Establishment of stellate ganglion block in mice.

BACKGROUND: There have been no reports on the successful implementation of stellate ganglion block (SGB) in mice. OBJECTIVES: This study aims to investigate a new method for implementing SGB in mice by placing them in a supine position with abducted upper limbs and touching the trachea and sternoclavicular joint with the hand. METHODS: Fifty BABL/C mice, 8-10 weeks, were selected and randomly divided into four groups: control group (n = 5); SGB-R group (n = 15); SGB-L group (n = 15); and SGB-L + R (group n = 15). SGB was administered with 0.15% ropivacaine solution in a volume of 0.1 mL. The control group received equal volumes of saline. Horner's syndrome, heart rate, and complications such as brachial plexus block, vascular injury, pneumothorax, local anesthetic toxicity, and death were observed. RESULTS: Horner's syndrome developed in 100% of SGB surviving mice; no difference was seen in the time to onset (100.4 ± 13.4 vs 96.7 ± 12.4, mean ± SD, seconds) and duration (264.1 ± 40.5 vs 296.3 ± 48.0, mean ± SD, min) of Horner's syndrome in the left and right SGB (P > 0.05). Compared with the control group (722 [708-726], median [IQR], bpm), the heart rate was significantly slowed down in the right SGB (475 [451.5-491], median [IQR], bpm) (P < 0.05). While the heart rate was slowed down after performing the left SGB, the difference was not statistically significant (P > 0.05). The overall complication rate was 18.4%, with a brachial plexus block rate of 12.3%, a vascular injury rate of 4.6%, and a mortality rate of 1.5%, as well as no local anesthetic toxicity (includes bilateral implementation of SGB) or pneumothorax manifestations were found. CONCLUSIONS: This method allows for the successful implementation of SGB in a mouse model.

Impact of simulation-based training on bougie-assisted cricothyrotomy technique: a quasi-experimental study.

BACKGROUND: Cricothyrotomy is a lifesaving surgical technique in critical airway events. However, a large proportion of anesthesiologists have little experience with cricothyrotomy due to its low incidence. This study aimed to develop a multisensory, readily available training curriculum for learning cricothyrotomy and evaluate its training effectiveness. METHODS: Seventy board-certificated anesthesiologists were recruited into the study. Participants first viewed an instructional video and observed an expert performing the bougie-assisted cricothyrotomy on a self-made simulator. They were tested before and after a one-hour practice on their cricothyrotomy skills and evaluated by a checklist and a global rating scale (GRS). Additionally, a questionnaire survey regarding participants' confidence in performing cricothyrotomy was conducted during the training session. RESULTS: The duration to complete cricothyrotomy was decreased from the pretest (median = 85.0 s, IQR = 72.5-103.0 s) to the posttest (median = 59.0 s, IQR = 49.0-69.0 s). Furthermore, the median checklist score was increased significantly from the pretest (median = 30.0, IQR = 27.0-33.5) to the posttest (median = 37.0, IQR = 35.5-39.0), as well as the GRS score (pretest median = 22.5, IQR = 18.0-25.0, posttest median = 32.0, IQR = 31.0-33.5). Participants' confidence levels in performing cricothyrotomy also improved after the curriculum. CONCLUSION: The simulation-based training with a self-made simulator is effective for teaching anesthesiologists to perform cricothyrotomy.

Perioperative fluid management for lung transplantation is challenging.

Lung transplantation is the definitive end-stage treatment for many lung diseases, and postoperative pulmonary oedema severely affects survival after lung transplantation. Optimizing perioperative fluid management can reduce the incidence of postoperative pulmonary oedema and improve the prognosis of lung transplant patients by removing the influence of patient, donor's lung and ECMO factors. Therefore, this article reviews seven aspects of lung transplant patients' pathophysiological characteristics, physiological characteristics of fluids, the influence of the donor lung on pulmonary oedema as well as current fluid rehydration concepts, advantages or disadvantages of intraoperative monitoring tools or types of fluids on postoperative pulmonary oedema, while showing the existing challenges in section 7. The aim is to show the specificity of perioperative fluid management in lung transplant patients and to provide new ideas for individualised fluid management in lung transplantation.

Scalpel cricothyrotomy versus punctured cricothyrotomy in the context of the CICO crisis. A systematic review and Meta-analysis.

IMPORTANCE: The preferential use of a scalpel (SCT) or puncture techniques (PCT) for cricothyrotomy remains a controversial topic. OBJECTIVE: We performed a systematic review and meta-analysis comparing puncture cricothyrotomy with scalpel cricothyrotomy using overall success rate, first-time success rate, and time taken to perform the procedure as the primary outcome together with complications as a secondary outcome. EVIDENCE REVIEW: Pubmed databases, EMBASE databases, MEDLINE, Google Scholar, and Cochrane Central Register of Controlled Trials, from 1980 to October 2022. FINDINGS: A total of 32 studies were included in the systematic review and meta-analysis. It also showed that PCT was close to SCT in terms of overall success rate (82.2% vs. 82.6%, Odd Ratios OR = 0.91, [95%CI: 0.52-1.58], p = 0.74) as well as first-performance success rate (62.9% vs. 65.3%, OR = 0.52, [0.22-1.25], p = 0.15). PCT does not compare favorably with SCT in terms of required time for the procedure (the mean time required for PCT versus SCT incision in the intervention groups was 0.34 standard deviations higher (Mean Difference MD = 17.12, [3.37-30.87], p = 0.01) as well as complications (21.4% vs. 15.1%, Relative Risk RR = 1.49, [0.80-2.77], p = 0.21). CONCLUSIONS AND RELEVANCE: The results show that SCT has an advantage over PCT in terms of time required for the procedure, while there is no difference in overall success rate, first-time success rate after training, and complications. The superiority of SCT may be the result of fewer and more reliable procedural steps. However, the level of evidence is low (GRADE).

