scholarly journals Micron-sized intrapulmonary particle deposition in the developing rat lung

2012 ◽  
Vol 112 (5) ◽  
pp. 759-765
Author(s):  
Holger Schulz ◽  
Gunter Eder ◽  
Ines Bolle ◽  
Akira Tsuda ◽  
Stefan Karrasch
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Surface Area ◽  
Lung Development ◽  
Particle Deposition ◽  
Structural Changes ◽  
Breathing Patterns ◽  
Respiratory Parameters ◽  
Wistar Kyoto ◽  
Postnatal Lung Development

Little is known about the effects of postnatal developmental changes in lung architecture and breathing patterns on intrapulmonary particle deposition. We measured deposition in the developing Wistar-Kyoto rat, whose lung development largely parallels that of humans. Deposition of 2-μm sebacate particles was determined in anesthetized, intubated, spontaneously breathing rats on postnatal days (P) 7 to 90 by aerosol photometry (Karrasch S, Eder G, Bolle I, Tsuda A, Schulz H. J Appl Physiol 107: 1293–1299, 2009). Respiratory parameters were determined by body plethysmography. Tidal volume increased substantially from P7 (0.19 ml) to P90 (2.1 ml) while respiratory rate declined from 182 to 107/min. Breath-specific deposition was lowest (9%) at P7 and P90 and markedly higher at P35 (almost 16%). Structural changes of the alveolar region include a ninefold increase in surface area (Bolle I, Eder G, Takenaka S, Ganguly K, Karrasch S, Zeller C, Neuner M, Kreyling WG, Tsuda A, Schulz H. J Appl Physiol 104: 1167–1176, 2008). Particle deposition per unit of time and surface area peaked at P35 and showed a minimum at P90. At an inhaled particle number concentration of 105/cm3, there was an estimated 450, 690, and 330 particles/(min × cm2) at P7, P35, and P90, respectively. Multiple regression models showed that deposition depends on the mean linear intercept as structural component and the breathing parameters, tidal volume, and respiratory rate ( r2 > 0.9). In conclusion, micron-sized particle deposition was dependent on the stage of postnatal lung development. A maximum was observed during late alveolarization (P35), which corresponds to human lungs of about eight years of age. Children at this age may therefore be more susceptible to micron-sized airborne environmental health hazards.

Suppression of cell proliferation and programmed cell death by dexamethasone during postnatal lung development

2002 ◽  
Vol 282 (3) ◽  
pp. L477-L483 ◽  
Author(s):  
Cédric Luyet ◽  
Peter H. Burri ◽  
Johannes C. Schittny
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Lung Development ◽  
Structural Changes ◽  
Tissue Transglutaminase ◽  
Lung Parenchyma ◽  
Lung Maturation ◽  
Morphological Criteria ◽  
Postnatal Lung Development

Prematurely born babies are often treated with glucocorticoids. We studied the consequences of an early postnatal and short dexamethasone treatment (0.1–0.01 μg/g, days 1–4) on lung development in rats, focusing on its influence on peaks of cell proliferation around day 4 and of programmed cell death at days 19–21. By morphological criteria, we observed a dexamethasone-induced premature maturation of the septa ( day 4), followed by a transient septal immatureness and delayed alveolarization leading to complete rescue of the structural changes. The numbers of proliferating (anti-Ki67) and dying cells (TdT-mediated dUTP nick end labeling) were determined and compared with controls. In dexamethasone-treated animals, both the peak of cell proliferation and the peak of programmed cell death were reduced to baseline, whereas the expression of tissue transglutaminase (transglutaminase-C), another marker for postnatal lung maturation, was not significantly altered. We hypothesize that a short neonatal course of dexamethasone leads to severe but transient structural changes of the lung parenchyma and influences the balance between cell proliferation and cell death even in later stages of lung maturation.

scholarly journals Effects of leptin deficiency on postnatal lung development in mice

