潮气呼吸肺功能支气管舒张试验在5岁以内儿童喘息性疾病诊断中的作用

目的 探讨潮气呼吸肺功能检测在5岁以内儿童喘息性疾病中的临床意义.方法 选取2015年1月至2016年11月西安交通大学第一附属医院儿科门诊及住院部5岁以内(包括5岁)喘息患儿159例作为观察组,根据所患疾病将观察组分为肺炎组(支气管肺炎94例)、喘支组(喘息性支气管炎12例)、哮喘组(哮喘53例),另选取健康体检儿童64例作为对照组,进行潮气呼吸肺功能检测,观察喘息性疾病患儿支气管舒张试验前后肺功能指标及改善率的变化.结果 观察组患儿潮气呼吸流量-容积曲线环形态以阻塞性改变为主(83.02％).用药前,各组之间每公斤潮气量(Vt)、呼吸频率(RR)、吸气时间(Ti)、呼气时间(Te)、达峰时间比(TPTEF/TE)、达峰容积比(VPrEF/VE)差异具有统计学意义(F值分别为13.21、4.91、3.08、2.74、36.50、40.00,均P＜0.05).肺炎组吸入支气管舒张剂后的TPTEF/TE、VPTEF/VE与用药前比较差异有统计学意义(t值分别为2.86、3.14,均P＜0.05).哮喘组用药前后TPTEF/TE、VPTEF/VE差异无统计学意义(t值分别为1.36、1.18,均P＞0.05).各观察组用药前后,TtTEF/TE、VPTEF/VE改善率比较差异无统计学意义(x2值分别为o.02、o.91,均P＞0.05).以TPTEF/TE、VPTEF/VE任意一个改善率≥15％作为支气管舒张试验的阳性标准,灵敏度为20.75％,特异度为73.58％.结论 5岁以内喘息患儿肺功能损害以阻塞性通气障碍为主;潮气呼吸支气管舒张试验可在一定程度上反映哮喘气道可逆性特征,在5岁以内儿童中以潮气呼吸支气管舒张试验诊断哮喘的敏感性不高.     

沧州地区农村毛细支气管炎后反复喘息患儿潮气呼吸肺功能检测及临床意义

目的 探讨沧州地区农村不同类型毛细支气管炎(简称毛支)后反复喘息患儿潮气呼吸肺功能变化及临床意义。方法 选取3岁以下沧州地区农村毛支后反复喘息患儿102例为研究对象,依据哮喘预测指数分为阳性组45例和阴性组57例。另选30例健康婴幼儿为对照组。分阶段于喘息发作急性期、缓解期和恢复期(喘息缓解3个月后)对两组患儿进行潮气呼吸肺功能检测,比较参数达峰时间比TPTEF/TE和达峰容积比VPEF/VE的变化,并与健康对照组对比。结果 在喘息急性期阳性组、阴性组的TPTEF/TE、VPEF/V、VT、Ti、Te差异均无统计学意义(P>0.05),但与对照组比较,两组患儿TPTEF/TE、VPEF/V均明显降低(P<0.01)。在缓解期阳性组、阴性组的TPTEF/TE、VPEF/VE比急性期均升高,仍低于对照组,且阴性组高于阳性组,差异均有统计学意义(P<0.05)。在恢复期阳性组的TPTEF/TE、VPEF/VE较缓解期升高,但仍明显低于对照组,差异有统计学意义(P<0.01),而阴性组与对照组差异已无统计学意义(P>0.05)。结论 沧州地区农村毛细支气管炎后反复喘息患儿,阳性组喘息缓解3个月后仍持续存在肺功能损害,较阴性组肺功能损害持续时间长,恢复慢,潮气呼吸肺功能检测可为早期识别哮喘并制定规范的治疗方案防治哮喘的发生提供一些临床参考。     