Design and Experimental Study of a Stepping Piezoelectric Actuator with Large Stroke and High Speed.

A stepping piezoelectric actuator is proposed with large stroke and high speed. The piezoelectric actuator consists of two symmetrical stators and a mover. The actuator can operate with a "double-drive, four-clamp" mode. The proposed actuator solves the problems of short stroke, low speed, and small load inherent in the currently published stepping piezoelectric actuators. By combining Workbench software with APDL language, finite element simulation and statics and dynamics analysis are carried out to guide the design of the actuator. The new piezoelectric simulation method can solve the difficulties regarding parameter setting and loading voltage on multiple interfaces for a complex piezoelectric model. Therefore, the novel method is helpful to develop the simulation of multilayer thin piezoelectric devices. The prototype of the actuator is developed and tested. Experimental results show that the actuator can run stably in the range of 0 to 600 Hz. The driving stroke is greater than 85 mm, the resolution can reach 535 nm, the maximum driving speed is 6.11 mm/s, and the maximum load is 49 N.

In vitro human cell-based models to study airway remodeling in asthma.

Airway remodeling, as a predominant characteristic of asthma, refers to the structural changes that occurred both in the large and small airways. These pathological changes not only contribute to airway hyperresponsiveness and airway obstruction, but also predict poor outcomes of patients. In vitro models are the alternatives to animal models that facilitate airway remodeling research. Current approaches to mimic airway remodeling in vitro include mono cultures of cell lines and primary cells that are derived from the respiratory tract, and co-culture systems that consist of different cell subpopulations. Moreover, recent advances in microfluid chips and organoids show promise in simulating the complex architecture and functionality of native organs. According, they enable highly physiological-relevant investigations of human diseases in vitro. Here we aim to detail the current human cell-based models regarding their key pros and cons, and to discuss how they may be used to facilitate our understanding of airway remodeling in asthma.

Dexmedetomidine reduces IL-4 and IgE expression through downregulation of theTLR4/NF-κB signaling pathway to alleviate airway hyperresponsiveness in OVA mice.

BACKGROUND: Airway hyperresponsiveness (AHR) is a clinical manifestation of airflow limitation due to abnormal tracheal and bronchial sensitivity and is the main basis for the diagnosis of asthma. Patients with AHR are at high risk of perioperative tracheal and bronchospasm, which can lead to hypoxaemia and haemodynamic instability and, in severe cases, to a life-threatening 'silent lung'. It is therefore important to reduce the incidence or intensity of AHR episodes in the perioperative period. The inflammatory response is key to the development and progression of AHR. HYPOTHESIS/PURPOSE: Based on the modulatory role of dexmedetomidine (DEX) in the inflammatory response, we hypothesised that dexmedetomidine (DEX) attenuates inflammatory properties by inhibiting the toll-like receptor 4 (TLR4)/nuclear factor (NF-κB) signalling pathway and can reduce the respiratory parameters of mechanical ventilation in ovalbumin-induced allergic airway hyperresponsiveness. STUDY DESIGN: BABL/C mice were divided into control and OVA groups (ovalbumin-induced allergy. Ten mice in all OVA models were randomly selected for in vivo invasive lung function monitoring to analyse airway resistance parameters and demonstrate successful model establishment. The remaining OVA mice were treated with dexmedetomidine 25 µg/kg for 5 days (OVA + DEX group) or dexmedetomidine 25 µg/kg + yohimbine 1 mg/kg for 5 days (OVA + DEX + yohimbine). After treatment, bronchoalveolar lavage fluid (BAL) and peripheral blood (ELISA) and lung tissue (H&E and PAS) were collected for analysis of inflammatory factors, and lung tissue was verified by PCR for genes and proteins that do correlate with inflammatory mediators. RESULTS: All airway resistance parameters were increased in OVA mice by invasive lung function monitoring. Proximal airway resistance (parameter Rn) and total respiratory resistance (parameter Rrs) were attenuated after dexmedetomidine intervention treatment. Dexmedetomidine reduced total inflammatory cell count and inflammatory infiltration of lung tissue in BALF and down-regulated IL-4 and IgE levels in BALF and peripheral blood, as shown by Giemsa, H&E, PAS staining and ELISA; this mechanism of action was found to be related to the TLR4/NFκB pathway, but not to TLR4/NFκB, as measured by PCR. CONCLUSION: Dexmedetomidine reduces hyperresponsiveness and airway inflammatory responses. This mechanism of action may be related to the TLR4/NFκB signalling pathway. Overall conclusions are presented in.

Endoplasmic reticulum stress in airway hyperresponsiveness.

Airway hyperresponsiveness(AHR) is a major clinical phenomenon in lung diseases (asthma, COPD and pulmonary fibrosis) and not only a high-risk factor for perioperative airway spasm leading to hypoxaemia, haemodynamic instability and even "silent lung", but also a potential risk for increased mortality from underlying diseases (e.g. asthma, COPD). Airway reactivity is closely linked to airway inflammation, remodelling and increased mucus secretion, and endoplasmic reticulum stress is an important mechanism for the development of these pathologies. This review, therefore, focuses on the effects of endoplasmic reticulum stress on the immune cells involved in airway hyperreactivity (epithelial cells, dendritic cells, eosinophils and neutrophils) in inflammation and mucus & sputum secretion; and on the differentiation and remodelling of airway smooth muscle cells and epithelial cells. The aim is to clarify the mechanisms associated with endoplasmic reticulum stress in airway hyperresponsiveness and to find new ideas and methods for the prevention of airway hyperresponsiveness in the perioperative period.