2008 ◽  
Vol 105 (1) ◽  
pp. 249-259 ◽  
Author(s):  
Kewu Huang ◽  
Richard Rabold ◽  
Eric Abston ◽  
Brian Schofield ◽  
Vikas Misra ◽  
...  
Keyword(s):  
Surface Area ◽  
Morphometric Analysis ◽  
Lung Development ◽  
Age Groups ◽  
Lung Parenchyma ◽  
Lung Maturation ◽  
Alveolar Surface Area ◽  
Leptin Deficiency ◽  
Postnatal Lung Development ◽  
Alveolar Surface

Leptin modulates energy metabolism and lung development. We hypothesize that the effects of leptin on postnatal lung development are volume dependent from 2 to 10 wk of age and are independent of hypometabolism associated with leptin deficiency. To test the hypotheses, effects of leptin deficiency on lung maturation were characterized in age groups of C57BL/6J mice with varying Lep ob genotypes. Quasi-static pressure-volume curves and respiratory impedance measurements were performed to profile differences in respiratory system mechanics. Morphometric analysis was conducted to estimate alveolar size and number. Oxygen consumption was measured to assess metabolic rate. Lung volume at 40-cmH2O airway pressure (V40) increased with age in each genotypic group, and V40 was significantly ( P < 0.05) lower in leptin-deficient ( ob/ ob) mice beginning at 2 wk. Differences were amplified through 7 wk of age relative to wild-type (+/+) mice. Morphometric analysis showed that alveolar surface area was lower in ob/ ob compared with +/+ and heterozygote ( ob/+) mice beginning at 2 wk. Unlike the other genotypic groups, alveolar size did not increase with age in ob/ ob mice. In another experiment, ob/ ob at 4 wk received leptin replacement (5 μg·g−1·day−1) for 8 days, and expression levels of the Col1a1, Col3a1, Col6a3, Mmp2, Tieg1, and Stat1 genes were significantly increased concomitantly with elevated V40. Leptin-induced increases in V40 corresponded with enlarged alveolar size and surface area. Gene expression suggested a remodeling event of lung parenchyma after exogenous leptin replacement. These data support the hypothesis that leptin is critical to postnatal lung remodeling, particularly related to increased V40 and enlarged alveolar surface area.

scholarly journals Physiological respiratory parameters in pre-hospital patients with suspected COVID-19: A prospective cohort study

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257018
Author(s):  
Johan Mälberg ◽  
Nermin Hadziosmanovic ◽  
David Smekal
Keyword(s):  
Logistic Regression ◽  
Hospital Admission ◽  
Tidal Volume ◽  
Respiratory Rate ◽  
Dead Space ◽  
Hospital Admissions ◽  
Rapid Shallow Breathing Index ◽  
Respiratory Parameters ◽  
Hospital Patients ◽  
Adjusted Logistic Regression

Background The COVID-19 pandemic has presented emergency medical services (EMS) worldwide with the difficult task of identifying patients with COVID-19 and predicting the severity of their illness. The aim of this study was to investigate whether physiological respiratory parameters in pre-hospital patients with COVID-19 differed from those without COVID-19 and if they could be used to aid EMS personnel in the prediction of illness severity. Methods Patients with suspected COVID-19 were included by EMS personnel in Uppsala, Sweden. A portable respiratory monitor based on pneumotachography was used to sample the included patient’s physiological respiratory parameters. A questionnaire with information about present symptoms and background data was completed. COVID-19 diagnoses and hospital admissions were gathered from the electronic medical record system. The physiological respiratory parameters of patients with and without COVID-19 were then analyzed using descriptive statistical analysis and logistic regression. Results Between May 2020 and January 2021, 95 patients were included, and their physiological respiratory parameters analyzed. Of these patients, 53 had COVID-19. Using adjusted logistic regression, the odds of having COVID-19 increased with respiratory rate (95% CI 1.000–1.118), tidal volume (95% CI 0.996–0.999) and negative inspiratory pressure (95% CI 1.017–1.152). Patients admitted to hospital had higher respiratory rates (p<0.001) and lower tidal volume (p = 0.010) compared to the patients who were not admitted. Using adjusted logistic regression, the odds of hospital admission increased with respiratory rate (95% CI 1.081–1.324), rapid shallow breathing index (95% CI 1.006–1.040) and dead space percentage of tidal volume (95% CI 1.027–1.159). Conclusion Patients taking smaller, faster breaths with less pressure had higher odds of having COVID-19 in this study. Smaller, faster breaths and higher dead space percentage also increased the odds of hospital admission. Physiological respiratory parameters could be a useful tool in detecting COVID-19 and predicting hospital admissions, although more research is needed.

