Reflex control of expiratory duration in newborn infants

1985 ◽  
Vol 58 (2) ◽  
pp. 575-581 ◽  
Author(s):  
P. C. Kosch ◽  
P. W. Davenport ◽  
J. A. Wozniak ◽  
A. R. Stark
Keyword(s):  
Airway Pressure ◽  
Newborn Infants ◽  
Neural Mechanism ◽  
Face Mask ◽  
Emg Activity ◽  
Healthy Infants ◽  
Elastic Loading ◽  
Respiratory Valve ◽  
Lung Deflation ◽  
Manifold System

We investigated the effect on expiratory duration (TE) of application of graded resistive and elastic loads and total airway occlusions to single expirations in 9 full-term healthy infants studied on the 2nd or 3rd day of life. The infants breathed through a face mask and pneumotachograph, and flow, volume, airway pressure, and diaphragm electromyogram (EMG) were recorded. Loads were applied to the expiratory outlet of a two-way respiratory valve using a manifold system. Application of all loads resulted in expired volumes (VE) decreased from control (P less than 0.05), and changes were progressive with increasing loads. As VE became smaller, end-expiratory volume (EEV) became greater. TE, measured either from the pattern of airflow or airway pressure, or from diaphragm EMG activity, progressively increased with increasing loads and was greatest with total occlusions (P less than 0.05, compared with control). Resistive loading resulted in a greater accumulated VE history than elastic loading to the same EEV. For equivalent changes in EEV, TE was more prolonged with resistive than with elastic loading. Expiratory loading did not change the inspiratory duration determined from the diaphragm EMG activity of the breath immediately following each loaded expiration. These findings in infants are consistent with an integrative neural mechanism that modulates TE in response to the accumulated VE history, including both EEV and rate of lung deflation.

Reflex control of inspiratory duration in newborn infants

1986 ◽  
Vol 60 (6) ◽  
pp. 2007-2014 ◽  
Author(s):  
P. C. Kosch ◽  
P. W. Davenport ◽  
J. A. Wozniak ◽  
A. R. Stark
Keyword(s):  
Newborn Infants ◽  
Face Mask ◽  
Curvilinear Relationship ◽  
Flow Volume ◽  
Healthy Infants ◽  
Switch Mechanism ◽  
Respiratory Valve ◽  
Reflex Control ◽  
Resistive Loads ◽  
Manifold System

We applied graded resistive and elastic loads and total airway occlusions to single inspirations in six full-term healthy infants on days 2–3 of life to investigate the effect on neural and mechanical inspiratory duration (TI). The infants breathed through a face mask and pneumotachograph, and flow, volume, airway pressure, and diaphragm electromyogram (EMG) were recorded. Loads were applied to the inspiratory outlet of a two-way respiratory valve using a manifold system. Application of all loads resulted in inspired volumes decreased from control (P less than 0.001), and changes were progressive with increasing loads. TI measured from the pattern of the diaphragm EMG (TIEMG) was prolonged from control by application of all elastic and resistive loads and by total airway occlusions, resulting in a single curvilinear relationship between inspired volume and TIEMG that was independent of inspired volume trajectory. In contrast, when TI was measured from the pattern of airflow, the effect of loading on the mechanical time constant of the respiratory system resulted in different inspired volume-TI relationships for elastic and resistive loads. Mechanical and neural inspired volume and duration of the following unloaded inspiration were unchanged from control values. These findings indicate that neural inspiratory timing in infants depends on magnitude of phasic volume change during inspiration. They are consistent with the hypothesis that termination of inspiration is accomplished by an “off-switch” mechanism and that inspired volume determines the level of vagally mediated inspiratory inhibition to trigger this mechanism.

A VALVE FOR RESPIRATORY STUDIES IN INFANTS

PEDIATRICS ◽  
1961 ◽  
Vol 27 (4) ◽  
pp. 645-647
Author(s):  
Richard J. Golinko ◽  
Abraham M. Rudolph
Keyword(s):  
Dead Space ◽  
Newborn Infants ◽  
Dilution Effect ◽  
Face Mask ◽  
The Body ◽  
Large Head ◽  
The Face ◽  
Residual Capacity ◽  
Respiratory Valve ◽  
Body Plethysmograph

