Airway reactivity in infants: a positive response to methacholine and metaproterenol

1987 ◽  
Vol 62 (3) ◽  
pp. 1155-1159 ◽  
Author(s):  
R. S. Tepper
Keyword(s):  
Challenge Test ◽  
Threshold Concentration ◽  
Base Line ◽  
Tidal Breathing ◽  
Airway Reactivity ◽  
Bronchial Smooth Muscle ◽  
Bronchial Challenge ◽  
Control Value ◽  
Residual Capacity ◽  
The Mean

Because the presence of bronchial smooth muscle reactivity in infants remains controversial, airway reactivity was assessed in 10 normal, asymptomatic male infants less than 15 mo of age by measuring the changes that occurred in the maximal expiratory flows at functional residual capacity (VmaxFRC) during a methacholine bronchial challenge test. Sleeping infants inhaled doubling concentrations of methacholine by 2 min of tidal breathing, starting with a concentration of 0.075 mg/ml, and the bronchial challenge was stopped when VmaxFRC decreased by at least 40%. The threshold concentration of methacholine required to produce a decrease in VmaxFRC by 2 SD's of the control value was 0.43 mg/ml (0.11–0.90). By a methacholine concentration of 1.2 mg/ml, all infants decreased VmaxFRC by at least 40% (range 40–75%), and the mean dose required to produce a 40% decrease was 0.72 mg/ml. The airway reactivity was not related to base-line flows. During the methacholine challenge, no infant developed wheezing, but the percent oxygen saturation for the group decreased significantly (P less than 0.05) from 94 to 92%. Following the methacholine, the infants inhaled the bronchodilator metaproterenol, and 10 min later, VmaxFRC returned to base line. This study demonstrates that infants exhibit airway reactivity as evidenced by bronchoconstriction with methacholine and the subsequent bronchodilation with metaproterenol.

Airway reactivity and lung function in triiodothyronine-induced thyrotoxicosis

1985 ◽  
Vol 58 (5) ◽  
pp. 1485-1488 ◽  
Author(s):  
R. S. Irwin ◽  
M. R. Pratter ◽  
D. H. Stivers ◽  
L. E. Braverman
Keyword(s):  
Lung Function ◽  
Pulmonary Function ◽  
Respiratory Symptoms ◽  
Pulmonary Function Tests ◽  
Forced Expiratory Volume ◽  
Base Line ◽  
Airway Reactivity ◽  
Percent Change ◽  
Serum T3 ◽  
The Mean

To evaluate the possible relationship between asthma and hyperthyroidism, airway reactivity and lung function were prospectively compared in healthy volunteers before, during, and after liothyronine (triiodothyronine, T3)-induced hyperthyroidism. Base-line evaluation of the 10 subjects included clinical evaluation, thyroid and pulmonary function tests, and airway reactivity assessed by methacholine inhalational challenge (MIC). All studies were normal. During T3-induced hyperthyroidism, no subject developed respiratory symptoms or changes in pulmonary function or airway reactivity. The mean percent change in forced expiratory volume at 1 s from base line (delta FEV1) of -2.4 +/- 3.0 after MIC was not significantly different from that obtained before T3 administration (-1.4 +/- 1.5, P greater than 0.2). When all serum T3 concentrations and delta FEV1 values before, during and after T3-induced hyperthyroidism were compared, there was no significant correlation. We conclude that T3-induced hyperthyroidism of 3-wk duration has no effect on airway reactivity or lung function in normal volunteers.

