Electromagnetic inductance plethysmography is well suited to measure tidal breathing in infants

Reliable, accurate and noninvasive methods for measuring lung function in infants are desirable. Electromagnetic inductance plethysmography has been used to perform infant spirometry and VoluSense Pediatrics (VSP) (VoluSense, Bergen, Norway) represents an updated version of this technique. We aimed to examine its accuracy compared to a validated system measuring airflow via a facemask using an ultrasonic flowmeter.We tested 30 infants with postmenstrual ages between 36 to 43 weeks and weights from 2.3 to 4.8 kg, applying both methods simultaneously and applying VSP alone. Agreement between the methods was calculated using Bland–Altman analyses and we also estimated the effect of applying the mask.Mean differences for all breathing parameters were within ±5.5% and limits of agreement between the two methods were acceptable, except perhaps for peak tidal expiratory flow (PTEF). Application of the facemask significantly increased tidal volume, minute ventilation, PTEF, the ratio of inspiratory to expiratory time and the ratio of expiratory flow at 50% of expired volume to PTEF.VSP accurately measured tidal breathing parameters and seems well suited for tidal breathing measurements in infants under treatment with equipment that precludes the use of a facemask.

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Respiration during exercise in conscious laryngectomized humans

Journal of Applied Physiology ◽

10.1152/jappl.1989.66.5.2071 ◽

1989 ◽

Vol 66 (5) ◽

pp. 2071-2078 ◽

Cited By ~ 5

Author(s):

W. N. Gardner ◽

M. S. Meah

Keyword(s):

Minute Ventilation ◽

Work Rate ◽

Inspiratory Flow ◽

Control Group ◽

Respiratory Drive ◽

Upper Airways ◽

Expiratory Time ◽

Expiratory Flow ◽

End Tidal ◽

Normal Controls

We compared respiratory patterning at rest and during steady cycle exercise at work rates of 30, 60, and 90 W in 7 male chronically laryngectomized subjects and 13 normal controls. Breathing was measured with a pneumotachograph and end-tidal PCO2 by mass spectrometer. Inspired air was humidified and enriched to 35% O2. Peak flow, volume, and times for the inspiratory and expiratory half cycles, time for expiratory flow, minute ventilation, and mean inspiratory flow were computer averaged over at least 40 breaths at rest and during the last 2 min of 5-min periods at each work rate. During the transition from rest to exercise and with increasing work rate in both groups, there was an increase in respiratory rate and depth with selective and progressive shortening of expiratory time; these responses were not significantly different between the two groups, but there was a suggestion that respiratory “drive” as quantitated by mean inspiratory flow may limit in the laryngectomized subjects at high work rates. Time for expiratory flow increased on transition from rest to exercise and then decreased in both groups as the work rate increased; it was shorter in the laryngectomy than control group at all levels. In the laryngectomized subjects there was significantly more breath-by-breath scatter in some variables at rest, but there was no difference during exercise. It is concluded that chronic removal of the larynx and upper airways in mildly hyperoxic conscious humans has only subtle and, therefore, functionally insignificant effects on breathing during moderate exercise. Evidence is provided that the upper airways can modulate expiratory flow but not expiratory time during exercise.

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Effect of Continuous Positive Airway Pressure on the Ventilatory Response to CO2 in Preterm Infants

PEDIATRICS ◽

10.1542/peds.71.4.634 ◽

1983 ◽

Vol 71 (4) ◽

pp. 634-638

Author(s):

Manuel Durand ◽

Ellen McCann ◽

June P. Brady

Keyword(s):