超重/肥胖对反复喘息婴幼儿潮气肺功能的影响

目的 分析超重/肥胖对反复喘息婴幼儿潮气肺功能的影响,为哮喘的预防和管理奠定基础。方法 选择在广东省妇幼保健院儿童呼吸科就诊的100例0～3岁反复喘息的急性发作期患儿为研究对象,按体重指数(BMI)分为喘息非超重组70例、喘息超重/肥胖组30例;选择80例0～3岁无呼吸系统疾病婴幼儿为对照组,其中非超重组50例,超重/肥胖组30例。测定各组受试患儿潮气呼吸流量-容积曲线(TBFV),记录各参数并进行比较。结果 喘息非超重组与对照非超重组比较,达峰时间比(TPTEF/TE)、达峰容积比(VPTEF/VE)、吸呼比(TI∶TE)、呼出75%潮气量时的呼气流速/呼气峰流速(25/PF)均明显下降 (t＝8.518、7.767、3.142、7.860,P＜0.05);呼气峰流速(PTEF)、呼出25%潮气量时的呼气流量(TEF75)显著增加(t=6.728、8.540,P＜0.05)。分别在对照组、喘息组中,与非超重儿童肺功能参数相比,超重/肥胖儿童仅潮气量(VT/kg)显著下降(t=2.872、3.048,P＜0.05)。结论 超重/肥胖影响婴幼儿肺功能潮气量(VT/kg),但不影响气道阻塞的指标。     

支气管肺发育不良患儿肺功能变化的动态随访研究

目的监测支气管肺发育不良(bronchopulmonary dysplasia,BPD)生后3年内潮气呼吸肺功能动态变化,以探讨BPD对患儿远期肺功能的影响。方法收集BPD患儿生后3年内临床资料及肺功能结果,与同龄非BPD患儿对比。结果 BPD患儿生后3年内均存在肺功能异常,肺功能参数如潮气量(VT)、吸气时间(TI)、达峰时间比(TPTEF/TE)、达峰容积比(VPTEF/VE)降低,呼吸频率(RR)、呼气时间(TE)升高,与非BPD患儿比较,差异有统计学意义(P0.05);身高及体重均较同龄非BPD儿童下降(P0.05)。结论 BPD导致婴儿肺功能异常,并影响生长发育。     

不同雾化吸入策略对中度支气管肺发育不良患儿生活质量的影响

目的 研究不同布地奈德雾化吸入策略对中度支气管肺发育不良(BPD)早产儿生后矫正胎龄12月内生活质量的影响。方法 收集扬州大学附属连云港市妇幼保健院2016年9月1日-2019年9月1日新生儿重症监护室出院的中度BPD患儿31例,采用前瞻性方法,出院后均以 0.9%氯化钠2 ml+布地奈德1 ml雾化吸入 bid×1月。然后根据随机方式,将出院1月后～矫正胎龄12月时雾化吸入策略分为3种:长期吸入组(n=11)、按需吸入组(n=10)及无吸入组(n=10)。分析雾化吸入策略对中度BPD患儿矫正胎龄12月内呼吸道症状如喘息及发热、上感及肺部感染频次、入住儿科重症监护室(PICU)次数及矫正胎龄1月及12月潮气肺功能指标的影响。结果 与按需吸入组及无吸入组相比,长期吸入组患儿1年内发生喘息及发热、肺部感染频次、入住PICU次数及健康状态时活动后气急之间差异均无统计学意义(P＞0.05),但长期吸入组患儿上感次数明显减少(P＜0.05)。31例中度BPD患儿矫正胎龄12月后,三组间潮气量(VT/kg)、 吸呼比(Ti/Te)、达峰时间比(TPTEF/TE)及呼出25%潮气容积时段的平均呼气流量(TEF75)差异均无统计学意义(P＞0.05);与按需吸入组及无吸入组相比,长期吸入组矫正胎龄12月时达峰容积比(VPEF/VE)明显升高(F＝36.36,P＜0.05);长期吸入组矫正胎龄12月VPTEF/VE较1月时明显升高,差异具有统计学意义(P＜0.05)。结论 长期布地奈德吸入策略可减少中度BPD患儿矫正胎龄12月内上呼吸道感染发生频次,改善VPTEF/VE,但对呼吸系统症状急性加重或恶化的保护作用有限。     

