Developmental changes in upper airway dynamics

2004 ◽  
Vol 97 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Carole L. Marcus ◽  
Lucila B. Fernandes Do Prado ◽  
Janita Lutz ◽  
Eliot S. Katz ◽  
Cheryl A. Black ◽  
...  
Keyword(s):  
Upper Airway ◽  
Older Children ◽  
Normal Children ◽  
Compensatory Response ◽  
Pharyngeal Airway ◽  
Ventilatory Drive ◽  
Airway Response ◽  
Airway Responses ◽  
Airway Dynamics ◽  
Normal Adults

Normal children have a less collapsible upper airway in response to subatmospheric pressure administration (PNEG) during sleep than normal adults do, and this upper airway response appears to be modulated by the central ventilatory drive. Children have a greater ventilatory drive than adults. We, therefore, hypothesized that children have increased neuromotor activation of their pharyngeal airway during sleep compared with adults. As infants have few obstructive apneas during sleep, we hypothesized that infants would have an upper airway that was resistant to collapse. We, therefore, compared the upper airway pressure-flow (V̇) relationship during sleep between normal infants, prepubertal children, and adults. We evaluated the upper airway response to 1) intermittent, acute PNEG (infants, children, and adults), and 2) hypercapnia (children and adults). We found that adults had a more collapsible upper airway during sleep than either infants or children. The children exhibited a vigorous response to both PNEG and hypercapnia during sleep ( P < 0.01), whereas adults had no significant change. Infants had an airway that was resistant to collapse and showed a very rapid response to PNEG. We conclude that the upper airway is resistant to collapse during sleep in infants and children. Normal children have preservation of upper airway responses to PNEG and hypercapnia during sleep, whereas responses are diminished in adults. Infants appear to have a different pattern of upper airway activation than older children. We speculate that the pharyngeal airway responses present in normal children are a compensatory response for a relatively narrow upper airway.

Ventilatory dynamics during transient arousal from NREM sleep: implications for respiratory control stability

1996 ◽  
Vol 80 (5) ◽  
pp. 1475-1484 ◽  
Author(s):  
M. C. Khoo ◽  
S. S. Koh ◽  
J. J. Shin ◽  
P. R. Westbrook ◽  
R. B. Berry
Keyword(s):  
Respiratory Control ◽  
Upper Airway ◽  
Nrem Sleep ◽  
Before And After ◽  
Stage 2 Sleep ◽  
Repeated Administrations ◽  
Time Courses ◽  
Control Stability ◽  
Airway Dynamics ◽  
Normal Adults

The polysomnographic and ventilatory patterns of nine normal adults were measured during non-rapid-eye-movement (NREM) stage 2 sleep before and after repeated administrations of a tone (40-72 dB) lasting 5 s. The ventilatory response to arousal (VRA) was determined in data sections showing electrocortical arousal following the start of the tone. Mean inspiratory flow and tidal volume increased significantly above control levels in the first seven breaths after the start of arousal, with peak increases (64.2% > control) occurring on the second breath. Breath-to-breath occlusion pressure 100 ms after the start of inspiration showed significant increases only on the second and third postarousal breaths, whereas upper airway resistance declined immediately and remained below control for > or = 7 consecutive breaths. These results suggest that the first breath and latter portion of the VRA are determined more by upper airway dynamics than by changes in the neural drive to breathe. Computer model simulations comparing different VRA time courses show that sustained periodic apnea is more likely to occur when the fall in the postarousal increase in ventilation is more abrupt.

Comparison of upper and lower airway responses of two sensitized rat strains to inhaled antigen

1992 ◽  
Vol 73 (4) ◽  
pp. 1608-1613 ◽  
Author(s):  
L. J. Xu ◽  
S. Sapienza ◽  
T. Du ◽  
S. Waserman ◽  
J. G. Martin
Keyword(s):  
Upper Airway ◽  
Brown Norway ◽  
Lower Airway ◽  
Sprague Dawley ◽  
Pulmonary Resistance ◽  
Upper Airways ◽  
Tracheal Pressure ◽  
Airway Response ◽  
Airway Responses ◽  
Inbred Rat

