噻托溴铵对慢性阻塞性肺疾病患者呼吸中枢驱动影响的临床研究

目的探讨慢性阻塞性肺疾病(慢阻肺)患者吸入噻托溴铵后呼吸中枢驱动的变化。方法将2017年1—12月广州医科大学附属第一医院门诊的50例稳定期慢阻肺患者随机分为两组,对照组给予基础治疗方案,药物组在基础治疗上加用噻托溴铵18μg,每日1次。治疗前后记录呼吸困难严重程度分级标准(MRC评分)、肺功能测定值,通过多导食道电极管记录静息状态、最大用力吸气时的食道压(Pes)、胃内压(Pga)、膈肌肌电(EMGdi);比较两组间的差异及治疗前后的变化。结果治疗4周后,药物组MRC评分(2.6±0.5对2.1±0.3,P0.05)较前降低;肺功能指标、Pes、Pga、跨膈压(Pdi)及最大食道压(Pes-max)、最大胃内压(Pga-max)、最大跨膈压(Pdi-max)、膈肌肌电最大值(EMGdi-max)治疗前后差异无统计学意义;而EMGdi治疗前后[(67.7±30.1)μV对(52.0±24.3)μV]、膈肌肌电占最大值百分比(EMGdi%max)治疗前后[(35.7±12.8)%对(27.3±10.4)%]差异均有统计学意义(P0.05)。对照组前后各指标差异无统计学意义。结论吸入噻托溴铵后,慢阻肺患者的膈肌肌电值降低,反映呼吸中枢驱动的EMGdi可能是一项判断疗效的新指标。     

体表膈肌肌电评价睡眠呼吸暂停综合征患者呼吸努力的价值

目的 使用表面电极记录膈肌肌电,评价OSAHS患者的呼吸努力及呼吸中枢驱动.方法 选择2007年6月至10月因存在打鼾、嗜睡等症状,怀疑OSAHS前来广州呼吸病研究所睡眠中心行整夜(>7h)多导睡眠(PSG)监测的患者11例,PSG监测同时记录食管压力,并通过胸部表面电极记录膈肌肌电活动信号,其中5例同时记录食管膈肌肌电信号.结果 当发生阻塞性呼吸暂停(OSA)时,表面电极记录的膈肌肌电信号(8.1±7.1)μV、食管膈肌肌电信号(21.1±10.7)μV和食管压信号(18.1±6.8)cm H_2O(1cm H_2O=0.098kPa)均逐渐增加.食管压变化幅度在呼吸暂停末达到最大值(31.1±13.4)cm H_2O,气流恢复后骤然降低(21.0±8.8)cm H_2O;体表膈肌肌电和食管膈肌肌电活动在气流恢复初期[(14.9±13.9)μV、(41.6±22.1)μV]仍继续增加,表面电极记录的膈肌肌电的最大均方根与食管压变化幅度在发生OSA时呈线性相关(r=0.66),而膈肌肌电与食管膈肌肌电在发生OSA时呈线性相关(r=0.72).结论 表面电极所记录的膈肌肌电可作为判断睡眠呼吸事件时呼吸努力存在与否的辅助方法,有助于鉴别睡眠呼吸暂停的类型.     

两种膈肌电信号处理方法对气道阻塞状态下呼吸中枢评价的准确性比较研究

目的比较膈肌肌电均方根(RMSdi)与积分肌电值(i EMGdi)两种膈肌电信号处理方法对气道阻力增加状态下呼吸中枢评价的准确性。方法选择2015年1-6月广州12名健康志愿者,接受不同程度的吸气阻力,并测量膈肌肌电以及跨膈压,膈肌肌电分别采用均方根和积分值处理,两种算法得出的结果分别与吸气跨膈压作相关性分析,比较其相关系数。结果在低、中、高水平吸气阻力时,膈肌肌电均方根与吸气跨膈压之间的相关系数分别为0.198,0.141及0.569(P=0.054),均无相关性(均P0.05);而3个阻力下的积分肌电值与吸气跨膈压之间的相关系数分别为0.896,0.885及0.876,均存在明显相关性(均P0.01)。结论吸气阻力存在时,积分肌电值比膈肌肌电均方根更能准确地评价呼吸中枢的吸气努力程度。     