不同雾化吸入策略对中度支气管肺发育不良患儿生活质量的影响

目的 研究不同布地奈德雾化吸入策略对中度支气管肺发育不良(BPD)早产儿生后矫正胎龄12月内生活质量的影响。方法 收集扬州大学附属连云港市妇幼保健院2016年9月1日-2019年9月1日新生儿重症监护室出院的中度BPD患儿31例,采用前瞻性方法,出院后均以 0.9%氯化钠2 ml+布地奈德1 ml雾化吸入 bid×1月。然后根据随机方式,将出院1月后～矫正胎龄12月时雾化吸入策略分为3种:长期吸入组(n=11)、按需吸入组(n=10)及无吸入组(n=10)。分析雾化吸入策略对中度BPD患儿矫正胎龄12月内呼吸道症状如喘息及发热、上感及肺部感染频次、入住儿科重症监护室(PICU)次数及矫正胎龄1月及12月潮气肺功能指标的影响。结果 与按需吸入组及无吸入组相比,长期吸入组患儿1年内发生喘息及发热、肺部感染频次、入住PICU次数及健康状态时活动后气急之间差异均无统计学意义(P＞0.05),但长期吸入组患儿上感次数明显减少(P＜0.05)。31例中度BPD患儿矫正胎龄12月后,三组间潮气量(VT/kg)、 吸呼比(Ti/Te)、达峰时间比(TPTEF/TE)及呼出25%潮气容积时段的平均呼气流量(TEF75)差异均无统计学意义(P＞0.05);与按需吸入组及无吸入组相比,长期吸入组矫正胎龄12月时达峰容积比(VPEF/VE)明显升高(F＝36.36,P＜0.05);长期吸入组矫正胎龄12月VPTEF/VE较1月时明显升高,差异具有统计学意义(P＜0.05)。结论 长期布地奈德吸入策略可减少中度BPD患儿矫正胎龄12月内上呼吸道感染发生频次,改善VPTEF/VE,但对呼吸系统症状急性加重或恶化的保护作用有限。     

婴幼儿反复喘息危险因素分析及其潮气肺功能检测的临床意义

目的 分析婴幼儿反复喘息危险因素及其与潮气肺功能的相关性。方法 2015年3月-2017年3月选择湖北省武汉市第一医院儿科反复喘息≥3次住院治疗的患儿为观察组, 同时选取同期儿科门诊健康体检儿为对照组,采用问卷调查法对危险因素进行研究。 采用CareFusion公司肺功能仪对两组婴幼儿呼吸频率(RR)、 每公斤体重潮气量(TV/ kg)、 吸/呼比(Ti/Te)、达 峰 时 间 比 ( TPTEF / TE) 及 达 峰 容 积 时 间 比( VPEF/VE)进行测定。结果 1)湿疹(OR= 5.86,95%CI:1.72~22.06)、被动吸烟(OR=2.16, 95%CI:1.36~5.29)、父母有哮喘或过敏性鼻炎病史(OR=7.83, 95%CI:2.56~30.31)、居住地城市(OR=3.12,95%CI:1.17~12.46)、临近马路(OR=2.05,95%CI:1.08~3.03)是婴幼儿反复喘息的独立危险因素。2)与对照组比较,喘息急性期、缓解期的RR均显著增快(均P<0.05);与喘息急性期比较,喘息缓解期RR显著降低(P<0.05)。与对照组比较,喘息急性期组、喘息缓解期组TPTEF/TE、VPEF/VE均显著降低(P均<0.01);且经积极治疗后,与喘息急性期比较,喘息缓解期TPTEF/TE、VPEF/VE均显著升高(P均<0.05)。结论 湿疹、被动吸烟、父母有哮喘或过敏性鼻炎病史、居住地城市、临近马路是婴幼儿反复喘息的独立危险因素。潮气肺功能是婴幼儿哮喘早期监测的良好客观指标。     

Effects of Sarcopenia on Ventilatory Behavior and the Multidimensional Nature of Dyspnea in Patients With Chronic Obstructive Pulmonary Disease

ObjectivesThis study tested the hypothesis that sarcopenia, a common extrapulmonary feature of chronic obstructive pulmonary disease (COPD), can affect ventilatory behavior, and worsen the multidimensional nature of dyspnea in patients with COPD.DesignCross-sectional survey study.Settingand Participants: Stable outpatients with COPD encountered in general practice and respiratory clinic.MethodSarcopenia was diagnosed according to an appendicular skeletal muscle mass index based on measurements of electrical impedance and handgrip strength. Exertional dyspnea was tested using a 3-minute Step Test and a 6-minute Walk Test. The dimensions of dyspnea were assessed by a multidimensional dyspnea profile.ResultsOf 60 stable patients with COPD, 16 met the criteria for sarcopenia. During the 3-minute Step Test, minute ventilation as a proportion of exercise time, tidal volume as a proportion of inspiratory capacity, the change in inspiratory capacity, and ventilation as a proportion of maximal voluntary ventilation did not differ between patients with and without sarcopenia. Patients with sarcopenia exhibited lower evolution of tidal volume, higher evolution of respiratory frequency versus ventilation and breathing discomfort on the 3-minute Step Test, as well as increased physical breathing effort on the 6-minute Walk Test, compared with those without sarcopenia. In a multivariable model adjusted using inverse probability weighting, sarcopenia was independently associated with breathing discomfort during the 3-minute Step Test and physical breathing effort during the 6-minute Walk Test.Conclusions and ImplicationsSarcopenia may be associated with shallow breathing and diverse sensory and affective components of exertional dyspnea in patients with COPD. The study indicates that improvement of the rapid breathing pattern may offer unique ways to alleviate dyspnea in older patients with COPD and sarcopenia.     