Tidal Volume ◽

Preterm Infants ◽

Airway Pressure ◽

Positive Airway Pressure ◽

Ventilatory Response ◽

Minute Ventilation ◽

Respiratory Frequency ◽

Co2 Response ◽

Expiratory Time ◽

Ventilatory Response To Co2

The effect of continuous positive airway pressure (CPAP) on the ventilatory response to CO2 in newborn infants is unknown. The CO2 response to 4% CO2 in air was studied in nine preterm infants without lung disease before and during administration of CPAP (4 to 5 cm H2O) delivered by face mask. Minute ventilation, tidal volume, respiratory frequency, and end-tidal Pco2 were measured, and the slope and intercept of the CO2 response were calculated. Respiratory pattern and changes in oxygenation were also analyzed by measuring inspiratory and expiratory time, mean inspiratory flow, mean expiratory flow, effective respiratory timing, endtidal Po2, and transcutaneous Po2. CPAP significantly decreased minute ventilation from 278.7 to 197.6 mL/mm/kg (P < .001). Tidal volume and respiratory frequency were also significantly decreased. The slope of the CO2 response during CPAP was not significantly different from the slope before CPAP (36 v 33 mL/min/kg/mm Hg, P > .1), but the intercept was shifted to the right (P < .001). The decrease in respiratory frequency was primarily due to a prolongation of expiratory time (P < .05). In addition, transcutaneous Po2 increased during administration of CPAP (P < .001). These findings indicate that: (1) CPAP significantly decreases ventilation in preterm infants without lung disease, affecting both tidal volume and respiratory frequency; (2) CPAP does not appreciably alter the ventilatory response to CO2; (3) the changes in respiratory frequency are primarily accounted for by a prolongation of expiratory time; (4) CPAP improves oxygenation.

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Separation of factors responsible for change in breathing pattern induced by instrumentation

Journal of Applied Physiology ◽

10.1152/jappl.1985.59.5.1515 ◽

1985 ◽

Vol 59 (5) ◽

pp. 1515-1520 ◽

Cited By ~ 104

Author(s):

W. Perez ◽

M. J. Tobin

Keyword(s):

Tidal Volume ◽

Breathing Pattern ◽

Minute Ventilation ◽

Sensory Receptors ◽

Inspiratory Time ◽

Expiratory Time ◽

Oral Breathing ◽

Oral Stimulation ◽

Additional Stimulation ◽

Stimulation Of

Employment of mouthpiece and noseclips (MP + NC) has repeatedly been shown to increase tidal volume (VT), but its effect on respiratory frequency (f) and its subsets is controversial. The mechanisms accounting for this alteration in breathing pattern are poorly understood and may include stimulation of oral or nasal sensory receptors or alteration in the route of breathing. In this study we demonstrated that use of a MP + NC, compared with nonobtrusive measurement with a calibrated respiratory inductive plethysmograph, alters the majority of the volume and time indexes of breathing pattern, with increases in minute ventilation (P less than 0.01), VT (P less than 0.001), inspiratory time (TI, P less than 0.05), expiratory time (TE, P less than 0.05), mean inspiratory flow (P less than 0.05), and mean expiratory flow (P less than 0.05) and a decrease in f(P less than 0.05). Separating the potential mechanisms we found that when the respiratory route was not altered, independent oral stimulation (using an occluded MP) or nasal stimulation (by applying paper clips to the alae nasi) did not change the breathing pattern. In contrast, obligatory oral breathing without additional stimulation of the oral or nasal sensory receptors caused increases in VT (P less than 0.05), TI (P less than 0.05), and TE (P less than 0.01) and a fall in f(P less than 0.05). Heating and humidifying the inspired air did not prevent the alteration in breathing pattern with a MP. Thus change in the respiratory route is the major determinant of the alteration in breathing pattern with a MP + NC.

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Diaphragm and lung afferents contribute to inspiratory load compensation in awake ponies

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.3.1330 ◽

1994 ◽

Vol 76 (3) ◽

pp. 1330-1339 ◽

Cited By ~ 14

Author(s):

H. V. Forster ◽

T. F. Lowry ◽

L. G. Pan ◽

B. K. Erickson ◽

M. J. Korducki ◽

...

Keyword(s):

Tidal Volume ◽

Treadmill Exercise ◽

Minute Ventilation ◽

Inspiratory Time ◽

Arterial Pco2 ◽

Load Compensation ◽

Expiratory Time ◽

Inspiratory Load

We determined the effect of pulmonary vagal (hilar nerve) denervation (HND) and diaphragm deafferentation (DD) on inspiratory load compensation. We studied awake intact (I; n = 10), DD (n = 5), HND (n = 4), and DD+HND (n = 7) ponies at rest and during mild (1.8 mph, 5% grade) and moderate (1.8 mph, 15% grade) treadmill exercise before, during, and after resistance of the inspiratory circuit was increased from approximately 1.5 to approximately 20 cmH2O.l–1.s. During the first loaded breath in I ponies at rest, inspiratory time (TI) increased, expiratory time decreased, and inspiratory drive increased. There were minimal changes after the first breath, and inspiratory minute ventilation (VI) and arterial PCO2 did not change (P > 0.10) from control values. On the first loaded breath during exercise, TI increased but inspiratory drive either did not change or decreased from control values. TI and drive increased after the first breath, but the increases were insufficient to maintain VI and arterial PCO2 at control levels. First-breath load compensation remained after DD, HND, and DD+HND, but after DD+HND tidal volume and VI were compensated 5–10% less (P < 0.05) than in I ponies. In all groups inspiratory drive, tidal volume, and VI were markedly augmented on the first breath after loading was terminated with a gradual return toward control. We conclude that diaphragm and pulmonary afferents contribute to but are not essential for inspiratory load compensation in awake ponies.

