Phasic vagal influence on inspiratory motor output in anesthetized human subjects

Polacheck, J.; Strong, Russell W.; Arens, James F.; Davies, C. T. M.; Metcalf, I.; Younes, Magdy

doi:10.1152/jappl.1980.49.4.609

Cited by 50 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the magnitude of the increase in intrinsic tongue muscle EMG activities as a result of airway occlusion at end-expiration was significantly greater in mild hypoxia compared with the control gas condition (i.e., as shown in Figure 3). The extent to which such vagal influences may be expected to affect tongue muscle activities in human subjects is less clear, however, for although humans have functioning pulmonary stretch receptors, during quiet breathing their activity is believed to have little or no influence on inspiratory motor output (28,29). Nevertheless, this is an important observation because it may indicate a preferential, lung inflation-mediated suppression of intrinsic versus extrinsic tongue muscle activities when the drive to breathe increases, such as in mild hypoxia or hypercapnia.…”

Section: Influence Of Airway Occlusionmentioning

confidence: 99%

PO₂-dependent Changes in Intrinsic and Extrinsic Tongue Muscle Activities in the Rat

Bailey

Janssen

Fregosi

2005

Am J Respir Crit Care Med

View full text Add to dashboard Cite

Rationale: Historically, respiratory-related research in sleep apnea has focused exclusively on the extrinsic tongue muscles (i.e., genioglossus, hyoglossus, and styloglossus). Until recently, the respiratory control and function of intrinsic tongue muscles (i.e., inferior and superior longitudinalis, transverses, and verticalis), which comprise the bulk of the tongue, were unknown. Objectives: The current study sought to determine if extrinsic and intrinsic tongue muscles are coactivated in conditions of hypoxemia comparable to that experienced by adults with obstructive sleep apnea. Measurements: Esophageal pressure and EMG activity of an extrinsic (hyoglossus) and an intrinsic (superior longitudinal) tongue muscle were studied in anesthetized, tracheotomized, spontaneously breathing rats. Average EMG activity was compared in a control gas condition (Pa O 2 , 160 Ϯ 12 mm Hg) and in mild isocapnic hypoxia (Pa O 2 , 69 Ϯ 7.2 mm Hg), with and without brief (3-breath) airway occlusions, pre-and postbilateral vagotomy. Main Results: (1 ) intrinsic and extrinsic tongue muscles are coactivated in mild hypoxia, (2 ) airway occlusion increased the activities of intrinsic retractor muscles in mild hypoxia, and (3 ) extrinsic retractor muscles have a steeper rate of rise of activity and an earlier burst onset relative to intrinsic retractor activities in mild hypoxia. Conclusions: These findings support our working hypothesis that airway patency is maintained not simply by activation of extrinsic tongue muscles but by the coactivation of intrinsic and extrinsic protrudor and retractor muscles. Keywords: EMG; hypoxia; sleep apneaThe tongue participates in a range of complex oromotor behaviors, including mastication, swallowing, and respiration. Functional deficits in tongue movement contribute to a host of disorders, including obstructive sleep apnea (1), dysarthria, and dysphagia (2-4). To date, studies that have examined the respiratoryrelated control of the tongue have focused primarily on the extrinsic tongue protrudor muscle, the genioglossus. As a result of this work, we know that the genioglossus is phasically active during the respiratory cycle and that its discharge onset precedes the onset of inspiratory airflow, stabilizing the airway for the negative pressure generated by the diaphragm (5-7). Although the genioglossus muscle is an important tongue muscle, it is only one of eight paired muscles that comprise the bulk of the tongue (8). Recent work in mammals has shown that the genioglossus and tongue retractor muscles are coactive in eupnea and hypercapnia (9-12), and that this coactivation improves pharyngeal airway patency (13,14). These findings confirm that numerous tongue muscles are involved in the maintenance of airway pat-(Received in original form November 19, 2004; accepted in final form March 12, 2005) Supported by the National Institutes of Health grants DC-05728 and HL-56876. Evidence of intrinsic tongue muscle activities in hypercapnia indicates that these muscles also have the potential to con...

show abstract

Section: Influence Of Airway Occlusionmentioning

confidence: 99%

PO₂-dependent Changes in Intrinsic and Extrinsic Tongue Muscle Activities in the Rat

Bailey

Janssen

Fregosi

2005

Am J Respir Crit Care Med

View full text Add to dashboard Cite

show abstract

“…Although the relati ve importance of vagal influences on breathing in human s remains a topic of debate, the classic respon ses referred to as Breuer-Hering (BH) reflexes have been well described in humans. These include Vr-dependent variations in inspiratory time (6) and apnea or prolongation of expiration following a single lung inflation (5,7). BH reflexes can be abolished by vagal blockade (5) and are absent in patients with lungs that are vagally denervated through transplantation (7).…”

Section: The Effect Of Volume-related Feedback On Respiratory Rate Anmentioning

confidence: 99%

“…Single lung inflations have been shown to prolong expiration in sleeping or anesthetized humans (5)(6)(7). We hypothesized that large lung inflations delivered during mechanical ventilation would also prolong expiration and consequently slow the rate of breathing.…”

mentioning

confidence: 99%

The determinants of respiratory rate during mechanical ventilation.

