WRITTEN BY: Claire K. Miller, Ph.D., CCC-SLP

Problems with oral feeding occur in varying degrees in infants born with cleft lip/palate and/or craniofacial syndromes. The extent of clefting is associated with the severity of feeding problems, and if cleft lip/palate occurs in conjunction with a craniofacial syndrome, additional structural, airway, and neuromotor issues may be present. The infant’s feeding and swallowing skills may be significantly impaired, characterized by inefficient oral feeding skills coupled with poor airway protection ability during swallowing. Inadequate airway protection during swallowing has serious implications for the infant’s respiratory health as sequelae of chronic aspiration during feeding may include recurrent respiratory illness, pneumonia, and lung damage. Feeding difficulty in nonsyndromic and syndromic cleft lip/palate infants has been documented as source of considerable stress for parents and can have a potential negative effect on the parent-infant bonding process. Therefore, timely identification of feeding problems by the speech pathologist with subsequent intervention and modification in the feeding method is essential, along with provision of early feeding instruction to families. The objective of this article is to review expert opinion and available evidence regarding factors that influence feeding success and efficiency in infants with nonsyndromic and syndromic cleft lip/palate. The types of compensatory strategies or interventions that are effective in alleviation of feeding and swallowing difficulties will be described. Descriptive reports, expert opinion, and available evidence from clinical trials to support the use of feeding interventions in treatment are reviewed.

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WRITTEN BY: N. Bertoncelli, G. Cuomo, S. Cattani, C. Mazzi, M. Pugliese, E. Coccolini, P. Zagni, B. Mordini, and F. Ferrari

Background.

With increasing sophistication and technology, survival rates hugely improved among preterm infants admitted to the neonatal intensive care unit. Nutrition and feeding remain a challenge and preterm infants are at high risk of encountering oral feeding difficulties.

Objective.

To determine what facts may impact on oral feeding readiness and competence and which kind of interventions should enhance oral feeding performance in preterm infants.

Search Strategy.

MEDILINE database was explored and articles relevant to this topic were collected starting from 2009 up to 2011.

Main Results.

Increasingly robust alertness prior to and during feeding does positively impact the infant’s feeding Skills. The review found that oral and non-oral sensorimotor interventions, provided singly or in combination, shortened the transition time to independent oral feeding in preterm infants and that preterm infants who received a combined oral and sensorimotor intervention demonstrated more advanced nutritive sucking, suck-swallow and swallow-respiration coordination than those who received an oral or sensorimotor intervention singly.

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WRITTEN BY: Sandra Fucile • Erika Gisel • Richard J. Schanler • Chantal Lau

We have shown that a controlled-flow vacuum-free bottle system (CFVFB) vs. a standard bottle (SB) facilitates overall transfer and rate of milk transfer, and shortens oral feeding duration in very-low-birth-weight (VLBW) infants. We aimed to understand the basis by which this occurs. Thirty infants (19 males; 27 ± 1 weeks gestation) were randomized to a CFVFB or SB. Outcomes monitored at 1–2 and 6–8 oral feedings/day when infants were around 34 and 36 weeks postmenstrual age, respectively, included: overall transfer (% volume taken/volume prescribed), rate of milk transfer (ml/min), sucking stage, frequency of suction (#S/s) and expression (#E/s), suction amplitude (mmHg), and sucking burst duration (s). At both periods we confirmed that infants using a CFVFB vs. SB demonstrated greater overall transfer and rate of milk transfer, along with more mature sucking stages. Suction and expression frequencies were decreased with CFVFB vs. SB at 1–2 oral feeding/day; only that of suction was reduced at 6–8 oral feedings/day. No group differences in suction amplitude and burst duration were observed. We speculate that oral feeding performance improves without significant change in sucking effort with a CFVFB vs. SB. In addition, we have shown that VLBW infants can tolerate faster milk flow than currently presumed. Finally, the use of a CFVFB may reduce energy expenditure as it enhances feeding performance without increasing sucking effort.

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WRITTEN BY: Lau C, Schanler RJ.

