Reduced lung volume during behavioral active sleep in the newborn

1979 ◽  
Vol 46 (6) ◽  
pp. 1081-1085 ◽  
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.

Regulation of end-expiratory lung volume during sleep in premature infants

1987 ◽  
Vol 62 (3) ◽  
pp. 1117-1123 ◽  
Author(s):  
A. R. Stark ◽  
B. A. Cohlan ◽  
T. B. Waggener ◽  
I. D. Frantz ◽  
P. C. Kosch
Keyword(s):  
Tidal Volume ◽  
Premature Infants ◽  
Lung Volume ◽  
Emg Activity ◽  
Active Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Volume Curve ◽  
Variable Extent ◽  
Expiratory Flow

To investigate the regulation of end-expiratory lung volume (EEV) in premature infants, we recorded airflow, tidal volume, diaphragm electromyogram (EMG), and chest wall displacement during sleep. In quiet sleep, EEV during breathing was 10.8 +/- 3.6 (SD) ml greater than the minimum volume reached during unobstructed apneas. In active sleep, no decrease in EEV was observed during 28 of 35 unobstructed apneas. Breaths during quiet sleep had a variable extent of expiratory airflow retardation (braking), and inspiratory interruption occurred at substantial expiratory flow rates. During active sleep, the expiratory flow-volume curve was nearly linear, proceeding nearly to the volume axis at zero flow, and diaphragm EMG activity terminated near the peak of mechanical inspiration. Expiratory duration (TE) and inspiratory duration (TI) were significantly shortened in quiet sleep vs. active sleep although tidal volume was not significantly different. In quiet sleep, diaphragmatic braking activity and shortened TE combined to maintain EEV during breathing substantially above relaxation volume. In active sleep, reduced expiratory braking and prolongation of TE resulted in an EEV that was close to relaxation volume. We conclude that breathing strategy to regulateEEV in premature infants appears to be strongly influenced by sleep state.

Mechanics of the rib cage and diaphragm during sleep

1977 ◽  
Vol 43 (4) ◽  
pp. 600-602 ◽  
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.

Comparison of calibration methods for respiratory inductive plethysmography in infants

1987 ◽  
Vol 63 (5) ◽  
pp. 1853-1861 ◽  
Author(s):  
M. D. Revow ◽  
S. J. England ◽  
H. A. Stogryn ◽  
D. L. Wilkes
Keyword(s):  
Compartment Model ◽  
Sleep State ◽  
Quiet Sleep ◽  
Multiple Points ◽  
Rib Cage ◽  
Respiratory Inductive Plethysmography ◽  
State Dependent ◽  
Two Compartment Model ◽  
Calibration Methods ◽  
Substantial Change

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.

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

1981 ◽  
Vol 51 (4) ◽  
pp. 830-834 ◽  
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.

scholarly journals Postnatal maturation of laryngeal chemoreflexes in the preterm lamb

2007 ◽  
Vol 102 (4) ◽  
pp. 1429-1438 ◽  
Author(s):  
Marie St-Hilaire ◽  
Nathalie Samson ◽  
Elise Nsegbe ◽  
Charles Duvareille ◽  
François Moreau-Bussière ◽  
...  
Keyword(s):  
Heart Rate ◽  
Lower Airway ◽  
Distilled Water ◽  
Active Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
General Belief ◽  
Postnatal Maturation ◽  
Laryngeal Mucosa ◽  
Life Threatening

Laryngeal chemoreflexes (LCR) are triggered by the contact of liquids with the laryngeal mucosa. In the mature organism, LCR trigger lower airway protective responses (coughing, effective swallowing, and arousal) to prevent aspiration. General belief holds that LCR are responsible for apnea and bradycardia in the newborn mammal, including humans. Our laboratory has recently shown that LCR in full-term lambs are consistently analogous to the mature LCR reported in adult mammals, without significant apneas and bradycardias (St-Hilaire M, Nsegbe E, Gagnon-Gervais K, Samson N, Moreau-Bussiere F, Fortier PH, and Praud J-P. J Appl Physiol 98: 2197–2203, 2005). The aim of the present study was to assess LCR in nonsedated, newborn preterm lambs born at 132 days of gestation (term = 147 days). The preterm lambs were instrumented for recording glottal adductor electromyogram, electroencephalogram, eye movements, heart rate, respiration, and oximetry. A chronic supraglottal catheter was used for injecting 0.5 ml of saline, distilled water, and HCl (pH 2) during quiet sleep, active sleep, and wakefulness on postnatal days 7 (D7) and 14 (D14). Laryngeal stimulation by water or HCl on D7 induced significant apneas, bradycardia, and desaturation, which, at times, appeared potentially life-threatening. No significant apneas, bradycardias, or desaturation were observed on D14. No consistent effects of sleep state could be shown in the present study. In conclusion, laryngeal stimulation by liquids triggers potentially dangerous LCR in preterm lambs on D7, but not on D14. It is proposed that maturation of the LCR between D7 and D14 is partly involved in the disappearance of apneas/bradycardias of prematurity with postnatal age.

