years old, undergoing selective lower abdominal operation were divided into 3 groups, group A with anesthesia using propofol combined with epidural block, group B with anesthesia using propofol and remifentanil (plasma concentration 4 microg/L), group C with anesthesia using propofol and remifentanil (plasma concentration 7 microg/L). BIS value, heart rate, blood pressure, heart rate variability and so on, were recorded during anesthesia and operation. Radial arterial blood samples for analysis of plasma concentration of propofol were taken during operation. RESULTS: (1) The intubation response of groups B and C was lower than that of group A . (2) The depth of anesthesia was enough during operation (BIS value=45-60). (3) TCI propofol combined with remifentanil didn't lengthen the awaking time of patients; (4) MDPE of target-controlled infusion using propofol with Marsh parameters was 11.17%, MDAPE was 12.16% in Chinese elderly patients. CONCLUSION: Remifentanil with plasma concentration of 4 and 7 microg/L combined with propofol could be safely used during clinical anesthesia of old patient, but monitoring must be strengthened during induction when plasma concentration of remifentanil was 7 microg/L. TCI propofol with Marsh parameters could be applied to Chinese elderly patients safely and efficiently.

[Elimination half-life of propofol in effect-site of mice].

OBJECTIVE: To study the elimination half-life of propofol in mouse brain. METHODS: One hundred and forty mice were injected with propofol 32 mg/kg through caudal vein. The mice were divided into 14 groups with different time points, i.e. 1, 2, 3, 4, 5, 6, 7, 8, 9 , 10, 15, 30, 45, and 60 min, with 10 mice in each group. The mice were killed to obtain arterial blood by picking off their eyeballs, and their brains by cutting off their heads. The concentrations of propofol in serum and brain were measured by high performance liquid chromatography. The parameters of elimination half-life were calculated by software 3P97. RESULTS: Time to peak concentration of propofol in serum was about 1 min, and time to peak concentration of propofol in brain was about 3 min. The elimination half-life of propofol in brain were (9.6+/-0.5) mins. CONCLUSION: The peak concentrations of propofol in brain was later than it in serum. There is correlation between the concentrations of propofol in blood and in brain. The metabolism of propofol in effect site could be measured accurately by the elimination half-life in brain.

[Effect of general and epidural anesthesia on autonomic nervous system].

OBJECTIVE: To evaluate autonomic nervous tone during general and epidural anesthesia. METHODS: Thirty-two female patients(ASA grade I-II), scheduled for elective hysterectomy, were randomized to receive epidural anesthesia (group EA, n = 16) or general anesthesia (group GA, n = 16). The changes of HRV were observed with power spectral analysis of heart rate variability (HRV-PSA) at the following time intervals: immediately pre-anesthesia (T1), 15 min after induction (T2), 1 min after incision (T3), dragging uterus (T4), after removing uterus (T5) and end of surgery (T6). RESULTS: Patients in group EA demonstrated a significant advance in LF/HF at T4 and descending in LF and HF at T5, T6 to compare with T1, LF, HF and LF/HF remained unchanged at the rest time intervals. In group GA, compared with T1, LF, HF and LF/HF dropped remarkably except for an increase in LF/HF at T6. CONCLUSION: The autonomic nervous tone is inhibited by both epidural and general anesthesia. EA reveals a shift in the sympathovagal balance toward sympathetic predominance. GA is associated with a shift toward parasympathetic predominance intraoperatively, while postoperatively appears a dramatic increase in LF/HF. Relative to EA, there is a greater effect on autonomic nervous system with GA.