Rapid Thoracic Compression Technique Research Articles

Early follow-up of lung disease in infants with cystic fibrosis using the raised volume rapid thoracic compression technique and computed tomography during quiet breathing.

Among the different techniques used to monitor lung disease progression in infants with CF diagnosed by Newborn screening (NBS), raised volume-rapid thoracic compression (RVRTC) remains a promising tool. However, the need of sedation and positive pressure ventilation considerably limits its clinical use. We recently described a semi-quantitative method to evaluate air trapping by chest tomography during quite breathing without sedation (CTqb score). This parameter is the radiological sign of airway obstruction and could be also used for lung disease follow-up in infants with CF. However, its discriminative power compared with RVRTC and correlation with lung function parameters are not known. To compare the discriminative powers of the CTqb score and RVRTC parameters and to determine their correlation during the first year of life of infants with CF. In this multicenter longitudinal study, infants with CF diagnosed by NBS underwent RVRTC and CT during quite breathing at 10 ± 4 weeks (n = 30) and then at 13 ± 1 months of age (n = 28). All RVRTC parameters and the CTqb score remained stable between evaluations. The CTqb score showed a higher discriminative power than forced expiratory volume in 0.5 s (FEV0.5 ; the main RVRTC parameter) at both visits (66% and 50% of abnormal values vs 30% and 28%, respectively). No correlation was found between CTqb score and, the different RVRTC parameters or the plethysmographic functional residual capacity, indicating that they evaluate different aspect of CF lung disease.

Bronchodilator response in wheezing infants assessed by the raised volume rapid thoracic compression technique

BackgroundBronchodilator response (BDR) analyzed by the raised volume rapid thoracic compression (RVRTC) in wheezing infants is not yet well described, although bronchodilators (BD) are routine in the treatment of this population. ObjectiveTo evaluate BDR by RVRTC technique in infants with recurrent wheezing and compare to control group. MethodCross sectional study, 45 infants, age 56 weeks (38–67 weeks). Two groups: wheezing group (WG: history of recurrent wheezing) and control group (CG). RVRTC was evaluated, FVC, FEV0.5, FEF50, FEF75, FEF85, FEF25–75 were measured. Salbutamol was delivered to infants and RVRTC evaluated again. BDR was determined by the increase greater than two standard deviation from the mean change in the CG. ResultsIn WG (n = 32) lung function was worse than in CG (n = 13): FEV0.5: 0.0(−0.9–0.9z score) vs 0.8(0.2–1.4z score); FEF50: 0.2(−0.3–1.1z score) vs 0.9(0.5–1.4z score); and FEF25–75: 0.2(−0.5–1.1z score) vs 1.1(0.6–1.6z score), respectively, p < 0.05. Both groups had similar increase after BD. In WG 11 patients (34%) were responder and these had worse lung function compared to nonresponder (n = 21) (p < 0.05). The increase in lung function after BD in responder was higher than in nonresponder: FEV0.5: 6.5(2.1–7.1%) vs −0.5(−2.5–0.7%), FEF50: 5.1(2.7–11.7%) vs 0.4(−1.1–2.8%), FEF75: 20.7(4.7–23.6%) vs −1.3(−6.4–3.9%), FEF25–75: 9.9(3.8–16.4%) vs 0.0(−1.5–1.0%), respectively, p < 0.05. Conclusion34% WG showed BDR measured by the RVRTC. The best variables to detect BDR were FEF75, FEF25–75 and FEV0.5. Patients with worse lung function showed better response to BD.

Lung function over the first 3 years of life in children with congenital diaphragmatic hernia.