scholarly journals A Comparison of the T-Piece, Venturi T-Piece and T-Bag for Emergence with the Laryngeal Mask

1998 ◽  
Vol 26 (5) ◽  
pp. 526-528 ◽  
Author(s):  
J. Poh ◽  
J. Brimacombe
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Oxygen Enrichment ◽  
Laryngeal Mask ◽  
Visual Signal ◽  
Breathing Patterns ◽  
Flow Rates ◽  
Small Reservoir ◽  
Normal Breathing ◽  
Frequency Of Respiration

We have compared the performance of a standard T-piece, a Venturi T-piece and a T-bag (T-piece with a small reservoir bag) for emergence with the laryngeal mask airway in 20 awake volunteers. FiO2, ETCO2 and FiCO2 were measured at oxygen flow rates of 2, 4 and 6 l.min-1 during three different breathing patterns: normal tidal volume, respiratory rate 12 .min-1; normal tidal volume, respiratory rate 20 .min-1; high tidal volume, respirutory rate 12 .min-1. The T-piece and T-bag delivered a higher overall average FiO2 than the Venturi T-piece (P<0.00001). Compared with normal breathing, FiO2 was reduced at the higher respiratory rate and tidal volume with the T-piece and T-bag hut was not reduced with the Venturi T-piece. FiO2 increased with increasing flow rates for all devices except the Venturi T-piece during normal breathing. ETCO2 was higher during normal breathing (4.4±0.0%) compared with higher respiratory rate (3.7±0.9%) and tidal volume (3.4±0.7%) for all devices. There were no differences in overall ETCO2 between devices. The FiCO2 was never higher than 0.2% in any subject. We conclude that the T-piece and T-bag are more effective oxygen enrichment devices than the Venturi T-piece. The T-bag provides a useful visual signal about depth and frequency of respiration.

Pulmonary Particle Deposition Is Dependent On The Stage Of Postnatal Lung Development

2010 ◽  
Author(s):  
Stefan Karrasch ◽  
Gunter Eder ◽  
Ines Bolle ◽  
Oliver Eickelberg ◽  
Akira Tsuda ◽  
...  
Keyword(s):  
Lung Development ◽  
Particle Deposition ◽  
Postnatal Lung Development

Ventilatory responses to repeated short hypercapnic challenges

1995 ◽  
Vol 78 (4) ◽  
pp. 1374-1381 ◽  
Author(s):  
D. Gozal ◽  
J. H. Ben-Ari ◽  
R. M. Harper ◽  
T. G. Keens
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Minute Ventilation ◽  
Breathing Patterns ◽  
Ventilatory Strategy ◽  
Continuous Increase ◽  
Ventilatory Responses ◽  
Central Controller ◽  
Controller Gain

