Effects of caffeine and/or nasal CPAP treatment on laryngeal chemoreflexes in preterm lambs

Current knowledge suggests that laryngeal chemoreflexes (LCR) are involved in the occurrence of certain neonatal apneas/bradycardias, especially in the preterm newborn. While caffeine and/or nasal continuous positive airway pressure (nCPAP) are the most frequent options used for treating apneas in preterm newborns, their effects on LCR-related apneas/bradycardias are virtually unknown. The aim of the present study was to test the hypothesis that caffeine and/or nCPAP decreases LCR-related cardiorespiratory inhibition in a preterm ovine model. Seven preterm lambs were born vaginally on gestational day 133 (normal gestation: 147 days) after intramuscular injections of betamethasone and mifepristone. Five days after birth, a chronic surgical instrumentation was performed to record states of alertness, electrocardiogram, systemic arterial pressure, and electromyographic activity of a laryngeal constrictor muscle, as well as to insert a transcutaneous supraglottal catheter. LCR were induced in quiet sleep under four conditions: 1) control (without caffeine or nCPAP); 2) nCPAP (5 cmH2O, without caffeine); 3) caffeine (10 mg/kg infused intravenously for 30 min, without nCPAP); and 4) nCPAP + caffeine. Our results showed that nCPAP consistently blunted LCR-related cardiorespiratory inhibition vs. control condition, contrary to caffeine whose overall effect was nonsignificant. In addition, nCPAP condition was characterized by a more consistent and rapid arousal after HCl injection. No significant differences were observed between all tested conditions with regard to swallowing and cough. It is concluded that nCPAP should be further assessed for its usefulness in treating neonatal apneas linked to LCR.

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Effect of nasal continuous or intermittent positive airway pressure on nonnutritive swallowing in the newborn lamb

Journal of Applied Physiology ◽

10.1152/japplphysiol.00464.2005 ◽

2005 ◽

Vol 99 (5) ◽

pp. 1636-1642 ◽

Cited By ~ 23

Author(s):

Nathalie Samson ◽

Marie St-Hilaire ◽

Elise Nsegbe ◽

Philippe Reix ◽

François Moreau-Bussière ◽

...

Keyword(s):

Airway Pressure ◽

Positive Airway Pressure ◽

Random Order ◽

Intermittent Positive Pressure Ventilation ◽

Respiratory Cycle ◽

Positive Pressure ◽

Electromyographic Activity ◽

Active Sleep ◽

Quiet Sleep ◽

Upper Airways

The present study was aimed at investigating the effects of nasal continuous positive airway pressure (nCPAP; 6 cmH2O) or intermittent positive pressure ventilation (nIPPV; 10/4 cmH2O) on nonnutritive swallowing (NNS) and on the coordination between NNS and phases of the respiratory cycle, while taking into account the potential effects of states of alertness. Twelve full-term lambs were chronically instrumented at 48 h after birth for polysomnographic recordings, including NNS, diaphragm electromyographic activity, respiratory movements, pulse oximetry, and states of alertness. Studies in control conditions, with nCPAP and nIPPV, were performed in random order in nonsedated lambs at 4, 5, and 6 days of life. Results demonstrate that nCPAP significantly decreased overall NNS frequency, more specifically isolated NNS during quiet sleep and bursts of NNS in active sleep. In comparison, the effects of nIPPV on NNS frequency were more variable, with an inhibition of NNS only in wakefulness and an increase in isolated NNS frequency in active sleep. In addition, neither nCPAP nor nIPPV disrupted the coordination between NNS and phases of the respiratory cycle. In conclusion, nCPAP inhibits NNS occurrence in newborn lambs. Clinical relevance of this novel finding is related to the importance of NNS for clearing the upper airways from secretions and gastric content frequently regurgitated in the neonatal period.

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A comparison of the effect of nasal bi-level positive airway pressure and sigh-positive airway pressure on the treatment of the preterm newborns weighing less than 1500 g affiliated with respiratory distress syndrome

International Journal of Preventive Medicine ◽

10.4103/2008-7802.173930 ◽

2016 ◽

Vol 7 (1) ◽

pp. 21 ◽

Cited By ~ 1

Author(s):

Alireza Sadeghnia ◽

Navid Danaei ◽

Behzad Barkatein

Keyword(s):

Respiratory Distress Syndrome ◽

Respiratory Distress ◽

Airway Pressure ◽

Distress Syndrome ◽

Positive Airway Pressure ◽

Preterm Newborns

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Effects of nasal continuous positive-airway pressure on nutritive swallowing in lambs

Journal of Applied Physiology ◽

10.1152/japplphysiol.01559.2011 ◽

2012 ◽

Vol 112 (12) ◽

pp. 1984-1991 ◽

Cited By ~ 14

Author(s):

Anne Bernier ◽

Céline Catelin ◽

Mohamed Amine Hadj Ahmed ◽

Nathalie Samson ◽

Pauline Bonneau ◽

...

Keyword(s):

Continuous Positive Airway Pressure ◽

Airway Pressure ◽

Positive Airway Pressure ◽

Current Knowledge ◽

Ventilatory Support ◽

Bottle Feeding ◽

Oral Feeding ◽

Great Success ◽

Arterial Blood ◽

Laryngeal Penetration

Current knowledge suggests that, to be successful, oral feeding in preterm infants should be initiated as soon as possible, often at an age where immature respiration still requires ventilatory support in the form of nasal continuous positive airway pressure (nCPAP). While some neonatologist teams claim great success with initiation of oral feeding in immature infants with nCPAP, others strictly wait for this ventilatory support to be no longer necessary before any attempt at oral feeding, fearing laryngeal penetration and tracheal aspiration. Therefore, the aim of the present study was to provide a first assessment of the effect of various levels of nCPAP on bottle-feeding in a neonatal ovine model, including feeding safety, feeding efficiency, and nutritive swallowing-breathing coordination. Eight lambs born at term were surgically instrumented 48 h after birth to collect recordings of electrical activity of laryngeal constrictor muscle, electrocardiography, and arterial blood gases. Two days after surgery, lambs were bottle-fed under five randomized nCPAP conditions, including without any nCPAP or nasal mask and nCPAP of 0, 4, 7, and 10 cmH2O. Results revealed that application of nCPAP in the full-term lamb had no deleterious effect on feeding safety and efficiency or on nutritive swallowing-breathing coordination. The present study provides a first and unique insight on the effect of nCPAP on oral feeding, demonstrating its safety in newborn lambs born at term. These results open the way for further research in preterm lambs to better mimic the problems encountered in neonatology.

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