Breuer-Hering inflation reflex and breathing pattern in anesthetized humans and cats

1981 ◽  
Vol 51 (5) ◽  
pp. 1162-1168 ◽  
Author(s):  
H. Gautier ◽  
M. Bonora ◽  
J. H. Gaudy
Keyword(s):  
Tidal Volume ◽  
Breathing Pattern ◽  
Respiratory Activity ◽  
Human Subjects ◽  
Threshold Curve ◽  
Ventilatory Pattern ◽  
Tracheal Pressure ◽  
Switch Mechanism

In nine cats and nine human subjects anesthetized with alfaxalone, respiratory activity and tracheal pressure were recorded prior to and during occlusion of the airway at end inspiration or end expiration. Lung inflations at the end of expiration were also performed. In addition, the ventilatory pattern was analyzed during hypercapnia. The results show that occlusions at the end of inspiration or inflations provoked an apnea in both cats and humans. However, concomitant with increases in tidal volume during hypercapnia, inspiratory duration decreased in cats and did not change in human subjects. These results indicate that the Breuer-Hering reflex, which delays the onset of inspiration during inflation was equally operative in cats and humans. In contrast, the “Breuer-Hering threshold curve,” which accounts for the off-switch“ of inspiration was different in cats and humans. Thus, in summary, the Breuer-Hering inflation reflex is operative in human subjects, but it does not seem to be involved in the control of the inspiratory off-switch mechanism during increases respiratory activity resulting from hypercapnia.

Phasic vagal influence on inspiratory motor output in anesthetized human subjects

1980 ◽  
Vol 49 (4) ◽  
pp. 609-619 ◽  
Author(s):  
J. Polacheck ◽  
R. Strong ◽  
J. Arens ◽  
C. Davies ◽  
I. Metcalf ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Human Subjects ◽  
Normal Subjects ◽  
Airway Disease ◽  
Apparent Volume ◽  
Motor Output ◽  
Restrictive Lung Disease ◽  
Tracheal Pressure ◽  
Inspiratory Motor ◽  
Vagal Influence

Vagal influence on inspiratory motor output was assessed in 20 normal subjects and in 12 patients with respiratory disorders under enflurane anethesia using the method of airway occlusion. The change in inspiratory duration during occlusion (delta TI) was measured from mechanical parameters (respiratory flow and tracheal pressure). In eight of the subjects, however, the effect of occlusion and augmentation of tidal volume was further evaluated from diaphragmatic electromyogram. In normal subjects delta TI (mechanical) averaged 0.15 s (range -0.1 to +0.77 s) and correlated with the duration of inspiration during occlusion. Electromyographic observations indicated that the change in neural TI exceeds the change in mechanical TI by approximately 0.2 s and that augmentation of tidal volume shortens TI with no apparent volume threshold. There was a tendency for vagal influence to be higher with restrictive lung disease and lower with obstructive airway disease. These observations indicate that a majority of humans display a significant vagal influence on TI in the spontaneous tidal volume range under anesthesia.

Ventilatory responses to dead space and CO2 breathing under inspiratory resistive load

1995 ◽  
Vol 78 (2) ◽  
pp. 555-561 ◽  
Author(s):  
D. A. Sidney ◽  
C. S. Poon
Keyword(s):  
Breathing Pattern ◽  
Human Subjects ◽  
Minute Ventilation ◽  
Resistive Load ◽  
Healthy Human ◽  
Ventilatory Responses ◽  
Ventilatory Pattern ◽  
Volume Relationship ◽  
The Mean ◽  
End Tidal

To investigate how breathing is controlled during CO2 stimulation, steady-state ventilatory responses to rebreathing through a tube (DS) and inspiring a fixed PCO2 (INH) were compared in healthy human subjects. Tests were performed in hyperoxia with (IRL) and without (NL) an inspiratory resistive load (15 cmH2O.l–1.s at 1 l/s). The mean slope of the minute ventilation (VE)-end-tidal PCO2 relationship was significantly higher in DS-IRL than in INH-IRL [1.86 +/- 0.67 (SD) vs. 1.40 +/- 0.32 l.min-1.Torr-1, P < 0.01], and it was significantly different between INH-NL and INH-IRL (1.64 +/- 0.41 vs. 1.40 +/- 0.32 l.min-1.Torr-1, P < 0.05) but not between DS-NL and DS-IRL (1.85 +/- 0.72 vs. 1.86 +/- 0.67 l.min-1.Torr-1). The slope of the VE-tidal volume relationship was significantly lower in DS-NL than in INH-NL (19.6 +/- 3.8 vs. 21.2 +/- 5.1 min-1, P < 0.05), but other comparisons in breathing pattern between NL and IRL and between DS and INH failed to reach significance. We concluded that 1) alterations in alveolar PCO2 temporal profile by DS could induce changes in VE-end-tidal PCO2 sensitivity and ventilatory pattern, 2) these changes may be modified by increased mechanical impairment resulting from IRL, and 3) carotid chemoreceptor mediation is not necessary for the observed effects of DS.