An earlier study demonstrated that oral feeding of premature infants (<30 wk gestation) was enhanced when milk was delivered through a self-paced flow system. The aims of this study were to identify the principle(s) by which this occurred and to develop a practical method to implement the self-paced system in neonatal nurseries. Feeding performance, measured by overall transfer, duration of oral feedings, efficiency, and percentage of successful feedings, was assessed at three time periods, when infants were taking 1–2, 3–5, and 6–8 oral feedings/day. At each time period, infants were fed, sequentially and in a random order, with a self-paced system, a standard bottle, and a test bottle, the shape of which allowed the elimination of the internal hydrostatic pressure. In a second study, infants were similarly fed with the self-paced system and a vacuum-free bottle which eliminated both hydrostatic pressure and vacuum within the bottle. The duration of oral feedings, efficiency, and percentage of successful feedings were improved with the self-paced system as compared to the standard and test bottles. The results were similar in the comparison between the self-paced system and the vacuum-free bottle. Elimination of the vacuum build-up naturally occurring in bottles enhances the feeding performance of infants born <30 wk gestation as they are transitioned from tube to oral feeding. The vacuum-free bottle is a tool which caretakers can readily use in neonatal nurseries. Click here to download the report

WRITTEN BY: Consumer Analysis Ltd.

In this 2010 UK study, 253 health professionals who work closely with new babies and moms were interviewed in depth about colic causes and treatments. 78% of health professionals agreed that the most common causes of colic in babies is digestive or feeding problems, including swallowing air. Using Dr. Brown’s® fully-vented bottles was cited as a key solution.

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WRITTEN BY: Dr. Brown’s®

This web site highlights the findings of a research study, later published in International Breastfeeding Journal, that compares the nutrient levels in breastmilk or formula in various baby bottles. Titled “Comparative Analysis of Retinol, Ascorbic Acid, and Alpha-Tocopherol in Baby Milk Using Varied Delivery Systems,” the study was designed to investigate changes in nutrient levels that might occur during a typical bottle feeding time of 20 minutes, using both expressed human milk and infant formula, in both vented bottles and unvented bottles. The study looked at the amount of nutrients in the milk when delivered through seven commonly used baby bottles, including Dr. Brown’s® – which fared the best at preserving key nutrients.

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WRITTEN BY: Meghann Rose OTR/L

Not every bottle/teat works for every baby but making frequent changes of feeding method is not helpful either. This was the premise for our bottle trial. By identifying bottles/teats that would work best in specific situations and modeling the practice of using a consistent feeding plan, we hoped to change the feeding practices in our unit and improve feeding outcomes. In 2007, the Feeding Team (Occupational and Speech Therapy) and nurses in the NICU at Golisano Children’s Hospital at Strong decided to conduct a bottle/teat trial. Goals of the trial included: (1) to decrease in the over-use of specialty bottles for mild feeding issues, (2) to find teat choices that provided more consistent feeding experiences, and (3) to provide an opportunity to educate staff on how teat choices can affect infant feeding skills. Through collaboration on this clinical trial, the occupational and speech therapists also hoped to educate the NICU nurses about the role of the Feeding Team.

Procedure

At the initiation of the trial the NICU stocked the teats primarily Abbott teats and a couple cleft palate babies. The first stage of the trial was to identify the bottle/teats to be used. The Occupational Therapist researched varieties of bottles and teats and set up a vendor fair where nurses and therapists were encouraged to meet with vendors, trial bottles in the clinic setting, and provide feedback on each feeding system The bottle/teats that were selected for the trial were Evenflo Comfi, Dr Brown, Bionix, Second Nature and Enfamil.

The next stage of the trial was the formation of a group of NICU Nurses to assist the therapists with trialing the selected bottles/teats and getting feedback. These nurses were educated on the features of each teat, the possible benefits of each teat and the process for entering an infant in the trial.

The third stage of the trial was to assess bottles/teats in a trial using nurses’ feedback. Nurses who cared for infants in the trial were encouraged to provide feedback on how the bottle worked and whether it was better than what was currently used in the NICU. At approximately 24 hours into the trial, the Occupational Therapist followed up with parents and nurses of the entered infants to answer questions and get verbal feedback. All of this data was then entered into a spread sheet and analyzed for trends.