Tobert

Simon

Stroetz

et al. 1997

Am J Respir Crit Care Med

View full text Add to dashboard Cite

The independent and interactive effect of feedback related to volume, CO2, inspiratory flow, and arousal state on the regulation of respiratory rate in mechanically ventilated humans is not well characterized. We examined the rate response of eight normal volunteers during both quiet wakefulness and non-rapid-eye-movement (NREM) sleep, while mechanically ventilated through a nasal mask in an assist/control mode with a machine back-up rate of 2 breaths/min. Tidal volume (VT) was set slightly above spontaneous VT and then increased by 0.2 L every 3 min up to 1.8 L or 25 ml/kg. Either an inspiratory flow of 40 L/min or an inspiratory time of 2 s (iso-T(I)) was set, with CO2 added (F(I)CO2 > 0) or F(I)CO2 = 0. Measurements were made during both quiet wakefulness and NREM sleep. We found that as VT increased, the respiratory rate decreased; the rate decline was observed during wakefulness and sleep, and under isocapnic as well as hypocapnic conditions. Increasing inspiratory flow raised the respiratory rate during wakefulness and NREM sleep. During NREM sleep, hypocapnia resulted in wasted ventilator trigger efforts. In summary, both VT and inspiratory flow settings affect the respiratory rate, and depending on state, can affect CO2 homeostasis. Ventilator settings appropriate for wakefulness may cause ventilatory instability during sleep.

show abstract

“…THE HERING-BREUER REFLEX, in which passive overinflation of the lungs or prevention of inspiration or expiration alters respiratory timing (11), has been documented in humans by using airway occlusion during anesthesia (19) or passive overinflation of the lungs during sleep (12). The reflex has been more difficult to elicit during wakefulness in humans.…”

mentioning

confidence: 99%

Termination of inspiration by phase-dependent respiratory vagal feedback in awake normal humans

BuSha

Stella²,

Manning³

et al. 2002

Journal of Applied Physiology

View full text Add to dashboard Cite

. Termination of inspiration by phasedependent respiratory vagal feedback in awake normal humans. J Appl Physiol 93: 903-910, 2002. First published May 10, 2002 10.1152/japplphysiol.00153.2002-Imperceptible levels of proportional assist ventilation applied throughout inspiration reduced inspiratory time (TI) in awake humans. More recently, the reduction in TI was associated with flow assist, but flow assist also reaches a maximum value early during inspiration. To test the separate effects of flow assist and timing of assist, we applied a pseudorandom binary sequence of flow-assisted breaths during early, late, or throughout inspiration in eight normal subjects. We hypothesized that imperceptible flow assist would shorten TI most effectively when applied during early inspiration. Tidal volume, integrated respiratory muscle pressure per breath, TI, and TE were recorded. All stimuli (early, late, or flow assist applied throughout inspiration) resulted in a significant increase in inspiratory flow; however, only when the flow assist was applied during early inspiration was there a significant reduction in TI and the integrated respiratory muscle pressure per breath. These results provide further evidence that vagal feedback modulates breathing on a breath-by-breath basis in conscious humans within a physiological range of breath sizes.vagus; control of respiration; mechanical ventilation; HeringBreuer reflex THE HERING-BREUER REFLEX, in which passive overinflation of the lungs or prevention of inspiration or expiration alters respiratory timing (11), has been documented in humans by using airway occlusion during anesthesia (19) or passive overinflation of the lungs during sleep (12). The reflex has been more difficult to elicit during wakefulness in humans. However, airway occlusion and overinflation of the lungs are potent stimuli not typically encountered during eupneic breathing, and these stimuli may evoke behavioral responses if applied during wakefulness, which could mask the effects of the Hering-Breuer reflex. In a previous study in adult human subjects (3), our laboratory investigated the effect of unloading the respiratory system by using imperceptible levels of proportional assist ventilation applied in a pseudorandom binary sequence. We found that a small but significant increase in tidal volume (VT) and inspiratory flow rate (VT/TI) resulted in a significant reduction in inspiratory time (TI), consistent with the action of the HeringBreuer reflex. In a subsequent investigation using a similar technique (4), our laboratory examined the separate effects of imperceptible flow and volume-assist ventilation on respiratory timing. Although flow and volume assist resulted in similar increases in VT and VT/TI, only during flow-assisted breaths was there a significant reduction in TI. Flow-assist ventilation occurs early during inspiration and has a decrementing pressure profile, whereas volume assist has an augmenting pressure profile and reaches a maximum level of assist at the end of the breath. Thus the ti...

show abstract

Phasic vagal influence on inspiratory motor output in anesthetized human subjects

Cited by 50 publications

References 0 publications

PO₂-dependent Changes in Intrinsic and Extrinsic Tongue Muscle Activities in the Rat

PO₂-dependent Changes in Intrinsic and Extrinsic Tongue Muscle Activities in the Rat

The determinants of respiratory rate during mechanical ventilation.

Termination of inspiration by phase-dependent respiratory vagal feedback in awake normal humans

Contact Info

Product

Resources

About

Phasic vagal influence on inspiratory motor output in anesthetized human subjects

Cited by 50 publications

References 0 publications

PO2-dependent Changes in Intrinsic and Extrinsic Tongue Muscle Activities in the Rat

PO2-dependent Changes in Intrinsic and Extrinsic Tongue Muscle Activities in the Rat

The determinants of respiratory rate during mechanical ventilation.

Termination of inspiration by phase-dependent respiratory vagal feedback in awake normal humans

Contact Info

Product

Resources

About

PO₂-dependent Changes in Intrinsic and Extrinsic Tongue Muscle Activities in the Rat

PO₂-dependent Changes in Intrinsic and Extrinsic Tongue Muscle Activities in the Rat