Changes in ventilatory pattern induced by intravenous anesthetic agents in human subjects

1978 ◽  
Vol 45 (2) ◽  
pp. 171-176 ◽  
Author(s):  
H. Gautier ◽  
J. H. Gaudy
Keyword(s):  
Tidal Volume ◽  
Human Subject ◽  
Opposite Effect ◽  
Animal Species ◽  
Human Subjects ◽  
Breathing Rate ◽  
Intravenous Anesthetic ◽  
Anesthetic Agents ◽  
Ventilatory Pattern ◽  
Duration Relationship

The tidal volume-inspiratory duration relationship was studied during air breathing and rebreathing in conscious and anesthetized human subjects using three different intravenous agents. The results observed have been compared with similar experiments carried out in cats. Its has been shown that anesthesia provokes an increase in breathing rate associated with a decrease in tidal volume in human subjects; an opposite effect on breathing rate was observed in cats. Thus, the tidal volume-inspiratory duration relationship, although very similar in the conscious cat or human subject, is very different under anesthesia. The results were quite consistent in a given species whatever the nature of the drug used. It is suggested that modifications of the breathing rate by anesthesia, related to animal species, are caused by central effects of the drug. These effects are probably mediated by different actions on inputs to the inspiratory –off-switch” mechanisms in the two species.

Effects of expiratory resistive load on respiratory motor output in conscious humans

1987 ◽  
Vol 63 (5) ◽  
pp. 1837-1845 ◽  
Author(s):  
C. S. Poon ◽  
M. Younes ◽  
C. G. Gallagher
Keyword(s):  
Tidal Volume ◽  
Time Course ◽  
Human Subjects ◽  
Minute Ventilation ◽  
Resistive Load ◽  
Quiet Breathing ◽  
Relative Time ◽  
Ventilatory Pattern ◽  
Resistive Loading ◽  
Residual Capacity

We examined, in five conscious human subjects, the steady-state effects of expiratory resistive loading (ERL; R = 8 cmH2O.l–1.s) on the time course of inspiratory and postinspiratory muscle activities (IA and PIA, respectively) and ventilatory pattern during quiet breathing. Driving pressure (DP) was calculated by means of a respiratory neuromechanical model (J. Appl. Physiol. 51: 963–989, 1981) that permitted the derivation, from tidal volume and flow, of the occlusion pressure equivalent (at functional residual capacity) of respiratory neural output throughout the breath. ERL caused a prolongation of both neural inspiratory duration (12.2 +/- 6.9% SD) and expiratory duration (25.0 +/- 10.1%) and an increase in the amplitude of DP (16.5 +/- 10.2%) without any changes in the waveshape of IA and in end-expiratory level. The relative time course of PIA was not altered by ERL. Minute ventilation was depressed (-6.75 +/- 2.88%) during ERL with little change in alveolar PCO2. The results indicate that pulmonary gas exchange may be improved during ERL through increased tidal volume as well as delayed expiratory lung emptying secondary to sustained PIA.

Respiratory phase locking during mechanical ventilation in anesthetized human subjects

1986 ◽  
Vol 250 (5) ◽  
pp. R902-R909 ◽  
Author(s):  
C. Graves ◽  
L. Glass ◽  
D. Laporta ◽  
R. Meloche ◽  
A. Grassino
Keyword(s):  
Spontaneous Breathing ◽  
Breathing Pattern ◽  
Human Subjects ◽  
Phase Locking ◽  
Phase Relationship ◽  
Mechanical Ventilator ◽  
Lung Inflation ◽  
Fixed Phase ◽  
Simple Phase ◽  
Ventilator Settings

The coupling patterns between the rhythm of a mechanical ventilator and the rhythm of spontaneous breathing were studied in enflurane-anesthetized adult human subjects. The spontaneous breathing pattern was altered in response to different frequencies and amplitudes of forced lung inflations. A 1:1 phase locking (the frequency of the mechanical ventilator is matched by the frequency of spontaneous breathing with a fixed phase between the 2 rhythms) was observed in a range of up to +/- 40% of some of the subject's spontaneous breathing frequencies. During 1:1 phase locking, there were marked changes in the expiratory duration as measured from the electromyogram of the diaphragm. The phase relationship between onset of inflation and onset of inspiration depended on the frequency and amplitude of mechanical inflation. At ventilator settings that did not give 1:1 phase locking, other simple phase-locked patterns, such as 1:2 and 2:1, or irregular non-phase-locked patterns were observed. Reflexes arising from lung inflation, which may underlie the entrainment, are discussed in the context of these results.