Results

Bionix Controlled Flow Baby Feeder bottles are a complex institutionally available feeding system that adjusts flow from 0 to 5. None of the infants who used the bottle were receptive to the teat with tube through the center. This feeding system has multiple pieces to wash and reassemble, as well as the least accessible for families to purchase.

Dr Brown Bottles are a commercially available bottle advertised for use with infants with gas or reflux. The level 1 (slow flow) teat, with a consistent slow flow and minimal free dripping, was easier for some preemies to handle compared to the other teat choices. Dr Brown teats/ bottles are silicone and more similar to the pacifiers used for the NICU infants. Staff were pleased with the fact the bottle/teats were easily accessible in many local stores and that the teats come in levels preemie to level four.

An unanticipated result in using the Dr Brown system was a better ability to independently pace infants who gulped and fed very quickly. This resulted in a more reasonably timed and less stressful feeding for the infant.

Some concerns about the Dr Brown bottle/teat centered on measuring the amount consumed, the size/shape of the wide-mouth bottle and number of pieces in the system. Since this feeding system lacks the ability to measure amounts less than 1 ounce, providing and measuring small volumes was difficult. Because the Dr Brown bottle is made of 4 pieces cleaning and reassembly before and after each feeding is more labor-intensive.

Mead-Johnson teats are a complementary product with formula purchase for our institution but are not available in most local stores. Mead-Johnson teats were found to be similar to the Abbott teats that were previously being used. Both of these teats did not have consistent flow and both dripped spontaneously. The crosscut teat was found to be useful when an infant is receiving formula with multiple additives or thickener.

Evenflo Comfi Teats are commercially available and are in many local stores.
The trial results showed that these teats were most appropriately used with infants with a poor seal and leakage as well as those who need a no drip teat because of long rest breaks. However, some staff identified that lack of drip can be a problem for some infants. Since there is no drip to remind infants to continue/initiate suck, they must work to keep formula flowing. Evenflo teats are silicone, a familiar material to NICU infants who use silicone pacifiers. Parents appreciated that these teats can be used on most bottles.

Haberman Feeder is a commercially available bottle that can be rotated to adjust the flow or squeezed to facilitate the feeding. Both staff and parents found the assembly challenging and frustrating because of the number of pieces. Although commercially available, the system may not be easily accessible in stores and is more expensive compared to other bottles.

Mead Johnson Cleft Feeder is a bottle/teat system manufactured for infants with craniofacial abnormalities. This system has either a long thin teat or a long flat teat and a soft plastic bottle that can be squeezed to facilitate flow during feeding. At times nursing staff found this bottle hard to squeeze and recommended that parents practice with it prior to using it with their infant. This is a less expensive option than the Haberman and has fewer pieces so that assembly and care are easier.

Pigeon is an institutionally available bottle that is designed for infants with cleft palates. The trial found that it was most appropriately used on infants with a neurological impairment who need increased stimulation. The large, soft, non-drip teat provides stimulation to the roof of the mouth while the soft underside makes it easy for infants to create milk transfer. The multiple pieces that need to be washed and reassembled made it less favorable for staff. Both nurses and parents were concerned about the lack of accessibility in local stores and that the bottles came with Japanese instructions rather than English

Second Nature is manufactured for breastfed infants because the way it releases milk is similar to the human breast. The teat head is flat with multiple holes to release milk more naturally. None of the infants who trialed it were receptive to its shape, therefore Second Nature was not found to be a useful bottle in our setting

Abbott teats are complementary with formula purchase for our institution and are not available in local stores. Abbott standard teats are equal to the Mead-Johnson standard teats. Abbott teats have inconsistent flow between teats and they tend to drip/free-flow when infants stop sucking. Both the preemie and Special Care teats were found to have too-fast a flow for most infants in the trial. Their NUK/orthodontic teat worked well for some infants who exhibit limited cupping of the tongue during sucking and those who required more stimulation to the roof of the mouth.  However because the Abbott NUK/orthodontic teats are not shaped the same as the commercially available NUK teats the transition to home was difficult.

