Volume of activation of the Hering-Breuer inflation reflex in the newborn infant

2001 ◽  
Vol 90 (3) ◽  
pp. 763-769 ◽  
Author(s):  
A. Hassan ◽  
J. Gossage ◽  
D. Ingram ◽  
S. Lee ◽  
A. D. Milner
Keyword(s):  
Lung Volume ◽  
Polynomial Regression ◽  
Neonatal Period ◽  
Face Mask ◽  
Progressive Increase ◽  
Inspiratory Time ◽  
Tidal Breathing ◽  
Expiratory Time ◽  
Healthy Infants ◽  
Residual Capacity

Although the Hering-Breuer inflation reflex (HBIR) is active within tidal breathing range in the neonatal period, there is no information regarding whether a critical volume has to be exceeded before any effect can be observed. To explore this, effects of multiple airway occlusions on inspiratory and expiratory timing were measured throughout tidal breathing range using a face mask and shutter system. In 20 of the 22 healthy infants studied, there was significant shortening of inspiration because the volume at which occlusion occurred rose from functional residual capacity (FRC) to end-inspiratory volume [14.9% reduction in inspiratory time (per ml/kg increase in lung volume at occlusion)]. All infants showed a significant increase in expiratory time [17.1% increase (per ml/kg increase in lung volume at occlusion)]. Polynomial regression analyses revealed a progressive increase in strength of HBIR from FRC to ∼4 ml/kg above FRC. Eighteen infants showed no further shortening of inspiratory time and 10 infants no further lengthening of expiratory time with increasing occlusion volumes, indicating maximal stimulation of the reflex had been achieved. There was a significant relationship between strength of HBIR and respiratory rate, suggesting that HBIR modifies the breathing pattern in the neonatal period.

Effect of lung volume on expiratory time in the newborn infant

1978 ◽  
Vol 45 (1) ◽  
pp. 18-23 ◽  
Author(s):  
R. J. Martin ◽  
A. Okken ◽  
P. G. Katona ◽  
M. H. Klaus
Keyword(s):  
Newborn Infant ◽  
Lung Volume ◽  
Positive Airway Pressure ◽  
Face Mask ◽  
Progressive Increase ◽  
Inspiratory Time ◽  
Term Infants ◽  
Variable Effect ◽  
Expiratory Time ◽  
Residual Capacity

The effect of an increased end-expiratory lung volume on inspiratory and expiratory duration was examined in 13 term infants at 4, 30, and 70 h of age. This was accomplished by the administration of a continuous positive airway pressure (CPAP) of 0, 3, and 6 cmH2O by use of a face mask connected to a pneumotachometer, and by measurement of the timing of the respiratory cycle over 1-min intervals. At increasing functional residual capacity (FRC) there was a progressive increase in expiratory time (TE) and fall in respiratory rate, with a variable effect on inspiratory time (TI). As CPAP increased from 0 to 6 cmH2O, the TI/TE ratio fell from 0.75 to 0.62 (P less than 0.01), 0.90 to 0.66 (P less than 0.001), and 0.87 to 0.64 (P less than 0.001) at 4, 30, and 70 h, respectively. We conclude that alterations in end-expiratory lung volume significantly alter expiratory duration in the newborn infant at term. This may be analogous to the vagally mediated tonic control of expiratory time with changing FRC recently described in anesthetized animals.

Respiratory movements of the vocal cords

1983 ◽  
Vol 54 (5) ◽  
pp. 1269-1276 ◽  
Author(s):  
T. Brancatisano ◽  
P. W. Collett ◽  
L. A. Engel
Keyword(s):  
Lung Volume ◽  
Respiratory Control ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Tight Coupling ◽  
Tidal Breathing ◽  
Vocal Cords ◽  
Residual Capacity ◽  
The Relationship ◽  
Respiratory Movements

We examined the movements of the vocal cords during tidal breathing, panting, and large changes in lung volume in 12 normal subjects. The glottis was observed with a fiber-optic bronchoscope, and the glottic image was recorded together with flow, volume, and a time marker onto videotape. Phasic respiratory swings in glottic width (dg) and glottic area (Ag) were reproducible in all subjects but differed substantially between subjects. In the group as a whole dg and Ag increased during inspiration to 10.1 +/- 5.6 mm and 126 +/- 8 mm2 (mean +/- SE), respectively, whereas during expiration the lowest values were 5.7 +/- 0.5 mm and 70 +/- 7 mm2, respectively. These extreme dimensions corresponded closely to the midtidal volume points in the respiratory cycle. Glottic width during vital capacity (VC) expirations was nearly 30% greater at a flow of 1.2 l/s than at 0.5 l/s, but the relationship between dg and lung volume differed between subjects. When swings in dg were minimized by panting, there was no difference in dg between functional residual capacity (FRC) and a volume corresponding to midinspiratory capacity. However, tidal breathing at this lung volume was associated with a 20% decrease in dg compared with breathing at FRC. Our observations indicate a tight coupling between the pattern of glottic movement and the respiratory volume cycle. The results suggest that during voluntary respiratory maneuvers both intrinsic laryngeal and respiratory muscles are recruited, participating as effector organs in ventilatory and respiratory control.