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Development of the ventilatory response to hypoxia in Swiss CD-1 mice

Journal of Applied Physiology ◽

10.1152/jappl.2000.88.5.1907 ◽

2000 ◽

Vol 88 (5) ◽

pp. 1907-1914 ◽

Cited By ~ 23

Author(s):

Dean M. Robinson ◽

Henry Kwok ◽

Brandon M. Adams ◽

Karen C. Peebles ◽

Gregory D. Funk

Keyword(s):

Tidal Volume ◽

Body Mass ◽

Breathing Pattern ◽

Ventilatory Response ◽

Minute Ventilation ◽

Developmental Changes ◽

Hypoxic Exposure ◽

Hypoxic Ventilatory Response ◽

Expiratory Time ◽

Ventilatory Response To Hypoxia

We examined developmental changes in breathing pattern and the ventilatory response to hypoxia (7.4% O2) in unanesthetized Swiss CD-1 mice ranging in age from postnatal day 0 to 42(P0–P42) using head-out plethysmography. The breathing pattern of P0 mice was unstable. Apneas were frequent at P0 (occupying 29 ± 6% of total time) but rare by P3 (5 ± 2% of total time). Tidal volume increased in proportion to body mass (∼10–13 ml/kg), but increases in respiratory frequency (f) (55 ± 7, 130 ± 13, and 207 ± 20 cycles/min for P0, P3, and P42, respectively) were responsible for developmental increases in minute ventilation (690 ± 90, 1,530 ± 250, and 2,170 ± 430 ml ⋅ min− 1 ⋅ kg− 1for P0, P3, and P42, respectively). Between P0 and P3, increases in f were mediated by reductions in apnea and inspiratory and expiratory times; beyond P3, increases were due to reductions in expiratory time. Mice of all ages showed a biphasic hypoxic ventilatory response, which differed in two respects from the response typical of most mammals. First, the initial hyperpnea, which was greatest in mature animals, decreased developmentally from a maximum, relative to control, of 2.58 ± 0.29 in P0 mice to 1.32 ± 0.09 in P42mice. Second, whereas ventilation typically falls to or below control in most neonatal mammals, ventilation remained elevated relative to control throughout the hypoxic exposure in P0 (1.73 ± 0.31), P3 (1.64 ± 0.29), and P9 (1.34 ± 0.17) mice but not in P19 or P42 mice.

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Forced Expiratory Time: A Composite of Airway Narrowing and Airway Closure

Journal of Applied Physiology ◽

10.1152/japplphysiol.00556.2020 ◽

2020 ◽

Author(s):

Gwen Susan Skloot ◽

Kieley L. O'Connor-Chapman ◽

Clyde B. Schechter ◽

Daniel J. Markley ◽

Jason H.T. Bates

Keyword(s):

Lung Function ◽

Smoking Status ◽

Detection Threshold ◽

Normal Lung ◽

Airway Narrowing ◽

Expiratory Time ◽

Normal Lung Function ◽

Forced Expiratory Flow ◽

Volume Profile ◽

Expiratory Flow

Forced expiratory time (FET) is a spirometrically-derived variable thought to reflect lung function, but its physiologic basis remains poorly understood. We developed a mathematical theory of FET assuming a linear forced expiratory flow-volume profile that terminates when expiratory flow falls below a defined detection threshold. FET is predicted to correlate negatively with both FEV1 and FVC if variations in the rate of lung emptying (relative to normal) among individuals in a population exceed variations in the amount of lung emptying. We retrospectively determined FET pre- and post-methacholine challenge in 1241 patients (818 had normal lung function, 137 were obstructed, and 229 were restricted) and examined its relationships to spirometric and demographic variables in both hyperresponsive and normoresponsive individuals. Mean FET was 9.6 ± 2.2 s in the normal group, 12.3 ± 3.0 s in those with obstruction, and 8.8 ± 1.9 s in those with restriction. FET was inversely related to FEV1/FVC in all groups, negatively related to FEV1 in the obstructed patients, and positively related to FVC in both the normal and restricted patients. There was no relationship with methacholine responsiveness. Overall, our theory of the relationship between FET to the spirometric indices is supported by these findings, and in addition potentially explains how FET is affected by gender, age, smoking status, and possibly body mass index.