Summary

Based on the results of the trial, the unit decided to purchase a supply of Dr. Brown and Evenflo teats which would be kept in a restricted area for distribution by the Feeding Team. It was recommended that in addition to keeping the new bottles restricted that the Haberman and Pigeon bottles also be pulled from the supply room and only be accessible through the Feeding Team. The Mead Johnson Cleft Palate Feeder remained in the supply room to be used for those infants with cleft palates without a feeding consult.

Follow up

Two years after the trial was completed, the Feeding Team reviewed the results and the current status in the NICU. The Bottle Resource Group was no longer active in the unit but some members continue to consult as resources regarding feeding. In addition the Feeding Team noted that they were still receiving more referrals than prior to the trial and that staff consulted the feeding team to problem solve when making feeding choices. Dr. Brown is the most commonly used specialty bottle and the use of the Haberman bottle has dropped off significantly.

During this time the unit completed a second trial to look specifically at the Enfamil slow flow teats. It was found that these were a better match for many of our preemies who were learning to feed orally and the decision was made to make these available to staff in the supply room. A series of educational emails and posters was created to facilitate the appropriate use of slow flow teats and consistency when feeding.

Acknowledgement: The author wishes to thank the following people who made this project possible: Katherine Maruska, Speech Language Pathologist, Chris Tryon, Child Life Specialist, Kevin Smith, NICU Nurse Manager, Paula Emrich RNC and the NICU nurses of the Bottle Resource Team. A special thank you to the vendors and the families who participated in the bottle trial. This study would not have been possible or successful without everyone’s help

Selected Reading:

1. Chang YJ, Lin CP, Lin YJ, Lin CH: Effects of single-hole and cross-cut teat units on feeding efficiency and physiologic parameters in premature infants J Nurs Res2007; 15:215.
2. Fadavi S, Punwani IC, Jain L, Vidyasagar D: Mechanics and energetic of nutritive sucking: A functional comparison of commercially available teats J Pediatr1997; 130:740.
3. Fucile S, Gisel E, Schanler RJ, Lau C: A controlled-flow vacuum-free bottle system enhances preterm infants’ nutritive sucking skills Dysphagia2009; 24: 145.
4. Mathew OP, Belan M, Thoppil CK:Sucking patterns of neoantes during bottle feeding: Comparison of different teat units Am J Perinatol1992; 9:265.
5. Mathew OP: Determinants of milk flow through teat units: Role of hole size and teat thickness Am J Dis Child1990; 144:222.
6. Mathew OP: Teat uits for newborn infants: A functional comparison Pediatrics 1988; 81:688.
7. Scheel CE, Schanler RJ, Lau C: Does the choice of bottle teat affect the oral feeding performance of very-low-birthweight (VLBW) infants? Acta Paediatr 2005; 94:1266.
8. Walden E, Pendergast J: Comparison of flow rates of holes versus cross-cut teats for bottle-fed babies Prof Care Mother Child2000; 10: 7.

About the Author:

Meghann Rose, a graduae of Keuka College, is a practicing pediatric Occupational Therapist at Strong memorial Hospital-Galisano Children’s Hospital in Rochester, NY. She works primarily in the NICU where she specializes in feeding, development, splinting, and brachial plexus injuries. Meghann is also a member of the NICU developmental care committee, the brachial plexus clinic and acts as a feeding consultant to the pediatric GI clinic. Meghann is also a loving wife and mother of her 2 children.

Published with permission from author, Meghann Rose, OTR/L

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WRITTEN BY: Lee Ann Damian, MA, CCC-SLP and Kaitlyn Johnson, MA-CCC-SLP

Due to the FDA recommendations that were stated in late 2012 regarding the use of commercial thickeners (primarily Simply Thick) in infants; we were forced to re-think and re-assess our current practice of thickening infant’s liquids for improvement of swallow function based on these recommendations. As a result, use of slow flow teats became popular to decrease flow rate with the hope of improving swallow function. It soon became apparent that “slow flow” was not consistent especially according to commercial packaging. This conclusion brought us to repeat and expand on the research of Kelly Jackman, MPT who published research on teat flow rates in 2013 in the Newborn and Infant Nursing Reviews 13 (2013) 31-34. We chose to repeat the study with some minor adaptations to determine if there was consistency of correlation between methods. This information will provide an evidence based practice approach to teat selection for slowing of rate to facilitate safe and efficient feeding. The information gained from the study was used to educate therapists, medical staff, nursing, and parents to aide in appropriate teat selection based on flow rate and what is commercially available.

