Tiptoe Through the NICU: Fundamentals of Neonatal Feeding and Swallowing
Author: Heather Bolan, MA, CCC-SLP
Edited by: Ainsley Martin, MS, CCC-SLP
Recently I started to reflect on NICU Awareness Month and how far my tiny rural hospital has come in managing neonatal care. When I was hired in the spring of 2016, we had no neonatal therapy program for our Level II NICU with our equipment and interventions leaving much to be desired. With the close teamwork of our Nursing Manager of Pediatrics, DOR, OT, and myself, we initiated a quality improvement project to start our own Level II NICU program in the spring of 2017. A few things became apparent, namely, we had minimal to no experience and training in the NICU. We were often left asking ourselves, “Where do we start?” “How do we get the knowledge we need to get this program off the ground?” “What should we expect?”
In this second post of our Tiptoe Through the ICU series, we will provide a rundown of the fundamentals of neonatal feeding and swallowing and NICU program development.
With new medical advancements have come booming neonatal survival rates also resulting in prolonged hospitalizations and increased health care costs (1). Unfortunately, equal scientific advancements in rehabilitation have not occurred to support and facilitate the safe and timely achievement of developmental milestones required for hospital discharge. Did you know neonatal feeding disorders are among the most prevalent causes of; prolonged hospitalization (2)? The infant’s inability to meet full nutritional needs while maintaining cardiopulmonary stability often persists after all other milestones have been achieved (3).
Aspiration frequently occurs in young infants and premature infants secondary to incomplete development in the suck/swallow/breathe pattern, fatigue in the swallow mechanism, reduced alertness, and immaturity (12).
Unfortunately, the medical field still has a long way to come when managing feeding disorders in this fragile population. Wang and colleagues found that 32.2% of later preterm infants from 35 0/7 to 36 6/7 gestation age (GA) were diagnosed with poor feeding (5). Less than 1% of moderately preterm infants are discharged home with tube feedings, yet 55% have problematic feeding behaviors by 6-18 months of age (2). You may ask why there is such a change from discharge home to 6 months of age. As feeding changes from a reflexive to a volitional act, feeding problems will start to reveal themselves if previous feeding experiences have been negative due to classical conditioning.
Recent scientific advancements now provide evidence-based guidelines on how to manage preterm feeding disorders, with positive outcomes of high-quality feeding programs in the NICU by improving parent-infant attachment, higher feeding success at discharge, reduced economic burden, and shorter hospitalizations (4).
What Is Neonatal Therapy and Why Do We Need Special Training?
Neonatal therapists are the main leaders in ensuring these infants are developmentally ready and promote positive feeding experiences to set the infant up for success. Even the most well-intended medical professionals continue to follow the trend of a volume-driven culture, counting the milliliters consumed until adequate for discharge without correlating behavioral changes during feeding to physiologic instability or stress (4). According to the National Association of Neonatal Therapists (NANT) and the American Speech-Language and Hearing Association (ASHA), the NICU is a specialized area of practice, requiring extensive knowledge, skills, and training. Straight to the point- neonates are not small pediatric patients. They have their own set of diagnoses, challenges, precautions, and successes. Medical professionals who have not had extensive training and achieved an adequate level of competency cannot safely work in this setting. In order to provide trauma-informed, age-appropriate care therapists must be up to date on the best evidence-based practice (6).
As neonatal SLPs, our primary goal is to deliver holistic, individualized developmental patient care in order to promote positive feeding experiences. Our specific role in supporting the transition to oral feeding includes;
Protecting oral experiences
Protecting sleep for adequate brain development and growth
Support Non-Nutritive Sucking
Taste Introduction
Ensuring Safety
Staff/Family education and guidance
Ongoing modifications for recommendations
Side-by-side guidance in care
Intervention is made up of a synergistic neurodevelopmental system that includes supporting the development of a variety of systems including;
Neurobehavioral
Neuromotor
Neuroendocrine
Musculoskeletal
Sensory
Psychosocial
These different systems balance each other to provide the foundation for the development of functional skills. It’s important to remember that we may be the specialist looking at brain development if no neurologist is involved. We are the keepers of the brain.