慢性阻塞性肺疾病患者在二氧化碳重复呼吸及运动过程中的膈肌肌电变化

研究发现，慢性阻塞性肺疾病(COPD)患者在激烈运动后，并不出现膈肌疲劳，提示COPD患者在运动时可能存在着呼吸中枢的反馈抑制以防止呼吸肌疲劳。要证明这一假设就必须准确地评价中枢驱动。膈肌肌电可能是评价中枢驱动的一个好方法。研究提示多导食道电极记录的膈肌肌电能有效地反映正常人的呼吸中枢驱动。我们运用多导食道电极记录膈肌肌电，观察COPD患者在CO2重复呼吸及运动过程中膈肌肌电的变化，以探讨其是否存在呼吸中枢反馈抑制现象。     

老年慢性阻塞性肺疾病患者夜间中枢驱动及呼吸力学的变化

目的研究老年慢性阻塞性肺疾病(COPD)患者夜间睡眠状态下中枢驱动及呼吸力学的变化和关系。方法选择该院呼吸内科2009年3月至2012年3月住院的中、重度缓解期的COPD患者45例和本院人员健康组30例,所有患者测定呼吸中枢驱动、肺功能、气道阻力、血气分析等指标。结果 COPD患者在睡眠状态下吸气相第0.1秒口腔阻断压(P0.1)、膈肌肌电(MGdi%max)、潮气量(V T)、分钟通气量(V E)、平均吸气流量(V T/Ti)、膈肌电电压均方根(RMS)和脉搏血氧饱和度(SpO2)有显著性降低(P<0.05或P<0.01);呼气末二氧化碳分压(PETCO2)睡眠状态有显著性的升高(P<0.05);呼吸频率(RR)和吸气时间占呼吸周期比值(Ti/TTOT)无显著性差异,(P>0.05)。对照组各项指标睡眠状态和清醒状态均无显著性变化(P>0.05)。结论老年COPD患者夜间睡眠呼吸力学异常,主要表现为气道阻力异常增高,呼吸肌力量减弱,呼吸做功显著增加,同时伴有中枢驱动和通气需求的降低;呼吸中枢驱动较清醒时显著下降,可能是造成患者夜间睡眠出现低通气、低氧血症、呼吸困难甚至是呼吸衰竭的重要原因之一。     

慢性阻塞性肺疾病大鼠模型中骨骼肌蛋白降解机制的研究

目的 研究慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)大鼠模型的骨骼肌蛋白降解机制,为有效防治COPD患者骨骼肌蛋白高分解,功能障碍等难题提供科学理论和依据.方法 成年雄性SD大鼠30只,分为模型组18只,对照组12只,采用反复熏香烟和气管内注入脂多糖复制COPD大鼠模型.酶联免疫吸附法(ELISA)测定血清和膈肌组织中的白介素6(IL-6),肿瘤坏死因子α(TNF-α),γ干扰素(IFN-γ)等含量.蛋白免疫印迹法测定大鼠膈肌和腓肠肌内的E2-14K、MAFbx、MuRF-1的蛋白表达.结果 在模型组中,血清和膈肌内的IL-6、TNF-α均较对照组显著升高,IFN-γ则较对照组显著降低.Western blot的结果显示:膈肌组织中E2-14K、MAFbx、MuRF-1均较对照组表达明显增强(各蛋白的相对表达量分别为0.96±0.12 vs 0.53±0.09、0.99±0.10 vs 0.53士0.08、0.95±0.08 vs 0.51±0.16,P＜0.0l).腓肠肌中E2-14K、MAFbx、MuRF-1亦较对照组表达增强(各蛋白的相对表达量分别为0.98±0.06 vs 0.83士0.05、1.00±0.04 vs 0.81±0.05、0.92±0.05 vs0.71±0.05,P＜0.05).体质量与TNF-α呈显著负相关(血清r=-0.84,膈肌r=-0.75,P值均＜0.01),与IFN-γ呈正相关(血清r=-0.71,膈肌r=-0.69,P值均＜0.01)；中性粒细胞百分比与1L-6呈正相关(血清r =0.82,膈肌r=0.91,P值均＜0.01)；膈肌组织中,IL-6、TNF-α的水平与膈肌的E2-14K、MAFbx、MuRF-1灰度值呈显著正相关,相关系数分别为r=0.86、r=0.94、r=0.89,P＜0.01和r=0.84、r=0.83、r=0.84,P＜0.01；IFN-y与E2-14K、MAFbx、MuRF-1灰度值呈显著负相关,相关系数为r =0.81、r=0.80、r=0.78,P＜0.01.结论 在COPD大鼠模型中,炎症因子、免疫调节因子的表达失衡和骨骼肌内泛素及泛素化蛋白的过度表达可能是引起骨骼肌蛋白降解加快的重要原因.     