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WRITTEN BY: Erin Ross

Infants who have feeding difficulties often struggle with coordinating sucking, swallowing, and breathing, and have difficulty eating sufficient quantities for adequate growth. Speech- language pathologists (SLPs) need advanced expertise across a number of areas (e.g., development, medical, swallowing) to work effectively with these young infants, and they use a variety of strategies when treating this population. Therapists working with infants who have feeding difficulties use bottles as a primary therapy tool; how the infant tolerates the flow rate from the bottle/teat is a major consideration. Caregivers must understand the influence of bottle/teat flow rates on eating skills, so they can support the emerging oral skill development for these fragile infants, and help parents decide what bottle system to use in their home. Both infant and equipment factors influence bottle/teat flow rates. This article discusses the influencing factors that need to be considered when determining the optimal flow rate for an individual infant.

Many infants struggle with eating skills in the first months of life, and some require speech-language pathologists (SLPs) to help them transition through early feeding milestones (Levine et al., 2011; Motion, Northstone, & Emond, 2001). Many of these infants begin life in the Neonatal Intensive Care Unit (NICU; Ross & Browne, 2013). The American Speech-Language and Hearing Association (ASHA) Practice Guidelines emphasize the advanced expertise necessary to provide appropriate support to infants in the NICU, with feeding being a primary area of focus (ASHA, 2004). The National Association of Neonatal Nurses (NANN) also recognizes that infants in the NICU need carefully thought-out bedside strategies to learn to eat safely (Sables-Baus et al., 2013). Preterm infants are often developing sucking/swallowing and breathing coordination, as well as integrating the sucking components of suction and expression (Gewolb & Vice, 2006b; Lau, Alagugurusamy, Schanler, Smith, & Shulman, 2000; Medoff-Cooper, 2005; Mizuno & Ueda, 2003). Medically complex infants often have difficulty with integrating breathing into the sucking burst, maintaining physiologic stability, and eating sufficient quantities to discharge home fully orally fed (Gewolb & Vice, 2006a; Jadcherla, Vijayapal, & Leuthner, 2009; Jadcherla, Wang, Vijayapal, & Leuthner, 2010; Sables-Baus, Kaufman, Cook, & da Cruz, 2012). The SLP needs to (a) understand normal development and the influence of medical comorbidities; (b) adjust expectations accordingly, and (c) be able to support the acquisition of feeding skills.

Feeding is a neurobehavioral skill, and the experiences in the NICU set the stage for future skill development that continues past discharge (Browne & Ross, 2011). Critical reviews of feeding outcomes at and post-discharge reveal that feeding remains a major focus of parents, and many infants continue to struggle with skill development (Ross & Browne, 2013; Thoyre, 2007). While volume is one measure of success, research suggests feedings that are focused on enjoyable experiences characterized by physiologic stability and motor organization (including coordination of sucking, swallowing, and breathing) may improve outcomes post-discharge (Horner et al., 2014). Feeding is increasingly viewed as a co-regulated process; one in which the decisions of the feeder can significantly improve both the experience and the longer-term feeding outcomes (Horner et al., 2014; Ross & Browne, 2002, 2013; Ross & Philbin, 2011; Shaker, 2010; Thoyre, Holditch-Davis, Schwartz, Melendez Roman, & Nix, 2012).

The NANN Oral Feeding Guidelines emphasize that bedside caregivers in the NICU need to focus on supporting breastfeeding and physiologic stability, and on providing an environment that helps the infant not only eat appropriate volumes, but also to enjoy the feeding experience (Sables-Baus et al., 2013). Research suggests that infants are more physiologically stable when they breastfeed than when they bottle feed (Dowling, 1999; Segami, Mizuno, Taki, & Itabashi, 2013). Infants breathe more frequently during sucking bursts, and have fewer episodes of oxygen desaturations when they breast feed compared to when these same infants bottle feed (Dowling, 1999; Goldfield, Richardson, Lee, & Margetts, 2006). However, in a cohort from the United States, only 52% of infants were ever breastfed during the initial hospitalisation (Pineda, 2011). Therefore, it is reasonable to assume that most infants in the NICU will be offered at least one bottle feeding, and many are discharged home with either a combination of breast and bottle feedings, or solely bottle feeding.

