Control of immunity and allergy by steroid hormones

Steroid hormones, especially glucocorticoids, androgens, and estrogens, have profound influence on immunity. Recent studies using cell-type specific steroid hormone receptor-deficient mice have revealed the precise roles of some of these hormones in the immune system. Glucocorticoids are known to have strong anti-inflammatory and immunosuppressive effects and pleiotropic effects on innate and adaptive immune responses. They suppress the production of inflammatory cytokines by macrophages and DCs and the production of IFN-γ by NK cells, thus inhibiting innate immunity. By contrast, glucocorticoids enhance the immune response by inducing the expression of IL-7R and CXCR4 in T cells and the accumulation of T cells in lymphoid organs in accordance with the diurnal change of the glucocorticoid concentration. Thus, glucocorticoids suppress innate immunity but enhance adaptive immunity. Androgens suppress the homeostasis and activation of ILC2s and the differentiation of Th2 and Th17 cells and enhance the suppressive function of Tregs, thereby alleviating allergic airway inflammation. Thus, these steroid hormones have pleiotropic functions in the immune system. Further investigations are awaited on the regulation of immunity and allergy by estrogens using cell-specific steroid hormone receptor-deficient mice.     

Tracheal intubation

Tracheal intubation is the act of placing a tube into the trachea. The tube enables oxygen delivery and removal of carbon dioxide, while also allowing for the administration of pharmacological agents. Intubation is the most reliable method of maintaining an airway under anaesthesia, and for protection against aspiration of stomach contents. Traditionally, intubation is achieved by direct visualization of the glottis, but now indirect laryngoscopy (via a videolaryngoscope) is a common alternative. Prior to embarking upon intubation, a thorough patient history and examination must be undertaken by the laryngoscopist; equipment must be prepared and checked; a trained assistant present; and an experienced anaesthetist available in case assistance is required. Once the endotracheal tube has been placed, correct positioning must be confirmed via both clinical examination and monitoring, including capnography. Tracheal intubation is a procedure that should only be undertaken by trained operators and is not without risk. It is important to note that it is failure to oxygenate patients rather than failure to intubate that ultimately leads to serious morbidity and mortality. The Difficult Airway Society has produced guidelines on how to manage unanticipated difficulty in tracheal intubation; it is essential that every practitioner trained to intubate patients is familiar with these algorithms and the key principles of safe airway management.     

Relationship Between Exhaled Carbon Monoxide and Airway Hyperresponsiveness in Asthmatic Patients

The study objectives were to analyze the changes in exhaled carbon monoxide (COex) induced by histamine provocation challenge in asthmatic patients and to evaluate the relationship between COex and airway sensitivity and reactivity. Levels of COex were measured in 105 nonsmoking mildly asthmatic subjects before and after histamine provocation challenge. Dose-response curves were characterized by their sensitivity (PD₂₀) and reactivity. Dose-response slope (DRS), continuous index of responsiveness (CIR), and bronchial reactivity index (BRI) were determined as reactivity indices. Bronchial challenge was positive for 47 subjects and negative for 58. The COex levels rose significantly after bronchial challenge in the positive response group (4.49 ± 0.4 vs. 5.74 ± 0.57 ppm, p = 0.025) and in the negative response group (2.84 ± 0.25 vs 4.00 ± 0.41 ppm, p = 0.000). An inverse relation between basal COex and PD₂₀ was found (r = - 0.318, p = 0.030). In all subjects, a proportional direct relationship between COex and DRS (r = 0.214, p = 0.015), CIR (r = 0.401, p = 0.000), and BRI (r = 0.208, p = 0.012) was observed. On stepwise multiple linear regression analysis, COex only significantly correlated with CIR (multiple r² = 0.174, p = 0.000). In conclusion, exhaled CO determination is a noninvasive inflammatory marker of the respiratory tract, which shows an acceptable association with airway hyperresponsiveness.     

Subakute Verlegung der Atemwege infolge eines retropharyngealen H?matoms nach Halstrauma

Mechanical airway obstruction secondary to retropharyngeal bleeding is rare. In most cases such a complication is described after head and neck trauma. Complicating factors include anticoagulant therapy, tumour, aneurysm, infection or major cervical spine injury. A precise initial diagnosis is necessary to avoid a life-threatening situation. Lateral X-ray and computed tomography is essential for safe management. Treatment depends upon size of the haematoma as well as the clinical course of the patient. Smaller haematomas may be observed. Lager haematomas and those that fail to reabsorb should undergo drainage.      

