Detection and Interaction of Elastic and Flow-Resistive Respiratory Loads in Man

Shahid, Sara; Goddard, Braden; Howell, J. B. L.

doi:10.1042/cs0610339

Cited by 6 publications

(1 citation statement)

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“…In an unpublished study, we found load detection was slightly reduced (0.6 cmH20 I-IS-I � 1.0 cmH20 I-IS-I) when loads were added around the chest rather than at the mouth. This reduction can be accounted for by the increase in background elastance due to phase differences in pressure around the chest (45). When loads are added around the chest cage, many subjects localize the detection of load to the mouth.…”

Section: Basic Sensationsmentioning

confidence: 98%

Dyspnea and Exercise

Killian¹,

Campbell²

1983

Annu. Rev. Physiol.

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Canada L8N 3Z5INTRODUCTION "Many physiologists and clinicians have written articles entitled 'Dyspnea' which were in fact articles on the regulation of respiration, the causes of hyperpnea or the causes of hyperventilation-which, in fact, had nothing to do with the sensation of dyspnea" (13). This remark was made by Julius Comroe in the opening statement of an international symposium on the topic of breathlessness in 1965. The remark remains true today. Although dyspnea occurs commonly during exercise, the role of exercise in the gener ation of respiratory distress is probably quantitative and there is nothing unique about exercise itself. Breathing is a particular motor act generating proprioceptive information of which we are not normally conscious. How ever, under certain circumstances this proprioceptive information gives rise to an unpleasant awareness of breathing and of respiratory distress.This review falls into two main parts: (a) a detailed review of psycho physical work on the nature of the stimulus underlying respiratory sensa tion, and (b) a review of factors during exercise that are likely to modify these sensory stimuli. Do Pulmonary Afferents Contribute directly to Dyspnea?The possibility that afferents arising in the airways, lungs, or pulmonary· circulation are sentient-i.e. are consciously perceived-and may contrib ute to dyspnea is implicit in much of the literature. No acceptable direct evidence enables a clear verdict on this question, but in our view the balance of evidence favors the view that these afferents contribute to dyspnea by altering the drives to the respiratory muscles and that the control and behavior of the respiratory muscles are the final common pathway to the respiratory sensation commonly meant by the term "dyspnea." 465 0066-4278/83/0315-0465$02.00 Annu. Rev. Physiol. 1983.45:465-479. Downloaded from www.annualreviews.org Access provided by Cambridge University on 02/07/15. For personal use only. Quick links to online contentFurther ANNUAL REVIEWS 466 KILLIAN & CAMPBELL The Basic SensationsThe basic proprioceptive sensations are: position, which in the respiratory system is expressed as volume; displacement, which is expressed as change of volume or flow; and force, which is expressed most conveniently as pressure. Of perhaps greater importance are the compound sensations of load (elastance, resistance), which have the dimensions of both force apd displacement. We review the basic and compound sensations after outlinihg the basic model and the methods used. Basic Sensory ModelThe model (Figure 1) we use is common to all sensory modalities but is perhaps most commonly used in relationship to the special senses. Neuro physiology comfortably encompasses the progression from sensory stimuli to the formation of sensory impression. However, we must not regard the formation of perception at the conscious level as merely the reconstruction of the primary sensory information. The sensory impression is interpreted in light of previous experience and learning and is thus modified by...

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Section: Basic Sensationsmentioning

confidence: 98%

Dyspnea and Exercise

Killian¹,

Campbell²

1983

Annu. Rev. Physiol.

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Afferent Inputs to Breathing: Respiratory Sensation

Zechman¹,

Wiley²

1986

Comprehensive Physiology

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Load detection in subjects with sleep-induced upper airway obstruction.

Clerk

Dunan²,

Guilleminault³

1994

Am J Respir Crit Care Med

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Respiratory flow-resistive load detection in obese patients has been shown to be impaired. We tested the hypothesis that there is no difference in inspiratory flow-resistive load detection measured in nonobese obstructive sleep apnea patients, nonobese snorers, and normal control subjects. Eleven male obstructive sleep apnea patients and seven male snorers were investigated and compared with 10 normal male control subjects. Severely obese patients (body mass index, BMI > 35 kg/m2) were excluded. Patients were investigated by nocturnal polysomnography with measurement of esophageal pressure (Pes). Awake pulmonary function tests were performed before the investigation. Airway resistance (Raw) and lung volumes were measured with plethysmography. Resistive loads were investigated according to Tapper and associates (13) and Killian and associates (12). Resistances were applied for the duration of one inspiratory cycle and a minimum of two breaths allowed between each resistive load. Six different resistances plus background shams were presented 10 times in random order. Flow, pressure, and subject response were recorded with a calibrated multichannel recorder. Subjects signaled detected changes of inspiratory resistance with a hand-held signaling device. The probability of detecting a particular resistance was calculated as the ratio of correct identification to the number of presentations (i.e., 10). The resistance corresponding to a 0.5 probability of detection was determined. The Weber fraction (wf) calculated as delta R/R(apparatus) +Raw. There were no differences between nonobese subjects and controls in terms of resistive load detection.

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Detection and Interaction of Elastic and Flow-Resistive Respiratory Loads in Man

Cited by 6 publications

References 0 publications

Dyspnea and Exercise

Dyspnea and Exercise

Afferent Inputs to Breathing: Respiratory Sensation

Load detection in subjects with sleep-induced upper airway obstruction.

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