To be successful in neonatal therapy, one must be committed to research and continued development in this area. Important recommended scientific knowledge identified by NANT includes;
Dynamic systems theory
Family-centered care
Attachment theory
Synactive theory of development
Acute and chronic stress
Acute and chronic pain
Neurodevelopment
Neuromotor system
Brain development
Embryology
Neurobehavior
As you can see, this is quite a large list of specialized knowledge and skill base you need before entering the NICU. NANT recommends two years of infant/child developmental services and competency/validation of NICU CEUs.
Why is it so important that we take an extensive amount of time to prepare ourselves for the NICU? There are a lot of factors that impact the transition to oral feeding such as (17,18);
Gestational age at birth
Parent preferences
Sensory
Cardiorespiratory status
Low gestational weight
Neurologic status
Oral anatomy
Medical procedures (i.e. intubation, tube feeding, suctioning
These factors go well beyond what would have been covered for those of us fortunate enough to have had a pediatric feeding and swallowing class in graduate school. It is not hard to see why there is (or at least should be) strict criteria for working in a NICU.
Anatomical and Physiological Considerations
Anatomy:
As summarized by Arvedson and Brodsky, here’s a breakdown of the anatomical differences between infants and older children (10, 11).
Physiology:
As most neonatal infants require artificial teats, the physiology of the swallow for purposes of this blog will focus on sucking on an artificial teat.
Oral Phase
The cycle begins with the infant drawing the teat into the oral cavity. During this time the tongue is resting beneath the teat and the soft palate is relaxed. The lips initiate an airtight closure around the teat when the infant initiates sucking, thereby helping to maintain negative pressure inside the mouth.
The lower jaw elevates and the anterior tongue moves upward, thereby creating compression on the base of the teat. This initiates the expression of milk from the teat.
The posterior tongue depresses, leaving space for the milk to collect in the oral cavity.
The peristaltic wave creates a roller-like motion, further expressing milk from the teat into the mouth. The downward movement of the jaw aids in further facilitation of negative pressure.
As the peristaltic wave of the tongue meets the back of the teat, the soft palate raises and seals the milk within the oropharynx. At this point, swallowing is triggered and the palate seals off the nasal cavity.
We should understand that there are two different pressure forces required for successful nipple feeding: positive and negative pressures
Positive pressure refers to the application of positive pressure on the nipple created by the surface of the tongue in order to extract milk from the nipple.
Negative pressure is created by the back portion of the tongue as it depresses and lowering of the jaw, thereby drawing the nipple and its milk contents into the mouth. The main purpose of negative pressure (i.e. suction) is to retain the 'teat' shape of the nipple and to aid in refilling the nipple of milk. The lips, gums, and tongue form an effective seal against the breast/nipple, thereby allowing negative pressures to be maintained.
Pharyngeal Phase
The bolus stimulates the baro- (pressure), chemo- (chemical), and thermo- (temperature) receptors which generate afferent activity (carry information from the body to the CNS). Sensory relay nuclei and the central pattern generator (located in the brainstem) receive this information and trigger the swallow.
Glottal closure and laryngeal elevation occur concurrently.
Esophageal Phase
UES relaxes, followed by peristalsis of the esophagus.
Feeding is a combination of maturation and experience- the infant must be developmentally ready to feed and then have the opportunity to practice. As previously mentioned, neonates are not small children. They have a unique anatomical and physiologic approach to feeding. It’s important we have a solid understanding of the anatomical and physiological factors involved in neonatal feeding before we consider stepping foot into the NICU. The ability to suck and to suck/swallow is seen prior to the infant’s ability to coordinate all the phases of the swallow. Coordination of the suck-swallow-breathe (S/S/B) is highly related to and influenced by gestational age and respiratory status (39,40). A study completed by Gewolb & Vice in 2006 found that the key to a successful S/S/B was the integration of breathing (41). Authors found that apneic swallows during the feed decreased, and swallowing/respiratory coordination improved with increasing post menstrual age (PMA represents the age of the infant in weeks at discharge home, death or first birthday).
