Use of a combination of diaphragmatic ultrasound and muscle relaxation monitoring in predicting post-extubation adverse respiratory events among elderly patients in an anesthesia intensive care unit.

OBJECTIVE: The purpose of this study was to examine the feasibility of using a combination of diaphragmatic ultrasound and muscle relaxation monitoring in predicting adverse respiratory events after extubation among elderly patients in an anesthetic intensive care unit (AICU). METHODS: The study participants were 120 elderly patients who were in the AICU after laparoscopic radical resection for colorectal cancer. Based on whether there were critical respiratory events (CREs) after extubation, they were divided into the adverse event group and the non-adverse event group. We used logistic regression to identify factors influencing the occurrence of CREs post-extubation in elderly patients. Using the receiver operating characteristic (ROC) curve, we analyzed the value of each indicator in predicting CREs post-extubation. RESULTS: We included 109 patients in the final analysis. In the adverse event group (n = 19), the age, proportion of females, and proportion of preoperative respiratory diseases were higher than in the non-adverse event group (n = 90). The muscle relaxation value, quiet breathing diaphragmatic excursion during extubation (DE-QB), deep breathing diaphragmatic excursion during extubation (DE-DB), and deep breathing diaphragmatic thickening fraction during extubation (DTF-DB) of patients in the adverse event group were significantly lower than those in the non-adverse event group (P < 0.05). Using binary logistic regression analysis, we identified muscle relaxation value, DE-DB, and DTF-DB during extubation as significant predictors of CREs post-extubation in elderly patients (P < 0.05). The area under the curve (AUC) of the combination of the muscle relaxation value, DE-DB, and DTF-DB during extubation for predicting CREs after extubation in elderly patients was 0.949, which was higher than that of any single indicator. CONCLUSION: The combination of diaphragmatic ultrasound and muscle relaxation monitoring was more accurate in predicting CREs post-extubation among elderly patients in the AICU.

Genetic polymorphisms are associated with individual susceptibility to dexmedetomidine.

Introduction: Dexmedetomidine (DXM) is widely used as an adjuvant to anesthesia or a sedative medicine, and differences in individual sensitivity to the drug exist. This study aimed to investigate the effect of genetic polymorphisms on these differences. Methods: A total of 112 patients undergoing hand surgery were recruited. DXM 0.5 µg/kg was administered within 10 min and then continuously injected (0.4 µg/kg/h). Narcotrend index, effective dose and onset time of sedation, MAP, and HR were measured. Forty-five single nucleotide polymorphisms (SNPs) were selected for genotype. Results: We observed individual differences in the sedation and hemodynamics induced by DXM. ABCG2 rs2231142, CYP2D6 rs16947, WBP2NL rs5758550, KATP rs141294036, KCNMB1 rs11739136, KCNMA1 rs16934182, ABCC9 rs11046209, ADRA2A rs1800544, and ADRB2 rs1042713 were shown to cause statistically significant (p < 0.05) influence on the individual variation of DXM on sedation and hemodynamics. Moreover, the multiple linear regression analysis indicated sex, BMI, and ADRA2A rs1800544 are statistically related to the effective dose of DXM sedation. Discussion: The evidence suggests that the nine SNPs involved in transport proteins, metabolic enzymes, and target proteins of DXM could explain the individual variability in the sedative and hemodynamic effects of DXM. Therefore, with SNP genotyping, these results could guide personalized medication and promote clinical and surgical management.

Effect of postoperative ultrasound-guided internal superior laryngeal nerve block on sore throat after intubation of double-lumen bronchial tube: a randomized controlled double-blind trial.

BACKGROUND: Postoperative sore throat (POST) is one of the main adverse postoperative outcome after tracheal intubation using double-lumen endobronchial tubes (DLTs). The aim of this study was to investigate the effectiveness and safety of ultrasound (US)-guided block of the internal branch of the superior laryngeal nerve (iSLN) for alleviating POST after intubation of DLTs. METHODS: Patients undergoing thoracic surgery between August 2019 and August 2021 were randomized into two groups depending on whether they received US-guided iSLN block immediately after the operation. In the control group, the patients underwent a thoracic surgery under general anesthesia (GA) with DLTs without any special treatment, while the patients in the experimental group received US-guided iSLN block bilaterally with 2 ml of 0.25% ropivacaine on either side immediately after the operation. The primary outcome was the grading of sore throat at three-time points after the operation, i.e., immediate extubation, 2 h after extubation, and 24 h after extubation. Secondary outcomes included the rate of nausea and vomiting, hoarseness, dyspnea, and choking cough after swallowing saliva at 2 h after extubation. RESULTS: The incidence and severity of sore throat were significantly lower in the experimental group than the control group at all time intervals (all P < 0.01). The rate of nausea and vomiting, hoarseness, dyspnea, and choking cough after swallow saliva at 2 h after extubation had no statistical difference (all P > 0.05). CONCLUSIONS: The use of US-guided iSLN block can be effectively and safely applied to relieve POST after intubation of DLTs on thoracic surgery. TRIAL REGISTRATION: The study protocol was registered at the Chinese Clinical Trial Registry ( http://www.chictr.org.cn , NO. ChiCTR2000032188, 22/04/2020).

Polymer-regulated epitaxial crystallization of methanofullerene on mica.