In early phases of respiratory disease, patients are more likely to experience intermittent hypercapnia than a continuous increase in PCO2. The effect of intermittent arterial PCO2 elevation on subsequent breathing patterns is unclear. To examine this issue, a series of six ventilatory challenges (CH1-CH6), consisting of 2 min of breathing 5% CO2 in O2, followed by 5 min in room air (RA) were performed in 10 naive healthy subjects (age 12–39 yr). Minute ventilation (VE) increased from 11.9 +/- 1.0 (SE) l/min in RA to 27.6 +/- 3.0 l/min in 5% CO2 (P < 0.0005) in each of the six hypercapnic challenges. Respiratory rate increased from 21.3 +/- 2.6 breaths/min on RA to 29.6 +/- 3.9 breaths/min during CH1 (P < 0.05). However, respiratory rate consistently decreased with successive CO2 challenges (CH6: 21.5 +/- 2.6 breaths/min; P < 0.02). Thus, maintenance of VE was achieved by gradual increases in tidal volume with each of the first four consecutive CO2 challenges (CH1: 1.05 +/- 0.09 liters; CH4: 1.44 +/- 0.13 liters; P < 0.002). Similarly, the ratio of tidal volume to inspiratory time increased from CH1 (1.16 +/- 0.16 l/s) to CH6 (1.57 +/- 0.21 l/s; P < 0.001). These changes in ventilatory strategy were not observed when RA recovery periods were extended to 15 min in five subjects. We conclude that during repeated short hypercapnic challenges similar levels of VE are achieved. However, increased mean inspiratory flows are generated to maintain VE. We speculate that intermittent hypercapnia either modifies central controller gain or induces a long-term modulatory effect to account for the progressive changes in ventilatory components.

scholarly journals Comparison of Geometrical Lung Models to Calculate Tidal Volumes during Spontaneous Breathing

2021 ◽  
Vol 7 (2) ◽  
pp. 819-822
Author(s):  
Simon Beck ◽  
Bernhard Laufer ◽  
Knut Moeller
Keyword(s):  
Air Pollution ◽  
Tidal Volume ◽  
Spontaneous Breathing ◽  
Use Case ◽  
Demographic Changes ◽  
Breathing Patterns ◽  
Volume Calculation ◽  
Respiratory Parameters ◽  
System Data ◽  
Human Thorax

Abstract Demographic changes, increasing air pollution and the ongoing Covid-19 pandemic, causing virus-induced respiratory failures, monitoring of respiratory parameters is the focus of international interest. In this study, motioncapture- system data was used to get circumferences of the human thorax while executing different breathing patterns. Four geometric models were used to model tidal volumes of the tracked person while using spirometry data as a reference. The results show that all four introduced models can be used for tidal volume calculation based on changes in the thoracic circumference. In terms of accuracy, the use-case must be considered

Effect of transverse acceleration on pulmonary function

1959 ◽  
Vol 14 (6) ◽  
pp. 914-916 ◽  
Author(s):  
Neil S. Cherniack ◽  
Alvin S. Hyde ◽  
F. W. Zechman
Keyword(s):  
Pulmonary Function ◽  
Tidal Volume ◽  
Respiratory Rate ◽  
Centrifugal Force ◽  
Vital Capacity ◽  
Minute Volume ◽  
Respiratory Parameters

Since difficulty with respiration limits tolerance to transverse acceleration, the effect of this acceleration on different respiratory factors was tested in 15 subjects. Minute volume, respiratory rate, tidal volume, maximum breathing capacity, 0.5-second timed vital capacity and total vital capacity were measured at 3 and 5 g with the subject's trunk perpendicular to the centrifugal force and legs and knees flexed at 90 degrees. Vital capacity was reduced significantly at 3 and 5 g. Maximum breathing capacity was significantly reduced at 5 g. One-half-second timed vital capacity represented an increasing fraction of total vital capacity as acceleration increased. Minute volume and respiratory rate also increased significantly at 5 g while tidal volume was essentially unchanged. Results are obtained which indicate that the nature of the predominant respiratory defect during forward acceleration is restrictive. Of the respiratory parameters measured, vital capacity showed the greatest decrement. Submitted on April 17, 1959

Obesity, tidal volume, and pulmonary deposition of fine particulate matter in children with asthma

