scholarly journals Effect of upper airway negative pressure on inspiratory drive during sleep

1998 ◽  
Vol 84 (3) ◽  
pp. 1063-1075 ◽  
Author(s):  
P. R. Eastwood ◽  
A. K. Curran ◽  
C. A. Smith ◽  
J. A. Dempsey

To determine the effect of upper airway (UA) negative pressure and collapse during inspiration on regulation of breathing, we studied four unanesthetized female dogs during wakefulness and sleep while they breathed via a fenestrated tracheostomy tube, which was sealed around the permanent tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration (Fen) was closed and exposing the UA to intrathoracic pressure changes, but not to flow changes, when Fen was open. During tracheal occlusion with Fen closed, inspiratory time (Ti) increased during wakefulness, non-rapid-eye-movement (NREM) sleep and rapid-eye-movement (REM) sleep (155 ± 8, 164 ± 11, and 161 ± 32%, respectively), reflecting the removal of inhibitory lung inflation reflexes. During tracheal occlusion with Fen open (vs. Fen closed): 1) the UA remained patent; 2) Ti further increased during wakefulness and NREM (215 ± 52 and 197 ± 28%, respectively) but nonsignificantly during REM sleep (196 ± 42%); 3) mean rate of rise of diaphragm EMG (EMGdi/Ti) and rate of fall of tracheal pressure (Ptr/Ti) were decreased, reflecting an additional inhibitory input from UA receptors; and 4) both EMGdi/Ti and Ptr/Ti were decreased proportionately more as inspiration proceeded, suggesting greater reflex inhibition later in the effort. Similar inhibitory effects of exposing the UA to negative pressure (via an open tracheal Fen) were seen when an inspiratory resistive load was applied over several breaths during wakefulness and sleep. These inhibitory effects persisted even in the face of rising chemical stimuli. This inhibition of inspiratory motor output is alinear within an inspiration and reflects the activation of UA pressure-sensitive receptors by UA distortion, with greater distortion possibly occurring later in the effort.

1996 ◽  
Vol 80 (5) ◽  
pp. 1528-1539 ◽  
Author(s):  
C. A. Harms ◽  
Y. J. Zeng ◽  
C. A. Smith ◽  
E. H. Vidruk ◽  
J. A. Dempsey

We investigated the effects of negative pressure (NP) in the isolated upper airway (UA) in three unanesthetized dogs. The UA was isolated, and the dogs breathed through an endotracheal tube while wearing a fitted fiberglass snout mask. NP (-2 to -32 cmH2O) was applied in a square wave below the larynx or at the snout at end expiration and was held until inspiratory effort during wakefulness, non-rapid-eye-movement (NREM) sleep, and rapid-eye-movement (REM) sleep. During all states of consciousness, NP applied to the UA prolonged expiratory time (TE) 1) below a threshold of -8 to -10 cmH2O, which coincided with closure of the oro- and/or velopharynx; and 2) in a progressive fashion at more negative pressures than threshold, up to a mean apneic length of 324% of the control value (or 13.9 s) at -30 cmH2O. TE prolongation was less during REM sleep at a given NP (P < 0.05). Augmented tonic genioglossal electromyographic activity also occurred with the applied NP during wakefulness and NREM sleep but not with REM sleep. NP (-20 to -32 cmH2O) applied as a brief pulse (300-500 ms) during NREM sleep caused transient airway occlusion, terminated the breath during inspiration, and prolonged TE when applied at end expiration. Central apneas always persisted beyond the termination of the UA closure. TE prolongation in response to NP persisted in the presence of a topical anesthetic nebulized through the UA sufficient to abolish the laryngeal gag reflexes. We conclude that UA closure and deformation will cause significant TE prolongation during all states of consciousness and activation of the genioglossus muscle during wakefulness and NREM sleep but not during REM sleep.