The purpose of the study was to investigate the relationships between upper airways responses and pulmonary responses of two strains of highly inbred rats to inhaled antigen. To do this we measured the upper and lower airways resistance for 60 min after challenge of Brown-Norway rats (BN; n = 13) and an inbred rat strain (MF; n = 11), derived from Sprague-Dawley, with aerosolized ovalbumin (OA). Rats were actively sensitized with OA (1 mg sc) using Bordetella pertussis as an adjuvant. Two weeks later the animals were anesthetized and challenged. Tracheal pressure, esophageal pressure, and airflow were measured, from which total pulmonary resistance was partitioned into upper airway and lower pulmonary resistance (RL). The peak upper airway response to inhaled OA was similar in BN (1.89 +/- 0.66 cmH2O.ml-1.s; n = 7) and MF (2.85 +/- 0.68 cmH2O.ml-1.s; n = 6). The lower airway response to OA challenge was substantially greater in BN, and RL changed from 0.07 +/- 0.01 to 0.34 +/- 0.13 (n = 6; P < 0.05). The MF did not have any significant increase in RL after challenge; the baseline RL was 0.12 +/- 0.02 and only reached a peak value of 0.15 +/- 0.05 (n = 5; P = NS). Lower airway responsiveness of BN (n = 10) to serotonin, an important mediator early allergic airway responses, was similar to MF (n = 7).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effects on the Upper Airway Morphology with Intravenous Addition of Ketamine after Dexmedetomidine Administration in Normal Children

2020 ◽  
Vol 9 (11) ◽  
pp. 3723
Author(s):  
Goutham Mylavarapu ◽  
Robert J. Fleck ◽  
Michale S. Ok ◽  
Lili Ding ◽  
Ali Kandil ◽  
...  
Keyword(s):  
General Anesthesia ◽  
Upper Airway ◽  
Region Growing ◽  
Final Analysis ◽  
Normal Children ◽  
Cross Sectional ◽  
Pharyngeal Airway ◽  
Airway Morphology ◽  
Dexmedetomidine Infusion ◽  
Airway Dimensions

General anesthesia decreases the tone of upper airway muscles in a dose-dependent fashion, potentially narrowing the pharyngeal airway. We examined the effects of adding ketamine on the airway configuration after dexmedetomidine administration in spontaneously breathing children with normal airways. 25 children presenting for Magnetic Resonance Imaging (MRI) of the brain/spine under general anesthesia were prospectively recruited in the study. Patients were anesthetized with dexmedetomidine bolus (2 mcg over 10 min) followed by dexmedetomidine infusion (2 mcg·kg−1·h) and ketamine and permitted to breathe spontaneously via the native airway. MR-CINE images of the upper airway were obtained with dexmedetomidine infusion alone (baseline) and 5, 10, and 15 min after administering ketamine bolus (2 mg·kg−1) in two anatomical axial planes at the nasopharynx and the retroglossal upper airway. Airway lumen is segmented with a semi-automatic image processing approach using a region-growing algorithm. Outcome measures of cross-sectional area, transverse and anterior-posterior diameters of the airway in axial planes at the level of the epiglottis in the retroglossal airway, and in the superior nasopharynx were evaluated for changes in airway size with sedation. Airway dimensions corresponding to the maximum, mean, and minimum sizes during a respiratory cycle were obtained to compare the temporal changes in the airway size. The dose-response of adding ketamine to dexmedetomidine alone condition on airway dimensions were examined using mixed-effects of covariance models. 22/25 patients based on inclusion/exclusion criteria were included in the final analysis. The changes in airway measures with the addition of ketamine, when compared to the baseline of dexmedetomidine alone, were statistically insignificant. The modest changes in airway dimensions are clinically less impactful and within the accuracy of the semi-automatic airway segmentation approach. The effect sizes were small for most airway measures. The duration of ketamine seems to not affect the airway size. In conclusion, adding ketamine to dexmedetomidine did not significantly reduce upper airway configuration when compared to dexmedetomidine alone.

Developmental changes in response to subatmospheric pressure loading of the upper airway

1999 ◽  
Vol 87 (2) ◽  
pp. 626-633 ◽  
Author(s):  
Carole L. Marcus ◽  
Janita Lutz ◽  
Audrey Hamer ◽  
Philip L. Smith ◽  
Alan Schwartz
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Upper Airway ◽  
Pressure Loading ◽  
Subatmospheric Pressure ◽  
Pressure Flow ◽  
Ventilatory Drive ◽  
Upstream Pressure ◽  
Airway Responses ◽  
Upper Airway Structure