Infants with congenital diaphragmatic hernia (CDH) have variable degrees of pulmonary hypoplasia at birth. Few reports of lung function over the first years of life exist in this group of children. Pulmonary function abnormalities correlate with severity of neonatal disease and intensity of neonatal therapies needed. We also hypothesized that longitudinal measurements of lung function over the usual period of rapid lung growth would lend some insight into how the lung remodels in CDH infants. Ninety-eight infants with CDH between 11 days and 44 months of age underwent pulmonary function testing (PFT) on 1-5 occasions using the raised volume rapid thoracic compression technique. Demographic data were also collected. Forced expiratory flows were below normal. Total lung capacity was normal, but residual volume and functional residual capacity were elevated. Children requiring patch closure, ECMO, or pulmonary vasodilators generally had lower lung functions at follow up. Additionally, longer duration of mechanical ventilation correlated with worse lung function. Lung functions of survivors of CDH remain abnormal throughout the first 3 years of life. The degree of pulmonary function impairment correlated both with markers of the initial degree of pulmonary hypoplasia and the duration of mechanical ventilation. Understanding the relationship between the phenotypic presentation of CDH and the potential for subsequent lung growth could help refine both pre- and postnatal therapies to optimize lung growth in CDH infants.

Assessment of early pulmonary function abnormalities in giant omphalocele survivors

PurposeInfants with giant omphalocele (GO) are at increased risk for persistent respiratory insufficiency, yet information regarding the systematic assessment of their lung function is limited. We performed a group of pulmonary function tests (PFTs) including spirometry, fractional lung volume measurements, assessment of bronchodilator responsiveness, and passive respiratory mechanics in GO survivors during infancy and early childhood to evaluate the nature and degree of pulmonary dysfunction. Material and MethodsBetween July 2004 and June 2008, 30 consecutive GO survivors were enrolled in our interdisciplinary follow-up program. Forty-seven percent (14/30) underwent PFT during follow-up evaluation using the raised volume rapid thoracic compression technique to measure forced expiratory flows and bronchodilator responsiveness, body plethysmography to calculate lung volumes, and the single breath occlusion technique to measure passive mechanics of the respiratory system. ResultsThe mean age at PFT assessment was 19.3 ± 19.7 months (range, 1.0-58). Mean forced vital capacity and mean forced expiratory volume in the first 0.5 second were significantly reduced compared with published normative values (P = .03 and P < .01, respectively). Total lung capacity was significantly reduced (P < .001), whereas functional residual capacity, residual volume, and residual volume to total lung capacity ratio were within the normative range (P = .21, P = .34, and P = .48, respectively). Among the 46% who demonstrated significant bronchodilator responsiveness, there were greater increases in the mean percentage changes in flow at 25% to 75% (P = .01), flow at 75% (P < .001), and flow at 85% (P < .001) compared with those participants that did not respond. Specific compliance was reduced, whereas specific conductance increased, compared with published normal results. ConclusionsAbnormalities of pulmonary function in GO survivors include lung volume restriction without airway obstruction, an increased likelihood of airway hyperresponsivness, and reduced respiratory system specific compliance. Early recognition of pulmonary functional impairment in GO survivors could help to develop targeted treatment strategies to reduce the risk of subsequent pulmonary morbidity.

Lung function from infancy to preschool in a cohort of children with cystic fibrosis

This study aimed to describe lung function in a cohort of children with cystic fibrosis (CF) who underwent infant pulmonary function tests (IPFTs) and preschool spirometry. Children performed up to four IPFTs (raised volume rapid thoracic compression technique) over 1 yr and five preschool spirometry tests over up to 2 yrs during participation in prospective, multicentre studies of infant and preschool lung function. All lung function data were reviewed centrally for measurement acceptability. 45 children had 252 acceptable measurements (137 IPFTs and 115 preschool spirometries) at ages 0.3-6.5 yrs. The median number of measurements per participant was 6 (range 3-9). Recent Pseudomonas aeruginosa infection was associated with 5.1% (95% CI 0.01-9.9%) lower forced expiratory volume in 0.5 s (FEV(0.5)) and 16.4% (95% CI 7.0-24.9%) lower forced expiratory flow at 25-25% of forced vital capacity (FEF(25-75%)), after adjustment for length, test type and centre. Recent cough was associated with 5.7% (95% CI 1.1-10.1%) lower FEV(0.5) and 10.1% (95% CI 0.6-18.7%) lower FEF(25-75%). Even after accounting for infection status, cough, sex, length, test type and centre, there was significant inter-individual variability in lung function (p<0.01 for each of FEV(0.5), FEF(25-75%) and forced vital capacity). Recent P. aeruginosa infection and cough are associated with lower lung function in children with CF. Significant inter-individual variability in lung function remains to be explained.