1984 ◽  
Vol 57 (2) ◽  
pp. 520-527 ◽  
Author(s):  
F. G. Issa ◽  
C. E. Sullivan

We studied 18 patients with obstructive sleep apnea (OSA). Each subject slept while breathing through the nose with a specially designed valveless breathing circuit. Low levels of continuous positive airway pressure (CPAP) applied through the nose (2.5–15.0 cmH2O) prevented OSA and allowed long periods of stable stage III/IV sleep and rapid-eye-movement (REM) sleep. Externally applied complete nasal occlusion while the upper airway was patent resulted in upper airway closure during inspiration which was identified by a sudden deviation of nasal pressure from tracheal or esophageal pressure. The level of upper airway closing pressure (UACP) did not change throughout the occlusion test, suggesting that upper airway dilator muscles do not respond to asphyxia during sleep. The upper airway was more collapsible during stage I/II non-rapid-eye-movement (NREM) and REM sleep compared with stage III/IV NREM sleep. The pooled mean UACP was 3.1 +/- 0.4 cmH2O in stage I/II NREM, 4.2 +/- 0.2 cmH2O in stage III/IV NREM, and 2.4 +/- 0.2 cmH2O in REM sleep. Nasal occlusion at successively higher levels of CPAP did not alter the level of UACP in stage I/II NREM and REM sleep but resulted in the upper airway becoming more stable in stage III/IV NREM sleep, suggesting a reflex which augments the tone of upper airway dilator muscles.


1988 ◽  
Vol 64 (3) ◽  
pp. 1186-1195 ◽  
Author(s):  
L. Wiegand ◽  
C. W. Zwillich ◽  
D. P. White

Since upper airway resistance is known to increase during sleep, inadequate resistive load compensation may contribute to the normal decline in sleeping ventilation. We determined the acute and sustained (4 min) ventilatory response to a range of external inspiratory resistive loads (4, 8, 12, and 25 cmH2O.l-1.s) during wakefulness and non-rapid-eye-movement (NREM) and rapid-eye-movement (REM) sleep in seven normal men. We found that minute ventilation (VI) was well maintained with acute and sustained resistive loading during wakefulness. Immediate adjustments in ventilatory timing (prolongation of inspiratory duration) provided full compensation for airflow reduction. In marked contrast, resistive load application during NREM sleep invariably produced a significant (P less than 0.05) reduction in VI with progressively larger resistive loads producing progressively greater ventilatory decrements. This decline in ventilation was a product of a falling inspiratory flow rate with inadequate prolongation of inspiratory duration (TI). The largest decrements in ventilation occurred immediately after load application followed by partial ventilatory recovery, which occurred over time in concert with rising PCO2 and augmented ventilatory effort (as reflected by P0.1 or mouth occlusion pressure). Similar observations were made during REM sleep, although the responses were less consistent and fewer data were obtained. These observations support the hypothesis that poor load compensation for increased upper airway resistance contributes to the hypoventilation characteristic of normal sleep.


1998 ◽  
Vol 510 (3) ◽  
pp. 963-976 ◽  
Author(s):  
James A. Rowley ◽  
Brian R. Zahn ◽  
Mark A. Babcock ◽  
M. Safwan Badr

1993 ◽  
Vol 75 (5) ◽  
pp. 2117-2124 ◽  
Author(s):  
J. R. Wheatley ◽  
D. J. Tangel ◽  
W. S. Mezzanotte ◽  
D. P. White

Increased retropalatal airway resistance may be caused by a sleep-induced loss of palatal muscle activity and a diminished ability of these muscles to respond to the increasing intrapharyngeal negative pressure that develops during sleep. To investigate these possibilities, in six normal subjects, we determined the effect of non-rapid-eye-movement sleep on 1) the tensor palatini (TP) electromyogram (EMG) response to rapid-onset negative-pressure generations (NPG) in the upper airway and 2) the collapsibility of the retropalatal airway during these NPGs. During wakefulness, the change in TP EMG from basal to peak levels (during NPG) was 19.8 +/- 3.2 arbitrary units (P < 0.005). This was markedly reduced during sleep (3.6 +/- 1.5 arbitrary units; P < 0.001). The latency of the TP EMG response was 48.5 +/- 5.6 ms during wakefulness but was prolonged during sleep (105.0 +/- 12.2 ms; P < 0.02). The peak transpalatal pressure during NPG (a measure of airway collapse) was 2.1 +/- 0.7 cmH2O during wakefulness and increased to 5.3 +/- 0.8 cmH2O during sleep (P < 0.05). We conclude that the brisk reflex response of the TP muscle to negative pressure during wakefulness is markedly reduced during non-rapid-eye-movement sleep, in association with a more collapsible retropalatal airway. We speculate that the reduction in this TP reflex response contributes to retropalatal airway narrowing during sleep in normal subjects.