Children snore less than adults and have fewer obstructive apneas, suggesting a less collapsible upper airway. We therefore hypothesized that the compensatory upper airway responses to subatmospheric pressure loading decrease with age because of changes in upper airway structure and ventilatory drive. We measured upper airway upstream pressure-flow relationships during sleep in 20 nonsnoring, nonobese children and adults. Measurements were made by correlating maximal inspiratory airflow with the level of nasal pressure applied via a mask. The slope of the upstream pressure-flow curve ( SPF) was used to characterize upper airway function. We found that SPFwas flatter in children than in adults (8 ± 5 vs. 30 ± 18 ml ⋅ s−1⋅ cmH2O−1, P < 0.002) and that SPFcorrelated with age ( r = 0.62, P < 0.01) and body mass index ( r = 0.63, P < 0.01). The occlusion pressure in 100 ms during sleep was measured in six children and two adults; it correlated inversely with SPF( r = −0.80, P < 0.02). We conclude that the upper airway compensatory responses to subatmospheric pressure loading decrease with age. This is associated with increased body mass index, even in nonsnoring, nonobese subjects. Ventilatory drive during sleep plays a role in modulating upper airway responses.

scholarly journals Changes in the Upper and Lower Pharyngeal Airway Spaces Associated with Rapid Maxillary Expansion

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Fitin Aloufi ◽  
Charles B. Preston ◽  
Khalid H. Zawawi
Keyword(s):  
Orthodontic Treatment ◽  
Upper Airway ◽  
Rapid Maxillary Expansion ◽  
Lower Airway ◽  
Control Group ◽  
Maxillary Expansion ◽  
Pharyngeal Airway ◽  
Significant Difference ◽  
And Gender ◽  
Maxillary Constriction

Objectives. The primary objectives of this retrospective study were first to compare the upper and lower pharyngeal airway spaces between orthodontic patients with and without maxillary constriction and second to evaluate the effect of rapid maxillary expansion (RME) on these airway spaces. A secondary objective was to compare the mode of breathing between groups. Materials and Methods. The experimental (RME) group consisted of 30 patients (mean age, years, 16 boys and 14 girls) with maxillary constriction who were treated with hyrax-type RME. The control group comprised the records of age- and gender matched patients (mean age, years, 16 boys and 14 girls) with no maxillary constriction but requiring nonextraction comprehensive orthodontic treatment. Cephalometric measurements in the sagittal dimension of upper and lower airway spaces for the initial and final records were recorded. Mode of breathing and length of treatment were also compared. Results. The sagittal dimension of the upper airway increased significantly in the RME group ( mm) compared to the control group ( mm), . However, there was no significant difference in the lower pharyngeal airway measurement between the RME group () and the control group (), . There was no significant difference with respect to mode of breathing between the two groups (). Conclusion. Rapid maxillary expansion (RME) during orthodontic treatment may have a positive effect on the upper pharyngeal airway, with no significant change on the lower pharyngeal airway.

Varicella Vaccine: A Point of Decision

PEDIATRICS ◽  
1986 ◽  
Vol 78 (4) ◽  
pp. 705-707
Author(s):  
Stanley A. Plotkin
Keyword(s):  
Varicella Vaccine ◽  
Normal Children ◽  
Normal Adults

The governmental authorities on biologics soon will be asked to decide on the licensure of a live varicella vaccine. Pediatricians may then have to decide whether and how to use it. This commentary summarizes the data and provides a viewpoint in favor of licensure and use in normal children and adults. Additional articles are published in the accompanying supplement to this issue of Pediatrics. The goals of a varicella vaccine are three: (1) to protect normal children against the complications of varicella, (2) to protect normal adults against the complications of varicella, and (3) to protect immunosuppressed children (particularly those with leukemia) against disseminated varicella.

A Versatile IBM-Based AMR Method for Studying Human Snoring

2021 ◽  
Author(s):  
Wei Zhang ◽  
Yu Pan ◽  
Yuchen Gong ◽  
Haibo Dong ◽  
Jinxiang Xi
Keyword(s):  
Adaptive Mesh Refinement ◽  
Stokes Equations ◽  
Flow Behavior ◽  
Upper Airway ◽  
Magnetic Resonance Images ◽  
Immersed Boundary ◽  
Cross Sectional ◽  
Pharyngeal Airway ◽  
Aerodynamic Pressure ◽  
Head Neck

Abstract In this work, a local adaptive mesh refinement (AMR) embedded incompressible flow solver is developed for biomedical flows. This AMR technique is based on the block-structured mesh and adapted from an in-house numerical solver for the Navier-Stokes equations with immersed-boundary method embedded, which is suitable for flows with complex and moving boundaries in biomedical applications. Flow behavior of the human upper airway under various head-neck postures is evaluated using the developed AMR technique, where the head-neck posture is hypothesized to change the cross-sectional area of the airway, therefore the airflow and aerodynamic behavior. The anatomically accurate three-dimensional human upper airway model is reconstructed from human magnetic resonance images (MRI) with measurements from the literature. Analyses were performed on vortex dynamics and pressure fluctuations in the pharyngeal airway. It was found that the vortex formation and aerodynamic pressure were affected by the airway bending. The sniffing position or the head-neck junction extension posture tend to facilitate the airflow through the upper human airway.