What does this mean for your neonates? The variation in maturation and in the infant’s individual medical comorbidities influences their feeding abilities. The use of the infant’s gestational age alone to determine readiness for feeding is outdated and inappropriate. With the focus changing from quantity to quality of the feed, how are healthcare providers supposed to accomplish this?
Core Theory of Practice in the NICU
The Synactive Theory of Development puts an emphasis on the infant’s subsystems of development (13). The infant is in continuous interaction with its environment and each behavior demonstrated by the neonate is specific and has meaning. This theory serves as the foundation for many other theories in the NICU. Knowing this theory and its subsystems will allow you to look comprehensively at the infant’s neurobehavioral systems by observing the infant pre/during/post caregiving and intervention. Feeding ability is heavily influenced by the infant’s environment, caregiver support, and the infant's overall stability.
Autonomic State:
The autonomic state is the top priority. We cannot expect the neonate to achieve higher levels if the infant is in distress.
Immature: Respiratory pauses/tachypnea/gasping, color changes (to dusky/mottled/gray), gagging or grunting, spitting up, hiccoughing, straining, seizures, tremors/twitches, coughing, sneezing, yawning, sighing
Mature: The emerging ability to regular color or respirations, reduction of seizures, tremors, or twitches
**If we have an issue or a stressful event, we may see some of these unstable behaviors. GI is often in heavy play in the autonomic system.
Motor State:
Direct observations are your best assessment. If signs of immaturity/stress are present, this is often when intervention would be initiated to enable the infant to reach mature/stable behavior.
Immature: Flaccidity (trunk, face, extremities), finger splays, facial grimace, frantic diffuse activity, gaping open mouth, hypertonicity with hyperextension of legs/arms/trunk
Mature: Flexed/tucked position, hand clasp, leg bracing, sucking, hands to mouth, hands on face, smooth movement, consistent muscle tone
State Behaviors:
As neonatal therapists, we want to see if the infant can maintain a state or transition smoothly between states. Babies that stay in the active alert or crying state are typically Neonatal Abstinence Syndrome (NAS) babies. Neonates with neuro problems also tend to exhibit transitional problems. Neuro/NAS infants get stuck in a “neuro cry” and have a difficult time getting out of without intervention. This is important to understand so you can discuss why the infant is not eating, growing, developing, etc.
Gaze aversion (i.e. the neonate is looking away) may be a sign that the infant is trying to decrease stimulation to the nervous system in an effort to maintain or transition states.
When the infant is crying there is constant interference with feeding/sleeping/handling which can make state behaviors a big problem.
If the infant is constantly in a stressed state, brain growth and development are negatively impacted.
However, it is also important to remember that a crying baby is a communicating baby. It is crucial to take these moments to teach the family how their infant is communicating and how to transition their neonate to a lower level of state.
Immature:
Sleep: Diffuse, disorganized sleep states with jerky movements, irregular breathing, fussing, twitches, grimaces, whimpers
Attention: Floating eyes, facial twitch, staring or gaze aversion, panic/worried alertness, glassy-eyed alertness
Mature: Clear sleep states, rhythmic crying, active/self quieting consoling, focused alertness with intent or animated facial expression, cooing, intentional smiling
Attention/Interaction:
In this phase, we are assessing the neonate's ability to maintain attention and tolerate attention with interaction. This involves stable autonomic, motor, and state behaviors. This is important because it is how the infant learns. It is important to educate parents that when their infant pays attention to the environment that is when learning occurs.
Self-Regulatory:
This state consists of true homeostasis and organization. The infant is now able to do things on their own. This is often seen after leaving the NICU. However, it is important to detail how self-regulation presents and why it is important. Emphasize to parents that the infant is now able to do things on their own. Additionally, it is important to continue to support the relationship between the infant and parents as recovery extends far beyond graduating from the NICU.
Learning about neuro and physiology of swallowing can be a lot to digest! Stay tuned for our next post on our next tiptoe to the NICU post where we tackle neonatal feeding interventions, when to refer to feeding therapy, infant driven feeding, and compensatory strategies.
If you have not yet had the opportunity, be sure to check out our first installment in the Tiptoe Through the NICU Series, Common NICU Terminology and Typical Vital Signs.
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