Recovery of diaphragm function after laparotomy and chronic sonomicrometer implantation

1989 ◽  
Vol 66 (2) ◽  
pp. 613-621 ◽  
Author(s):  
P. A. Easton ◽  
J. W. Fitting ◽  
R. Arnoux ◽  
A. Guerraty ◽  
A. E. Grassino
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Breathing Pattern ◽  
Recovery Process ◽  
Postoperative Recovery ◽  
Postmortem Examination ◽  
Midline Laparotomy ◽  
Left Hemidiaphragm ◽  
Direct Measurements ◽  
Phrenic Stimulation

If sonomicrometry transducers could be implanted permanently into the diaphragm, direct measurements of costal and crural length and shortening could be made during recovery from the laparotomy and then indefinitely in an awake, non-anesthetized mammal. We report results from six canines in which we successfully implanted transducers onto the left hemidiaphragm through a midline laparotomy and measured segmental shortening and ventilation at intervals through 22 days of postoperative recovery. After laparotomy, breathing pattern, including tidal volume, respiratory rate and mean inspiratory flow, stabilized by the 4th postoperative day (POD). Tidal shortening of costal and crural segments increased from 1.82 and 1.45% of end-expiratory length (%LFRC) on the 2nd POD to 5.32 and 8.56% LFRC, respectively, after a mean of 22 POD. Segmental shortening did not stabilize until 10 POD, and the recovery process displayed a sequence of segmental motions: lengthening, biphasic inspiratory lengthening-shortening, and increasing simple shortening. Three weeks after implantation, costal and crural segments were stable and shortening 5.32 and 8.56% LFRC, respectively, and capable of shortening 49% LFRC with maximal phrenic stimulation. In a pair of recovered animals, the initial postoperative dysfunction did not recur after a subsequent, simple laparotomy. At postmortem examination, the chronically implanted sonomicrometer transducers were found to have evoked only a thin fibrotic capsule within the diaphragm.

Normoxic and hypoxic breathing pattern in newborn grey seals

1989 ◽  
Vol 67 (2) ◽  
pp. 483-487 ◽  
Author(s):  
Jacopo P. Mortola ◽  
Clement Lanthier
Keyword(s):  
Tidal Volume ◽  
Breathing Pattern ◽  
Halichoerus Grypus ◽  
Breathing Rate ◽  
Allometric Relationships ◽  
Breathing Patterns ◽  
Hypoxic Conditions ◽  
Regulation Of Breathing ◽  
Expiratory Flow

We studied the breathing patterns of three newborn grey seals (Halichoerus grypus) at 2 – 3 days of age under normoxic and hypoxic conditions with the barometric technique, which does not require the animal to be restrained. Normoxic tidal volume was deeper and breathing rate slower than expected for newborns of this size on the basis of previously published allometric relationships. In addition, two characteristics were readily apparent: (i) occasional sudden long apneas, often exceeding 30 s in duration, and (ii) consistent brief interruptions of expiratory flow. Neither aspect is common in terrestrial newborns of this age, but both have been previously observed in adult seals. During hypoxia (10 min of 15% O2 and 10 min of 10% O2), ventilation increased markedly and steadily, at variance with what occurs in newborns of other species, indicating a precocial development of the regulation of breathing. This latter result also suggests that the blunted response to hypoxia previously reported in adult seals may be acquired postnatally with diving experience.

Effect of body position on spontaneous respiratory rate and tidal volume in patients with obesity, abdominal distension and ascites

1994 ◽  
Vol 3 (2) ◽  
pp. 102-106 ◽  
Author(s):  
SM Burns ◽  
MB Egloff ◽  
B Ryan ◽  
R Carpenter ◽  
JE Burns
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Breathing Pattern ◽  
Body Position ◽  
Abdominal Distension ◽  
The Body ◽  
Abdominal Distention ◽  
Optimal Position ◽  
Nursing Textbooks ◽  
Spontaneously Breathing

BACKGROUND: Nursing textbooks and tradition suggest that the high-Fowler's position is best to optimize diaphragmatic excursion and effective breathing pattern. The optimal position for intubated patients with obesity, ascites or abdominal distention has yet to be determined but is important because weaning trial outcomes may reflect the effect of position rather than weaning trial tolerance. OBJECTIVE: To determine the body position that optimizes breathing pattern (tidal volume and respiratory rate) in spontaneously breathing, intubated patients with a large abdomen. METHODS: Nineteen intubated patients with abdominal distention, ascites or obesity who were on continuous positive airway pressure or the pressure support ventilation mode were studied in the 0 degrees, 45 degrees, 90 degrees and reverse Trendelenburg's at 45 degrees positions for 5 minutes prior to data collection. RESULTS: The RT at 45 degrees position resulted in a significantly larger tidal volume and lower respiratory rate than the 90 degrees position in intubated, spontaneously breathing patients with a large abdomen. The 45 degrees position resulted in a significantly lower respiratory rate than at 90 degrees; however, no difference in tidal volume was demonstrated. DISCUSSION: A high respiratory rate and low tidal volume potentiates atelectasis and ultimately failure to wean. It is important that the effect of positioning on breathing pattern in intubated patients be determined so that care planning results in optimal outcomes. CONCLUSIONS: The results of this study have implications for the selection of chair and bed positioning during weaning trials.