Comparison of glottic areas measured by acoustic reflections vs. computerized tomography

1988 ◽  
Vol 64 (1) ◽  
pp. 367-370 ◽  
Author(s):  
A. D. D'Urzo ◽  
I. Rubinstein ◽  
V. G. Lawson ◽  
K. P. Vassal ◽  
A. S. Rebuck ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression Analysis ◽  
Acoustic Method ◽  
Ct Scans ◽  
Tidal Breathing ◽  
Acoustic Reflection ◽  
Acoustic Technique ◽  
Residual Capacity ◽  
Equivalent Area ◽  
The Mean

We compared measurements of glottic area obtained by acoustic reflection technique with anatomically equivalent area measured from computerized tomographic (CT) scans of the neck in 11 subjects with glottic pathology. Both measurements were performed in the supine position during tidal breathing at functional residual capacity. We found excellent agreement in glottic areas obtained by both methods: the mean (+/- SD) values were 1.8 +/- 0.8 cm2 for the acoustic method and 1.7 +/- 0.9 cm2 for the CT method. Linear regression analysis revealed the following relationship between the area measured by acoustic technique (AAC) and that measured by CT (ACT): AAC = 0.81.ACT + 0.36. There was a significant correlation between the two measurements of glottic area (r = 0.95, P less than 0.0001). We conclude that the acoustic reflection technique may be used reliably in clinical and physiological studies concerned with glottic geometry.

Effect of age on lung mechanics and airway reactivity in lambs

1986 ◽  
Vol 61 (6) ◽  
pp. 2074-2080 ◽  
Author(s):  
R. A. Sauder ◽  
K. J. McNicol ◽  
A. A. Stecenko
Keyword(s):  
Citric Acid ◽  
Dynamic Compliance ◽  
Lung Mechanics ◽  
Base Line ◽  
Airway Reactivity ◽  
Airway Opening ◽  
Residual Capacity ◽  
Nasotracheal Tube ◽  
Males And Females ◽  
Significant Change

We studied airway reactivity (AR) to aerosolized histamine, carbachol, and citric acid in lambs 1 mo of age to adulthood. Awake lambs were intubated and studied in a plethysmograph that measured dynamic compliance (Cdyn), resistance of the lung (RL), and functional residual capacity (FRC). Pleural pressure was measured using a Silastic balloon in the pleural space, and airway opening pressure (Pao) was measured using a catheter placed 1–2 cm distal to the nasotracheal tube. At the ages of 1, 3, 5, and 7 mo and adulthood, measurements of Cdyn, RL, and FRC were obtained in 46 sheep (22 males, 24 females). AR to carbachol, histamine, and citric acid was measured in each sheep in randomized order on three separate days by giving increasing concentrations of the drug in a noncumulative fashion. The dose that would have caused a 35% reduction in Cdyn (ED65Cdyn), a doubling of RL (ED200RL), or a 50% increase in FRC (ED150FRC) was calculated. In both males and females, base-line Cdyn increased (r = 0.81, P less than 0.01) with age, as did FRC (r = 0.87, P less than 0.01). There was no significant change in RL in either sex with age or in the group as a whole. There was a significant increase in AR to both histamine and carbachol with increasing age as measured by a decrease in ED65Cdyn (P less than 0.01 and P less than 0.05, respectively) with age. There was no significant change in AR with age as measured by RL or FRC for any of the three bronchoconstrictors tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary mechanics during exercise in normal males

1980 ◽  
Vol 49 (3) ◽  
pp. 506-510 ◽  
Author(s):  
D. G. Stubbing ◽  
L. D. Pengelly ◽  
J. L. Morse ◽  
N. L. Jones
Keyword(s):  
Transpulmonary Pressure ◽  
Progressive Increase ◽  
Cycle Ergometer ◽  
Pulmonary Mechanics ◽  
Normal Male ◽  
Tidal Breathing ◽  
Control Value ◽  
Pulmonary Compliance ◽  
Capillary Blood Volume ◽  
Residual Capacity

A body plethysmograph adapted to contain the pedals of an electrically braked cycle ergometer was used to measure pulmonary mechanics during steady-state exercise in 12 normal male subjects aged 22-65 yr. During exercise there was a progressive increase in residual volume to 119% of the value at rest (P less than 0.01), but functional residual capacity and total lung capacity did not change. The maximum expiratory flow-volume (MEFV) curves did not change and flow rates during tidal breathing did not exceed the MEFV curve. Dynamic pulmonary compliance fell to 91.3% of the control value and static expiratory pulmonary compliance fell to 76.9% of the control value (P less than 0.05). Pulmonary resistance did not change during exercise. Transpulmonary pressure during tidal breathing was negative even at the highest power outputs. The fall in compliance may be due to an increase in pulmonary capillary blood volume. These results demonstrate the importance of measuring absolute thoracic gas volume and the elastic properties of the lung when comparing pulmonary mechanics at rest and during exercise.