Structure-Respiration Function Relationships Before and After Surgical Treatment of Early-onset Scoliosis

Spine and chest wall deformities in children with early onset scoliosis (EOS) frequently impair respiratory function and postnatal growth of the lung. While a relationship between deformity and such impairment has been reported in children with adolescent idiopathic scoliosis it is not well understood in children with early-onset scoliosis (EOS). We therefore describe (1) the preoperative relation between Cobb angle and forced vital capacity (FVC) in infants with EOS; (2) how changes in Cobb angle before and after surgery relate to changes in lung ventilation and perfusion in the right and left lungs. We measured FVC in 10 children with EOS<3years old using the raised volume rapid thoracic compression (RVRTC) technique and correlated them with Cobb angles. We then measured right lung contributions to total lung ventilation and perfusion using lung scans before and 4 to 57months after placement of vertical expandable prosthetic titanium ribs (VEPTRs) in 15 children with EOS and correlated changes in right lung function with postoperative changes in Cobb angles. In children 4 to 57months of age, preoperative FVC (mean value, 83%; range, 63%-109% of predicted values) did not correlate with Cobb angles (mean value, 56º; range, 14°-120º). In children 1.8 to 11.5years old, right lung ventilation and perfusion were abnormal in eight and seven children, respectively, but neither ventilation nor perfusion predictably normalized despite reductions in Cobb angle postoperatively. The data extend the age range of children with EOS whose Cobb angles correlate poorly with FVC preoperatively. The data are also consistent with reports that reduced Cobb angles after VEPTR insertion do not correlate with postoperative changes in respiratory function.

Effect of inhaled fluticasone on lung function in infants with recurrent wheezing: a randomised controlled trial

BackgroundInhaled corticosteroids are used to treat infants with troublesome asthma-like symptoms but their effect on the lung function of these young patients is controversial. Material and MethodsForty-four infants with recurrent wheezing (more than 3 episodes) and family history of asthma completed this randomised, parallel, double-blind, controlled trial to compare the effect on lung function (main endpoint) of once-daily inhaled fluticasone (375μg) versus placebo for 3 months. Pulmonary function was measured while infants were asymptomatic, using the raised volume rapid thoracic compression technique (spirometry-like), and values were converted to z-scores. ResultsThe fluticasone group showed a significant increase in forced flows, (p<0.001), a lower number of physician diagnosed wheezing episodes (p<0.002), and a significant decrease in the parent-reported number of wheezing episodes per month (p<0.03), as compared to placebo. One third of parents in the placebo group reported a clinical improvement in their infants. There was no significant difference in morning plasma cortisol between groups at entry or discharge. ConclusionsWe conclude that once-daily treatment with 375μg fluticasone increased forced flows and controlled symptoms in infants with recurrent wheezing without altering plasma cortisol levels. The spirometry-like technique is a useful tool to objectively assess the efficacy of anti-asthma medications in infants with repeated troublesome asthma-like symptoms.