Hypercapnia increases expiratory braking in preterm infants

1993 ◽  
Vol 75 (6) ◽  
pp. 2665-2670 ◽  
Author(s):  
E. C. Eichenwald ◽  
R. A. Ungarelli ◽  
A. R. Stark
Keyword(s):  
Tidal Volume ◽  
Premature Infants ◽  
Lung Volume ◽  
Newborn Infants ◽  
Emg Activity ◽  
Quiet Sleep ◽  
Activity Peak ◽  
Posterior Cricoarytenoid ◽  
Respiratory Muscle Activity ◽  
Ventilatory Response To Co2

In contrast to adults, newborn infants breathe from an elevated end-expiratory lung volume, determined by the interaction of airflow retardation (braking) by the diaphragm and larynx, and expiratory duration. To determine the effect of hypercapnia on this strategy, we examined changes in respiratory muscle activity and the ventilatory response to CO2 breathing in eight premature infants 33–34 wk gestational age in the first 3 postnatal days. We recorded tidal volume, airflow, and electromyograms (EMG) of the laryngeal abductor [posterior cricoarytenoid (PCA)], which abducts the vocal cords, and diaphragm during behaviorally determined quiet sleep in room air and during steady-state inhalation of 2% CO2 in air. As expected, tidal volume increased (P < 0.0005) without a change in inspiratory duration with hypercapnia. Unexpectedly, in all subjects, expiratory duration was longer during CO2 inhalation (P < 0.001), accompanied by marked changes in expiratory flow patterns consistent with increased expiratory braking. Diaphragm post-inspiratory EMG activity increased with hypercapnia (P < 0.005) with no change in baseline diaphragm or PCA EMG activity. Peak inspiratory EMG activity of the diaphragm and PCA increased with CO2 (10 and 37%, respectively; P < 0.05). We conclude that the mechanisms used to elevate end-expiratory lung volume are enhanced during hypercapnia in premature infants. This breathing strategy may be important in maintaining gas exchange in infants with lung disease.

Periodic Apnea in the Full-Term Infant: Individual Consistency, Sex Differences, and State Specificity

PEDIATRICS ◽  
1982 ◽  
Vol 70 (1) ◽  
pp. 79-86
Author(s):  
Stephen P. Waite ◽  
Evelyn B. Thoman
Keyword(s):  
Periodic Breathing ◽  
Term Infant ◽  
Full Term ◽  
Respiratory Pattern ◽  
Active Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Term Infants ◽  
The Mean ◽  
Individual Consistency

The occurrence of periodic apnea (apnea during periodic breathing) was studied in 27 normal, full-term infants during the first five weeks of life. The rate and mean length of apnea were analyzed both with respect to sleep state and with respect to respiratory pattern, ie, periodic vs nonperiodic breathing. The rate of apnea was found to vary according to sleep state and the pattern of breathing. The highest apnea rates were non-periodic apneas in active sleep. Periodic apnea rates were relatively low in both active and quiet sleep; however, this type of apnea was consistently observed from weeks 2 through 5. The proportion of apneas that are periodic is much higher in quiet sleep than in active sleep. Rates of periodic and nonperiodic apnea were more consistently correlated in active sleep than in quiet sleep. The mean length of periodic apnea was found to be significantly greater than the mean length of nonperiodic apnea in both sleep states, a difference that reflected a greater positive skew in the distribution of the nonperiodic apnea lengths. This variation in length between periodic and nonperiodic apnea explains, in part, the increased mean length in quiet sleep compared with active sleep. There were significant individual differences over weeks in both forms of apnea in active sleep and in quiet sleep. Female infants were observed to have higher rates of nonperiodic apnea than male infants in active sleep, although no significant differences in the distribution of lengths were obtained.

Ventilatory responses of newborn calves to progressive hypoxia in quiet and active sleep

1980 ◽  
Vol 48 (5) ◽  
pp. 892-895 ◽  
Author(s):  
H. E. Jeffery ◽  
D. J. Read
Keyword(s):  
Ventilatory Response ◽  
Active Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Ventilatory Responses ◽  
Progressive Hypoxia ◽  
Newborn Calves ◽  
End Tidal ◽  
Arterial O2 Saturation ◽  
And Behavior