Airways responsiveness determined by consecutive histamine challenges in asymptomatic asthmatics

1989 ◽  
Vol 67 (6) ◽  
pp. 2622-2626 ◽  
Author(s):  
M. Kung ◽  
G. C. Scott ◽  
N. K. Burki
Keyword(s):  
Bronchial Asthma ◽  
Recovery Time ◽  
Forced Expiratory Volume ◽  
Base Line ◽  
Characteristic Finding ◽  
Normal Value ◽  
Control Value ◽  
The Mean ◽  
Buffer Control ◽  
Initial Base

The effect of two consecutive histamine inhalation challenges on airways responsiveness was assessed in a group of eight nonsmoking nonmedicated asthmatics aged 19-27 yr. All subjects had a base-line forced expiratory volume in 1 s (FEV1) of greater than 80% of their predicted normal value before the initial challenge and were allowed to recover to greater than 95% of the initial base-line FEV1 value before the second challenge was initiated. The average airways recovery time after the first challenge was 44 min but ranged between 30 and 90 min. The mean +/- SD values of cumulative histamine dose units provoking a 20% decrease of the FEV1 from the buffer control value (PD20FEV1) were 10.79 +/- 5.95 determined with the first and 30.50 +/- 46.36 with the second challenge (P greater than 0.05). We conclude that sequential histamine challenges performed in mild asthmatics with closely controlled prechallenge airways function are well tolerated. Although some variance does exist in intersubject airways recovery time and in intra-subject histamine airways responsiveness determined by sequential challenges, our data do not support recent observations (J. Appl. Physiol. 63: 1572-1577, 1987) that histamine tolerance is a characteristic finding associated with bronchial asthma.

scholarly journals Measurement of tidal breathing flows in infants using impedance pneumography

2016 ◽  
Vol 49 (2) ◽  
pp. 1600926 ◽  
Author(s):  
Leo Pekka Malmberg ◽  
Ville-Pekka Seppä ◽  
Anne Kotaniemi-Syrjänen ◽  
Kristiina Malmström ◽  
Merja Kajosaari ◽  
...  
Keyword(s):  
Lung Function ◽  
Tidal Flow ◽  
Mean Deviation ◽  
Flow Volume ◽  
Tidal Breathing ◽  
Impedance Pneumography ◽  
Similar Association ◽  
Residual Capacity ◽  
The Mean ◽  
Airway Conductance

Tidal breathing flow volume (TBFV) profiles have been used to characterise altered lung function. Impedance pneumography (IP) is a novel option for assessing TBFV curves noninvasively. The aim of this study was to extend the application of IP for infants and to estimate the agreement between IP and direct pneumotachograph (PNT) measurements in assessing tidal airflow and flow-derived indices.Tidal flow profiles were recorded for 1 min simultaneously with PNT and uncalibrated IP at baseline in 44 symptomatic infants, and after methacholine-induced bronchoconstriction in a subgroup (n=20).The agreement expressed as the mean deviation from linearity ranged between 3.9 and 4.3% of tidal peak inspiratory flow, but was associated with specific airway conductance (p=0.002) and maximal flow at functional residual capacity (V′maxFRC) (p=0.004) at baseline. Acute bronchoconstriction induced by methacholine did not significantly affect the agreement of IP with PNT. TBFV indices derived from IP were slightly underestimated compared to PNT, but were equally well repeatable and associated with baseline V′maxFRC (p=0.012 and p=0.013, respectively).TBFV profiles were consistent between IP and PNT in most infants, but the agreement was affected by reduced lung function. TBFV parameters were not interchangeable between IP and PNT, but had a similar association with lung function in infants.

