潮气流速容量曲线测定在毛细支气管炎患儿中的意义

目的通过对240例毛细支气管炎患儿的潮气流速容量曲线的测定,以探讨毛细支气管炎患儿气道阻力的变化规律。方法采用美国Sensor Medics公司生产的2600型全自动小儿肺功能测定仪,在潮气状态下对毛细支气管炎患儿进行肺功能测定,连续记录潮气呼气流速容量曲线。结果所有毛细支气管炎患儿都有不同程度的气道阻力增高,尤以小气道阻力增高为主,其增高程度与患儿病情的轻重呈正相关。结论毛细支气管炎患儿应尽早进行潮气流速容量曲线的测定,以判断患儿病情,为其治疗和护理提供客观依据;潮气流速容量曲线的测定操作简单易行,并且无创,在临床上应广泛应用。     

毛细支气管炎患儿潮气流速容量环及参数变化的临床意义

目的 探讨毛细支气管炎患儿肺功能变化的临床意义。方法 用美国森迪公司2600儿童肺功能检测仪对毛细支气炎患儿及对照组婴儿进行呼吸频率(BF)、到达呼气峰值的呼出量与总呼气量之比(VPEF/VE)、从开始呼气至达到最大呼气流速时间与总呼气时间之比(TPEF/TE)、呼出50％潮气量时呼气流速与呼气峰流速之比(50％PE)、呼出75％时呼出流速与呼气峰流速之比(25％PF)等参数的检测，并描记潮气流速容量环(TFV环)。结果 毛细支气管炎组患儿治疗前与治疗后相比、与对照组相比，VPEF／VE、TPEF／TE、50％PF、25％PF等指标均明显下降，差异有显著意义。治疗前后TFV环形状也有明显区别。结论 VHEF／VE、TPEF／TE、50％PF、25％PF及TFV环可作为评价婴幼儿气道阻塞程度的可靠指标。     

潮气呼吸流速容量环对毛细支气管炎患儿肺功能的评价

目的:研究毛细支气管炎时小气道阻塞的程度及动态变化的情况,并探讨其临床意义。方法:采用德国耶格公司MasterScreen小儿肺功能仪,运用潮气呼吸流速容量环评价115例毛细支气管炎急性期婴儿(按月龄分为3组)肺功能。并对其中30例患儿进行临床恢复期肺功能复查。结果:115例患儿中肺功能正常5例,单纯限制性改变3例,余107例患儿均有不同程度的气道阻塞性改变,其中轻度阻塞(达峰时间比为28%-22%)25例,占23.3%,中度阻塞(达峰时间比为22%-16%)34例,占31.7%,重度阻塞(达峰时间比为<16%)48例,占44.8%。中度以上阻塞的患儿约达76%。107例患儿中有38例同时伴有限制性改变。临床恢复期上述异常指标明显好转。结论:毛细支气管炎急性期,肺功能大多呈中度以上阻塞性通气功能障碍,主要为小气道阻塞,恢复期有显著好转。潮气呼吸流速容量环检测能较好地反映小婴儿的肺功能。     

毛细支气管炎婴幼儿患者潮气肺功能研究

毛细支气管炎（简称毛支）是〈2岁婴幼儿特有的呼吸道感染性疾病，主要为病毒感染，〉50％系呼吸道合胞病毒（RSV）感染。以婴儿为多见。近年来用TBFV环取代用力流速容量曲线（MEFV）在婴幼儿进行肺功能检查逐渐开展。作者自2002年12月至2007年2月对不同月龄毛支患儿及RSV与非RSV毛支患儿的肺功能改变进行观察，为临床提供参考。     

雾化吸入治疗婴幼儿毛细支气管炎护理体会

毛细支气管炎是2岁以内婴幼儿较常见的一种呼吸道感染性疾病，多发生于6个月-2岁的婴儿。引起毛细支气管炎最常见的病毒是呼吸道合胞病毒，其次为流感病毒、副流感病毒和腺病毒。常见致病菌有肺炎球菌、链球菌、葡萄球菌、流感杆菌等。该病发病急，临床表现为呼吸困难、烦躁不安等缺氧症状，并可诱发心衰。如不及时给予治疗和护理，可危及婴幼儿的生命。     

毛细支气管炎患儿T细胞亚群检测的意义

毛细支气管炎（简称毛支）是婴幼儿时期常见的与感染相关的喘息性疾病，多由病毒感染引起，呼吸道合胞病毒（RSV）是最常见的病原。毛支的临床表现、转归与哮喘密切相关，其具体的发病机制尚未阐明。鉴于T淋巴细胞比例和功能的失衡在哮喘发病过程中起关键作用，作者检测了毛支患儿急性期外周血T细胞亚群，以探讨毛支的免疫学发病机制。     