Infant feeding and dysphagia are both complex topics, requiring the SLP to have a high level of experience and expertise. Infants may be expected to eat when, either developmentally or because of medical instability, they lack the ability t o coordinate sucking, swallowing, and breathing. Therapists often consider diet modifications (e.g., thickeners) when attempting to improve swallowing function. However, there are many other interventions that can improve the coordination of a suck/ swallow/breathe sequence and support safe swallowing that do not include dietary modifications. This article focuses only on flow rate as one intervention to support suck/swallow and breathe coordination. Feeding is a neurobehavioral skill that relies heavily on maturation, and therefore bottle and teat selection should not be a substitute for a thoughtful caregiver who understands infant behaviors, and who is competent at determining whether an infant is both stable and mature enough for oral feeding (Browne & Ross, 2011; Ross & Philbin, 2011; Shaker, 2013). The reader is reminded that quality feedings emphasize recognizing and responding to the ongoing communication of the infant, and on providing interventions if needed that focus on stability in the physiologic, motor, and behavioral state systems while facilitating appropriate volume (Browne & Ross, 2011; Shaker, 2013). Infant-driven feeding guidelines are replacing volume-driven feedings as the standard (Alberta Health Services, 2004; Sables-Baus et al., 2013; Shaker, 2010).

This article will delve into the role of the bottle and synthetic teat selection as one way to support infant stability while eating. For ease of discussion, the term “ teat ” will refer to synthetic bottle teats. This review will not address factors su ch as developmentally appropriate expectations, positioning considerations, or other interventio ns often implemented in the NICU. Bottle design and flow rates have been shown to influence sucking parameters and physiological stability (Chang, Lin, Lin, & Lin, 2007; Eishima, 1991; Goldfield et al., 2006; Lau & Schanler, 2000; Mathew, 1990; Mathew, 1988, 1991; Segami et al., 2013). Healthy, term infants are often competent at adjusting their sucking patterns to maintain their physiologic stability and eat safely when flow rates are altered (Eishima, 1991). Preterm and/or medically complex infants are not as competent, and need bottle flow rate to be matched carefully to their emerging capabilities.

The bedside caregiver generally determines what flow rate is best for each individual infant which is not a simple task. Recently, there was a published study that attempted to shed light on the flow rates of twenty-five single-use teats and commercially available teats and bottle systems (Jackman, 2013). The author used a breast pump with a standard suction rate for one minute, and measured flow rate three times for each system tested. Results indicated a wide variation of flow rates within flow rate distinctions (slow, fast) and within trials using the same teat/bottle system (tests 1, 2, and 3.) Additionally, when single-use teats of the same brand were tested, there was variability in flow rates. The author concluded that the results could be used by the caregiver to determine the best bottles for the infant both within the hospital setting and for discharge to home, despite presenting data indicating a wide variability in results (Jackman, 2013).

One reason that there was so much variability in the results of this study could be that there are multiple equipment factors that contribute to flow rate not just the size of the teat hole. When breast pumps are used to determine flow rate, they primarily use suction to assess only one factor known to influence flow rate: the size of the teat hole. There are several infant factors (e.g., the strength of their suck), as well as a number of additional teat and bottle factors that must also be considered. The following information describes the influence of both infant and bottle/teat characteristics on flow rate, in an attempt to expand the understanding of which bottle system and/or teat might be best for an individual infant.