枸橼酸咖啡因对原发性呼吸暂停早产儿早期肺功能及智能发育的影响研究

目的 探讨枸橼酸咖啡因对原发性呼吸暂停(AOP)早产儿早期肺功能及智能发育的影响。方法 2016年1月—2017年1月选取在仙桃市第一人民医院新生儿科的160例原发性AOP早产儿,按随机数字表法分为观察组(n=80)与对照组(n=80)。对照组采用氨茶碱治疗,观察组采用枸橼酸咖啡因治疗。比较两组治疗情况及并发症发生情况,测定治疗后早期肺功能指标、血清胰岛素样生长因子结合蛋白 3(IGFBP-3)和β-内啡肽(β-EP),比较两组治疗前、校正月龄6个月和12个月时Gesell发育量表评分。结果 观察组的正压通气时间、总吸氧时间均较对照组明显缩短,且观察组治疗24、48、72 h呼吸暂停发作次数显著低于对照组(P<0.05);治疗后,两组呼吸频率(RR)、吸呼比差异无统计学意义(P>0.05),但观察组的每分钟通气量(MV)、潮气量(VT)、达峰时间比(TPTEF/TE)、达峰容积比(VPEF/VE)、潮气呼吸呼气流速(PEF)、25%/50%/75%潮气量时呼气流速(TEF25、TEF50、TEF75)均显著高于对照组(P<0.05);治疗后,观察组的血清GFBP-3显著高于对照组,β-EP显著低于对照组(P<0.05);观察组总并发症率显著低于对照组(21.25% VS. 43.75%,P<0.05);校正月龄6、12个月,观察组的Gesell评分均显著高于对照组(P<0.05)。结论 枸橼酸咖啡因辅助治疗早产儿原发性AOP能够保护患儿肺功能及神经功能,促进其智能发育,减少并发症发生。     

储雾罐吸入丙酸氟替卡松气雾剂对毛细支气管炎预后的效果评价

目的 比较储雾罐吸入丙酸氟替卡松气雾剂与雾化吸入布地奈德混悬液对毛细支气管炎预后的影响。方法 选取2016年9月-2018年6月在北京市通州区妇幼保健院入院并确诊毛细支气管炎患儿187例,根据随机数字表分为氟替卡松组(67例)、布地奈德组(63例)和对照组(57例)。分别在出院后给予储雾罐吸入丙酸氟替卡松气雾剂和雾化吸入布地奈德混悬液,对照组不予吸入任何糖皮质激素。随访观察1个月,比较三组患儿随访前后潮气肺功能、呼出气一氧化氮(FeNO),随访后喘息反复发作的情况。结果 完成随访患儿氟替卡松组67例、布地奈德组62例和对照组56例,干预后两组患儿潮气肺功能达峰时间比(TPTEF／TE)、达峰容积比(VPEF／VE)较干预前上升、FeNO较干预前下降,差异有统计学意义(P＜0.05)。两组在干预后1个月咳喘反复例数均明显低于对照组,组间比较差异无统计学意义(P＞0.05)。结论 吸入丙酸氟替卡松可在短期内有效防治毛细支气管炎感染后咳喘复发,减轻气道炎症反应,改善肺功能。储雾罐吸入方式可以替代雾化吸入改善毛细支气管炎预后,并具有便捷优势。     

Unilateral Pulmonary Function Study of Ozone Toxicity in Rabbits

In a unilateral pulmonary function study, Flemish giant rabbits breathing 12 ± 1 ppm ozone in the left lung exhibited an initial bilateral increase in respiratory rate and minute volume as well as a bilateral decrease in tidal volume and dynamic compliance. Pulmonary function parameters were not statistically different for ozone- and ambient-airtreated lungs until pulmonary edema developed in the lung exposed to ozone, as evidenced by a percent increase in the wet weight of that lung. Tidal and minute volumes, inspiratory and expiratory flows, and dynamic compliance decreased and pulmonary flow resistance increased in the lung exposed to ozone. Because pulmonary edema preceded significant functional changes, the former is considered a more sensitive indicator of the extent of ozone toxicity. Edema occurred only in the lung breathing ozone.     