Isocapnic progressive hypoxia was produced by rebreathing 8-10% oxygen in replicate tests during quiet and active sleep, in five full-term calves aged 1-8 days. Airflow through a tightly fitting mask was digitized at 50-ms intervals to calculate breath-by-breath ventilation and rate. Using a cuvette oximeter, arterial O2 saturation (SaO2) was recorded continuously. A mass-spectrometer record of end-tidal PO2 and PCO2 confirmed the mask seal and the constancy of PCO2. Sleep state was characterized by EEG, EOG, neck EMG, and behavior. In quiet sleep the ratio of ventilation to its normoxic control (VR) increased linearly as SaO2 fell; reflex arousal occurred at SaO2 84.9 ± 4.3% (SD) with VR 1.4 ± 0.39 (SD). In contrast, during active sleep, hypoxemia progressed without any ventilatory response to a very low SaO2; a reflex arousal occurred at SaO2 59.2 ±11.0%, often with a ventilatory response developing abruptly just prior to arousal. The slope of the VR/SaO2 regression lines for the overlapping range of SaO2 differed significantly with state in each animal (P < 0.001); the pooled VR values at SaO2 75% were 1.73± 0.15 (SD) and 0.91 ± 0.18 for quiet and active sleep respectively. The depression of the ventilatory response to hypoxia in active sleep differs from previous reports on adult dogs. The basis for this difference needs to be evaluated in relation to species and age, in particular in relation to both the mechanics of breathing and to chemoreceptor reflexes.

Linear and nonlinear properties of heart rate control in infants at risk

1997 ◽  
Vol 273 (2) ◽  
pp. R540-R547
Author(s):  
A. Patzak ◽  
B. Schluter ◽  
W. Orlow ◽  
R. Mrowka ◽  
D. Gerhardt ◽  
...  
Keyword(s):  
At Risk ◽  
Heart Rate ◽  
Chaotic Behavior ◽  
Total Power ◽  
Largest Lyapunov Exponent ◽  
Active Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Spectral Parameters ◽  
Nonlinear Properties

The aim of this study was to test whether the heart rate (HR) control in infants at risk differs in comparison with healthy infants. Twelve former preterm infants suffering from bronchopulmonary dysplasia and 18 control infants, matched for their postconceptional age, were examined polygraphically during quiet and active sleep. HR, low-frequency (LF) power, high-frequency (HF) power, total power, and the ratio of LF to HF power (LF/HF) of the instantaneous HR spectra were calculated for linear analysis. The largest Lyapunov exponent (LLE) of the R-R interval time series was calculated to determine a nonlinear property of HR. Infants at risk had significantly lower LF power (median: 0.51 x 10(-3) vs. 1.16 x 10(-3) Hz2) and lower LF/HF (median: 1.05 vs. 1.94) during quiet sleep. LLE was positive, revealing low-dimensional chaotic behavior of HR control, and did not differ between both groups (median: quiet sleep, 0.05 bit/s vs. 0.06 bit/s; active sleep, 0.16 bit/s vs. 0.15 bit/s). Sleep state-related changes in spectral parameters and LLE were similar in both groups. In infants at risk, the lower LF/HF during quiet sleep can be interpreted in terms of changes in the rhythmic components of the sympathovagal balance of the autonomic system, which is an expression of linear properties of HR control. Conversely, the lack of differences in LLE between both groups indicates similar nonlinear properties of the control system.

scholarly journals Cerebral Circulation in Sleep: Vasodilatory Response to Cerebral Hypotension

1998 ◽  
Vol 18 (6) ◽  
pp. 639-645 ◽  
Author(s):  
Daniel A. Grant ◽  
Carlo Franzini ◽  
Jennene Wild ◽  
Adrian M. Walker
Keyword(s):  
Cerebral Circulation ◽  
Perfusion Pressure ◽  
Superior Sagittal Sinus ◽  
Active Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Flow Probe ◽  
Sagittal Sinus ◽  
Cerebral Vasodilation ◽  
Cerebral Vascular Resistance

Little is known of the factors that regulate CBF in sleep. We therefore studied 10 lambs to assess the vasodilatory processes that underlie cerebral autoregulation during sleep. Lambs, instrumented to measure CBF (flow probe on the superior sagittal sinus), sleep state, and cerebral perfusion pressure (CPP), were rapidly made hypotensive by inflating a cuff around the brachiocephalic artery to reduce CPP to 30 mm Hg in each state. During control periods, cerebral vascular resistance (CVR in mm Hg/mL/min) was lower in active sleep (2.8±0.3, mean±SD, P ≤ 0.001) than in wakefulness (3.9±0.6) and quiet sleep (4.3±0.6). The CVR decreased promptly in each state as CPP was lowered. The time (seconds) required for maximal cerebral vasodilation to occur was longer in active sleep (35±11) than in quiet sleep (20±6, P ≤ 0.001) and wakefulness (27±11, P ≤ 0.05). The CVR decreased less in active sleep (0.6±0.3, P ≤ 0.001) than in quiet sleep (1.5±0.3), although the changes in CPP induced with brachiocephalic occlusion were equal in each state. In conclusion, our studies provide the first evidence that the vasoactive mechanisms that underlie autoregulation of the cerebral circulation function during sleep. Moreover, our data reveal that the speed and the magnitude of the vasodilatory reserves available for autoregulation are significantly less in active sleep than in quiet sleep.

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