2021 ◽  
pp. 2100209
Author(s):  
Nima Afshar-Mohajer ◽  
Tianshi David Wu ◽  
Rebecca Shade ◽  
Emily Brigham ◽  
Han Woo ◽  
...  
Keyword(s):  
Air Pollution ◽  
Particulate Matter ◽  
Tidal Volume ◽  
Respiratory Rate ◽  
Minute Ventilation ◽  
Fine Particulate Matter ◽  
Breathing Patterns ◽  
Obese Children ◽  
Fine Particulate ◽  
Children With Asthma

BackgroundObese children with asthma are more vulnerable to air pollution, especially fine particulate matter (PM2.5), but reasons are poorly understood. We hypothesised that differences in breathing patterns (tidal volume, respiratory rate, and minute ventilation) due to elevated body mass index (BMI) may contribute to this finding.ObjectiveTo investigate the association of BMI with breathing patterns and deposition of inhaled PM2.5.MethodsBaseline data from a prospective study of children with asthma was analysed (n=174). Tidal breathing was measured by a pitot-tube flowmeter, from which tidal volume, respiratory rate, and minute ventilation were obtained. The association of BMI z-score with breathing patterns was estimated in a multivariable model adjusted for age, height, race, sex, and asthma severity. A particle dosimetry model simulated PM2.5 lung deposition based on BMI-associated changes in breathing patterns.ResultsHigher BMI was associated with higher tidal volume (adjusted mean difference [aMD] between obese and normal-range BMI of 25 mL, 95% confidence interval [CI] 5–45 mL) and minute ventilation (aMD 453 mL·min−1, 95%CI 123–784 mL·min−1). Higher tidal volumes caused higher fractional deposition of PM2.5 in the lung, driven by greater alveolar deposition. This translated into obese participants having greater per-breath retention of inhaled PM2.5 (aMD in alveolar deposition fraction of 3.4%; 95% CI 1.3–5.5%), leading to worse PM2.5 deposition rates.ConclusionsObese children with asthma breathe at higher tidal volumes that may increase the efficiency of PM2.5 deposition in the lung. This finding may partially explain why obese children with asthma exhibit greater sensitivity to air pollution.

scholarly journals Breath-by-breath measurement of particle deposition in the lung of spontaneously breathing rats

2009 ◽  
Vol 107 (4) ◽  
pp. 1293-1299 ◽  
Author(s):  
S. Karrasch ◽  
G. Eder ◽  
I. Bolle ◽  
A. Tsuda ◽  
H. Schulz
Keyword(s):  
Dead Space ◽  
Particle Deposition ◽  
Breathing Patterns ◽  
Adult Rat ◽  
Wistar Kyoto ◽  
Conventional Models ◽  
Breath Measurement ◽  
Spontaneously Breathing ◽  
Best Fit ◽  
Deposition Models

A number of deposition models for humans, as well as experimental animals, have been described. However, no breath-by-breath deposition measurement in rats has been reported to date. The objective of this study is to determine lung deposition of micrometer-sized particles as a function of breathing parameters in the adult rat lung. A new aerosol photometry system was designed to measure deposition of nonhygroscopic, 2-μm sebacate particles in anesthetized, intubated, and spontaneously breathing 90-day-old Wistar-Kyoto rats placed in a size-adjusted body plethysmograph box. Instrumental dead space of the system was minimized down to 310 μl (i.e., ∼20% of respiratory dead space). The system allows continuous monitoring of particle concentration in the respired volume. Breathing parameters, such as respiratory rate (f), tidal volume (Vt), as well as inspiration/expiration times, were also monitored at different levels of anesthesia. The results showed that Vt typically varied between 1.5 and 4.0 ml for regular breathing and between 4.0 and 10.0 ml for single-sigh breaths; f ranged from 40 to 200 breaths/min. Corresponding deposition values varied between 5 and 50%, depending on breath-by-breath breathing patterns. The best fit of deposition (D) was achieved by a bilinear function of Vt and f and found to be D = 11.0 − 0.09·f + 3.75·Vt. We conclude that our approach provides more realistic conditions for the measurement of deposition than conventional models using ventilated animals and allows us to analyze the correlation between breath-specific deposition and spontaneous breathing patterns.

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