This work focuses on both the structure manipulation and the crystallizing mechanism investigation of the well-known methanofullerene, [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM). PCBM crystals with two novel structures, i.e., five-fold twinned and cubic crystals are obtained by the introduction of the mica substrate and the polymer blenders (P3HT and PS) into PCBM thin films under thermal annealing. The morphology and nanostructure of these crystals have been well investigated with AFM, TEM and XRD techniques. The roles of the mica substrate and the polymer blenders have been studied by varying the annealing temperature, the substrate, the polymer benders and the blending ratio. It has been proved that both the PCBM intermolecular and PCBM-mica interactions influence the PCBM crystallization process. The mica substrate has been proved to have the epitaxial effect on PCBM crystallization. The polymer blenders have been suggested to weaken the PCBM intermolecular interaction and limit PCBM molecular diffusion.

Solvated crystals based on [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) with the hexagonal structure and their phase transformation.

This work focuses on the structural exploration of micro-sized crystals based on a well-known methanofullerene, [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM). We have succeeded in producing PCBM crystals with the hexagonal symmetry through the liquid-liquid interfacial precipitation (LLIP) method. We found that smaller but more regular PCBM crystals tend to form in the oversaturated PCBM solutions with solvents of lower solubility for PCBM, such as tetrahydrofuran (THF) and 1,4-dioxane. The structure of the produced crystals also shows a dependence on the solvents, which can be attributed to the incorporation of different solvent molecules into PCBM crystals. Under thermal annealing, for the first time, we have observed a crystalline to crystalline phase transformation of these hexagonal PCBM crystals. Along with the phase transformation, the morphology of the crystals has also been transformed from the hexagon to long needles. In addition, the needlelike crystals arrange themselves with a relative angle of 60° to each other, which implies an intrinsic structural correlation between needlelike and hexagonal crystals.

Self-assembly of carbazole-based dendrimers by solvent vapor annealing: from fibers to spherulites.

The self-assembly behavior of H1-BCz, a first-generation dendrimer with phenyl-carbazole as core and carbazole as dendrons, was systemically studied by solvent-vapor annealing. The morphologies of spin-coated H1-BCz film on various substrates changed from giant crystalline fibers of several millimeters to spherulites with a decrease in tetrahydrofuran vapor pressure. At high vapor pressure, dewetting easily took place in the amorphous films, and single fibers or fiber clusters formed. The fibers grew from nuclei formed at the place where it does not dewet. The fibers grew larger by continuous nucleation and growth at the growth front of the fiber until all the substance on the substrate was consumed. As the vapor pressure decreased, dewetting did not so easily happen, and fibers packed more tightly and spherulites were obtained. Through characterization of the crystals and films, we speculate that 3D H1-BCz crystal formed by overlapping 2D lamellar structure. The π-π interactions and van der Waals interactions among H1-BCz molecules and solvent may be the main force driving the self-assembly of H1-BCz.

Morphology evolution and structural transformation of solution-processed methanofullerene thin film under thermal annealing.

The film morphology and nanostructure of the soluble fullerene, [6,6]-phenyl-C(61) butyric acid methyl ester (PCBM), are crucial for its applications in organic thin film devices, such as organic solar cells and organic thin film transistors. In this work, the morphology, structural transformation, and crystallite orientation of PCBM film under thermal annealing as a function of annealing temperature, processing solvents, and solution concentrations are systematically investigated. Crystalline PCBM films with needle-like crystallites, axialitic aggregates, and faceted slices are formed in the annealing process. The axialites, made up of needle-like aggregates, are proposed to be partially developed spherulites frozen at the early growth stage formed through low-angle branching. The faceted slices are found to be PCBM single crystallites with hexagonal packing in the film plane. The film undergoes both amorphous-to-crystalline and crystalline-to-crystalline phase transformations as the annealing temperature is increased. The former transformation, corresponding to the self-organization of disordered PCBM molecules in the kinetically frozen films, occurs at a relative low temperature once the motion of these molecules is thermally activated, whereas the later one, corresponding to the transformation between two thermally stable crystalline phases, occurs when further increasing the annealing temperature. The PCBM crystallites composing these films are found to have an orientation preference normal to the film surface, which can be attributed to the confinement of film thickness for PCBM crystallite growth.

Oriented poly(3-hexylthiophene) nanofibril with the π-π stacking growth direction by solvent directional evaporation.

In this article, the uniaxial alignment of poly(3-hexylthiophene) (P3HT) nanofibrils with a π-π stacking growth direction in which P3HT chains adopt a flat-on conformation was obtained by solvent directional evaporation using a glass cover slide and a poly(dimethylsiloxane) (PDMS) sheet to press the P3HT film in a carbon disulfide (CS(2)) atmosphere. By controlling the CS(2) vapor pressure during the film-forming process, we got a well-oriented P3HT film whose order parameter reached as high as 0.97. The orientation of the film was induced by the crystallization nucleation of P3HT and the directional evaporation of the solvent. Under a CS(2) vapor atmosphere, P3HT crystals preferred to adopt the form II modification, which started by nucleation. Owing to the solvent directional evaporation from the center to the margin, P3HT at the center of the sample would precipitate first to induce nucleation. Then the peripheral P3HT would directly diffuse, precipitate, and then adhere to the nucleus to form the uniaxial alignment of P3HT nanofibrils along the direction of solvent evaporation. Furthermore, in the P3HT nanofibrils, the π-π stacking direction of P3HT lamellae was parallel to the crystal growth direction, which would provide an effective path for charge transport.