Effect of Nasal Continuous Positive Airway Pressure on The Pharyngeal Swallow in Neonates
Condition: Deglutition Disorders; Respiratory Distress Syndrome In Premature Infants; Respiratory Aspiration; Newborn, Premature
MeSH terms: Deglutition Disorders; Respiratory Distress Syndrome; Respiratory Distress Syndrome, Newborn; Respiratory Aspiration; Premature Birth
Study type: Interventional

Summary: 
      Oral feeding of neonates while on nasal continuous positive airway pressure (NCPAP) is a
      common practice in many neonatal intensive care units (NICU) all over the country. However
      the safety of such practice has never been established. The Investigators hypothesize that
      mechanoreceptors, which should perceive sensory input from the liquid bolus, may be altered
      by the reception of pressurized airflow provided by the NCPAP, hence increase risk of
      aspiration. In this study, changes in the pharyngeal phase of swallowing were identified
      using video fluoroscopic swallow studies (VFSS) for infants while on NCPAP as compared to off
      NCPAP.
    

Detailed description: 
      Preterm infants with underdeveloped lungs and term infants with cardio-respiratory illness
      frequently need to be placed on ventilatory assistance. Nasal Continuous Positive Airway
      Pressure (NCPAP) has been proven to be an effective mode of noninvasive ventilation in
      neonates, as it delivers positive pressure to the airway throughout the respiratory cycle.
      NCPAP works by improving the breathing pattern in neonates; it increases the mean airway
      pressure, stents the upper airway, decreases proximal airway resistance, reduces
      physiological dead space, optimizes lung recruitment and improves diaphragmatic function.
      While many infants in the Neonatal Intensive Care Units (NICUs) require NCPAP, many of their
      other medical and developmental needs such as initiating oral feedings need to be addressed.
      Oral feeding of neonates while on NCPAP is a common practice in many NICUs, however the
      effect of such practice on neonatal swallowing mechanism has never been investigated.

      Swallowing is a complex sensorimotor function that allows infant to safely and effectively
      ingest liquid nutrition. The ability of an infant to successfully feed is dependent on the
      precise interconnection of anatomy, physiology and neurology pathways. Afferent sequences
      play an integral role in the infant swallowing mechanism as sensory feedback is required
      during all phases of swallowing to allow appropriate positioning of anatomic structures, as
      well as to modulate the strength, velocity, and timing of muscle contractions. Sensory
      information is received from various types of sensory receptors distributed throughout the
      oral cavity, pharynx, larynx and esophagus. Localized areas of the infant's anatomy are known
      to have particular types of sensory receptors that are excited by specific stimuli which
      elicit appropriate motor movements.

      One of the most densely populated sensory receptors are the mechanoreceptors which are
      sensitive to touch and pressure to help decipher the shape, texture, size and temperature of
      the bolus about to be swallowed. The mechanoreceptors are also sensitive to the pressure and
      movement of air flow during breathing.

      The sensations perceived by these receptors are responsible for sending afferent sensory
      information to the medullary region of the brainstem where they are processed by the central
      pattern generators (CPGs). CPGs are composed of dedicated networks of interneurons that are
      responsible to sequence and activate different motor neurons at specified intensities to
      generate motor patterns. Both the swallowing CPG and the respiratory CPG are housed within
      the medulla. The close proximity of these neurons allows for precise swallow and breathing
      coordination. A close interrelationship between the swallowing and respiratory processes is
      further evident as they encompass shared anatomic structures and muscular components within
      the pharynx, and act as physiologically and biomechanically reciprocal events.

      This close interrelationship between swallowing and breathing has led to some controversy and
      difference in opinion among neonatologists on the decision to start oral feedings while on
      NCPAP. Although there is no research directly related to the effect of NCPAP on swallowing
      process in neonates, NCPAP has been reported to induce dilatation of the laryngeal opening in
      preterm infants and inhibit the swallow reflex in adults.

      For preterm infants, some neonatologists advocate initiation of oral feeds at 34 weeks
      gestational age, even if they require NCPAP; others strictly wait for NCPAP to be
      discontinued before oral feeding is established, fearing that infants may have difficulty
      coordinating breathing and swallowing acts, resulting in airway compromise. For term infants,
      many propose that oral feedings can be established once physiologic stability is
      demonstrated, either with or without NCPAP. Such controversies exist due to lack of evidence
      on the effect(s) of NCPAP on swallowing safety in human neonates.

      To our knowledge no studies have been completed on human infants to evaluate the effect of
      NCPAP on the pharyngeal swallowing mechanism. Previous studies utilizing neonatal lambs,
      revealed that the application of NCPAP had no deleterious effect on cardiopulmonary safety,
      feeding efficiency and on nutritive swallowing- breathing coordination.

      This study was designed with the aim to effectively assess the effects of NCPAP on the
      pharyngeal swallow mechanism in human neonates. The investigators hypothesize that the
      presence of NCPAP will lead to alterations in the sensorimotor sequence of the pharyngeal
      swallowing mechanism, increasing the risk for airway compromise and aspiration. The
      mechanoreceptors, which perceive sensory input from the liquid bolus, may be altered by the
      reception of continuous stream of airflow, provided by the NCPAP.
    

Intervention name(s): NCPAP; Varibar® Thin Liquid Barium Sulfate for Suspension
Intervention type(s): Device; Dietary Supplement
Intervention description(s): Does NCPAP induce dysphagia in neonates? Each baby will be evaluated for dysphagia (using fluoroscopy) while on NCPAP and off NCPAP.; Liquid barium is used as a contrast material to allow visualization of swallowed boluses under fluoroscopy.
Other intervention name(s): Continuous Positive Airway Pressure
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: pharyngeal swallow; airway compromise; NICU