Comparison of calibration methods for respiratory inductive plethysmography in infants

In infants under the age of 6 mo respiratory inductive plethysmograph (RIP)-calculated tidal volumes (VT) were compared with simultaneously measured volumes using a pneumotachograph (PNT) to 1) assess whether using multiple points (MP) along the inspiratory profile of a breath is superior to using only VT when calculating volume-motion (VM) coefficients, 2) verify the assumption of independent contributions of the abdomen and rib cage to VT, which was accomplished by extending the normal RIP model to include a term representing interaction between these two compartments, and 3) investigate whether VM coefficients are sleep-state dependent. Neither use of multiple points nor inclusion of the interacting term improved the performance of the RIP over that observed using a simple two-compartment model with VT measurements. However, VM coefficients obtained during quiet sleep (QS) were not reliable when used during rapid-eye-movement (REM) sleep, suggesting that coefficients obtained during one sleep state may not be applicable to another state where there is a substantial change in the relative abdominal/rib cage contributions to VT.

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Mechanics of the rib cage and diaphragm during sleep

Journal of Applied Physiology ◽

10.1152/jappl.1977.43.4.600 ◽

1977 ◽

Vol 43 (4) ◽

pp. 600-602 ◽

Cited By ~ 87

Author(s):

K. Tusiewicz ◽

H. Moldofsky ◽

A. C. Bryan ◽

M. H. Bryan

Keyword(s):

Tidal Volume ◽

Supine Position ◽

Marked Reduction ◽

Normal Subjects ◽

Upright Position ◽

Rapid Eye Movement Sleep ◽

Sleep State ◽

Quiet Sleep ◽

Rib Cage ◽

The Subject

The pattern of motion of the rib cage and abdomen/diaphragm was studied in three normal subjects during sleep. Sleep state was monitored by electroencephalograph and electrocculograph. Intercostal electromyographs (EMG's) were recorded from the second interspace parasternally. Abdominothoracic motion was monitored with magnetometers and these signals calibrated by isovolume lines either immediately before going to sleep, or if there was movement, on awakening. Respiration was recorded using a jerkin plethysmograph. In the awake subject in the supine position, the rib cage contributed 44% to the tidal volume and had essentially the same contribution in quiet sleep. However, in active or rapid eye movement sleep the rib cage contribution fell to 19% of the tidal volume. This was accompanied by a marked reduction in the intercostal EMG. With the subject in the upright position the rib cage appears to be passively driven by the diaphragm. However, the present data suggest that active contraction of the intercostal muscles is required for normal rib cage expansion in the supine position.

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Importance of inspiratory muscle tone in maintenance of FRC in the newborn

Journal of Applied Physiology ◽

10.1152/jappl.1981.51.4.830 ◽

1981 ◽

Vol 51 (4) ◽

pp. 830-834 ◽

Cited By ~ 58

Author(s):

J. Lopes ◽

N. L. Muller ◽

M. H. Bryan ◽

A. C. Bryan

Keyword(s):

Muscle Tone ◽

Inspiratory Muscle ◽

Rapid Eye Movement Sleep ◽

Sleep State ◽

Quiet Sleep ◽

Rib Cage ◽

Surface Electrodes ◽

Inspiratory Muscles ◽

Residual Capacity ◽

Behavioral Criteria

The importance of inspiratory muscle tone in the maintenance of functional residual capacity (FRC) in newborns was studied in eight premature infants with birth weights of 1,166 +/- 217 g and gestational age 29 +/- 1.9 wk (mean +/- SD). Rib cage and abdominal anteroposterior diameters were monitored with magnetometers, and electromyograms of the diaphragm and intercostal muscles were recorded with surface electrodes. Sleep state was monitored using electrooculogram and behavioral criteria. We assessed the decrease in tonic activity of the inspiratory muscles and the fall in end-expiratory lung volume during apnea compared with the period just preceding apnea. A total of 98 apneas were analyzed. In all instances a decrease in diaphragmatic and intercostal tone was associated with a decrease in the anteroposterior diameter of both rib cage and abdomen, indicating a fall in FRC. These changes were more marked during quiet sleep than during rapid-eye-movement sleep (P less than 0.01). Our results suggest that inspiratory muscle tone is a major determinant of FRC in the newborn.

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Ventilatory and arousal patterns during sleep in normal young and elderly subjects

Journal of Applied Physiology ◽

10.1152/jappl.1985.59.5.1607 ◽

1985 ◽

Vol 59 (5) ◽

pp. 1607-1615 ◽

Cited By ~ 46

Author(s):

E. T. Shore ◽

R. P. Millman ◽

D. A. Silage ◽

D. C. Chung ◽

A. I. Pack

Keyword(s):

Sleep Apnea Syndrome ◽

Age Groups ◽

Periodic Breathing ◽

The Elderly ◽

Elderly Subjects ◽

Sleep State ◽

Respiratory Inductive Plethysmography ◽

State Dependent ◽

Young Subjects ◽

Stage 1

Since elderly subjects have lower chemosensitivity, we postulated that ventilation might be more state dependent in the elderly. To address this we investigated the changes in ventilation, measured by respiratory inductive plethysmography, with sleep in 12 healthy young (19–29 yr) and 13 elderly (greater than 65 yr) subjects. Ventilation was measured in representative periods in each sleep state. These data showed that there is no difference between the elderly and the young either in mean ventilation or in the variability of ventilation awake or in the different states of sleep. In both groups ventilation was variable in stage 1–2 sleep and least variable in stage 3–4 sleep. The variability in stage 1–2 sleep was due to periodic breathing (cycle time approximately 45 s) in both age groups. Although within a sleep state no differences were observed, over the night of study the elderly behaved differently from the young. Apneas occurred more frequently in the elderly, and 5 of 13 elderly met the criteria for sleep apnea syndrome compared with 1 of 12 young subjects. Apneas tended to occur predominantly in stage 1–2 sleep and seem to be an exaggeration of the periodicity that is typical of this state. Four of the elderly with apnea remained in this stage of sleep throughout the night of study. The apneic episodes usually terminated with an electroencephalogram arousal that occurred prior to or simultaneously with the onset of ventilation.