PULMONARY function studies in small infants have been limited in the past by failure to develop practical methods for collecting expired gas samples. Adaption of a respiratory valve suitable for use in small subjects with small tidal volumes has been difficult and has led to the use of techniques with the body plethysmograph, contour face mask and large head chamber. The body plethysmograph offers only indirect data and requires considerable prepration before each study. In addition, it has the disadvantage that once the infant is placed in the plethysmograph chamber further manipulations of the infant are not possible. Systems using the contour face mask on head chamber involve a large dead space which may be quite significant when one considers the small volumes dealt with. In order to overcome the problem of large dead space, Cayler et al., similar to others, circulated air across the face of the contour mask. However, because of the dilution effect, differences in the composition of the inspired and expired gases were very small and therefore the chance for error in the calculations was increased. Berglund and Karlberg, and Geubelle et al., while studying functional residual capacity in infants, found that practically all quiet, healthy newborn infants breathe through the nose and can also tolerate the insertion of small tubes in their nostrils for varying periods. On the basis of these observations, a respiratory valve has been designed for insertion directly into the nostrils, permitting collection of total expired air. The valve, especially adapted for use in small infants, offers minimal resistance to respiration and has a dead space of 0.8 ml.

Hemodynamic effects of nasal and face mask continuous positive airway pressure.

1994 ◽  
Vol 149 (6) ◽  
pp. 1614-1618 ◽  
Author(s):  
P K Montner ◽  
E R Greene ◽  
G H Murata ◽  
D M Stark ◽  
M Timms ◽  
...  
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Face Mask ◽  
Hemodynamic Effects

Renal Injury in Sick Newborn Infants: A Prospective Evaluation Using Urinary β2-Microglobulin Concentrations

PEDIATRICS ◽  
1988 ◽  
Vol 81 (3) ◽  
pp. 432-440
Author(s):  
Eric D. Tack ◽  
Jeffrey M. Perlman ◽  
Alan M. Robson ◽  
Cathy Hausel ◽  
Charles C. T. Chang
Keyword(s):  
Renal Injury ◽  
Confidence Limit ◽  
Newborn Infants ◽  
Tubular Injury ◽  
Creatinine Concentration ◽  
Term Infants ◽  
Urinary Creatinine ◽  
Β2 Microglobulin ◽  
Sick Newborn ◽  
Healthy Infants

Urinary concentrations of β2-microglobulin and creatinine were measured serially in 140 sick infants, of whom 109 were asphyxiated, and in 35 healthy preterm and term infants. First voided urines and samples from days 3 and 7 postpartum were studied. Urinary β2-microglobulin concentrations in healthy infants averaged 1.34 ± 1.34 mg/L (mean ± SD) in first voided specimens and 1.32 ± 0.98 mg/L in day 3 samples; the calculated upper limit of normal (95% confidence limit) was 4.00 mg/L. Elevated values (those exceeding the 95% confidence limit) occurred most often in the sick asphyxiated patients (56%); the first voided sample value in these patients was 10.0 ± 10.4 mg/L. The equivalent value in the sick nonasphyxiated infants was 8.32 ± 7.27 mg/L. Values were significantly and persistently elevated in the sick infants on days 3 and 7. Factoring β2-microglobulin levels by urinary creatinine concentration did not affect the significance of the findings. The increased urinary β2-microglobulin levels were not (1) related to gestational age; low β2-microglobulin values occurred at all gestational ages for both healthy and sick infants; (2) a consequence of urine flow rate; urinary β2-microglobulin did not correlate with urinary creatinine concentration or with urine to plasma creatinine ratio; and (3) a consequence of increased production of β2-microglobulin; urinary and serum β2-microglobulin values did not correlate (r = .03). Thus, we propose that the elevated levels of urinary β2-microglobulin in the sick infants were the consequence of tubular injury. This was associated with hematuria but not with a high incidence of azotemia or oliguria. In the most premature infants (<32 weeks), elevated urinary β2-microglobulin concentrations were associated with significantly increased urinary concentrations of sodium and potassium. These data suggest a higher prevalence of acute tubular injury in sick newborn infants than has been reported in previous studies in which more traditional indices of renal injury were used.