肺纤维化合并肺气肿肺功能及高分辨CT的特征

目的 探讨肺纤维化合并肺气肿(CPFE)患者临床症状、体征、肺功能和高分辨CT(HRCT)的特征;分析肺纤维化和肺气肿的程度与肺功能之间的关系.方法 前瞻性、随机临床病例对照研究.CPFE患者40例,COPD患者80例.比较两组患者一般特征及肺功能等,探讨CPFE肺纤维化和肺气肿的程度与肺功能之间的相关性.结果 40例CPFE患者,年龄(71.8±8.1)岁,男33例,有吸烟史者36例.病程6个月至15年.临床主要症状为咳嗽(34例)、呼吸困难(32例)及双下肺部爆裂音(23例).与COPD患者比较,CPFE患者PaO2降低(f=-2.016,P＜0.05).与COPD患者比较,CPFE患者FEV1％pred[(72.7±20.0)％vs (53.8±15.6)％,t=5.687,P＜0.01]和FEV1/FVC[(70.4±15.8)％vs (54.3±10.7)％,t=6.590,P＜0.01]增高,RV％ pred[(106.8±51.8)％vs(177.6±72.9)％,t=-5.484,P＜0.01]、TLC％pred[(90.1±22.5)％vs (135.4±86.2)％,t=-3.228,P＜0.01]和DL CO％ pred[(43.6±19.4)％vs (63.5±16.1)％,t=-5.900,P＜0.01]降低;VC％ pred和FVC％ pred两组之间比较差异无统计学意义(t值分别为-0.876、0.450,P值均＞0.05).CPFE患者胸部HRCT的主要表现为同时存在以双上肺野为主的肺气肿和双下肺野为主的肺间质改变.肺气肿表现为小叶中心型肺气肿(87.5％)、旁间隔型肺气肿(27.5％)、全小叶型肺气肿(10.0％)和肺大疱(35.0％).肺间质改变为网格影97.5％,磨玻璃影55.0％,蜂窝肺37.5％.调整性别、年龄和吸烟混杂因素后,肺纤维化程度与DL CO％ pred相关(P＜0.01),肺气肿严重程度与DLCO％ pred和FEV1/FVC相关(P＜0.05).结论 CPFE多发生在男性吸烟者,肺通气功能受损较轻,而弥散功能显著下降.HRCT是CPFE诊断的主要依据.HRCT显示肺纤维化和肺气肿严重者肺弥散功能更差.     