Mechanical effects of pharyngeal constrictor activation on pharyngeal airway function

1999 ◽  
Vol 86 (1) ◽  
pp. 411-417 ◽  
Author(s):  
Samuel T. Kuna ◽  
Christi R. Vanoye
Keyword(s):  
Axial Force ◽  
Airway Pressure ◽  
Muscle Activation ◽  
Upper Airway ◽  
Stimulation Frequency ◽  
Airway Patency ◽  
Pharyngeal Airway ◽  
Mechanical Effects ◽  
Airway Function ◽  
Pharyngeal Branch

The mechanical effects of pharyngeal constrictor (PC) muscle activation on pharyngeal airway function were determined in 20 decerebrate, tracheotomized cats. In 10 cats, a high-compliance balloon attached to a pressure transducer was partially inflated to just occlude the pharyngeal airway. During progressive hyperoxic hypercapnia, changes in pharyngeal balloon pressure were directly related to phasic expiratory hyopharyngeus (middle PC) activity. In two separate protocols in 10 additional cats, the following measurements were obtained with and without bilateral electrical stimulation (0.2-ms duration, threshold voltage) of the distal cut end of the vagus nerve’s pharyngeal branch supplying PC motor output: 1) pressure-volume relationships in an isolated, sealed upper airway at a stimulation frequency of 30 Hz and 2) rostrally directed axial force over a stimulation frequency range of 0–40 Hz. Airway compliance determined from the pressure-volume relationships decreased with PC stimulation at and below resting airway volume. Compared with the unstimulated condition, PC stimulation increased airway pressure at airway volumes at and above resting volume. This constrictor effect progressively diminished as airway volume was brought below resting volume. At relatively low airway volumes below resting volume, PC stimulation decreased airway pressure compared with that without stimulation. PC stimulation generated a rostrally directed axial force that was directly related to stimulation frequency. The results indicate that PC activation stiffens the pharyngeal airway, exerting both radial and axial effects. The radial effects are dependent on airway volume: constriction of the airway at relatively high airway volumes, and dilation of the airway at relatively low airway volumes. The results imply that, under certain conditions, PC muscle activation may promote pharyngeal airway patency.

Effects of elastase-induced emphysema on airway responsiveness to methacholine in rats

1989 ◽  
Vol 66 (2) ◽  
pp. 606-612 ◽  
Author(s):  
S. Bellofiore ◽  
D. H. Eidelman ◽  
P. T. Macklem ◽  
J. G. Martin
Keyword(s):  
Lung Volume ◽  
Brown Norway ◽  
Pulmonary Mechanics ◽  
Maximum Increase ◽  
Before And After ◽  
Airway Response ◽  
Residual Capacity ◽  
Airway Responses ◽  
Norway Rats ◽  
Concentration Response Curve

We examined the effects of elastase-induced emphysema on lung volumes, pulmonary mechanics, and airway responses to inhaled methacholine (MCh) of nine male Brown Norway rats. Measurements were made before and weekly for 4 wk after elastase in five rats. In four rats measurements were made before and at 3 wk after elastase; in these same animals the effects of changes in end-expiratory lung volume on the airway responses to MCh were evaluated before and after elastase. Airway responses were determined from peak pulmonary resistance (RL) calculated after 30-s aerosolizations of saline and doubling concentrations of MCh from 1 to 64 mg/ml. Porcine pancreatic elastase (1 IU/g) was administered intratracheally. Before elastase RL rose from 0.20 +/- 0.02 cmH2O.ml-1.s (mean +/- SE; n = 9) to 0.57 +/- 0.06 after MCh (64 mg/ml). A plateau was observed in the concentration-response curve. Static compliance and the maximum increase in RL (delta RL64) were significantly correlated (r = 0.799, P less than 0.01). Three weeks after elastase the maximal airway response to MCh was enhanced and no plateau was observed; delta RL64 was 0.78 +/- 0.07 cmH2O.ml-1.s, significantly higher than control delta RL64 (0.36 +/- 0.7, P less than 0.05). Before elastase, increase of end-expiratory lung volume to functional residual capacity + 1.56 ml (+/- 0.08 ml) significantly reduced RL at 64 mg MCh/ml from 0.62 +/- 0.05 cmH2O.ml-1.s to 0.50 +/- 0.03, P less than 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

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