Comprehensive assessment of ventilatory functions of patients with chronic heart failure

OBJECTIVE: A comprehensive assessment of the ventilatory functions of patients with chronic heart failure (CHF) both at rest and during a cardiopulmonary exercise test (CPET). We studied 42 males, divided into two groups--patients with CHF (n = 21) and age, weight, height and BMI matched healthy controls (n = 21). All subjects underwent a symptom-limited ramp CPET, arterial blood gas analysis, and complex functional examination of the pulmonary system. Subjective rating of dyspnea and exertion were measured by the Borg and ATS dyspnea scales. CHF patients showed a slight, but statistically significant decrease of the spirographic and diffusion parameters, as well as of the indices of respiratory muscle strength. There were no changes in blood gases and in tidal breathing parameters. The exercise capacity was markedly reduced (VO2peak ml.min-1 1352 +/- 335 CHF patients vs 2077 +/- 276 healthy controls; p < 0.001) and the anaerobic threshold occurred earlier (< 40% of predicted VO2peak) during CPET in CHF patients. The increase in VE/VCO2 in CHF patients (35.7 +/- 5.1 CHF; 28.9 +/- 2.5 HC, p < 0.001) indicates a compromised ventilatory efficiency which leads to a higher dyspneic cost of exercise (Borg peak 9.5 +/- 1.03 CHF; 6.0 +/- 1.28 HC; p < 0.001) as compared with healthy controls.     

Effects of industrial respirator wear during exercise in subjects with restrictive lung disease

Few studies have examined the response of individuals with restrictive lung disease (RLD) to respirator wear. Such information should be of theoretical and practical interest when the need to determine fitness to wear respirators is considered. Seventeen females performed progressive submaximal treadmill exercise. Twelve control subjects with total lung capacity (TLC) = 5.71 +/- .19L (mean +/- SEM) and DLCO = 25.8 +/- 1.0 mL/min/mmHg were compared to five RLD subjects with TLC = 3.70 +/- 0.22 and DLCO = 14.5 +/- 0.7. Mean age, height and weight were similar. Separate exercise trials were performed with no added resistance (NAR), and with 5 cm H2O/L/sec inspiratory and 1.5 cm H2O/L/sec expiratory resistance (R2) to stimulate widely used respiratory masks. Comparisons of exercise data were made at an oxygen consumption of 0.8 L/min. With NAR, RLD subjects had significantly higher minute ventilation (VE) (29.0 vs. 21.2 L/min for controls), higher respiratory rate (RR), and lower tidal volume (VT). Heart rate, end-tidal PCO2 (PETCO2), and mouth pressure swing (Poral) were not different from control values. With R2 compared to NAR, the controls had reduced RR and VE; and increased VT, PETCO2, and Poral. While changes with R2 for the RLD subjects were in the same directions as controls, only the increase in Poral was statistically significant. Analysis of the differences showed that none of the changes with R2 in RLD subjects was different from control changes except for the greater increase in Poral and the smaller increase in VT. The former was explained by the RLD subjects' higher VE and flow rates, and the non-linear nature of R2 at higher flow rates.(ABSTRACT TRUNCATED AT 250 WORDS)     

