The Pathophysiological Role of the Sniff-Like Aspiration Reflex

Tomori, Z; Javorka, K; Stránský, A; Jakus, J

doi:10.1016/b978-0-08-026823-1.50063-6

Cited by 3 publications

(7 citation statements)

References 13 publications

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“…The expiratory effort characterized by activity in internal intercostal and abdominal muscles is temporarily inhibited during both gasping [2,26] and aspiration reflex [12,13].…”

Section: Discussionmentioning

confidence: 99%

“…Hypoxic apnoea could be reversed more often by repeated evocation of the snifflike aspiration reflex [9). This reflex can be induced by mechanical stimulation of the nasopharyngeal mucosa and comprises an extremely strong and fast inspiratory effort [10][11][12][13] resembling a gasp, and also a sniff which is a semi-reflex response that occurs in animals when a new odour attracts attention [14]. In man, sniffing is mostly a voluntary behavioural act originating from the cortical area 6 b [15].…”

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confidence: 99%

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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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“…The expiratory effort characterized by activity in internal intercostal and abdominal muscles is temporarily inhibited during both gasping [2,26] and aspiration reflex [12,13].…”

Section: Discussionmentioning

confidence: 99%

mentioning

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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“…According to Tomori et al [1981], it is highly resistant to various drugs and phy sical factors and can even be elicited after the onset of apnoea. We failed to elicit an AR at the outset of hypoxic apnoea, but attribute the discrepancy to differences in the mechanism of origin of experimental apnoea.…”

Section: Discussionmentioning

confidence: 99%

“…We failed to elicit an AR at the outset of hypoxic apnoea, but attribute the discrepancy to differences in the mechanism of origin of experimental apnoea. Tomori et al [1981] used pureC02 for inhalation in their experiments.…”

Section: Discussionmentioning

confidence: 99%

Changes Induced by Severe Hypoxia in Respiratory Defence Reflexes in Anaesthetized Cats

Tatár¹,

Korpáš²,

Poláček³

et al. 1986

Respiration

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The authors studied the effects of progressive isobaric hypoxia (FO₂ = 0.11, 0.07, 0.06, 0.05, 0.04 and 0.03) on respiratory defence reflexes elicited by mechanical stimulation of the airways in 10 pentobarbital-anaesthetized cats. The intensity of the expiration reflex was already significantly reduced at a hypoxia level of only FO₂ = 0.11; the intensity of cough also showed a tendency to decrease. The number of efforts and the intensity of both tracheobronchial (TB) and laryngopharyngeal (LPh) cough fell significantly in hypoxia of FO₂ = 0.07. On an average, cough could no longer be elicited at PaO₂ = 2.0 ± 0.06 kPa. The aspiration reflex was found to be the most resistant to hypoxia, and could still be elicited just before hypoxic apnoea developed. During hypoxia with FO₂ ranging from 0.21 to 0.06, minute ventilation increased, while the intensity of respiratory defence reflexes diminished. TB cough could not be elicited during hypoxia until the breathing was depressed. It can be seen from the results that the regulatory mechanisms responsible for the intensity of respiratory defence reflexes are less resistant to the consequences of an inadequate systemic oxygen supply than the mechanisms controlling ventilation.

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“…In cats and some other mammals there is a sniff. or gasp-like aspiration reflex comprising powerful in• spiratory efforts [8][9][10][11][12]. The reflex elicited by mechanical stimulation of the nasopharynx can interrupt various types of apnoea (13] and it persists even in very deep stages of general anaesthesia, when cough and other respiratory reflexes have already disappeared [14).…”

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confidence: 99%

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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The Pathophysiological Role of the Sniff-Like Aspiration Reflex

Cited by 3 publications

References 13 publications

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

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

Changes Induced by Severe Hypoxia in Respiratory Defence Reflexes in Anaesthetized Cats

Reversal of apnoea by aspiration reflex in anaesthetized cats

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