Hypoxic apnoea induced by N2 inhalation can be reversed by the aspiration reflex in anaesthetized cats

Tomori, Z; Benacka, R; Donič, Viliam; Tkácová, R

doi:10.1016/s0954-6111(06)80257-x

Cited by 3 publications

(6 citation statements)

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“…The linear increase in the percentage of cough reactions with time from the onset of apnoea (fig. 2) could be ascribed mainly to the arousal caused by the aspiration reflex for the following reasons: 1) in spite of both the interruption of N 2 supply after 10 s of respiratory arrest and the access of 0 2 from air by diffusion, the arterial oxygen tension (PaoJ slowly decreased further during the proceeding apnoea [7,21]. This resulted in progressive diminution of ECoG activity [22], but it cannot explain the increase in cough reactivity; 2) tracheobronchial stimulations resulted in positive cough reactions more frequently when first tested after rather than before the aspiration reflex; 3) unlike nasopharyngeal stimulations, repeated tracheobronchial irritations alone did not result in successful resuscitation; 4) cough was never elicited in situations where there was failure to elicit an aspiration reflex.…”

Section: Discussionmentioning

confidence: 99%

“…After digitalization at a frequency of 100 Hz the flow signal was evaluated by microcomputers using a program in Basic and statistical analysis (Statgraphics). A total of 25 variables comprising various flow, volume and timing parameters as well as some quotients calculated from them, were obtained for each inspire-expiratory cycle [7].…”

Section: Methodsmentioning

confidence: 99%

“…In awake mice, both newborn and adult, hypoxic apnoea induced by inhalation of an anoxic mixture (97% N,.+ 3% COJ is usually interrupted by gasping resulting m recovery (autoresuscitation) (6]. In a model of reversible respiratory failure induced by N 2 inhalation (7] the anaesthetized cats mostly die unless artificial ventilation (A V) is applied after 40-60 s of apnoea.…”

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confidence: 99%

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Reversal of apnoea by aspiration reflex in anaesthetized cats

Tomori¹,

Benacka²,

Donič³

et al. 1991

Eur Respir J

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Various flow and timing characteristics of breathing as well as electrocorticographic (ECoG) records were analysed in a model of reversible respiratory failure induced by N2 inhalation in 27 anaesthetized cats. During the first minute of respiratory arrest, nasopharyngeal stimulation by an elastic nylon fibre elicited a typical sniff- or gasp-like aspiration reflex (in 88.8% of cases), whilst similar tracheobronchial irritation evoked a weak cough reaction in one third of cases (34.2%). The aspiration reflex could also be evoked in progressive stages of apnoea characterized by very low and even isoelectric ECoG activity immediately before imminent irreversible respiratory failure, and it could interrupt and replace the periodic gasping sometimes occurring during apnoea. The reflex, comprising powerful inspiration efforts, could be evoked during apnoea many times in succession. Repeated aspiration reflexes alone resulted in recovery from hypoxic apnoea with gradual normalization of ECoG and subsequent restitution of spontaneous breathing even more frequently than it occurred in periodic gasping. Successful resuscitation from hypoxic apnoea by the aspiration reflex in cats suggests that nasopharyngeal stimulation can affect the mechanisms underlying the failure and restitution of breathing at least in some forms of apnoea.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Reversal of apnoea by aspiration reflex in anaesthetized cats

Tomori¹,

Benacka²,

Donič³

et al. 1991

Eur Respir J

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“…Control recording of several eupnoeic breaths and aspiration reflexes was followed by N 2 inhalation, to induce hypoxic apnoea [21]. Usually, after 40-50 s of apnoea, there was marked mydriasis, indicating the onset of brainstem paralysis, and a mandatory type of artificial ventilation with air (Bird, Mark 7) combined with cyclic compression of the chest was induced.…”

Section: Methodsmentioning

confidence: 99%

Comparison of inspiratory effort in sniff-like aspiration reflex, gasping and normal breathing in cats

Tomori¹,

Donič²,

Kurpas³

1993

Eur Respir J

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The changes in airway occlusion pressure and airflow, occurring during two spasmodic breathing patterns, were studied and compared with normal breathing pattern in 12 anaesthetized cats. The inspiratory effort developed during the sniff-like aspiration reflex elicited by mechanical stimulation of the nasopharynx under control conditions proved to be very similar in character and intensity to the activity observed during gasping which occurred on resuscitation, of the same cats, from hypoxic apnoea. The starting (P50) and maximum (Pmax) airway occlusion pressure developed in these two spasmodic breathing patterns were very high. Extremely rapid rates of contraction and relaxation were detected by computer-assisted measurements of dynamic changes in both the pressure values and the slopes of pressure curves. The results suggest common effector mechanisms, reflecting similar forceful inspiratory drives, for the aspiration reflex and gasping. These two spasmodic processes differ substantially from normal breathing. Nevertheless, the aspiration reflex differs from gasping in that it can be elicited by activation of upper airway afferents during eupnea. Moreover, as yet, there is no definitive evidence that the brainstem mechanisms responsible for generating the aspiration reflex are the same as those of the gasp. The main benefits of this reflex are its rather easy elicitability under various conditions and its capability to induce important cardiorespiratory effects (e.g.) reversal of central apnoea) owing to its powerful activity.

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“…For instance, cough reflex is the frequent response to a punctuate tracheal stimulus delivered during inspiration, while expiration reflex is the typical response in expiration. Cough is downregulated when induced during a reflex apnea (Poussel et al, 2012 ), but appears unaffected during apnea induced by hyperventilation (Tomori et al, 1991 ). Simultaneous tracheobronchial and laryngeal stimulation results in increased coughs (Kondo and Hayama, 2009 ).…”

Section: Physiological Mechanisms Of Cough During Developmentmentioning

confidence: 99%

What is chronic cough in children?

et al. 2014

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The cough reflex is modulated throughout growth and development. Cough—but not expiration reflex—appears to be absent at birth, but increases with maturation. Thus, acute cough is the most frequent respiratory symptom during the first few years of life. Later on, the pubertal development seems to play a significant role in changing of the cough threshold during childhood and adolescence resulting in sex-related differences in cough reflex sensitivity in adulthood. Asthma is the major cause of chronic cough in children. Prolonged acute cough is usually related to the long-lasting effects of a previous viral airway infection or to the particular entity called protracted bacterial bronchitis. Cough pointers and type may orient toward specific etiologies, such as barking cough in croup or tracheomalacia, paroxystic whooping cough in Pertussis. Cough is productive in protracted bacterial bronchitis, sinusitis or bronchiectasis. Cough is usually associated with wheeze or dyspnea on exertion in asthma; however, it may be the sole symptom in cough variant asthma. Thus, pediatric cough has particularities differentiating it from adult cough, so the approach and management should be developmentally specific.

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Hypoxic apnoea induced by N2 inhalation can be reversed by the aspiration reflex in anaesthetized cats

Cited by 3 publications

References 5 publications

Reversal of apnoea by aspiration reflex in anaesthetized cats

Reversal of apnoea by aspiration reflex in anaesthetized cats

Comparison of inspiratory effort in sniff-like aspiration reflex, gasping and normal breathing in cats

What is chronic cough in children?

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