部分DatexOhmeda麻醉机小儿潮气量下呼吸参数的变化特点

目的:探讨部分DatexOhmeda麻醉机小儿潮气量容量控制模式下一些常用呼吸参数的变化特点,以期为临床小儿麻醉安全应用该机型麻醉机提供理论依据.方法:11台DatexOhmeda麻醉机,在预设定潮气量(预设VT)100、200、300 mL时进行临床模拟研究.氧流量固定为2 L/min,分别使用小儿及成人螺纹管和呼吸囊.风箱数值(VT)、实际潮气量(VTE)、分钟通气量(VE)、气道峰压表的数值(Pmax1)和显示屏的数值(Pmax2)、平均气道压(Pmean)均被测定.结果:所有麻醉机呼吸参数的比较:使用小儿螺纹管时,风箱VT比预设VT显著增加;VTE较风箱VT小;风箱VT、VE显著大于使用成人螺纹管时.各型号麻醉机呼吸参数的比较:Aestiva/5 (7900)使用小儿螺纹时,风箱VT大于预设VT;Aestiva/5 (7900)预设VT200、300 mL时以及Aespire (7100)所有使用小儿螺纹管时的风箱VT均显著大于使用成人螺纹管时.Aestiva/5(7900)预设VT100、200 mL时以及Aespire (7100)所有使用小儿螺纹管时VTE较使用成人螺纹管时大.Aestiva/5 (7900)预设VT100、300 mL时以及Aespire(7100)所有使用小儿螺纹管时的VE大于使用成人螺纹管时.结论:麻醉机的精准度是令人满意的;小儿麻醉时有使用小儿螺纹管及小儿呼吸囊的必要;Aestiva/5 (7900)更适用于小儿麻醉.     

Tidal breathing analysis in school-age children. Comparison with the parameters of forced expiration

Tidal breathing analysis is a method which has the potential to be used for distinguishing and follow-up of airflow obstruction (AFO) in infants, children and critically ill patients. The aim of the present study was to analyse the tidal breathing parameters (TBP) in healthy and in asthmatic school-age children and to compare them with the parameters of forced expiration. SUBJECTS: Two hundred and twenty five healthy children and 100 asthmatics (7 to 14 years- old) took part in the present study. RESULTS: The results show that TBPs exhibit great inter- and intraindividual variability, even if the mean value of 10 consecutive breathing cycles is used. Parameters that reflect the tidal expiratory flow pattern--V(PTEF)/V(E) and T(PTEF)/T(E) demonstrate high variability and no correlation with age, sex and anthropometric parameters in healthy children. These indices are useful for detection of acute changes in bronchomotor tonus in asthmatics - V(PTEF)/V(E) = 36.1 +/- 6.6% vs. 32.6 +/- 6.2% (methacholine) vs. 37.4 +/- 7.5% (salbutamol) and T(PTEF)/T(E) = 34.2 +/- 6.2% vs. 28.6 +/- 7.8% vs. 35.3 +/- 7.5%, resp. (P < 0.05 everywhere; n = 34) as well as for discriminating a group of subjects with AFO vs. controls (V(PTEF)/V(E) = 30.9 +/- 6.5% vs. 35.3 +/- 8.0%; P = 0.005, and T(PTEF)/T(E) = 29.0 +/- 6.7% vs. 32.8 +/- 7.6%; P = 0.016). The evaluation of the area under the ROC curves (AUC) in the asthmatic group showed weak discriminative capacity of T(PTEF)/T(E) and V(PTEF)/V(E) in comparison to FEV1 (AUC of T(PTEF)/T(E) = 0.62; 95%CI 0.51-0.74). CONCLUSIONS: Tidal breathing parameters could add insight t.o the functional profile but are not capable of substituting forced expiration regarding detection of overt airflow obstruction in school-age children.     

Respiratory function during oxygen administration in chronic obstructive pulmonary disease

Patient with severe chronic obstructive pulmonary disease (COPD) can develop respiratory muscle weakness and fatigue. Arterial hypoxemia can predispose to this condition. To assess whether O2 administration improved respiratory muscle function and respiratory pattern in COPD 11 patients with chronic hypoxemia were examined. Each patient was first submitted to respiratory function studies, including lung volumes, in normal and recumbent position, respiratory frequency, Ti/Te, Ti/Tot, maximal inspiratory and expiratory pressures (Pimax, Pemax) and arterial gas analysis breathing room air. All these tests were repeated during oxygen Administration through a nasal cannula. The arterial PO2 improved from 50 +/- 7 mmHg to 81 +/- 28 mmHg but the breathing pattern, Pimax and Pemax as well as lung volumes remained unchanged. It is concluded that oxygen, in short term administration, doesn't influence respiratory pattern and muscle function.     

模拟肺研究容量控制通气辅用自动变流的意义

目的观察容量控制通气辅用自动变流前后输送潮气量、气道峰压、平均压的变化.方法采用自身配对设计,比较模拟肺在不同顺应性、阻力设定下,采用不同吸气流速容量控制通气,辅用自动变流前后输送潮气量、气道峰压、平均压的变化.结果不同流速、阻力、顺应性设定下,辅用自动变流后输送潮气量不变(P均＞0.05),而气道峰压、气道平均压下降(P均＜0.05).结论在需要保证输送潮气量,又尽可能控制气道峰压、气道平均压时,容量控制通气辅用自动变流是一种较好的方法.     