Effect of changes in lung volume on respiratory system compliance in newborn infants

1989 ◽  
Vol 67 (3) ◽  
pp. 1192-1197 ◽  
Author(s):  
F. Ratjen ◽  
R. Zinman ◽  
A. R. Stark ◽  
L. E. Leszczynski ◽  
M. E. Wohl
Keyword(s):  
Tidal Volume ◽  
Respiratory System ◽  
Lung Volume ◽  
Newborn Infants ◽  
Face Mask ◽  
Flow Volume ◽  
Respiratory System Compliance ◽  
Tidal Breathing ◽  
Volume Changes ◽  
Passive Flow

Total respiratory system compliance (Crs) at volumes above the tidal volume (VT) was studied by use of the expiratory volume clamping (EVC) technique in 10 healthy sleeping unsedated newborn infants. Flow was measured with a pneumotachograph attached to a face mask and integrated to yield volume. Volume changes were confirmed by respiratory inductance plethysmography. Crs measured by EVC was compared with Crs during tidal breathing determined by the passive flow-volume (PFV) technique. Volume increases of approximately 75% VT were achieved with three to eight inspiratory efforts during expiratory occlusions. Crs above VT was consistently greater than during tidal breathing (P less than 0.0005). This increase in Crs likely reflects recruitment of lung units that are closed or atelectatic in the VT range. Within the VT range, Crs measured by PFV was compared with that obtained by the multiple-occlusion method (MO). PFV yielded greater values of Crs than MO (P less than 0.01). This may be due to braking of expiratory airflow after the release of an occlusion or nonlinearity of Crs. Thus both volume recruitment and airflow retardation may affect the measurement of Crs in unsedated newborn infants.

Lung volume, closing volume, and gas exchange

1982 ◽  
Vol 52 (6) ◽  
pp. 1453-1457 ◽  
Author(s):  
S. C. Morrison ◽  
D. G. Stubbing ◽  
P. V. Zimmerman ◽  
E. J. Campbell
Keyword(s):  
Gas Exchange ◽  
Lung Volume ◽  
Normal Subjects ◽  
Close Correlation ◽  
Closing Volume ◽  
Tidal Breathing ◽  
Co2 Partial Pressure ◽  
Residual Capacity ◽  
End Tidal ◽  
Arterial O2 Saturation

The effect of a voluntary reduction in lung volume on arterial O2 saturation (SaO2) was studied in 10 normal subjects aged 19–63 yr. SaO2 was measured by ear oximetry first during tidal breathing at functional residual capacity, and then during tidal breathing at 380 ml above residual volume. Tidal volume and breathing frequency were kept constant, and end-tidal CO2 partial pressure remained stable or fell in 9 out of 10 subjects. When lung volume was reduced, SaO2 fell by a mean of 1.5% (range 0–3%). Closing volume (CV) was measured by the N2-washout method (mean 0.89 liter, range 0.41–1.44). There was a close correlation between CV and the fall in SaO2 (r = 0.867, P = 0.001). Arterial and mixed venous CO2 were measured in one subject; the results indicated some fall in cardiac output following the lung volume change, but this accounted for less than half of the fall in SaO2. The relationship between CV and the lung volume at which tidal breathing occurs is an important determinant of pulmonary gas exchange through its effect on the matching of ventilation to perfusion.

Movement of the ribs in supine humans for small and large changes in lung volume

2021 ◽  
Author(s):  
Billy L. Luu ◽  
Rhys J. McDonald ◽  
Bart Bolsterlee ◽  
Martin E. Heroux ◽  
Jane E. Butler ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Chronic Obstructive ◽  
Tidal Breathing ◽  
Obstructive Pulmonary Disease ◽  
Before And After ◽  
Residual Capacity ◽  
Joint Coordinate System ◽  
Healthy Participants ◽  
Bucket Handle

An object tracking algorithm was used on computed tomography (CT) images of the thorax from six healthy participants and nine participants with chronic obstructive pulmonary disease (COPD) to describe the movement of the ribs between the static lung volumes of functional residual capacity (FRC) and total lung capacity (TLC). The continuous motion of the ribs during tidal breathing was also described using four-dimensional CT datasets from seven participants with thoracic esophageal malignancies. Rib motion was defined relative to a local joint coordinate system where rotations about the axes that predominantly affected the anteroposterior and transverse diameters of the rib cage were referred to as pump-handle and bucket-handle movements, respectively. Between TLC and FRC, pump-handle movements were 1.8 times larger in healthy participants than in participants with COPD, in line with their 1.6 times larger inspiratory capacities. However, when rib motion was normalized to the change in lung volume, pump-handle movements were similar for healthy and COPD participant groups. We found no differences in bucket-handle movements between participant groups before and after normalization. Pump-handle movement was the dominant rib motion between FRC and TLC, on average four times greater than bucket-handle movement in healthy participants. For expiratory tidal volume, pump-handle movements were 20% smaller than bucket-handle movements. When normalized to tidal volume and compared to inspiratory capacity, pump-handle movements were smaller and bucket-handle movements were larger during tidal breathing. The findings suggest that the pump-handle and bucket-handle components of rib motion vary for small and large changes in lung volume.

