Exploring the relationship between forced maximal flow at functional residual capacity and parameters of forced expiration from raised lung volume in healthy infants

2002 ◽  
Vol 33 (6) ◽  
pp. 419-428 ◽  
Author(s):  
S.C. Ranganathan ◽  
A.F. Hoo ◽  
S.Y. Lum ◽  
I. Goetz ◽  
R.A. Castle ◽  
...  
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Forced Expiration ◽  
Maximal Flow ◽  
Healthy Infants ◽  
Residual Capacity ◽  
The Relationship

Effects of lung volume on collateral and airways resistance in man

1979 ◽  
Vol 46 (1) ◽  
pp. 67-73 ◽  
Author(s):  
C. R. Inners ◽  
P. B. Terry ◽  
R. J. Traystman ◽  
H. A. Menkes
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Total Lung Capacity ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Collateral Pathways ◽  
Flow Through ◽  
Airways Resistance ◽  
Young Subjects ◽  
The Relationship

The effects of changing lung volume (VL) on collateral resistance (Rcoll) and total airways resistance (Raw) were compared in six young volunteers. At functional residual capacity (FRC) = 55% total lung capacity (TLC), mean Rcoll was 4,664 +/- 1,518 (SE) cmH2O/(l/s) and mean Raw was 1.57 +/- 0.11 (SE) cmH2O/l/s). When VL increased to 80% TLC, Rcoll decreased by 63.3 +/- 7.8%, and Raw decreased by 50.3 +/- 4.2 (SE) %. The decrease in Rcoll with increasing lung volume was not statistically different from that of Raw (P less than 0.05). If the airways obstructed for measurements of Rcoll served between 2 and 5% of the lungs, then Rcoll was approximately 50 times as great as the resistance to flow through airways serving the same volume of lung at FRC. The relationship did not change significantly when VL increased by 25% TLC. If changes in Raw reflect changes in airways supplying sublobar portions of lung, these results indicate that there is no tendency for the redistribution of ventilation through airways and collateral pathways with changes in VL in young subjects.

scholarly journals The effect of inert gas choice on multiple breath washout in healthy infants: differences in lung function outcomes and breathing pattern

2017 ◽  
Vol 123 (6) ◽  
pp. 1545-1554 ◽  
Author(s):  
Per M. Gustafsson ◽  
Lovisa Bengtsson ◽  
Anders Lindblad ◽  
Paul D. Robinson
Keyword(s):  
Functional Residual Capacity ◽  
Sulfur Hexafluoride ◽  
Breathing Pattern ◽  
Inert Gas ◽  
Respiratory Drive ◽  
Quiet Sleep ◽  
Lung Clearance ◽  
Healthy Infants ◽  
Lung Clearance Index ◽  
Residual Capacity

The detrimental effects on breathing pattern during multiple breath inert gas washout (MBW) have been described with different inhaled gases [100% oxygen (O2) and sulfur hexafluoride (SF6)] but detailed comparisons are lacking. N2- and SF6-based tests were performed during spontaneous quiet sleep in 10 healthy infants aged 0.7–1.3 yr using identical hardware. Differences in breathing pattern pre and post 100% O2 and 4% SF6 exposure were investigated, and the results obtained were compared [functional residual capacity (FRC) and lung clearance index (LCI)]. During 100% O2 exposure. mean inspiratory flow (“respiratory drive”) decreased transiently by mean (SD) 28 (9)% ( P < 0.001), and end-tidal CO2 (carbon dioxide) increased by mean (SD) 0.3 (0.4)% units ( P < 0.05) vs. air breathing prephase. During subsequent N2 washin (i.e., recovery phase), the pattern of change reversed. No significant effect on breathing pattern was observed during SF6 testing. In vitro testing confirmed that technical artifacts did not explain these changes. Mean (SD) FRC and LCI in vivo were significantly higher with N2 vs. SF6 washout: 216 (33) vs. 186 (22) ml ( P < 0.001) and 8.25 (0.85) vs. 7.55 (0.57) turnovers ( P = 0.021). Based on these results, SF6 based MBW is the preferred methodology for tests in this age range. NEW & NOTEWORTHY Inert gas choice for multiple breath inert gas washout (MBW) in infants has important consequences on both breathing pattern during test performance and the functional residual capacity and lung clearance index values obtained. Data suggest the detrimental effect of breathing pattern of 100% O2 and movement of O2 across the alveolar capillary membrane, with direct effects on MBW outcomes. SF6 MBW during infancy avoids this and can be further optimized by addressing the sources of technical artifact identified in this work.

LUNG VOLUME IN THE NEWBORN INFANT

PEDIATRICS ◽  
1962 ◽  
Vol 30 (1) ◽  
pp. 111-116
Author(s):  
M. Klaus ◽  
W. H. Tooley ◽  
K. H. Weaver ◽  
J. A. Clements
Keyword(s):  
Newborn Infant ◽  
Functional Residual Capacity ◽  
Lung Volume ◽  
Newborn Infants ◽  
Du Bois ◽  
Residual Capacity

The plethysmographic technique of Du-Bois and associates has been modified for use in newborn infants and found suitable for the measurement of lung volume. Of 37 normal infants studied with this method, most achieved full functional residual capacity during the first few minutes of life.

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.

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 forced expiratory flows during rapid thoracoabdominal compression in infants

1995 ◽  
Vol 78 (5) ◽  
pp. 1993-1997 ◽  
Author(s):  
J. Hammer ◽  
C. J. Newth
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Forced Expiration ◽  
Flow Volume ◽  
Older Children ◽  
Lung Volumes ◽  
Volume Segment ◽  
Forced Expiratory Flow ◽  
Residual Capacity ◽  
End Tidal

The rapid thoracoabdominal compression (RTC) technique is commonly used in pulmonary function laboratories to assess flow-volume relationships in infants unable to produce a voluntary forced expiration maneuver. This technique produces forced expiratory flows over only a small lung volume segment (i.e., tidal volume). It has been argued that the RTC technique should be modified to measure flow-volume relationships over a larger portion of the vital capacity range to imitate the voluntary maximal forced expiratory maneuver obtained in older children and adults. We examined the effect of volume history on forced expiratory flows by generating forced expiratory flow-volume curves by RTC from well-defined inspiratory volumes delineated by inspiratory pressures of 10, 20, 30, and 40 cmH2O down to residual volume (i.e., the reference volume) in seven intubated and anesthetized infants with normal lungs [age 8.0 +/- 2.0 (SE) mo, weight 6.7 +/- 0.6 kg]. We compared maximal expiratory flows at isovolume points (25 and 10% of forced vital capacity) and found no significant differences in maximal isovolume flow rates measured from the different lung volumes. We conclude that there is no obvious need to initiate RTC from higher lung volumes if the technique is used for flow comparisons. However, compared with measurements of maximal flows at functional residual capacity by RTC from end-tidal inspiration, the initiation of RTC from a defined and reproducible inspiratory level appears to decrease the intrasubject variability of the maximal expiratory flows at low lung volumes.

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