干扰素γ加喘乐宁吸入治疗呼吸道合胞病毒毛细支气管炎的临床疗效

目的：探讨基因重组干扰素γ（rIFN-γ)加喘乐宁吸入治疗呼吸道合胞病毒毛细支气管炎（RSV毛支）患儿的临床疗效。方法：RSV毛支60例，随机分为雾化吸入组28例，对照组32例，观察治愈率、症状体征的持续时间。结果：治疗组治愈率明显高于对照组（P＜0．05）。治疗组在喘憋、肺罗音、咳嗽消失时间较对照组明显缩短（P均＜0．01）。结论：rIFN-γ加喘乐宁雾化治疗RSV毛支有较好的临床疗效。     

干扰素治疗毛细支气管炎的疗效观察

毛细支气管炎是婴幼儿冬春季常见的下呼吸道感染性疾病，多由呼吸道合胞病毒（RSV）等感染引起，目前对毛细支气管炎无特效疗法。我科于2004年10月至2005年5月收治毛细支气管炎病例135例，其中70例予干扰素治疗，效果满意，现报道如下。     

干扰素联合布地奈德雾化吸人治疗毛细支气管炎的疗效

毛细支气管炎又称喘憋性肺炎,是小儿严重下呼吸道感染疾病,常见于〈2岁的婴幼儿,尤其是〈6个月的婴儿,常见的病原体是呼吸道合胞病毒、副流感病毒等。毛细支气管炎患儿,如未能及时治疗,急性气道炎症性病变可致气道阻塞,出现急性呼吸衰竭、败血症等并发症,甚至危及患儿生命。作者自2010年10月至2012年10月,采用干扰素联合布地奈德雾化吸入治疗毛细支气管炎,临床疗效满意,现报道如下。     

硫酸镁佐治毛细支气管炎的疗效观察

毛细支气管炎是2岁以下婴幼儿的常见病,主要由呼吸道合胞病毒引起,副流感病毒、鼻病毒、人类偏肺病毒、某些腺病毒、支原体亦可引起,以咳嗽、气喘、喘憋为主要临床特点.病毒感染无特效药治疗,主要给予对症处理,临床常用激素、沙丁胺醇抗炎平喘,但效果不甚理想.作者采用硫酸镁佐治,并与不用硫酸镁治疗组相比较,旨在观察硫酸镁辅助治疗毛细支气管炎的效果.     

Determinants of tidal volume during high-frequency oscillation

OBJECTIVE: High-frequency oscillation has been proposed for use in adult acute respiratory distress syndrome. However, limited data are available on the effect of pressure amplitude and rate (Hz) on tidal volumes delivered during high-frequency oscillation in adults. DESIGN: Prospective, animal model, lung injury study. SETTING: Large-animal laboratory of a university-affiliated medical center. SUBJECTS: Nine sheep (29.2 +/- 2.4 kg). INTERVENTIONS: Severe lung injury was induced by repeated saline lung lavage. After stabilization, high-frequency oscillation was initiated at a mean airway pressure equal to the point of maximum curvature on the deflation limb of the pressure-volume curve (26 +/- 1.9 cm H2O). Tidal volume at all combinations of rates of 4, 6, 8, and 10 Hz, pressure amplitudes of 30, 40, 50, and 60 cm H2O, and inspiratory/expiratory ratios of 1:1 and 1:2 (using the Sensormedics 3100B oscillator) were measured. Flow was measured by a pneumotachometer, amplified and digitized at 1000 Hz. Three breaths were analyzed at each setting. MEASUREMENTS AND MAIN RESULTS: At both inspiratory/expiratory ratios, tidal volume was directly proportional to pressure amplitude and inversely proportional to frequency. During an inspiratory/expiratory ratio of 1:1, at 60 cm H2O pressure amplitude and 4 Hz, a tidal volume of 129.1 +/- 34.8 mL (4.4 +/- 1.2 mL/kg) was delivered. CONCLUSIONS: At low rates and high-pressure amplitudes in this model, tidal volumes approaching conventional mechanical ventilation can be delivered during high-frequency oscillation.     

The oxygenation ratio during mechanical ventilation in children: The role of tidal volume and positive end-expiratory pressure

Objective

The objective of this study is to analyze the role of tidal volume (Vt) and positive end-expiratory pressure on the oxygenation ratio (OR) (Pao₂/Fio₂) during mechanical ventilation (MV) in children with a normal pulmonary gas exchange on admission.