1988 ◽  
Vol 64 (1) ◽  
pp. 347-353 ◽  
Author(s):  
S. T. Kuna ◽  
J. Smickley

To determine the combined effect of increased subatmospheric upper airway pressure and withdrawal of phasic volume feedback from the lung on genioglossus muscle activity, the response of this muscle to intermittent nasal airway occlusion was studied in 12 normal adult males during sleep. Nasal occlusion at end expiration was achieved by inflating balloon-tipped catheters located within the portals of a nose mask. No seal was placed over the mouth. During nose breathing in non-rapid-eye-movement (NREM) sleep, nasal airway occlusion resulted in multiple respiratory efforts before arousal. Mouth breathing was not initiated until arousal. Phasic inspiratory genioglossus activity was present in eight subjects during NREM sleep. In these subjects, comparison of peak genioglossus inspiratory activity on the first three occluded efforts to the value just before occlusion showed an increase of 4.7, 16.1, and 28.0%, respectively. The relative increases in peak genioglossus activity were very similar to respective increases in peak diaphragm activity. Arousal was associated with a large burst in genioglossus activity. During airway occlusion in rapid-eye-movement (REM) sleep, mouth breathing could occur without a change in sleep state. In general, genioglossus responses to airway occlusion in REM sleep were similar in pattern to those in NREM sleep. A relatively small reflex activation of upper airway muscles associated with a sudden increase in subatmospheric pressure in the potentially collapsible segment of the upper airway may help compromise upper airway patency during sleep.


1990 ◽  
Vol 69 (4) ◽  
pp. 1262-1269 ◽  
Author(s):  
D. A. Wiegand ◽  
B. Latz ◽  
C. W. Zwillich ◽  
L. Wiegand

Reduction in the activity of upper airway "dilator" muscles during sleep may allow the pharyngeal airway to collapse in some individuals. However, quantitative studies concerning the effect of sleep on specific upper airway muscles that may influence pharyngeal patency are sparse and inconclusive. We studied seven normal men (mean age 27, range 22-37 yr) during a single nocturnal sleep study and recorded sleep staging parameters, ventilation, and geniohyoid muscle electromyogram (EMGgh) during nasal breathing throughout the night. Anatomic landmarks for placement of intramuscular geniohyoid recording electrodes were determined from a cadaver study. These landmarks were used in percutaneous placement of wire electrodes, and raw and moving-time-averaged EMGgh activities were recorded. Sleep stage was determined using standard criteria. Stable periods of wakefulness and non-rapid-eye-movement (NREM) and rapid-eye-movement (REM) sleep were selected for analysis. The EMGgh exhibited phasic inspiratory activity during wakefulness and sleep in all subjects. In six of seven subjects, mean and peak inspiratory EMGgh activities were significant (P less than 0.05) reduced during stages 2 and 3/4 NREM sleep and REM sleep compared with wakefulness. This reduction of EMGgh activity was shown to result from a sleep-related decline in the level of tonic muscle activity. Phasic inspiratory EMGgh activity during all stages of sleep was not significantly different from that during wakefulness. Of interest, tonic, phasic, and peak EMGgh activities were not significantly reduced during REM sleep compared with any other sleep stage in any subject. In addition, the slope of onset of phasic EMGgh activity was not different during stage 2 NREM and REM sleep compared with wakefulness in these subjects.(ABSTRACT TRUNCATED AT 250 WORDS)


1993 ◽  
Vol 75 (2) ◽  
pp. 856-862 ◽  
Author(s):  
K. G. Henke ◽  
C. E. Sullivan

