The role of carotid bodies in the establishment of oral breathing during nasal obstruction in lambs and ewes

Harding, Richard; Wood, G. A.

doi:10.1016/0034-5687(90)90007-l

Cited by 6 publications

(3 citation statements)

References 14 publications

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“…1). These responses were attenuated and delayed following denervation of the carotid bodies, indicating that chemoreception by peripheral chemoreceptors plays an important role in the reflex activation of respiratory and upper airway muscles, leading to oral breathing, during airway obstruction (Harding 8 Wood 1990). Similar observations on the role of chemoreceptors have been made by Fewell et al (1990).…”

supporting

confidence: 62%

Postnatal Development of Responses to Airflow Obstruction

Harding

Jakubowska

McCrabb

1995

Clin Exp Pharma Physio

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1. Obstruction of the upper airway could be an initiating factor in the Sudden Infant Death Syndrome (SIDS). Responses to upper airway obstruction include augmentation of respiratory efforts, active dilation of the upper airway and electrocortical arousal. Vulnerable individuals may fail to mount these responses effectively. 2. Respiratory and arousal responses to obstruction of the upper airway have been investigated in newborn lambs. In conscious lambs, nasal obstruction causes a profound augmentation of inspiratory efforts, mild asphyxiation and eventual formation of an oral airway. The ability to establish an oral airway involves both chemoreception and mechanoreception and improves with age. 3. In sleeping lambs, obstruction of tidal airflow leads to progressive hypoxaemia, augmentation of inspiratory efforts, bradycardia and arousal. Arousal occurs earlier and with less hypoxaemia and bradycardia in non-REM sleep than in REM sleep. Arousal occurs after inspiratory efforts have increased to the same extent during both sleep states, suggesting that mechanoreception, or a sense of inspiratory effort, is important in initiating arousal. 4. Obstruction of nasal tubes tends to cause arousal from sleep earlier, and with less hypoxaemia and less augmentation of inspiratory effort, than when a more compliant face mask is obstructed. This supports the suggestion that mechanoreception, which may be involved in the perception of inspiratory effort, is a determinant of arousal. 5. With increasing postnatal age, lambs become less arousable in response to airflow obstruction when in REM sleep. This suggests that lambs may become progressively more vulnerable to the effects of airway obstruction during the immediate newborn period.(ABSTRACT TRUNCATED AT 250 WORDS)

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supporting

confidence: 62%

Postnatal Development of Responses to Airflow Obstruction

Harding

Jakubowska

McCrabb

1995

Clin Exp Pharma Physio

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“…In the lambs with chemodenervated carotid bodies the initiation of oral breathing in response to nasal occlusion took longer, showing that the contribution of the peripheral chemoreceptors to this response is important. 16 In our study, there was a consistent decrease in oxygen saturation prior to the establishment of oral breathing.…”

Section: Discussionsupporting

confidence: 73%

The effect of nasal occlusion on the initiation of oral breathing in preterm infants

deAlmeida¹,

Alvaro²,

Haider³

et al. 1994

Pediatric Pulmonology

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The ability to switch from nasal to oral breathing in response to nasal obstruction is crucial for survival, and has been suggested to be an important mechanism in preventing sudden infant death syndrome (SIDS). To know whether the ability to switch from nasal to oral breathing is uniformly present during the early neonatal period, we examined the effects of slow and fast nasal occlusions on the establishment of oral breathing in preterm infants. Slow occlusions were used to mimic more closely occlusions occurring spontaneously. We studied 17 healthy preterm infants [birth weight, 1830 +/- 27 g (mean +/- SE); study weight, 1800 +/- 109 g; gestational age, 32 +/- 1 weeks; postnatal age, 12 +/- 2 days]. We used a nosepiece with a nasal occluder and a flow-through system to measure ventilation. A CO2 sampling catheter at the mouth was used to detect oral breathing. Of 58 occlusions, 29 were slow [resistance increasing slowly from 0 to infinite (occlusion)], and 29 were fast (infinite elastance applied in < 1 sec). Oral breathing was always established following slow and fast occlusions. In 44% of the slow occlusions, oral breathing started before complete occlusion. Arousal was observed in 12/58 (17%) of all occlusions, occurring primarily after initiation of oral breathing. Oxygen saturation and respiratory rate decreased significantly following occlusions, from 96 +/- 0.6 to 87 +/- 1.2% and 49 +/- 2.8 to 38 +/- 2 breaths/min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…A third cause involves the respiratory process itself. The effects of imposed oral breathing obviously affect blood gas parameters, leading to acute hypoxia, hypercapnia, and acidemia [79, 80], especially in neonates [81]. Adult rats' blood pH and O 2 partial pressure are reduced 72 h after narial occlusion [82], leading to adverse changes in the homeostasis of blood gases.…”

Section: Multiple Impacts Of Nasal Obstruction: the Rat As A Modelmentioning

confidence: 99%

It Takes a Mouth to Eat and a Nose to Breathe: Abnormal Oral Respiration Affects Neonates' Oral Competence and Systemic Adaptation

Trabalon

Schaal

2012

International Journal of Pediatrics

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Mammalian, including human, neonates are considered to be obligate nose breathers. When constrained to breathe through their mouth in response to obstructed or closed nasal passages, the effects are pervasive and profound, and sometimes last into adulthood. The present paper briefly surveys neonates' and infants' responses to this atypical mobilisation of the mouth for breathing and focuses on comparisons between human newborns and infants and the neonatal rat model. We present the effects of forced oral breathing on neonatal rats induced by experimental nasal obstruction. We assessed the multilevel consequences on physiological, structural, and behavioural variables, both during and after the obstruction episode. The effects of the compensatory mobilisation of oral resources for breathing are discussed in the light of the adaptive development of oromotor functions.

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The role of carotid bodies in the establishment of oral breathing during nasal obstruction in lambs and ewes

Cited by 6 publications

References 14 publications

Postnatal Development of Responses to Airflow Obstruction

Postnatal Development of Responses to Airflow Obstruction

The effect of nasal occlusion on the initiation of oral breathing in preterm infants

It Takes a Mouth to Eat and a Nose to Breathe: Abnormal Oral Respiration Affects Neonates' Oral Competence and Systemic Adaptation

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