异烟肼诱导HepG2细胞损伤及其Fas/Fas配体的表达

目的 通过建立异烟肼致HepG2细胞坏死或凋亡模型,观察HepG2细胞Fas/Fas配体(FasL)的表达.方法 以HepG2细胞为模型,分别用含1、2、4、6、8 mg/mL异烟肼的细胞培养液,空白对照组加入新鲜培养液,培养24 h后观察各组细胞形态,膜联蛋白(Annexin)V和碘化丙啶染色,流式细胞仪检测HepG2细胞的坏死和凋亡情况以及其Fas/FasL的表达.数据采用单因素方差分析,各不同浓度药物组与空白对照组的比较采用Dunnett t检验.结果 随异烟肼浓度的增加(4、6、8 mg/mL),HepG2细胞出现逐渐增多的坏死和凋亡,总死亡率分别为(32.1±7.5)％、(34.9±8.1)％和(38.2±9.4)％,与正常对照组的(7.2±1.5)％相比,差异有统计学意义(t=4.62、5.14、5.75,均P＜0.01);Fas的表达也随之增加,异烟肼2、4、6和8 mg/mL浓度组Fas表达率分别为(8.7±2.2)％、(11.5±2.8)％、(12.3±3.0)％和(10.6±2.9)％,与正常对照组的(3.1±0.8)％比较,差异有统计学意义(t=2.97,P＜0.05;t=4.46,P＜0.01;t=4.88,P＜0.01;t=3.98,P＜0.05).异烟肼4、6、8 mg/mL浓度组FasL表达率分别为(16.2±3.5)％、(21.7±4.8)％、(18.7±4.9)％,与正常对照组的(7.4±1.4)％相比,差异有统计学意义(t=3.11,P＜0.01;t=5.06,P＜0.01;t=3.99,P＜0.05).异烟肼浓度为8 mg/mL时,HepG2细胞的死亡增加,主要以坏死为主,凋亡发生率未再增加.结论 异烟肼可以诱导HepG2细胞变性、坏死和凋亡,这种凋亡的发生可能与异烟肼诱导肝细胞表达Fas/FasL增多有关.     

慢性阻塞性肺疾病动态胸X线片膈肌运动与呼吸功能评估的意义

目的：评价动态胸X线片膈肌运动在慢性阻塞性肺疾病（COPD）呼吸功能评估中的意义。方法：选取我院就诊的96例稳定期COPD患者和50例健康受试者，完成肺功能检查及动态胸片检查。获得肺通气功能及动态胸X线片横膈移动幅度、速度及时间等参数。分析并对比两组间肺功能和动态胸片各参数的差异，评估动态胸片各参数在COPD呼吸功能评估中的价值。结果：COPD组FEV1、FEV1%pre以及FEV1/FVC均低于健康受试组，且差异均有统计学意义（P<0.01）。平静呼吸时，COPD组双侧膈肌运动幅度、双侧膈肌上升速度和双侧膈肌下降速度均高于健康受试组，且均差异有统计学意义（P<0.05）。用力呼吸时，COPD患者吸气时间和呼气时间以及双侧膈肌运动幅度均小于健康受试者，且均差异有统计学意义（P<0.05）。用力呼吸时，双侧膈肌运动幅度与肺功能各项指标均成正相关。对动态胸X线片参数做K-均值聚类分析，各变量对聚类结果的重要程度前五位分别为：用力呼吸左侧膈肌运动幅度（F=86.88），用力呼气左侧膈肌运动速度（F=79.37），用力吸气左侧膈肌运动速度（F=77.41），用力吸气右侧膈肌运...     

慢性阻塞性肺疾病患者膈肌厚度分数与活动耐力和呼吸困难相关性研究

目的观察慢性阻塞性肺疾病(慢阻肺)患者膈肌厚度变化,评价其与活动耐力和呼吸困难的关系。方法选取2015年8月至2016年8月上海市东方医院呼吸门诊收治的慢阻肺患者50例,同时选取该院职工肺功能正常的30名年龄与之接近的健康人作为对照组。分别行肺功能检查,在功能残气(FRC)、肺总量(TLC)位超声测量膈肌厚度(TD),计算膈肌厚度分数(TF,从FRC至TLC位膈肌厚度的变化),6 min步行距离(6MWT)、呼吸困难指数(m MRC);分析慢阻肺患者TD变化与肺功能和活动能力的相关性。结果慢阻肺组TLC位膈肌厚度和厚度分数分别为(0.38±0.10)cm和1.02±0.45,与健康对照组[(0.49±0.09)cm和(1.41±0.47)]比较差异有统计学意义(P0.05)。厚度分数与6MWT呈正相关(r=0.591,P0.01),与m MRC呈负相关(r=-0.472,P=0.001)。根据厚度分数水平,将慢阻肺组分为2亚组:G1(≤1.458),G2(1.458)。G1组6MWT为(371.95±95.73)m,较G2组[(512.00±108.61)m]降低(P0.05);G1组mMRC为2.63±1.08,较G2组(1.70±0.82)增高(P0.05);G1组气道阻塞(FEV_1)为(47.41±16.70)L,最大自主通气量(MVV)为(46.32±17.97)L,两者较G2组[FEV_1为(69.96±16.82)L,MVV(62.60±22.13)L]下降(均P0.05)。结论慢阻肺患者膈肌厚度和厚度分数下降影响患者活动耐力和呼吸困难。     