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Action of the diaphragm on the rib cage

Journal of Applied Physiology ◽

10.1152/japplphysiol.00268.2016 ◽

2016 ◽

Vol 121 (2) ◽

pp. 391-400 ◽

Cited By ~ 19

Author(s):

André De Troyer ◽

Theodore A. Wilson

Keyword(s):

Compartment Model ◽

Pleural Pressure ◽

Chronic Obstructive ◽

Abdominal Pressure ◽

Obstructive Pulmonary Disease ◽

Rib Cage ◽

Chest Wall Mechanics ◽

Two Compartment Model ◽

Residual Capacity ◽

Lateral Walls

When the diaphragm contracts, pleural pressure falls, exerting a caudal and inward force on the entire rib cage. However, the diaphragm also exerts forces in the cranial and outward direction on the lower ribs. One of these forces, the “insertional force,” is applied by the muscle at its attachments to the lower ribs. The second, the “appositional force,” is due to the transmission of abdominal pressure to the lower rib cage in the zone of apposition. In the control condition at functional residual capacity, the effects of these two forces on the lower ribs are nearly equal and outweigh the effect of pleural pressure, whereas for the upper ribs, the effect of pleural pressure is greater. The balance between these effects, however, may be altered. When the abdomen is given a mechanical support, the insertional and appositional forces are increased, so that the muscle produces a larger expansion of the lower rib cage and, with it, a smaller retraction of the upper rib cage. In contrast, at higher lung volumes the zone of apposition is decreased, and pleural pressure is the dominant force on the lower ribs as well. Consequently, although the force exerted by the diaphragm on these ribs remains inspiratory, rib displacement is reversed into a caudal-inward displacement. This mechanism likely explains the inspiratory retraction of the lateral walls of the lower rib cage observed in many subjects with chronic obstructive pulmonary disease (Hoover's sign). These observations support the use of a three-compartment, rather than a two-compartment, model to describe chest wall mechanics.

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Reduced lung volume during behavioral active sleep in the newborn

Journal of Applied Physiology ◽

10.1152/jappl.1979.46.6.1081 ◽

1979 ◽

Vol 46 (6) ◽

pp. 1081-1085 ◽

Cited By ~ 103

Author(s):

D. J. Henderson-Smart ◽

D. J. Read

Keyword(s):

Lung Volume ◽

Rapid Development ◽

Young Infant ◽

Newborn Infants ◽

Active Sleep ◽

Sleep State ◽

Quiet Sleep ◽

Rib Cage ◽

Age Related ◽

Oxygen Stores

In a previous study of newborn infants we observed overall rib cage collapse during active sleep and postulated that the lungs also could be deflated, leading to reduced oxygen stores and circumstances favoring the rapid development of hypoxemia during apnea. In this study, thoracic gas volume (TGV) has been measured directly by occlusion plethysmography in six normal babies during behavioral quiet and active sleep and related to the different movements of the rib cage and abdomen-diaphragm that occur during each sleep state. TGV was significantly reduced in each baby during active sleep and was associated with rib cage deflation and increased abdomen-diaphragm excursions. The average reduction of TGV was 31% when compared with the volume in quiet sleep and did not depend on the order in which the sleep states were tested. The reduced lung volume in active sleep could have implications for the regulation of breathing in that state. A reduction of lung oxygen stores in active sleep suggests an age-related vulnerability of the young infant to hypoxemia.

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Two-Compartment Model of Cholesterol Kinetics for Establishment of Treatment Strategy of LDL Apheresis in Nephrotic Hypercholesterolemia

Blood Purification ◽

10.1159/000170180 ◽

1994 ◽

Vol 12 (6) ◽

pp. 317-326 ◽

Cited By ~ 4

Author(s):

Masatomo Yashiro ◽

Eri Muso ◽

Munehiro Matsushima ◽

Ryoichi Nagura ◽

Kenji Sawanishi ◽

...

Keyword(s):

Treatment Strategy ◽

Compartment Model ◽

Ldl Apheresis ◽

Two Compartment Model

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Clearance and Non-Invasive Determination of the Hepatic Extraction of Indocyanine Green in Baboons and Man

Clinical Science ◽

10.1042/cs0640207 ◽

1983 ◽

Vol 64 (2) ◽

pp. 207-212 ◽

Cited By ~ 64

Author(s):

S. L. Grainger ◽

P. W. N. Keeling ◽

I. M. H. Brown ◽

J. H. Marigold ◽

R. P. H. Thompson

Keyword(s):

Indocyanine Green ◽

Accurate Determination ◽

Liver Blood Flow ◽

Compartment Model ◽

Hepatic Extraction ◽

Non Invasive ◽

Two Compartment Model ◽

Hepatic Extraction Ratio ◽

Plasma Disappearance Curve

1. The disposition of an intravenous bolus of indocyanine green (ICG) has been studied in healthy man and baboons using a novel analysis of a two compartment pharmacokinetic model. 2. This analysis enabled the hepatic extraction ratio (ER) of dye to be determined solely from the plasma disappearance curve, and the ER determined did not differ from that measured by hepatic vein catheterization. 3. When compared with clearance measured at steady state, the two compartment model gave a significantly more accurate determination of plasma clearance than did the conventional one compartment model. 4. It is concluded that, in health, liver blood flow may be calculated accurately and noninvasively after a single intravenous injection of ICG.

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