3种钾通道在哮喘豚鼠气道高反应中的作用

目的：探讨钙激活钾通道（KCa）、延迟整流型钾通道（Kdr）和ATP敏感型钾通道（KATP）在哮喘豚鼠气道高反应中的作用。 方法： 采用离体气管环张力实验，观察加入特异性钾通道阻断剂后，与不加阻断剂相比气管环对组胺反应的量效曲线的差异。 结果： （１）加入KCa阻断剂TEA后，对照组气管环对组胺的反应变化不显著，而哮喘组气管环对10-4mol/L、10-3mol/L组胺的收缩反应均显著低于不加TEA的气管环(P<0.01)，量效曲线明显下移；（2）加入Kdr阻断剂4-AP后，对照组气管环对10-3mol/L组胺的最大收缩反应明显下降(P<0.05)，组胺的量效曲线下移，哮喘组气管环对10-4mol/L、10-3mol/L组胺的收缩反应均低于不加4-AP的气管环(P<0.01)，且下降程度较对照组大（P<0.05），量效曲线明显下移；（3）加入KATP阻断剂glibenclamide后，对照组和哮喘组气管环对组胺的量效曲线与不加glibenclamide的气管环相比变化均无明显差异。 结论： 在豚鼠哮喘模型中，KCa和Kdr活性的降低在气道高反应的发生中起介导作用，KATP作用不明显。     

两种不同方法测定低水平压力支持通气时气道阻断压与自主呼吸时常规方法测定值的相关性分析

目的 拟比较以两种不同方法测定低水平压力支持通气（pressure support ventilation，PSV）病人的气道阻断压（P0．1）与自主呼吸时常规方法测定值的相关性。方法 12例机械通气病人，断开呼吸机自主呼吸时以常规方法测定P0．1得到P0．1-SB：在PSV水平为5cmH20，以常规方法和按压呼气末暂停键测定P0．1分别得到P0．1-PSV5和P0．1-PSV5eeo．分析后二者与前者之间的相关性。结果 P0．1-SB与P0．1-PSV5之间差异无显著性，P0．1-PSV5ee0分别小于P0．1-SB与P0．1-PSV5，差异有显著性；P0．1-PSV5eeo与P0．1-PSV5和P0．1-SB之间的相关系数均为0．97。结论 按压呼气末暂停键测定PSV水平为5cmH2O的P0．1值与常规方法测定的PSV水平为5cmH2O以及自主呼吸时的测定值相比，其值偏小,但前者与后二者之间具有良好的相关性。     

Airway troubles related to the double-lumen endobronchial tube in thoracic surgery

Purpose Several case reports indicate critical respiratory complications in relation to the double-lumen endobronchial tube (DLT). A prospective survey for the airway problems in using the DLT is presented. Methods One hundred adult patients undergoing thoracotomy for lung cancer were investigated. Tube malposition and airway obstruction were searched using a fiber-optic scope. The endobronchial cuff was positioned just below the trachcal carina while the trachea was intubated with a DLT (Rüsch). The distances of displacement, from the tracheal carina to the bronchial cuff, were measured during anesthesia using an epidural catheter, which had marks every 5 mm. The distances for correcting the tube position were measured at both the bronchial cuff and the level of the teethPaO₂,PaCO₂ andSPO₂ were also measured. Results Malposition (displacement over 5 mm from the correct position) was found in 42 patients, and 40 of them were in a withdrawal direction, occurring at the postural change and during one-lung ventilation, especially during manipulation of the lung hilum. Correcting distances at the level of the teeth were 15.3–3-times longer than those at the bronchial cuff. Airway deformities and gradual withdrawal of the bronchial cuff were found in association with surgical manipulation. Obstruction occurred at the tips of the tracheal tube in four patients and the bronchial tube in six patients, and at the tip of both in two patients. Hypoxemia (PaO₂<60 mmHg) occurred in four patients and hypercapnea (PaCO₂>60 mm Hg) in two patients. Conclusion Most of the DLT obstructions were associated with withdrawal malposition. Great attention to DLT displacement and airway deformity is advised.     

阻塞性睡眠呼吸暂停综合征患者手术治疗的麻醉研究

目的：探讨阻塞性睡眠呼吸暂停综合征(obstructive sleep apnea syndrome，OSAS)患者手术治疗的麻醉处理。方法：72例OSAS患者手术前先正压通气治疗(continue positive airway pressure，CPAP)和评价上气道，55例患者经鼻或经口气管插管全身麻醉；在手术完毕患者完全清醒后拔除插管。结果：72例患者中，轻度16例、中度24例、重度32例。合并晨起高血压28例，心电图均有不同程度心肌缺血的表现；红细胞增多症12例；腭咽平面Ⅰ级9例、Ⅱ级24例、Ⅲ级的27例、Ⅳ级12例。术前3．5d行自动调压正压通气治疗(Auto—CPAP)，经口气管内插管48例，经鼻气管内插管6例，均无术中插管困难和术后高血压危象，呼吸道梗阻发生。结论：充分认识OSAHS患者全身麻醉的手术风险，术前CPAP治疗和上气道评估，术中正确处理、严格掌握气管内插管、术后拔管的时机，是保证OSAHS患者手术成功、麻醉安全的关键。