术前、术中肺通气功能与术后呼吸衰竭的关系

目的探讨机械通气时呼吸力学与术前肺功能的关系．确定术前通气功能参数能否预测术后呼吸衰竭。方法择期行肺切除术的原发性肺癌病人100例．ASAⅠ级或Ⅱ级，术前测定肺功能：一秒用力呼气容量（FEV1）、用力肺活量（FVC）、一秒用力呼气量与用力肺活量之比（FEV1／FVC％）、最大肺活量（VC）、最大通气量（MVV）、75％肺活量位用力呼气流速（FEh）、最大中期呼气流速（MMEFm）、功能残气量（FRC）、残气量与肺总量之比（RV/TLC％）；测定脉冲震荡肺功能：共振频率（Fres）、呼吸总阻抗（Zres）、中心阻力（Rc）、5Hz和20Hz时粘性阻力（R5、R30）。分别记录插管后机械通气初始和开胸单肺通气后双肺气道峰压（Tpeak）、双肺胸肺顺应性（TCT）和单肺气道峰压（Opeak）、单肺胸肺顺应性（OCT），取其平均值。Opeak和OCT与身高、体重及肺功能的关系采用多元逐步回归。一般情况和肺功能与术后呼吸衰竭的关系采用非条件Logistic回归分析。根据术后是否发生呼吸衰竭分为2组：呼吸衰竭组（RF）和非呼吸衰竭组（NRF）。结果Opeak与Zres、身高、体重和FEF。呈线性关系（R2=0．504），OCT与Zres、身高、VC和RVfrLC％呈线性关系（R^2=0.602）。与NRF组比较，RF组FEV1、FVC、FEV1／FVC％、MVV、MMEFw均降低（P〈0．01）。年龄≥60岁的老年患者FEV1≤60％、FEV1／FVC≤60％、MVV≤50％、MMEn％≤35％时，RF组术后呼吸衰竭发生率高于NRF组（P〈0．05）。Logistic回归表明．年龄和MVV是术后呼吸衰竭的两个主要影响因素。结论术中单肺通气时的气道峰压和胸肺顺应性分别与身高、体重和术前肺功能呈线性相关。中度肺功能减退的老年患者行胸科手术后发生呼吸衰竭的风险性大：年龄和MVV是术后呼吸衰竭的两个主要影响因素。     

The impact of COVID-19 and masking practices on pertussis cases at a large academic medical center (2019-2021)

We reviewed cases of Bordatella pertussis (B. pertussis) cases in ambulatory clinics at a large academic health care institution in Los Angeles from 2019-2021. Public health prevention measures during the Coronavirus disease 19 (COVID-19) pandemic impacted the number of pertussis cases identified.     

成人呼吸系统疾病中呼吸道合胞病毒的监测

目的:了解呼吸道合胞病毒(RSV)在成人呼吸系统疾病中的发病情况。方法:对呼吸科住院患者253例及同期健康体检者200例静脉血清用酶联免疫法(ELISA)测定RSV抗体IgM。结果:对照组阳性12例,阳性率6%;患者组阳性37例,阳性率14.6%,其中慢性阻塞性肺病(COPD)、肺炎与对照组比较差异有显著性(P<0.05);急性支气管炎、肺间质纤维化、结核性胸膜炎与对照组比较差异有显著性(P<0.01)。本组患者秋冬季发病较多,阳性率19.5%,春夏季阳性率9.6%,二者相比差异有显著性(P<0.05)。结论:RSV是成人呼吸道感染的重要病原,可引起下呼吸道炎症(如COPD、肺炎、急性支气管炎、肺间质疾病等)的发生和反复发作,应引起重视。     

新型冠状病毒肺炎呼吸支持手段介入的时机与策略

呼吸支持技术作为救治重症新型冠状病毒肺炎的有效手段,正确应用会有效改善氧合、降低病死率.但不同呼吸支持技术介入的时机、如何合理应用在一定程度上直接关系到治疗的成败.本文就作者团队临床救治重症新型冠状病毒的经验结合国内外相关研究成果进行阐述,希望对当前救治重症新型冠状病毒有所帮助.     