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Effects of respiratory apparatus on breathing pattern

Journal of Applied Physiology ◽

10.1152/jappl.1980.48.4.577 ◽

1980 ◽

Vol 48 (4) ◽

pp. 577-580 ◽

Cited By ~ 158

Author(s):

J. Askanazi ◽

P. A. Silverberg ◽

R. J. Foster ◽

A. I. Hyman ◽

J. Milic-Emili ◽

...

Keyword(s):

Gas Exchange ◽

Tidal Volume ◽

Breathing Pattern ◽

Minute Ventilation ◽

Inspiratory Flow ◽

Co2 Production ◽

O2 Consumption ◽

Expiratory Time ◽

Respiratory Apparatus

The effects of ventilatory apparatus on breathing pattern and gas exchange were studied in normal supine subjects. Using a canopy system, measurements of O2 consumption, CO2 production, tidal volume (VT), frequency (f), minute ventilation, mean inspiratory flow, and inspiratory, and expiratory time (TI and TE) were made and compared to data obtained with the use of a mask (m) and mouthpiece plus noseclip (mp + nc). Use of the m or mp + nc caused a 32.5 and 15.5% increase in VT, respectively, whereas f, TI, and TE remained unchanged. As TI did not change the increase in VT was caused entirely by increased inspiratory flow.

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Volatile anesthetics maintain tidal volume and minute ventilation to a greater degree than propofol under spontaneous respiration

BMC Anesthesiology ◽

10.1186/s12871-021-01438-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Xuechao Hao ◽

Mengchan Ou ◽

Yu Li ◽

Cheng Zhou

Keyword(s):

Tidal Volume ◽

Minute Ventilation ◽

Volatile Anesthetics ◽

Whole Body ◽

Spontaneous Respiration ◽

General Anesthetics ◽

Expiratory Time ◽

Inhalational Anesthetics ◽

Respiratory Parameters

Abstract Background Although general anesthetics depress spontaneous respiration, the comprehensive effect of general anesthetics on respiratory function remains unclear. We aimed to investigate the effects of general anesthetics on spontaneous respiration in non-intubated mice with different types and doses of general anesthetic. Methods Adult C57BL/6 J mice were administered intravenous anesthetics, including propofol and etomidate, and inhalational anesthetics, including sevoflurane and isoflurane in vivo at doses of 0.5-, 1.0-, and 2.0-times the minimum alveolar concentration (MAC)/median effective dose (ED50) to induce loss of the righting reflex (LORR). Whole-body plethysmography (WBP) was applied to measure parameters of respiration under unrestricted conditions without endotracheal intubation. The alteration in respiratory sensitivity to carbon dioxide (CO2) under general anesthesia was also determined. The following respiratory parameters were continuously recorded during anesthesia or CO2 exposure: respiratory frequency (FR), tidal volume (TV), minute ventilation (MV), expiratory time (TE), inspiratory time (TI), and inspiratory–expiratory time ratio (I/E), and peak inspiratory flow. Results Sub-anesthetic concentrations (0.5 MAC) of sevoflurane or isoflurane increased FR, TV, and MV. With isoflurane and sevoflurane exposure, the CO2-evoked increases in FR, TV, and MV were decreased. Compared with inhalational anesthetics, propofol and etomidate induced respiratory suppression, affecting FR, TV, and MV. In 100% oxygen (O2), FR in the group that received propofol 1.0-times the ED50 was 69.63 ± 33.44 breaths/min compared with 155.68 ± 64.42 breaths/min in the etomidate-treated group. In the same groups, FR was 88.72 ± 34.51 breaths/min and 225.10 ± 59.82 breaths/min, respectively, in 3% CO2 and 144.17 ± 63.25 breaths/min and 197.70 ± 41.93 breaths/min, respectively, in 5% CO2. A higher CO2 sensitivity was found in etomidate-treated mice compared with propofol-treated mice. In addition, propofol induced a greater decrease in FR, MV, and I/E ratio compared with etomidate, sevoflurane, and isoflurane at equivalent doses (all P < 0.05). Conclusions General anesthetics differentially modulate spontaneous breathing in vivo. Volatile anesthetics increase FR, TV, and MV at sub-anesthetic concentrations, while they decrease FR at higher concentrations. Propofol consistently depressed respiratory parameters to a greater degree than etomidate.