We examined the effects of high-frequency- (30-Hz) low-pressure oscillations (< 1 cmH2O) applied to the upper airway, via a nose mask, on genioglossus (EMGgg), sternomastoid (EMGsm), and diaphragm electromyogram (EMGdia) activity in sleeping humans. Ten patients with sleep apnea and six normal subjects were studied. The pressure oscillations were applied through the mask for a single breath. The subjects were studied in non-rapid-eye-movement (NREM) and rapid-eye-movement (REM) sleep. In the normal subjects, during NREM sleep, peak EMGgg, EMGsm, and EMGdia activity increased significantly in response to the oscillations in 63, 51, and 46%, respectively, of all trials. During REM sleep, significant increases occurred in 73, 88, and 13%, respectively, of all trials. Similar responses were observed in the patients with obstructive sleep apnea. Peak EMGgg, EMGsm, and EMGdia activity increased significantly in 74, 50, and 67%, respectively, of all NREM sleep trials and in 55, 81, and 76%, respectively, of all REM sleep trials. An important finding was that in 46% of the trials in the patients with sleep apnea the oscillation-induced increase in EMGgg activity was associated with a partial or complete reversal of the upper airway obstruction with an increase in tidal volume. This was observed in NREM and REM sleep. We conclude that there are upper airway receptors that respond to low-pressure-high-frequency oscillations applied to the upper airway that have input to the genioglossus and other muscles of respiration. These responses may be utilized in future treatment for sleep apnea.


Physiology ◽  
1998 ◽  
Vol 13 (2) ◽  
pp. 91-97 ◽  
Author(s):  
Leszek Kubin ◽  
Richard O. Davies ◽  
Allan I. Pack

The loss of tone in upper airway muscles contributes to disorders of breathing during sleep. In an animal model of rapid eye movement sleep atonia, decrements in the activity of upper airway motoneurons are caused by withdrawal of excitation mediated by serotonin and other transmitters, rather than by state-dependent inhibition.


1990 ◽  
Vol 69 (4) ◽  
pp. 1252-1261 ◽  
Author(s):  
D. A. Wiegand ◽  
B. Latz ◽  
C. W. Zwillich ◽  
L. Wiegand

Sleep-related reduction in geniohyoid muscular support may lead to increased airway resistance in normal subjects. To test this hypothesis, we studied seven normal men throughout a single night of sleep. We recorded inspiratory supraglottic airway resistance, geniohyoid muscle electromyographic (EMGgh) activity, sleep staging, and ventilatory parameters in these subjects during supine nasal breathing. Mean inspiratory upper airway resistance was significantly (P less than 0.01) increased in these subjects during all stages of sleep compared with wakefulness, reaching highest levels during non-rapid-eye-movement (NREM) sleep [awake 2.5 +/- 0.6 (SE) cmH2O.l-1.s, stage 2 NREM sleep 24.1 +/- 11.1, stage 3/4 NREM sleep 30.2 +/- 12.3, rapid-eye-movement (REM) sleep 13.0 +/- 6.7]. Breath-by-breath linear correlation analyses of upper airway resistance and time-averaged EMGgh amplitude demonstrated a significant (P less than 0.05) negative correlation (r = -0.44 to -0.55) between these parameters in five of seven subjects when data from all states (wakefulness and sleep) were combined. However, we found no clear relationship between normalized upper airway resistance and EMGgh activity during individual states (wakefulness, stage 2 NREM sleep, stage 3/4 NREM sleep, and REM sleep) when data from all subjects were combined. The timing of EMGgh onset relative to the onset of inspiratory airflow did not change significantly during wakefulness, NREM sleep, and REM sleep. Inspiratory augmentation of geniohyoid activity generally preceded the start of inspiratory airflow. The time from onset of inspiratory airflow to peak inspiratory EMGgh activity was significantly increased during sleep compared with wakefulness (awake 0.81 +/- 0.04 s, NREM sleep 1.01 +/- 0.04, REM sleep 1.04 +/- 0.05; P less than 0.05). These data indicate that sleep-related changes in geniohyoid muscle activity may influence upper airway resistance in some subjects. However, the relationship between geniohyoid muscle activity and upper airway resistance was complex and varied among subjects, suggesting that other factors must also be considered to explain sleep influences on upper airway patency.


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