The effect of the outbreak of COVID-19 on respiratory physicians and healthcare in Japan: Serial nationwide surveys by the Japanese Respiratory Society

BackgroundThe impact of the outbreak of COVID-19 on the work of respiratory physicians in Japan has not yet been evaluated. The study investigates the impact of the outbreak on respiratory physicians’ work over time and identifies problems to be addressed in the future.MethodsWe conducted a web-based survey of respiratory physicians in 848 institutions. The survey comprised 32 questions and four sections: Survey 1 (April 20, 2020), Survey 2 (May 27, 2020), Survey 3 (August 31, 2020), and Survey 4 (December 4, 2020).ResultsThe mean survey response rate was 24.9%, and 502 facilities (59.2%) participated in at least one survey. The proportion of facilities that could perform PCR tests for diagnosis and more than 20 tests per day gradually increased. The percentage capable of managing extracorporeal membrane oxygenation (ECMO) or more than five ventilators did not increase over time. The proportion that reported work overload of 150% or more, stress associated with lack of personal protective equipment (PPE), and harassment or stigma in the surrounding community did not sufficiently improve.ConclusionWhile there was an improvement in expanding the examination system and medical cooperation in the community, there was no indication of enhancement of the critical care management system. The overwork of respiratory physicians, lack of PPE, and harassment and stigma related to COVID-19 did not sufficiently improve and need to be addressed urgently.     

A community-based, time-matched, case-control study of respiratory viruses and exacerbations of COPD

Respiratory viruses are associated with severe acute exacerbations of chronic obstructive pulmonary disease (COPD) in hospitalized patients. However, exacerbations are increasingly managed in the community, where the role of viruses is unclear. In community exacerbations, the causal association between viruses and exacerbation maybe confounded by random fluctuations in the prevalence of circulating respiratory viruses. Therefore, to determine whether viral respiratory tract infections are causally associated with community exacerbations, a time-matched case-control study was performed. Ninety-two subjects (mean age 72 yrs), with moderate to severe COPD, (mean FEV(1) 40% predicted), were enrolled. Nasopharyngeal swabs for viral multiplex polymerase chain reaction and atypical pneumonia serology were obtained at exacerbation onset. Control samples were collected in synchrony, from a randomly selected stable patient drawn from the same cohort. In 99 weeks of surveillance, there were 148 exacerbations. Odds of viral isolation were 11 times higher in cases, than their time-matched controls (34 discordant case-control pairs; in 31 pairs only the case had virus and in three pairs only control). Picornavirus (26), influenza A (3), parainfluenza 1,2,3 (2), respiratory syncytial virus (1), and adenovirus (1) were detected in cases while adenovirus (1) and picornavirus (2) were detected in controls. In patients with moderate or severe COPD the presence of a virus in upper airway secretions is strongly associated with the development of COPD exacerbations. These data support the causative role of viruses in triggering COPD exacerbations in the community.     

The Effects of Inhaled Albuterol and Salmeterol in 2- to 5-Year-Old Asthmatic Children as Measured by Impulse Oscillometry*