scholarly journals AB0393 EFFICACY OF HYDROXYCHLOROQUINE FOR LUPUS NEPHRITIS IN MAINTENANCE PHASE

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1496.2-1496
Author(s):  
M. Watanabe ◽  
Y. Haji ◽  
M. Kato ◽  
T. Ito ◽  
Y. Banno ◽  
...  
Keyword(s):  
Lupus Nephritis ◽  
Lupus Erythematosus ◽  
Therapeutic Option ◽  
Maintenance Phase ◽  
Base Line ◽  
Prednisolone Dose ◽  
Daily Urine ◽  
Group A ◽  
The Mean ◽  
Group B

Background:Hydroxychloroquine (HCQ) is an essential drug for systemic lupus erythematosus. But in Japan, chloroquine and HCQ remain unavailable until mid 2015 because of a series of lawsuits about its retinal toxicity in the 1970s. There is insufficient knowledge regarding renal protective effect of HCQ.Objectives:We aimed to investigate its efficacy of adding HCQ for Lupus nephritis (LN) as a maintenance-phase therapy.Methods:We conducted an observational retrospective cohort study included patients with LN (n=42) in maintenance-phase in Japan. We reviewed medical records of LN patients aged > 18 years who were initiated HCQ from May 2015 to May 2018. Maintenance phase was defined as stabilization in serum creatinine and urinary segment after induction therapy and who achieved complete or partial remission. The annual change of proteinuria was compared between patients on HCQ who have proteinuria (>0.5g/gCr) or not. Other outcome measures were disease flare, dose of steroids, renal and immunologic features.Results:A total of 42 patients were analyzed and allocated to two groups based on their amount of daily urine protein level: HCQ with proteinuria as group A (>0.5g/gCr, n=14) and HCQ without proteinuria as group B(≦0.5g/gCr, n=28). Both groups were comparable, with mean (SD) age of 36.1 (12.9) years and 37.5 (13.8), female 78.6% and 92.9% in each group, mean (SD) disease duration until HCQ of 3.5 (3.25) and 3.3 (2.9) years in group A and group B, with prednisolone dose at base line of 10.3 (7.1) mg and 7.9 (4.4) mg, respectively. The mean (SD) proteinuria at base line was 1.38 (1.11) g/gCr in group A and 0.20 (0.09) g/gCr in group B and after 12 months, proteinuria decreased in group A (-1.34 g/gCr in group A vs +0.03 g/gCr in group B; p<.001;95% CI,0.305-0.736). No relapse was experienced in group A during the study period.Conclusion:In patients with clinically stable LN but with proteinuria, hydroxychloroquine is a good therapeutic option for achievement of complete remission.Disclosure of Interests:None declared

Relationship of end-expiratory pressure, lung volume, and 99mTc-DTPA clearance

1987 ◽  
Vol 63 (4) ◽  
pp. 1586-1590 ◽  
Author(s):  
J. A. Cooper ◽  
H. van der Zee ◽  
B. R. Line ◽  
A. B. Malik
Keyword(s):  
Lung Volume ◽  
Clearance Rate ◽  
Base Line ◽  
Lung Inflation ◽  
Alveolar Epithelial ◽  
Pulmonary Clearance ◽  
Residual Capacity ◽  
Dose Response Effect ◽  
Relationship Of ◽  
Line P

We investigated the dose-response effect of positive end-expiratory pressure (PEEP) and increased lung volume on the pulmonary clearance rate of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA). Clearance of lung radioactivity was expressed as percent decrease per minute. Base-line clearance was measured while anesthetized sheep (n = 20) were ventilated with 0 cmH2O end-expiratory pressure. Clearance was remeasured during ventilation at 2.5, 5, 10, 15, or 20 cmH2O PEEP. Further studies showed stepwise increases in functional residual capacity (FRC) (P less than 0.05) measured at 0, 2.5, 5, 10, 15, and 20 cmH2O PEEP. At 2.5 cmH2O PEEP, the clearance rate was not different from that at base line (P less than 0.05), although FRC was increased from base line. Clearance rate increased progressively with increasing PEEP at 5, 10, and 15 cmH2O (P less than 0.05). Between 15 and 20 cmH2O PEEP, clearance rate was again unchanged, despite an increase in FRC. The pulmonary clearance of aerosolized 99mTc-DTPA shows a sigmoidal response to increasing FRC and PEEP, having both threshold and maximal effects. This relationship is most consistent with the hypothesis that alveolar epithelial permeability is increased by lung inflation.