Posterior cricoarytenoid and diaphragm activities during tidal breathing in neonates

1988 ◽  
Vol 64 (5) ◽  
pp. 1968-1978 ◽  
Author(s):  
P. C. Kosch ◽  
A. A. Hutchinson ◽  
J. A. Wozniak ◽  
W. A. Carlo ◽  
A. R. Stark
Keyword(s):  
Newborn Infants ◽  
Emg Activity ◽  
Time Interval ◽  
Sudden Increase ◽  
Tidal Breathing ◽  
Term Neonates ◽  
Dynamic Maintenance ◽  
Sequential Activation ◽  
Vagal Reflex ◽  
Posterior Cricoarytenoid

To investigate airflow regulation in newborn infants, we recorded airflow, volume, diaphragm (Di), and laryngeal electromyogram (EMG) during spontaneous breathing in eight supine unsedated sleeping full-term neonates. Using an esophageal catheter electrode, we recorded phasic respiratory activity consistent with that of the principal laryngeal abductors, the posterior cricoarytenoids (PCA). Sequential activation of PCA and Di preceded inspiration. PCA activity typically peaked early in inspiration followed by either a decrescendo or tonic EMG activity of variable amplitude during expiration. Expiratory airflow retardation, or braking, accompanied by expiratory prolongation and reduced ventilation, was commonly observed. In some subjects we observed a time interval between PCA onset and a sudden increase in expiratory airflow just before inspiration, suggesting that release of the brake involved an abrupt loss of antagonistic adductor activity. Our findings suggest that airflow in newborn infants is controlled throughout the breathing cycle by the coordinated action of the Di and the reciprocal action of PCA and laryngeal adductor activities. We conclude that braking mechanisms in infants interact with vagal reflex mechanisms that modulate respiratory cycle timing to influence both the dynamic maintenance of end-expiratory lung volume and ventilation.

scholarly journals NASAL HIGH FREQUENCY OSCILLATION AND NASAL CONTINUOUS POSITIVE AIRWAY PRESSURE FOR RESPIRATORY INSUFFIENCY IN NEWBORN INFANTS 1946

1996 ◽  
Vol 39 ◽  
pp. 327-327
Author(s):  
Eric G Brouwer ◽  
Mark A van der Hoeven ◽  
Danillo W Gavilanes ◽  
Pieter L Degraeuwe ◽  
Wiel J Maertzdort ◽  
...  
Keyword(s):  
Continuous Positive Airway Pressure ◽  
High Frequency ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Newborn Infants ◽  
High Frequency Oscillation ◽  
Frequency Oscillation

Effects of tactile stimulation on spontaneous breathing during face mask ventilation

2021 ◽  
pp. fetalneonatal-2021-322989
Author(s):  
Vincent D Gaertner ◽  
Christoph Martin Rüegger ◽  
Dirk Bassler ◽  
Eoin O'Currain ◽  
C Omar Farouk Kamlin ◽  
...  
Keyword(s):  
Surface Area ◽  
Tactile Stimulation ◽  
Randomised Trial ◽  
Secondary Analysis ◽  
Newborn Infants ◽  
Face Mask ◽  
Positive Pressure ◽  
Clinical Trial Registry ◽  
Term Infants ◽  
Prospective Randomised Trial

ObjectiveWe sought to determine the effect of stimulation during positive pressure ventilation (PPV) on the number of spontaneous breaths, exhaled tidal volume (VTe), mask leak and obstruction.DesignSecondary analysis of a prospective, randomised trial comparing two face masks.SettingSingle-centre delivery room study.PatientsNewborn infants ≥34 weeks’ gestation at birth.MethodsResuscitations were video recorded. Tactile stimulations during PPV were noted and the timing, duration and surface area of applied stimulus were recorded. Respiratory flow waveforms were evaluated to determine the number of spontaneous breaths, VTe, leak and obstruction. Variables were recorded throughout each tactile stimulation episode and compared with those recorded in the same time period immediately before stimulation.ResultsTwenty of 40 infants received tactile stimulation during PPV and we recorded 57 stimulations during PPV. During stimulation, the number of spontaneous breaths increased (median difference (IQR): 1 breath (0–3); padj<0.001) and VTe increased (0.5 mL/kg (−0.5 to 1.7), padj=0.028), whereas mask leak (0% (−20 to 1), padj=0.12) and percentage of obstructed inflations (0% (0–0), padj=0.14) did not change, compared with the period immediately prior to stimulation. Increased duration of stimulation (padj<0.001) and surface area of applied stimulus (padj=0.026) were associated with a larger increase in spontaneous breaths in response to tactile stimulation.ConclusionsTactile stimulation during PPV was associated with an increase in the number of spontaneous breaths compared with immediately before stimulation without a change in mask leak and obstruction. These data inform the discussion on continuing stimulation during PPV in term infants.Trial registration numberAustralian and New Zealand Clinical Trial Registry (ACTRN12616000768493).

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