The functional assessment of the response to bronchodilators in 2- to 5-year-old asthmatic children is technically difficult. For this reason, there have been no reports on the effects of long-acting bronchodilators, such as salmeterol, in this age group. Of the several techniques available for measuring resistance to airflow, forced oscillation remains the most adaptable to young children and the most practical for research and clinical use. In this study we used the Jaeger MasterScreen Impulse Oscillometry System to assess the response of 2 to 5 year-old asthmatic children to an inhaled long-acting bronchodilator, salmeterol, by comparing it to the effect of a standard dose of the short-acting bronchodilator, albuterol. We performed a placebo-controlled, randomized, crossover study in 10 children aged 2 to 5 years who had a history of physician-diagnosed asthma and who were not on regular controller therapy. At weekly intervals after baseline measurements of reversibility, each child received two inhalations from an albuterol metered-dose inhaler (MDI) with a spacer (200 µg), or placebo MDI with spacer, or two inhalations from a salmeterol MDI (50 µg), or 50 µg from a salmeterol Diskus®. Measurements were obtained at 5, 30, 60, 360, and 540 min, the last time interval only on the salmeterol days. Based on previous studies, total respiratory system reactance at 5 Hz (X₅), calculated by the MasterScreen computer from mouth pressure and flow data, was used as the primary efficacy variable. The mean intra-individual variability in X₅ was 10.5% (range 3.6% to 17.9%). The mean (SE) changes from baseline X₅ at each time point were as follows: for placebo, 9.6 (3.0), 10.1 (2.6), 5.1 (2.9), 6.1 (3.5), p=0.36 vs. baseline; after treatment with albuterol, 32.7 (3.8), 53.9 (1.2), 47.3 (5.4), 18.1 (5.8), p<0.01 vs. baseline at all time points; after salmeterol MDI, 16 (6.4), 28.9 (5.2), 32.7 (3.9), 34.6 (4.4), 31.2 (4.8), p<0.05 at 60, 360, and 540 min; and after salmeterol Diskus®, 16.4 (4.0), 16.9 (6.6), 27.8 (5.9), 28.6 (5.6), 33.8 (4.0), p<0.05 at 540 min. No significant adverse events or electrocardiographic changes were noted at any time. Impulse oscillometry is an acceptable method of assessing airway responses to bronchoactive drugs in this age group. Compared to albuterol and to its effect in older children and adults, the response to salmeterol Diskus® appears to be somewhat blunted in this age group. The MasterScreen system is well suited for pharmacodynamic studies and clinical investigations in pre-school-aged children.     

Respiratory infections: Community-acquired pneumonia and newer microbes

Respiratory infections, especially community-acquired forms of pneumonia (CAP), are challenging for clinicians because (1) a causative microorganism can only be found in about 50% of cases; (2) initial therapy, therefore, must be based on a probable or most likely etiology in the context of the patient's overall medical condition; and (3) new microbes or those considered previously as normal flora or less virulent forms seem responsible for some cases. It is important to be acquainted with new causes of infection which include Legionella species, Chlamydia pneumoniae, diphtheroids in certain instances (Corynebacterium pseudodiphtheriticum), and viruses such as the Hanta strains. Infections with Bordetella pertussis are increasing. However, the ever present and most common cause of CAP, Streptococcus pneumoniae, continues to present problems because of increasing antibiotic resistance, the high case fatality rate when bacteremia accompanies pneumonia, and the inability to give prophylactic immunization to all people with risk factors for this infection. Offprint requests to: H. Y. Reynolds     

Rehospitalisations for respiratory disease and respiratory syncytial virus infection in preterm infants of 29-36 weeks gestational age

BACKGROUND: To evaluate rates of rehospitalisation due to respiratory illness in preterm infants of 29-36 weeks gestation without chronic lung disease. PATIENTS AND METHODS: Retrospective single centre cohort study including infants from 1998 to 1999 with follow-up over two respiratory syncytial virus (RSV) seasons. RESULTS: Of 435 infants included 61 infants (14%) experienced 78 rehospitalisations. The overall RSV attack rate was 4.4% over two consecutive RSV seasons for infants below 6 months of age at onset of RSV season (7.7 and 1.1%, respectively, p=0.015), with significant differences between infants of 29-32 and 33-36 weeks gestational age (10.5% vs. 2.3%, p=0.008). None of the infants needed mechanical ventilation or admission to the intensive care unit. Infants with RSV infection were younger of age (mean 4.2 vs. 8.2 months; p=0.015), had longer stays at the hospital (11.5 vs. 7.0 days; p=0.006), and more severe courses of disease (score 3.0 vs. 1.8; p<0.001). Additional risk factors for RSV infection were multiple gestation (OR 5.5; CI 95% 1.439-21.028) and congenital heart disease (OR 4.2; CI 95% 1.005-17.669). CONCLUSION: The total burden of respiratory disease and RSV infection in this population was low. A lower gestational age, multiple gestation, and congenital heart disease were associated with increased risk of RSV infection.