Detection of diaphragmatic fatigue in man by phrenic stimulation

1981 ◽  
Vol 50 (3) ◽  
pp. 538-544 ◽  
Author(s):  
M. Aubier ◽  
G. Farkas ◽  
A. De Troyer ◽  
R. Mozes ◽  
C. Roussos
Keyword(s):  
Phrenic Nerve ◽  
Chronic Obstructive Lung Disease ◽  
Chronic Obstructive ◽  
Low Frequencies ◽  
Transdiaphragmatic Pressure ◽  
Control Value ◽  
Transcutaneous Stimulation ◽  
Diaphragmatic Fatigue ◽  
Residual Capacity ◽  
Stimulation Of

Transdiaphragmatic pressure (Pdi) was measured at functional residual capacity (FRC) in four normal seated subjects during supramaximal, supraclavicular transcutaneous stimulation of one phrenic nerve (10, 20, 50, and 100 Hz--0.1 ms duration) before and after diaphragmatic fatigue, produced by breathing through a high alinear inspiratory resistance. Constancy of chest wall configuration was achieved by placing a cast around the abdomen and the lower one-fourth of the rib cage. Pdi increased with frequency of stimulation, so that at 10, 20, and 50 Hz, the Pdi generated was 32 +/- 4 (SE), 70 +/- 3, and 98 +/- 2% of Pdi at 100 Hz, respectively. After diaphragmatic fatigue, Pdi was less than control at all frequencies of stimulation. Recovery for high stimulation frequencies was complete at 10 min, but at low stimulation frequencies recovery was slow: after 30 min of recovery, Pdi at 20 Hz was 31 +/- 7% of the control value. It is concluded that diaphragmatic fatigue can be detected in man by transcutaneous stimulation of the phrenic nerve and that diaphragmatic strength after fatigue recovers faster at high than at low frequencies of stimulation. Furthermore, it is suggested that this long-lasting element of fatigue might occur in patients with chronic obstructive lung disease, predisposing them to respiratory failure.

Effects of body position change on thoracoabdominal motion

1978 ◽  
Vol 45 (4) ◽  
pp. 581-589 ◽  
Author(s):  
V. P. Vellody ◽  
M. Nassery ◽  
W. S. Druz ◽  
J. T. Sharp
Keyword(s):  
Supine Position ◽  
Muscle Force ◽  
Body Position ◽  
Tidal Breathing ◽  
Position Change ◽  
Rib Cage ◽  
Inspiratory Muscles ◽  
Residual Capacity ◽  
Lateral Decubitus ◽  
Local Compliance

With a linearized respiratory magnetometer, measurements of anteroposterior and lateral diameters of both the rib cage and the abdomen were made at functional residual capacity and continuously during tidal breathing. Twenty-five subjects with normal respiratory systems were studied in the sitting, supine, lateral decubitus, and prone body positions. When subjects changed from sitting to supine position anteroposterior diameters of both rib cage and abdomen decreased while their lateral diameters increased. Both anteroposterior and lateral tidal excursions of the rib cage decreased; those of the abdomen increased. When subjects turned from supine to lateral decubitus position both anteroposterior diameters increased and the lateral diameters decreased. This was associated with an increase in both lateral excursions and a decrease in the abdominal anteroposterior excursions. Diameters and tidal excursions in the prone position resembled those in the supine position. Diameter changes could be explained by gravitational effects. Differences in tidal excursions accompanying body position change were probably related to 1) differences in the distribution of respiratory muscle force, 2) differences in the activity or mechanical advantage of various inspiratory muscles, and 3) local compliance changes in parts of the rib cage and abdomen.

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