Influence of sighs in the raised volume rapid thoracic compression technique (RVRTC) in infants

The raised volume rapid thoracic compression (RVRTC) technique has shown to be very promising in the evaluation of infant's lung function. In this technique lungs are inflated several times to a preset pressure prior to the thoracic compression. Many infants made a spontaneous inspiration (sigh) at the end of these inflations. Our hypothesis was that such sighs could change the major variables derived by this technique and the objective of this study was to evaluate the influence of these sighs during lung inflation in the RVRTC technique in infants. Pairs of maneuvers with and without sighs during lung inflation were obtained in 33 of 48 consecutive tests. Curves with sighs showed significantly higher values of FVC (median: 456 x 437 ml; P < 0.001) and FEV0.5 compared to those without, whereas FEF75 and FEF85 were significantly lower (median: 417 x 439 ml/sec, P = 0.008 and 251 x 273 ml/sec, P = 0.01; respectively). The mean percent change between maneuvers for FVC, FEV0.5, FEF75, and FEF85 was respectively: 6.4%, 3.8%, -3.1%, and -3.5%. These differences represent a mean change of 0.38 z score for FVC and of 0.12 z score for FEF75 and FEF85. In conclusion, the presence of sighs during lung inflation significantly changes RVRTC values in infants. We suggest that the presence or the absence of sighs should be registered for each maneuver and that it should be considered for within and between subject comparisons.

Growth Rate of Lung Function in Healthy Preterm Infants

It remains unclear whether premature birth, in the absence of neonatal respiratory disease, results in abnormal growth and development of the lung. We previously reported that a group of healthy infants born at 32-34 weeks' gestation and without respiratory complications had decreased forced expiratory flows and normal forced vital capacities at 2 months of age. Our current study evaluated whether these healthy infants born prematurely exhibited improvement or "catch-up" in their lung function during the second year of life. Longitudinal measurements of forced expiratory flows by the raised volume rapid thoracic compression technique were obtained in the first and the second years of life for infants born prematurely at 32.7 (range, 30-34) weeks' gestation (n = 26) and infants born at full term (n = 24). Healthy infants born prematurely demonstrate decreased forced expiratory flows and normal forced vital capacities in the first and second years of life. In addition, the increases in lung function with growth were similar to full-term infants. Persistently reduced flows in the presence of normal forced vital capacity and the absence of catch-up growth in airway function suggest that premature birth is associated with altered lung development.

High-resolution computed tomography imaging of airway disease in infants with cystic fibrosis.

The development of early lung disease in patients with cystic fibrosis (CF) remains poorly defined. Determine whether asymptomatic infants with CF have evidence for changes in airway structure when assessed by high-resolution computed tomography, and whether airway structure correlates with airway function in this age group. Thirteen infants with CF (8-33 mo) and 13 control infants (7-25 mo) were evaluated. Airway wall and lumen areas were measured from three 1-mm-thick cross-sectional images obtained from upper, middle, and lower lobes during a respiratory pause with the lungs inflated to an airway pressure of 20 cm H2O. Lung tissue density was measured from images obtained during a respiratory pause at FRC. Forced expiratory flows were measured by the rapid thoracic compression technique in 11 infants with CF. Airway wall area increased more per unit increase in airway size, whereas airway lumen area increased less per unit increase in airway size in the CF than in the control group. Among infants with CF, a greater ratio of wall to lumen area correlated with lower airway function. In addition, lung density at relaxed (passive) FRC was lower for infants with CF than for control infants (0.38 vs. 0.43 g/ml; p < 0.02). Our results indicate that infants with CF have thickened airway walls, narrowed airway lumens, and air trapping, when assessed by high-resolution computed tomography, and measurements of airway structure correlated with airway function.

The effect of montelukast on lung function and exhaled nitric oxide in infants with early childhood asthma

Effective treatment of respiratory symptoms, airway inflammation and impairment of lung function is the goal of any asthma therapy. Although montelukast has been shown to be a possible add-on therapy for anti-inflammatory treatment in older children, its efficacy in infants and young children is not well known. The aim of this study was to investigate its effect in infants and young children with early childhood asthma. In a prospective randomised double-blind placebo-controlled study, 24 young children (10-26 months) with wheeze, allergy and a positive family history of asthma consistent with the diagnosis of early childhood asthma were randomised to receive montelukast 4 mg or placebo. The forced expiratory volume in 0.5 seconds (FEV0.5) was measured using the raised volume rapid thoracic compression technique, and fractional exhaled nitric oxide (FeNO) and symptom scores were determined. No change was noted in FEV0.5, FeNO or symptom score in the placebo group following the treatment period. In contrast, significant improvements in mean+/-SD FEV0.5 (189.0+/-37.8 and 214.4+/-44.9 mL before and after treatment, respectively), FeNO (29.8+/-10.0 and 19.0+/-8.5 ppb) and median symptom score (5.5 and 1.5) were noted following treatment with montelukast. In conclusion, montelukast has a positive effect on lung function, airway inflammation and symptom scores in very young children with early childhood asthma.

