Effect of Inspiratory Flow on Methacholine Challenge in Children

Regulation of inspiratory flow alters the outcomes of the methacholine (MHC) challenge in adults and cough receptor sensitivity in children. The effect of inspiratory flow on the reproducibility of the MHC challenge in children is unknown. The aim of this study was to evaluate the effect of inspiratory flow alteration on the repeatabilty of the MHC challenge in children with and without asthma. Twenty‐five children undertook the MHC challenge on three different days by using a dosimeter connected to a setup that allowed regulation of inspiratory flow and pattern. Children were randomized to commence the challenges at 20 or 60 L/min, and the last challenge was performed at 20 L/min. The within‐subject standard deviation, 95% range for change, and doubling dose for the differing inspiratory flow (20 vs. 60 L/min) was more than twice that of when inspiratory flow was maintained at 20 L/min for both occasions. The range of the “limits of agreement” of the Bland and Altman plot was smaller when inspiratory flow was constant. For short‐term comparative individual studies in children, inspiratory flow should be regulated. Laboratories and research measuring change in airway hyperrepsonsiveness to MHC should determine and report reproducibility indices of the challenge so airway hyperresponsiveness changes can be interpreted meaningfully.     

SLIPA与经典喉罩的临床应用比较

目的全麻下行择期妇科腹腔镜手术的病人,进行SLIPA(Streamlined Liner of the Pharynx Air-way)或经典喉罩(laryngeal mask airway,LMA)的应用效果比较。方法 60例病人随机分成两组,所有病人使用相同的麻醉药物。有食管胃反流危险因素的病人被排除。评估两种通气道应用的容易程度;呼吸道密封效果;通气情况;插管反应;副作用。结果 SLIPA或LMA均容易插入和通气,除了SLIPA有较大的峰值气道压,分别是16.2 cmH2O±3.8 cmH2O,13.4 cmH2O±2.3 cmH2O(P=0.03),其它参数比较无明显差异。平均呼吸道密封压分别是24.1 cmH2O±5.4 cmH2O,25.7 cmH2O±6.4 cmH2O(P=0.2)。SLIPA或LMA的密封质量:均能允许低流量麻醉,环路最低气流量分别为558 mL/min±377 mL/min,573 mL/min±382 mL/min(P=0.88)。插管反应:插入2 min后的血压,心率与基础值,诱导后的血压比较,两组均无显著性差异。24 h的咽痛发生率:两组相比无差异(P=0.95)。结论应用SLIPA或LMA进行控制通气,两种通气道均较容易插入,气道管理满意。     

Safe extubation of a parturient using an airway exchange technique

The difficult obstetric airway is a well-recognised anaesthetic challenge but little emphasis is placed on the difficulty of performing a safe tracheal extubation. We report the use of an airway exchange technique to extubate a difficult obstetric airway and discuss the role of these techniques in the obstetric population.     

昏迷患者院前转诊气道管理的方案比较

目的 探讨对昏迷患者院前急救转运最佳气道管理方案.方法 选取2005~2010年院前昏迷患者127例(格拉斯评分8以下),分别给于口咽通气管(A组)、普通喉罩(B组)及气管插管(C组),根据病情常规治疗,观察一次性置管时间、院前重复置管及安全转运.结果 口咽通气管组和普通喉罩组一次性置管时间明显少于气管插管组(P<0.01),然而安全转运成功率气管插管组较口咽通气管组和普通喉罩组有明显优势(P<0.05).结论 气管插管组对院前昏迷患者安全转诊提供较安全的气道保护.     

Computer assisted detection of abnormal airway variation in CT scans related to paediatric tuberculosis

Airway deformation and stenosis can be key signs of pathology such as lymphadenopathy. This study presents a local airway point distribution model (LA-PDM) to automatically analyse regions of the airway tree in CT scans and identify abnormal airway deformation. In our method, the airway tree is segmented and the centreline identified from each chest CT scan. Thin-plate splines, along with a local mesh alignment method for tubular meshes, are used to register the airways and develop point distribution models (PDM). Each PDM is then used to analyse and classify local regions of the airway. This LA-PDM method was developed using 89 training cases and evaluated on a 90 CT test set, where each set includes paediatric tuberculosis (TB) cases (with airway involvement) and non-TB cases (without airway involvement). The LA-PDM was able to accurately distinguish cases with airway involvement with an AUC of the ROC classification (and 95% confidence interval) of 0.87 (0.77–0.94) for the Trachea–LMB–RMB region and 0.81 (0.68–0.90) for the RMB–RUL–BI region – outperforming a comparison method based on airway cross-sectional features. This has the potential to assist and improve airway analysis from CT scans by detecting involved airways and visualising affected airway regions.     

Airway Responsiveness to Indirect Challenges in COPD

ABSTRACT

Patients with chronic obstructive pulmonary disease (COPD) demonstrate airway hyperresponsiveness to a number of indirect stimuli. Hyperresponsiveness to cold air hyperventilation, exercise, and drugs like propranalol and methoxamine seem to be able to distinguish patients with COPD from those with asthma, whereas hyperresponsiveness to stimuli like adenosine 5-monophosphate (AMP) and hypertonic saline seem unable to do so. The relationship of airway responsiveness to indirect stimuli and airway inflammation has received little study. The clinical relevance of hyperresponsiveness to an indirect challenge, including the impact on the natural history, relation to types of bronchitis, baseline airway calibre, and response to treatment need to be studied.