Infant Factors

Caregivers must have a clear understanding of the developmental nature of feeding skill acquisition, and the influence of both compression and suction on flow rate. Both positive pressure (compression) and negative pressure (suction) are used when a healthy infant sucks fluid from a bottle (Medoff-Cooper, 2005). In development, the compression component of sucking develops prior to the acquisition and integration of suction (Lau, Alagugurusamy, et al., 2000). Volume transfer increases significantly with the acquisition and integration of suction (Lau, Alagugurusamy, et al., 2000; Medoff Cooper, Bilker, & Kaplan, 2001; Mizuno & Ueda, 2003). Therefore, when determining the best flow rate for an infant, one must consider the infant’s ability to engage both compression and suction. A second infant factor that needs to be considered is the ability of the infant to alter their use of suction in response to flow rates. This was initially shown in a study in 1991 (Eishima, 1991), and has since been further validated in the preterm population by Chang and colleagues (2007). Neither compression nor an infant’s ability to adjust their sucking to engage or disengage suction are considered when a breast pump is used to determine flow rates from bottle systems and/or teats.

Given the relationship between flow rate and infant characteristics, the caregiver must first determine whether the infant has developed suction. Infants who do not have suction (e.g., infants with craniofacial disorders or some infants with neur ologic disorders) need specialized bottle systems that maximize volume transfer with compressio n alone (Craig, Grealy, & Lee, 2000; Mizuno et al., 2006; Mizuno & Ueda, 2005). The Medela Special Needs Feeder, the Pidgeon Cleft Palate system, and the Mead Johnson Cleft Palate Nurser are examples of these specialized systems.

If an infant has the ability to use suction, bottle systems need to maximize volume transfer while at the same time supporting good suck/swallow and breathe coordination. Infants who have developed suction will purposefully disengage suction if the flow rate is too fast; the result is a decrease in volume transfer (Eishima, 1991). With good suction, the tongue amplitude during sucking is higher, the lateral edges of the tongue wrap around the teat, and the buccal pads stabilize the teat and help to seal off the oral cavity. In the study by Eishima (1991), infants who demonstrated good suction with a pacifier and a small-sized teat hole changed the position and the movement patterns of their tongue when offered a teat with a large hole and faster flow rate. With the faster flow, these infants disengaged suction, the tongue flattened, and the cheeks loosened, allowing the fluid to flow anteriorly past the lip border. In a study by Chang et al. (2007) infants took more fluid (57.5+/-8.3 ml vs. 51.6+/-9.5 ml, p=.011), had a shorter feeding time per meal (11.5+/-4.9 min vs. 20.9+/-5.0 min, p<.001), and sucked more efficiently (5.8+/-2.5 ml/min vs. 2.7+/-1.0 ml/min, p<.001) when given a teat that supported their use of suction, compared to when they ate with a fast flow teat. Without an understanding of whether the infant has integrated suction, caregivers may erroneously speed the flow rate when an infant is inefficient, rather than slowing the flow to encourage the infant to use suction. Across the 32 to 36 weeks gestation ages, infants increase by a factor of five the use of negative sucking pressure, with a resulting increase of tenfold in the amount of volume transferred (Mizuno & Ueda, 2003). Caregivers must begin their assessment of which bottle to offer based upon the infant; otherwise, the infant may change their oral motor patterns and negate any desired volume goal.

Equipment Factors

There are multiple bottle engineering factors that contribute to flow rates, and that combine with the infant factors to individualize each feeding opportunity. No single factor determines the flow rate. In general, equipment factors include (a) hole size; (b) pliability of the teat; (c) shape of the teat; (d) position of the fluid relative to the teat hole, and (e) air exchange within the bottle.

Hole Size
The size of the hole has been tested as a factor in infant feeding, and is often described as “ flow rate ” (Jackman, 2013). Larger hole sizes do provide larger volumes when all other factors are held constant; however, bottle systems with similar sized teat holes may have very different flow rates due to both the infant factors previously described, and the factors such as pliability and vacuum exchange, described below.

Pliability (Material)
Pliability of the teat is not assessed when a breast pump is used to determine flow rate; breast pumps assess flow rate via suction. Since infants use both suction and compression, the pliability of the teat is a factor that must be considered when assessing flow rate. Softer teats are easier to compress (using jaw and tongue movements), maximizing the influence of positive pressure. Firmer teats, by contrast, are less pliable and therefore require more pressure to compress. Commercially available teats are often made of silicone — which is more durable and often firmer than the latex-free plastic that is used for most single-use teats. Therefore, depending on the combined influence of both compression and pliability, the same teat/system will have different flow rates for different infants.