Variability of the raised volume rapid thoracic compression technique in infants with recurrent wheezing

Measuring forced expiratory flows from raised lung volume in infants represents a significant advance in the assessment of pulmonary function early in life. However, variability in the main parameters obtained with raised volume rapid thoracic compression (RVRTC), FVC, FEV 0.5, FEF 50, FEF 75, and FEF 25-75, has not been completely evaluated. This study was performed to determine the intra-subject variability of spirometric-like parameters in infants with recurrent wheezing obtained with RVRTC. One hundred and two infants with recurrent wheezing (mean age 62 ± 22 weeks) who were asymptomatic at the moment of measuring lung function participated in this study. For the variability analysis, three to five technically acceptable curves at flow-limitation jacket pressure were employed. The mean coefficient of variation (95 % CI) of spirometric parameters was as follows: FVC = 2.9 % (2.6-3.2); FEV 0.5 = 2.2% (1.9-2.5); FEF 50 = 3.7% (3.3-4.1); FEF 75 = 5.9% (5.2-6.6) and FEF 25-75 = 3.3% (2.9-3.7). This study demonstrates the high reproducibility of the spirometric parameters measured with the technique of raised lung volume in infants.

Parental Smoking and Airway Reactivity in Healthy Infants

Parental tobacco smoking is associated with lower airway function and an increased incidence of wheezy respiratory illnesses in infants. We evaluated in 76 healthy infants whether exposure to parental tobacco smoking was associated with airway hyperreactivity, which could contribute to lower airway function and the increased wheezy illnesses. Airway function was measured using the raised-volume rapid thoracic compression technique, and airway reactivity was assessed by methacholine challenge (0.015-10 mg/ml), which was stopped for a more than 30% decrease in forced expiratory flow (FEF)(75) or the final dose with a less than 30% decrease. Parental tobacco smoking was associated with lower baseline airway function (FEF(50), 600 vs. 676 ml/second, p < 0.04; FEF(25-75), 531 vs. 597 ml/second, p < 0.05). Infants exposed to tobacco smoking were approximately half as likely to develop a more than 30% decline in FEF(75) at any given methacholine dose (hazard ratio = 0.4, p = 0.001). In addition, a history of asthma in an extended family member increased the likelihood that an infant would develop a more than 30% decline in FEF(75) (hazard ratio = 1.7, p = 0.04). We conclude that exposure to parental smoking is associated with lower airway function but not increased airway reactivity; however, family history of asthma is associated with heightened airway reactivity.

