The Effect of Wearing a Cervical Orthosis on Pulmonary Function and Respiratory Muscle Activity during Spirometry

A variable fluctuating pattern of arterial BP often precedes intraventricular hemorrhage in mechanically ventilated preterm infants. To learn more about the origin of this pattern, arterial BP and respiratory muscle activity were studied in five intubated premature infants who were at high risk for intraventricular hemorrhage. We monitored esophageal pressure, gastric pressure, and arterial BP. Consistent findings were: (1) arterial BP fluctuations have the same frequency and direction of change as esophageal and gastric pressure changes associated with spontaneous breathing (R ranged from .93 to .98, P < .001); (2) spontaneous apneic pauses were accompanied by sudden and complete cessation of arterial BP fluctuations; (3) large "cough-like" fluctuations in esophageal and gastric pressures, seen in all infants, were associated with the largest fluctuations in arterial BP; (4) cutaneous stimulation had negligible effect on fluctuation in arterial BP provided no change in esophageal and gastric pressures occurred; (5) the effects of change in esophageal and gastric pressures on arterial BP were nearly simultaneous (0.05 to 0.25 second latency); (6) respirator pressure fluctuations had negligible effects on the fluctuations in arterial BP. These data suggest that the fluctuations in arterial BP are directly related to respiratory muscle activity and are most consistent with the familiar pulsus paradoxus that occurs in various other cardiorespiratory diseases.

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Changes in respiratory muscle activity in ponies when end-expiratory lung volume is increased

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.5.2015 ◽

1994 ◽

Vol 76 (5) ◽

pp. 2015-2025 ◽

Cited By ~ 8

Author(s):

B. K. Erickson ◽

H. V. Forster ◽

T. F. Lowry ◽

L. G. Pan ◽

M. J. Korducki ◽

...

Keyword(s):

Tidal Volume ◽

Lung Volume ◽

Negative Pressure ◽

Muscle Activity ◽

Respiratory Muscle ◽

Transversus Abdominis ◽

Vagal Afferents ◽

Breathing Frequency ◽

Respiratory Muscle Activity

The objective of the present study was to determine whether lung and diaphragm afferents contribute to the changes in respiratory muscle activity when end-expiratory lung volume (EELV) is changed in ponies. We studied the responses of the diaphragm and the transversus abdominis (TA) muscles to passive increases in EELV in awake intact (I), diaphragm-deafferented (DD), pulmonary vagal- (hilar nerve) denervated (HND), and DD + HND ponies. Negative pressure of -10 or -20 cmH2O applied around the ponies′ torsos [positive transrespiratory (TR) pressure] increased (P < 0.05) EELV in all ponies; the increases were more (P < 0.05) in HND and less (P < 0.05) in DD than in I ponies. In I ponies, positive TR pressure increased (P < 0.05) the rate of rise of the integrated diaphragmatic electromyogram (EMG), reflecting increased drive to the muscle. This increase was less (P < 0.05) in DD and HND than in I ponies. In DD + HND ponies, there was no significant (P > 0.10) change in drive to the diaphragm during positive TR pressure. In I ponies, positive TR pressure increased (P < 0.05) the duration and mean activity of the TA EMG. In HND and DD + HND ponies, the TA EMG was not altered by positive TR pressure. I and DD ponies decreased (P < 0.05) breathing frequency but maintained tidal volume (VT) during positive TR pressure. HND and DD+HND ponies increased breathing frequency (P < 0.05) and decreased (P < 0.05) VT during positive TR pressure. We conclude that, during positive TR pressure when the diaphragm is presumably at a mechanical disadvantage, diaphragm and vagal afferents mediate increased drive to the diaphragm to prevent VT from decreasing. In addition, during positive TR pressure, vagal afferents mediate an increase in duration of TA activity, which minimizes the increase in EELV.

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Effects of Inspiratory Load on Chest Wall Kinematics, Breathing Pattern, and Respiratory Muscle Activity of Mouth-Breathing Children

Respiratory Care ◽

10.4187/respcare.06908 ◽

2020 ◽

Vol 65 (9) ◽

pp. 1285-1294

Author(s):

Jéssica Danielle Medeiros da Fonsêca ◽

Vanessa Regiane Resqueti ◽

Kadja Benício ◽

Valéria Soraya de Farias Sales ◽

Luciana Fontes Silva da Cunha Lima ◽

...

Keyword(s):

Chest Wall ◽

Muscle Activity ◽

Respiratory Muscle ◽

Breathing Pattern ◽

Mouth Breathing ◽

Chest Wall Kinematics ◽

Respiratory Muscle Activity ◽

Inspiratory Load

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Respiratory muscle activity during repeated airflow interruption

Journal of Applied Physiology ◽

10.1152/jappl.1988.64.6.2314 ◽

1988 ◽

Vol 64 (6) ◽

pp. 2314-2317 ◽

Cited By ~ 10

Author(s):

J. Mead ◽

M. B. Reid

Keyword(s):

Muscle Activity ◽

Respiratory Muscle ◽

Rapid Succession ◽

Expiratory Muscles ◽

Respiratory Muscle Activity

We observed striking differences in respiratory muscle electromyogram activity when active expirations were interrupted in rapid succession, depending on the mode of interruption. When the interruptions were produced at the level of the glottis (utterances, uh-uh-uh-uh, at 5–8 Hz) there were synchronous bursts of activity from expiratory muscles in all three subjects during the periods of no flow and rapid bursts of diaphragmatic activity during the flow phases in one subject. In contrast, when similarly rapid interruptions of active expirations were produced with the tongue on a mouthpiece (utterance, te-te-te-te) or with an external valve, no synchronous bursts were observed. Since all interruptions would have been mechanically similar at expiratory muscular and pulmonary levels, we reasoned that the bursts with glottic interruptions were either programmed centrally or driven reflexly at the laryngeal level.

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