Methods

A retrospective cohort study of children with an admission OR greater than 300 mm Hg and duration of MV greater than 48 hours (n = 96) was done. We analyzed Vt, Fio₂, Pao₂, and positive end-expiratory pressure and calculated Vt (mL/kg) and Pao₂/Fio₂ based on the measured Vt and weight. Patients were divided into group 1, Vt less than 9 mL/kg (n = 24); 2, Vt 9 to 12 mL/kg (n = 58); and 3, Vt 12 mL/kg or higher (n = 14).

Results

Baseline characteristics and OR were comparable. Forty-one percent of patients developed OR less than 300 mm Hg. The proportion of patients developing an OR less than 300 mm Hg was lowest in group 1 and highest in group 3, and differences became more pronounced with longer MV duration: 56%, 58%, and 89% on day 5; 29%, 65%, and 100% on day 7 (P = .05); 0%, 40%, and 100% on day 10 (P = .03). In patients maintaining an OR greater than 300 mm Hg during 10 days of MV, Vt was 9.3 ± 1.0 vs 12.7 ± 4.8 mL/kg in patients developing an OR less than 300 mm Hg (P = .05). Mechanical ventilation duration was longer in children developing OR less than 300 mm Hg (P < .01). Positive end-expiratory pressure levels were not significantly different between groups.

Conclusion

In ventilated children, Vt was greater than 9 mL/kg were associated with increased development of an OR less than 300 mm Hg and longer duration of MV.     

根据压力-容积曲线选择理想潮气量对呼吸机护理的指导

目的探讨使用呼吸机时,不同的潮气量对急性肺损伤患者血流动力学、肺通气和肺机械力学的影响及护理要点。方法对ICU急性肺损伤16例患者采取自身对照的方法,利用压力-容积（P．v）曲线下曲点＋0．196kPa确定呼气末正压（PEEP）后,再根据P—V曲线的上拐点（VUIP）,分别取上拐点对应的潮气量100％Vt、85％Vt和70％Vt分为3组,以相同的分钟通气量和吸入氧浓度分别给予定容机械通气,监测肺机械力学、血流动力学、血气改变及P—V曲线的变化。结果85％Vt组在心率、中心静脉压、动脉血氧分压、气道峰值压、气道平均压及系统静态顺应性等对患者的综合影响优于100％Vt组和70％Vt组。结论以呼吸系统P-V曲线的下曲点（Pinf）确定PEEP值,以上拐点压力对应的潮气量的85％调节潮气量符合个体化保护性通气策略,对改善肺的顺应性、降低肺病理性损伤效果最好。护理时应注重P—V曲线的变化。     

Pharmacodynamic modeling of propofol-induced tidal volume depression in children

Objective  

This investigation aimed to develop a pediatric pharmacodynamic model of propofol-induced tidal volume depression towards an ultimate goal of developing a dosing schedule that would preserve spontaneous breathing following a loading dose of propofol.     

根据压力-容积曲线选择理想潮气量对呼吸机护理的指导

目的 探讨使用呼吸机时,不同的潮气量对急性肺损伤患者血流动力学、肺通气和肺机械力学的影响及护理要点.方法 对ICU急性肺损伤16例患者采取自身对照的方法,利用压力-容积(P-V)曲线下曲点+0.196 kPa确定呼气末正压(PEEP)后,再根据P-V曲线的上拐点(VUIP),分别取上拐点对应的潮气量100%Vt、85%Vt和70%Vt分为3组,以相同的分钟通气量和吸入氧浓度分别给予定容机械通气,监测肺机械力学、血流动力学、血气改变及P-V曲线的变化.结果 85%Vt组在心率、中心静脉压、动脉血氧分压、气道峰值压、气道平均压及系统静态顺应性等对患者的综合影响优于100%Vt组和70%Vt组.结论 以呼吸系统P-V曲线的下曲点(Pinf)确定PEEP值,以上拐点压力对应的潮气量的85%调节潮气量符合个体化保护性通气策略,对改善肺的顺应性、降低肺病理性损伤效果最好.护理时应注重P-V曲线的变化.     

Measurement of tidal volume using a pneumotachometer during high-frequency oscillation

To assess the accuracy of a pneumotachometer (PN) for tidal volume (VT) measurements during high-frequency oscillation (HFO), we determined simultaneously VT using a PN and a full body plethysmograph (PL) in 12 rabbits. HFO was delivered with an oscillator at a frequency of 10 Hz, mean airway pressure of 8 cm H2O, and inspiratory time of 50%. Pressure amplitude (delta P) was varied as follows: 40, 60, 80, 20, 100, 40 cm H2O. Finally, in ten rabbits a spacer equal in deadspace (VD) to that of the PN (15 ml) was left in-line for 5 min. Blood gases were obtained before and after the spacer was added. We found that VT-PN correlates well with VT-PL (r = .92), although the difference between VT-PN and VT-PL is greater at large VT. Significant respiratory acidosis developed with the spacer in-line. PN may be used to trend VT during HFO but PN must not be left in-line, as increased VD seriously affects ventilation.     