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Lung function at term in extremely preterm-born infants: a regional prospective cohort study

BMJ Open ◽

10.1136/bmjopen-2017-016868 ◽

2017 ◽

Vol 7 (10) ◽

pp. e016868 ◽

Cited By ~ 15

Author(s):

Mariann Haavik Bentsen ◽

Trond Markestad ◽

Knut Øymar ◽

Thomas Halvorsen

Keyword(s):

Lung Function ◽

Minute Ventilation ◽

Hospital Readmissions ◽

Respiratory Morbidity ◽

First Year ◽

Tidal Breathing ◽

Equivalent Age ◽

Antenatal Steroids ◽

Extremely Preterm ◽

First Year Of Life

ObjectivesTo compare lung function of extremely preterm (EP)-born infants with and without bronchopulmonary dysplasia (BPD) with that of healthy term-born infants, and to determine which perinatal characteristics were associated with lung function at term and how predictive these measurements were for later respiratory health in EP-born infants.MethodsPerinatal variables were recorded prospectively, and tidal breathing parameters were measured at term-equivalent age using electromagnetic inductance plethysmography. Respiratory morbidity was defined by hospital readmissions and/or treatment with asthma medications during the first year of life.ResultsFifty-two EP-born infants (mean gestational age 261, range 226–276weeks) and 45 term-born infants were included. There was evidence of significant airway obstruction, higher tidal volumes and increased minute ventilation in the EP-born infants with and without BPD, although generally more pronounced for those with BPD. Male gender, antenatal steroids and number of days on continuous positive airway pressure were associated with lung function outcomes at term. A prediction model incorporating two unrelated tidal breathing parameters, BPD, birth weight z-score and gender, predicted respiratory morbidity in the first year of life with good accuracy (area under the curve 0.818, sensitivity and specificity 81.8% and 75.0%, respectively).ConclusionLung function measured at term-equivalent age was strikingly abnormal in EP-born infants, irrespective of BPD. Tidal breathing parameters may be of value in predicting future pulmonary health in infants born premature.Trial registration numberNCT01150396; Results.

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No effect of artificial gravity on lung function with exercise training during head-down bed rest

International Journal of Astrobiology ◽

10.1017/s1473550415000294 ◽

2015 ◽

pp. 1-7

Author(s):

Longxiang Su ◽

Yinghua Guo ◽

Yajuan Wang ◽

Delong Wang ◽

Changting Liu

Keyword(s):

Lung Function ◽

Pulse Rate ◽

Vital Capacity ◽

Pulmonary Ventilation ◽

Bed Rest ◽

Forced Expiratory Volume ◽

Observation Time ◽

Artificial Gravity ◽

Postural Changes ◽

Expiratory Flow

AbstractTo explore the effectiveness of microgravity simulated by head-down bed rest (HDBR) and artificial gravity (AG) with exercise on lung function. Twenty-four volunteers were randomly divided into control and exercise countermeasure (CM) groups for 96 h of 6° HDBR. Comparisons of pulse rate, pulse oxygen saturation (SpO2) and lung function were made between these two groups at 0, 24, 48, 72, 96 h. Compared with the sitting position, inspiratory capacity and respiratory reserve volume were significantly higher than before HDBR (0° position) (P< 0.05). Vital capacity, expiratory reserve volume, forced vital capacity, forced expiratory volume in 1 s, forced inspiratory vital capacity, forced inspiratory volume in 1 s, forced expiratory flow at 25, 50 and 75%, maximal mid-expiratory flow and peak expiratory flow were all significantly lower than those before HDBR (P< 0.05). Neither control nor CM groups showed significant differences in the pulse rate, SpO2, pulmonary volume and pulmonary ventilation function over the HDBR observation time. Postural changes can lead to variation in lung volume and ventilation function, but a HDBR model induced no changes in pulmonary function and therefore should not be used to study AG CMs.

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