Measurement of Forced Expiratory Flows and Lung Volumes

After completing this article, readers should be able to: 1. Describe the information that measurements of forced expiratory flow can provide in spontaneously breathing and mechanically ventilated infants. 2. Delineate how lung volume can be measured. The measurements of forced expiratory flows and lung volumes are important to the evaluation of patients who have respiratory symptoms. Until recently, measurements have been restricted to adults and children old enough to cooperate with testing maneuvers. Newer techniques have enabled such measurements to be made in infants and led to improved understanding of normal lung and airway growth during infancy and early childhood, when dramatic changes occur. The measurements have had important clinical uses in the evaluation and treatment of infants who have respiratory disease, but their use has been limited because they require specialized equipment and expertise as well as sedation of the infant. In this article, we discuss the techniques required for measurement of forced expiratory flows and lung volumes, their limitations, and applications in clinical practice. Detection of airflow obstruction, by physical examination or by quantitative measurement techniques, is facilitated by increasing expiratory flow rates. Measurement of forced expiratory flows is useful because flow rates are inversely proportional to the fourth power of the radius of the airway and, therefore, are indicative of airway size when flow is limited. Disease states affecting the airways, including asthma, bronchopulmonary dysplasia (BPD), or congenital lesions such as pulmonary hypoplasia or vascular airway compression, are expected to decrease expiratory flow. Infants typically are sedated for testing to maintain relaxed breathing with a face mask placed over the mouth and nose. This sedation often is perceived by parents and physicians as one of the barriers to such testing. (1) However, sedation can be achieved safely using oral chloral hydrate at a dose of 80 to 100 mg/kg. …

The Role of Pulmonary Function Testing in Infants

Tests of pulmonary function are used routinely in school-age and older children to augment or confirm clinical findings obtained by a careful history and physical examination. Spirometry allows both detection of airway obstruction even before wheezing can be heard and objective assessment of medical interventions. Measurement of lung volumes separates those processes that cause restriction from those that do not affect lung size or those that cause air trapping. Serial measurements have yielded important insights into the normal growth and aging of the lung as well as showing how various diseases affect lung and airway growth and repair. Although techniques to measure lung function in infants and toddlers have been available for more than 40 years, they have not been used clinically to the same degree that pulmonary function testing has been used in older children and adults. Possible reasons for infant pulmonary function testing not to be performed routinely relate both to the testing conditions and to the information gained. Chief among the former is the need to sedate all but the youngest infants to perform many of these studies. Both parents (1) and physicians (2) express concern over the need to sedate sick infants, even though the sedation typically is tolerated well. Some tests, such as respiratory inductive plethysmography or the forced oscillation technique, do not require sedation of the infant. Other procedural barriers include what must be done to the infant to obtain the necessary information. For example, measurements of dynamic pulmonary compliance and resistance require placement of an esophageal balloon or catheter and, therefore, are considered invasive. Forced expiratory flows by the rapid thoracic compression (“squeeze”) technique may appear uncomfortable for the infant, although infants do not demonstrate any physiologic signs of distress or discomfort during the testing. Some parents have expressed negative feelings after …

Assessment of exhaled nitric oxide kinetics in healthy infants.

Exhaled nitric oxide (Fe(NO)) measurements provide a noninvasive approach to the evaluation of airway inflammation. Flow-independent NO exchange parameters [airway NO transfer factor (D(NO)) and airway wall NO concentration (Cw(NO))] can be estimated from Fe(NO) measurements at low flows and may elucidate mechanisms of disturbances in NO exchange. We measured Fe(NO) in sedated infants by using an adaptation of a raised lung volume rapid thoracic compression technique that creates forced expiration through a mass-flow controller that lasts 5-10 s, at a constant preset flow. We measured Fe(NO) at expired flows of 50, 25, and 15 ml/s in five healthy infants (7-31 mo). Median Fe(NO) increased [24, 40, and 60 parts per billion (ppb)] with decreasing expiratory flows (50, 25, and 15 ml/s). Group median (range) for D(NO) and Cw(NO) were 12.7 (3.2-37) x 10(-3) nl. s(-1). ppb(-1) and 108.9 (49-385) ppb, respectively, similar to values reported in healthy adults. Exhaled NO is flow dependent; flow-independent parameters of exhaled NO kinetics can be assessed in infants and are similar to values described in adults.