The Role of Spirometry in Evaluating Therapeutic Responses in Advanced COPD

Traditional spirometry, while of unquestionable diagnostic utility, provides imprecise information about the nature and extent of physiological impairment or the resultant clinical consequences in any given patient with chronic obstructive pulmonary disease (COPD). The corollary is that exclusive reliance on spirometric forced expiratory flow rates as the primary outcome measure for the evaluation of therapeutic efficacy can lead to significant underestimation of clinical benefit. Recognition of the limitations of routinely used physiological parameters has prompted a search for additional simple and reliable tests for use in clinical trials. Among these, the spirometric inspiratory capacity (IC) shows early promise as a useful, clinically relevant outcome measure that complements traditional expiratory flow measurements. Consistent improvements in IC after bronchodilator therapy signify reduction in lung hyperinflation and can occur in the setting of minimal or no change in maximal expiratory flow rates, particularly in patients with more severe disease. Moreover, improved IC has been shown to correlate well with improvement in important clinical outcomes such as dyspnea and exercise endurance in patients with moderate to severe COPD. This review charts the evolving experience with this novel parameter in the clinical trial setting.     

Plasma levels of amino acids and hypermetabolism in patients with chronic obstructive pulmonary disease

Plasma levels of amino acids were measured by ion-exchange, high-pressure liquid chromatography in 30 ambulatory patients with chronic obstructive pulmonary disease (COPD; mean +/- SD: age 64 +/- 13 y and forced expiratory volume in 1 s [FEV1] 0.85 +/- 0.25 L) and 30 age- and sex-matched healthy control subjects with regard to nutritional status, resting energy expenditure (REE), and pulmonary function. The ratio of branched-chain amino acids to aromatic amino acids was significantly (P < 0.001) decreased in COPD patients and was significantly correlated with percentage of ideal body weight (r = 0.403, P < 0.05), percentage of arm-muscle circumference (r = 0.492, P < 0.01), and %FEV1 (r = 0.467, P < 0.05). Plasma levels of alanine and cysteine were decreased, whereas levels of glutamine, aspartic acid, serine, and ornithine were elevated in COPD patients as opposed to control subjects. The ratio of resting energy expenditure to predicted resting energy expenditure was negatively correlated with the ratio of branched-chain to aromatic amino acids (r = -0.716, P < 0.01), percentage of arm-muscle circumference (r = -0.770, P < 0.05), %FEV1 (r = -0.839, P < 0.01), and the maximal inspiratory pressure (r = -0.803, P < 0.001). Underweight COPD patients also exhibited a greater degree of hyperinflation (percentage of residual volume = 205 +/- 15 for underweight patients and 156 +/- 8 for normal-weight patients). In conclusion, a decrease in plasma levels of branched-chain amino acids in relation to hypermetabolism, possibly resulting from the severity of COPD and respiratory muscle weakness, and various disturbances in plasma amino-acid levels were found in underweight COPD patients.     

Static lung load and posture effects on pulmonary mechanics and comfort in underwater exercise.

Static lung load (SLL), or transrespiratory pressure gradient, imposed by underwater breathing apparatus can affect breathing comfort and mechanics, especially during exertion. We examined the effects of body position and SLL on two factors known to affect or limit exertion: a) tidal flow-volume limitation, i.e., the percentage of the tidal volume that meets the boundary of the maximum expiratory flow-volume curve; and b) breathing discomfort. Eight healthy male scuba divers (28 +/- 4 yr) performed cycle ergometry to exhaustion during immersion in each of four combinations of body position and SLL: upright, prone, +10 cmH2O, -10 cmH2O. SLL was referenced to the sternal notch. Tidal flow-volume limitation was significantly greater with the negative SLL (P less than 0.05). In the prone position, higher expiratory flows were achieved (P less than 0.01) and flow limitation was not significantly increased. Respiratory discomfort was quantified with a psychophysical rating scale and increased significantly as exercise intensity increased (P less than 0.01). No effect of posture or SLL on discomfort was found. We conclude that, although respiratory comfort is unaffected, positive static lung loading and the prone body position minimize adverse changes in respiratory mechanics during exercise in immersion.