Four methods of measuring tidal volume during high-frequency oscillatory ventilation

OBJECTIVE: Assess the accuracy of four different methods of measuring tidal volume during simulated high-frequency oscillatory ventilation. DESIGN: In vitro study. SETTING: Research laboratory. SUBJECTS: Three differential pressure pneumotachometers, a modified Pitot tube, an ultrasound flowmeter, and an adult hot wire anemometer. INTERVENTIONS: Each device was placed in series with a Sensormedics 3100B high-frequency ventilator and an 8.0-mm endotracheal tube attached to a 48.9-L plethysmograph. Inspiratory/expiratory ratio was fixed at 1:1 and mean airway pressure at 10 cm H2O. Tidal volumes were calculated at each combination of frequency (f: 3, 4, 6, 8, 10, 12 Hz) and pressure amplitude (DeltaP: 30, 60, 90 cm H2O) by digital integration of the sampled flow signals from each device and compared with those calculated from pressure changes within the plethysmograph. The protocol was repeated after incorporation of frequency-specific calibrations to the flow-measuring algorithm of each device. The hot wire anemometer was further evaluated at Fio2 of 1.0, 37 degrees C, 80% humidity, mean airway pressure of 20 cm H2O, and an inspiratory/expiratory ratio of 1:2. MEASUREMENTS AND MAIN RESULTS: Tidal volumes were 36-305 mL. Bland-Altman analysis demonstrated that each device exhibited systematic bias before frequency-specific adjustment. After frequency-specific adjustment of the flow-measuring algorithm, the two most accurate and precise devices were the Hans Rudolph pneumotachometer, which exhibited a mean error of 0.2% (95% confidence interval, -3.0% to 3.4%), and the hot wire anemometer, which had a mean error of -1.1% (95% confidence interval, -5.5% to 3.3%). The hot wire anemometer remained accurate at Fio2 1.0, 37 degrees C, 80% humidity, mean airway pressure of 20 cm H2O, and an inspiratory/expiratory ratio of 1:2. CONCLUSIONS: Tidal volume can be measured during high-frequency oscillatory ventilation using a variety of techniques. Frequency-specific calibration improves the accuracy and precision of tidal volume measurements. Hot wire anemometry exhibits stable performance characteristics across the range of temperature, humidity, Fio2, and inspiratory/expiratory ratios encountered clinically, has a small deadspace, is unaffected by mean airway pressure, and is therefore suitable for clinical applications.     

Effect of tidal volume in children with acute hypoxemic respiratory failure

Objectives  To determine if tidal volume (V _T) between 6 and 10 ml/kg body weight using pressure control ventilation affects outcome for children with acute hypoxemic respiratory failure (AHRF) or acute lung injury (ALI). To validate lung injury severity markers such as oxygenation index (OI), PaO₂/FiO₂ (PF) ratio, and lung injury score (LIS). Design  Retrospective, January 2000–July 2007. Setting  Tertiary care, 20-bed PICU. Patients  Three hundred and ninety-eight endotracheally intubated and mechanically ventilated children with PF ratio <300. Outcomes were mortality and 28-day ventilator free days. Measurements and main results  Three hundred and ninety-eight children met study criteria, with 20% mortality. 192 children had ALI. Using >90% pressure control ventilation, 85% of patients achieved V _T less than 10 ml/kg. Median V _T was not significantly different between survivors and non-survivors during the first 3 days of mechanical ventilation. After controlling for diagnostic category, age, delta P (PIP-PEEP), PEEP, and severity of lung disease, V _T was not associated with mortality (P > 0.1), but higher V _T at baseline and on day 1 of mechanical ventilation was associated with more ventilator free days (P < 0.05). This was particularly seen in patients with better respiratory system compliance [Crs > 0.5 ml/cmH₂0/kg, OR = 0.70 (0.52, 0.95)]. OI, PF ratio, and LIS were all associated with mortality (P < 0.05). Conclusions  When ventilating children using lung protective strategies with pressure control ventilation, observed V _T is between 6 and 10 ml/kg and is not associated with increased mortality. Moreover, higher V _T within this range is associated with more ventilator free days, particularly for patients with less severe disease. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.