Comparison of Subjective and Objective Measures in Recurrently Wheezy Infants

Objectives: The aim of this study was to compare subjective measures (overall health assessment both by the study physician and the child’s mother) with objective measurements of forced expiratory volumes (FEV_t) and maximal flow at functional residual capacity v̇_maxFRC) in recurrently wheezy infants. Methods: Sixteen wheezy infants (12 boys) aged 8–26 months were studied. A clinical assessment at visit 1 was followed by the run-in period during which day- and nighttime asthma symptom scores were obtained. The actual study period consisted of 2 visits when patient’s lung function was assessed. The first of which was during an acute exacerbation (visit 2), while the second was when the infant was asymptomatic (visit 3). FEV_t were obtained by the raised volume rapid thoracic compression technique (RVRTC) and v̇_maxFRC by the tidal volume rapid thoracic compression technique (TVRTC). Results: Mean FEV_t but not mean v̇_maxFRC were significantly lower at visit 2 compared to visit 3 (FEV_0.5: p = 0.005, and FEV_0.75: p = 0.002; v̇_maxFRC: p = 0.15) and correlated well with overall health assessment by the study physician (FEV_0.5: r = 0.82, and FEV_0.75: r = 0.84), but not with the overall health assessment by the mother. Conclusions: We have shown in the present study that objective measurements of FEV_t from a raised lung volume correlate well with the overall health assessment by the study physician; this was in contrast to measurements of v̇_maxFRC in the tidal volume range. We therefore conclude that the RVRTC technique is a feasible method to assess and monitor obstructive lung disease in infancy.

Clinical Assessment of Airway Function in Health and Disease

After completing this article, readers should be able to: 1. Describe which pulmonary function tests can be used to measure tidal lung mechanics and forces of expiratory flow. 2. Describe the airway conditions that can be assessed radiographically. 3. Delineate clinical methods of diagnosing central airway collapse and quantifying airway wall stiffness. Clinical assessment of pulmonary function is a valuable tool in the identification and treatment of neonatal disease. As shown in the Table⇓, a multitude of tests is available to identify and measure airway function clinically in pediatric populations. These tests often identify functional abnormalities in the airways of preterm infants exposed to mechanical ventilation, including elevated resistance, decreased forced expiratory flow, airway hyperreactivity, and excessive central airway collapsibility. In addition to aiding in diagnosis, these procedures help predict the effects of early injury on future airway growth and function and can be used to evaluate the effectiveness of newer therapies. Serial evaluation of airway function is especially useful for infants who fail to improve as expected; who have frequent severe exacerbations of pulmonary dysfunction; or who demonstrate stridor, chronic wheezing, or focal areas of chronic atelectasis or hyperinflation. View this table: Table Clinical Evaluation of Airway Function With the simultaneous measurement of respiratory pressures, volumes, and air flow, pulmonary mechanics can be monitored relatively noninvasively. Pulmonary function profiles can be determined to assess initial disease etiology, the response to therapy, and disease sequelae during follow-up. For example, the pressure-volume relationship of a preterm infant can identify the degree of respiratory function and monitor the response following surfactant administration (Fig. 1). The evaluation of tidal breath pressure-volume relationships serves as a tool to optimize the parameters of mechanical ventilation (Fig. 2). Over time, sequential pulmonary mechanics can be used to monitor the progression and improvement in both lung and airway abnormalities (Fig. 3). Dynamic …

Association of tobacco smoke exposure and respiratory syncitial virus infection with airways reactivity in early childhood.

Exposure to infectious agents and environmental tobacco smoke are thought to induce bronchial hyperresponsiveness (BHR). This study was undertaken to determine the effects of passive exposure to tobacco smoke and respiratory syncitial virus (RSV) lower respiratory infection (LRI) during infancy on the occurrence of BHR in the first 2 years of life. Eighty-six cases of documented RSV (mean age, 188 days) and 78 controls (mean age, 162 days) were enrolled from the clinic and in-patient service of a single hospital. None had a history of prior LRI. Subjects were studied at 6-month intervals up to 19 months of age with a standardized respiratory illness and parental smoking questionnaire, partial expiratory flow-volume curves by the "hug" (rapid thoracic compression) technique, and methacholine challenge. Exposure to maternal and paternal cigarette smoking, maternal history of asthma, and mold exposure were associated with decreased levels of length-corrected maximal flow at functional residual capacity (V'(maxFRC)). RSV-LRI was not related to V'(maxFRC). After adjustment of V'(maxFRC) for these factors, V'(maxFRC) was a significantly and positively correlated with a methacholine concentration provoking a 40% fall in V'(maxFRC) (PC40) and negatively correlated with dose-response slope. After adjustment for V'(maxFRC), there were no independent effects of tobacco smoke exposure or RSV-LRI on methacholine responses. These data do not support a role for RSV as a risk factor for airways reactivity in childhood and indicate that exposure to tobacco smoke affects airways reactivity through its effects on airways.