Depression of cough reflex by microinjections of antitussive agents into caudal ventral respiratory group of the rabbit

2010 ◽  
Vol 109 (4) ◽  
pp. 1002-1010 ◽  
Author(s):  
Donatella Mutolo ◽  
Fulvia Bongianni ◽  
Elenia Cinelli ◽  
Tito Pantaleo
Keyword(s):  
Receptor Antagonist ◽  
Respiratory Activity ◽  
Neural Substrates ◽  
Cough Reflex ◽  
Ventral Respiratory Group ◽  
Tracheal Pressure ◽  
Site Of Action ◽  
A Site ◽  
Antitussive Agents ◽  
Antitussive Drugs

We have previously shown that the caudal nucleus tractus solitarii is a site of action of some antitussive drugs and that the caudal ventral respiratory group (cVRG) region has a crucial role in determining both the expiratory and inspiratory components of the cough motor pattern. These findings led us to suggest that the cVRG region, and possibly other neural substrates involved in cough regulation, may be sites of action of antitussive drugs. To address this issue, we investigated changes in baseline respiratory activity and cough responses to tracheobronchial mechanical stimulation following microinjections (30–50 nl) of some antitussive drugs into the cVRG of pentobarbital-anesthetized, spontaneously breathing rabbits. [d-Ala2, N-Me-Phe4,Gly5-ol]-enkephalin (DAMGO) and baclofen at the lower concentrations (0.5 mM and 0.1 mM, respectively) decreased cough number, peak abdominal activity, and peak tracheal pressure and increased cough-related total cycle duration (Tt). At the higher concentrations (5 mM and 1 mM, respectively), both drugs abolished the cough reflex. DAMGO and baclofen also affected baseline respiratory activity. Both drugs reduced peak abdominal activity, while only DAMGO increased Tt, owing to increases in expiratory time. The neurokinin-1 (NK1) receptor antagonist CP-99,994 (10 mM) decreased cough number, peak abdominal activity, and peak tracheal pressure, without affecting baseline respiration. The NK2 receptor antagonist MEN 10376 (5 mM) had no effect. The results indicate that the cVRG is a site of action of some antitussive agents and support the hypothesis that several neural substrates involved in cough regulation may share this characteristic.

Effort sensation, chemoresponsiveness, and breathing pattern during inspiratory resistive loading

1992 ◽  
Vol 73 (2) ◽  
pp. 440-445 ◽  
Author(s):  
J. E. Clague ◽  
J. Carter ◽  
M. G. Pearson ◽  
P. M. Calverley
Keyword(s):  
Tidal Volume ◽  
Breathing Pattern ◽  
Free Breathing ◽  
Normal Subjects ◽  
Inspiratory Effort ◽  
Sustained Load ◽  
Resistive Loading ◽  
End Tidal ◽  
Few Data ◽  
Normal Men

Although inspiratory resistive loading (IRL) reduces the ventilatory response to CO2 (VE/PCO2) and increases the sensation of inspiratory effort (IES), there are few data about the converse situation: whether CO2 responsiveness influences sustained load compensation and whether awareness of respiratory effort modifies this behavior. We studied 12 normal men during CO2 rebreathing while free breathing and with a 10-cmH2O.l-1.s IRL and compared these data with 5 min of resting breathing with and without the IRL. Breathing pattern, end-tidal PCO2, IES, and mouth occlusion pressure (P0.1) were recorded. Free-breathing VE/PCO2 was inversely related to an index of effort perception (IES/VE; r = -0.63, P less than 0.05), and the reduction in VE/PCO2 produced by IRL was related to the initial free-breathing VE/PCO2 (r = 0.87, P less than 0.01). IRL produced variable increases in inspiratory duration (TI), IES, and P0.1 at rest, and the change in tidal volume correlated with both VE/PCO2 (r = 0.63, P less than 0.05) and IES/VE (r = -0.69, P less than 0.05), this latter index also predicting the changes in TI with loading (r = -0.83, P less than 0.01). These data suggest that in normal subjects perception of inspiratory effort can modify free-breathing CO2 responsiveness and is as important as CO2 sensitivity in determining the response to short-term resistive loading. Individuals with good perception choose a small-tidal volume and short-TI breathing pattern during loading, possibly to minimize the discomfort of breathing.

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