Onset of respiration in infants delivered by cesarean section

1982 ◽  
Vol 52 (3) ◽  
pp. 716-724 ◽  
Author(s):  
J. P. Mortola ◽  
J. T. Fisher ◽  
J. B. Smith ◽  
G. S. Fox ◽  
S. Weeks ◽  
...  
Keyword(s):  
Cesarean Section ◽  
Tidal Volume ◽  
Respiratory Pattern ◽  
Lung Inflation ◽  
Cesarean Section Delivery ◽  
Expiratory Time ◽  
Healthy Infants ◽  
Ventilatory Parameters ◽  
Residual Capacity ◽  
Marked Tendency

We studied the ventilatory parameters and the pattern of breathing including the onset of respiration in 20 healthy infants immediately after cesarean-section delivery. In eight of the infants further measurements were obtained at 60 min of life. The pattern of breathing immediately after delivery is very irregular with a marked tendency to keep the lung inflated mainly through interruptions of expiration. After the first expiration some air remains in the lung representing the formation of functional residual capacity (FRC). FRC obtained with the first breath is proportional to the previous inspired volume and is the largest contribution towards the full establishment of FRC. Tidal volume and FRC of the first breath are similar to that reported in babies delivered vaginally, which suggests that the forces required for lung inflation are similar in the two groups of infants. The first breath tends to be deeper and slower and has a longer expiratory time than subsequent breaths. At 60 min of life the respiratory pattern becomes more regular, tidal volume is further decreased, and respiratory frequency is increased through a reduction of expiratory time.

Gravity effects on regional lung ventilation determined by functional EIT during parabolic flights

2001 ◽  
Vol 91 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Inéz Frerichs ◽  
Taras Dudykevych ◽  
José Hinz ◽  
Marc Bodenstein ◽  
Günter Hahn ◽  
...  
Keyword(s):  
Lung Volume ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Lung Ventilation ◽  
Tidal Breathing ◽  
Parabolic Flights ◽  
Regional Lung ◽  
Residual Capacity ◽  
The Right ◽  
Regional Lung Ventilation

Gravity-dependent changes of regional lung function were studied during normogravity, hypergravity, and microgravity induced by parabolic flights. Seven healthy subjects were followed in the right lateral and supine postures during tidal breathing, forced vital capacity, and slow expiratory vital capacity maneuvers. Regional 1) lung ventilation, 2) lung volumes, and 3) lung emptying behavior were studied in a transverse thoracic plane by functional electrical impedance tomography (EIT). The results showed gravity-dependent changes of regional lung ventilation parameters. A significant effect of gravity on regional functional residual capacity with a rapid lung volume redistribution during the gravity transition phases was established. The most homogeneous functional residual capacity distribution was found at microgravity. During vital capacity and forced vital capacity in the right lateral posture, the decrease in lung volume on expiration was larger in the right lung region at all gravity phases. During tidal breathing, the differences in ventilation magnitudes between the right and left lung regions were not significant in either posture or gravity phase. A significant nonlinearity of lung emptying was determined at normogravity and hypergravity. The pattern of lung emptying was homogeneous during microgravity.

Persistence of the Hering-Breuer reflex beyond the neonatal period

1991 ◽  
Vol 71 (2) ◽  
pp. 474-480 ◽  
Author(s):  
P. S. Rabbette ◽  
K. L. Costeloe ◽  
J. Stocks
Keyword(s):  
Spontaneous Breathing ◽  
Neonatal Period ◽  
Tidal Breathing ◽  
Natural Sleep ◽  
Airway Occlusion ◽  
Conflicting Evidence ◽  
Healthy Infants ◽  
Occlusion Technique ◽  
Relative Change ◽  
Stimulation Of

There is conflicting evidence regarding the persistence of the Hering-Breuer reflex (HBR) beyond the 1st wk of life. This study was designed to assess the influence of postnatal age on the HBR. The airway occlusion technique was used to assess changes in respiratory timing during stimulation of the HBR in healthy full-term unsedated infants measured shortly after birth and at 6–8 wk of life. The strength of the HBR was assessed from the relative change in expiratory time (TE) after end-inspiratory occlusion compared with resting TE during spontaneous breathing. Paired studies were performed in 31 infants at approximately 2 days and 6 wk of age. There was a significant increase in TE during each occlusion in every infant irrespective of age at measurement. No maturational changes were observed. The increase in TE after end-inspiratory occlusion was 91.9 +/- 31.6% (SD) (range 38–158%) at approximately 2 days and 89.8 +/- 30.7% (range 44–175%) at approximately 6 wk. We conclude that the activity of the HBR during tidal breathing persists beyond the neonatal period and that there is no statistically significant change in its strength during the first 2 mo life in healthy infants during natural sleep.

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.

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