Infant's Airway Responsiveness Predicts Asthma at 6 Years of Age

Pulmonology| July 01 2001 Infant’s Airway Responsiveness Predicts Asthma at 6 Years of Age AAP Grand Rounds (2001) 6 (1): 9–10. https://doi.org/10.1542/gr.6-1-9 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Infant’s Airway Responsiveness Predicts Asthma at 6 Years of Age. AAP Grand Rounds July 2001; 6 (1): 9–10. https://doi.org/10.1542/gr.6-1-9 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search toolbar search search input Search input auto suggest filter your search All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: airway device, airway structure, asthma, histamine, wheezing Source: Palmer LJ, Rye PJ, Gibson NA, et al. Airway responsiveness in early infancy predicts asthma, lung function, and respiratory symptoms by school age. Am J Respir Crit Care Med. 2001;163:37–42. The purpose of this study by investigators at the University of Western Australia and the TVW Telethon Institute for Child Health Research in Perth, Australia, was to determine the relationship between airway hyper-responsiveness in healthy neonates at 1 month of age and the subsequent development of asthma, atopy, lower respiratory tract symptoms, and lung function at 6 years of age. The subjects were randomly recruited from a metropolitan hospital prior to birth between 1987 and 1991. Initial pulmonary function and histamine challenge were performed at approximately 1 month of age, prior to any lower respiratory tract infection or clinical illness. Of the initial 253 children, 120 could be contacted and all agreed to participate in follow-up studies on about their sixth birthday. Comparing the infants available for follow-up with those lost to follow-up identified no significant differences at 1 month of age for any parameters of interest. The infant pulmonary function testing was achieved by the rapid thoracic compression technique measuring maximal flow at functional residual capacity (VmaxFRC). The histamine challenge consisted of increasing doses of nebulized histamine from .125g/L to a maximum of 8.0g/L; the provocation concentration producing a 40% decrease in VmaxFRC was estimated from the log dose-response curve. Skin reactivity was assessed for dust mites, rye grass, cow’s milk and egg white. Pulmonary function testing at 6 years of age was done by conventional spirometry according to American Thoracic Society standards. Repeated pulmonary function testing after increasing nebulized doses of histamine was used to establish the dose-response slope to histamine challenge. Skin testing at this time included the same allergens as before in addition to mixed grass, cat and dog. Careful family histories for respiratory and allergic diseases were obtained at both data intervals. Generalized linear models were constructed to investigate the relationships between the histamine responsiveness at 1 month of age and the respiratory outcome at age 6 years. Of the 120 6-year-olds, 14.2% reported wheezing apart from colds, 35.0% reported wheezing with colds, 25.8% had a usual cough and 32.5% had current or previous physician-diagnosed asthma. The histamine sensitivity at 1 month of age was significantly associated with physician-diagnosed asthma (ever) (P=.003), physician-diagnosed current asthma (P<.001), wheeze with colds (P=.003), wheeze apart from colds (P<.001), and usual cough (P=.05). The subjects with the greatest response to histamine at both 1 month and 6 years of age had the lowest forced expiratory volume at 1 second (FEV1) at 6 years of age. There was no significant association between the histamine sensitivity at 1 month and the atopy-associated factors such as eosinophil count, total serum IgE, and positive skin test reactivity assessed at 6 years of age. The authors conclude from this data that airway... You do not currently have access to this content.