Shape and Size
Teats come in various shapes — orthodontic teats and the more traditional shaped teat. Teats may also have different “ lengths ” ; shorter ones allow the teat to sit further forward in the oral cavity, whereas longer ones position the teat further posterior. The majority of force used for compression originates from the back half of the tongue (Eishima, 1991). Additionally, teats have varying diameters near the teat collar. Suction is a negative pressure, which is created when the entire teat is encased by the tongue, palates, and cheeks of the infant (Eishima, 1991). The width of the teat near the collar alters the angle of the chin during feeding, and may also change the pressures used (Segami et al., 2013). Therefore, the shape of the teat influences how the oral structures engage. The wider collar on the teat may engage the masseter muscles more, similar to what is seen during breastfeeding (Gomes, Da Costa Gois, Oliveira, Thomson, & Cardoso, 2013; Segami et al., 2013). Since the width and diameter of the teat collar are influencing factors in how infants suck, they likely also influence flow rate.

Hydrostatic Pressure in the Bottle
Hydrostatic pressure is a force seen within typical bottles, and studies by Lau and colleagues have shown that it can be eliminated when the fluid of the bottle is kept at the level of the infant’s mouth during feedings (Lau & Schanler, 2000; Lau, Sheena, Shulman, & Schanler, 1997). Hydrostatic pressure “ pushes ” fluid out of the bottle when the fluid is elevated above the teat. This is the reason fluid drips out of the teat when the bottle is tipped upside-down, and does not drip when the bottle is laid on its side. By eliminating this pressure, infants have more control over the flow rate, as fluid does not come from the teat unless the infant is actively sucking. Infants eating from a “ self-paced ” bottle system (e.g., once that does not flow unless the infant is actively sucking) are more coordinated; this factor has been studied in some detail by Lau and colleagues (Lau & Schanler, 2000; Lau et al., 1997).

Air Exchange
An often lost factor in clinical bedside assessment is the influence of air exchange. There is a gradual build-up of negative pressure (vacuum) within bottles that must be relieved to avoid a decrease in flow rate. This factor was also described in the studies by Lau and colleagues (Lau & Schanler, 2000; Lau et al., 1997). This is perhaps the biggest uncontrolled factor at the bedside. Many bottle systems exchange air around the collar of the bottle — between the collar and teat itself. However, many commercially available bottles now use complicated systems to influence this negative pressure build-up. Some use internal venting systems; others have one-way venting systems or fairly large vents within the teat itself. This factor does not influence bottles that use collapsible “ bag ” inserts (e.g., Kiindie, Playtex Drop-Ins), as there is no vacuum build-up with these collapsible systems. Rather, the suction draws the bag inward. For all of the other systems, the more air exchange that occurs, the faster the flow rate from the bottle. There are some bottle systems (e.g., the Controlled Flow Baby Feeder by Bionix Medical Technologies) that alter the flow rate through an increase or decrease in air exchange.

Since air exchange typically happens around the teat collar, tightening the collar will decrease air exchange and, as a consequence, decrease flow rate; loosening the collar will increase flow. This may account for some of the variability seen in the Jackman study (2013), when the single-use teats demonstrated variable flow rates even when the same teat and/or three teats from the same manufacturer were used. In research studies focused on sucking development, air exchange is carefully controlled.

Conclusion

Since there are always new bottles being created, understanding the basics of bottles and/or teats is important to support emerging skills in the infant, and to assist caregivers in choosing a bottle for home use. However, comprehensive clinical research addressing how the bedside caregiver can both assess and provide appropriate bottle/teats to support quality feedings is scarce. While the Jackman study adds to the information available to the bedside clinician, there are a number of additional factors that need to be considered. Clearly, more research is necessary to guide evidence-based practice for clinical use. Many of the references cited herein provide research- based information that can be used by the clinician to understand the complex interaction between both bottle/teat factors and infant factors. However, the information is focused on assessment of oral feeding, rather than on assisting the caregiver in choosing specific flow rates to support infants in a clinical setting. A recent comprehensive review of available instrumental assessments for infant sucking development is also focused on evaluation, not treatment (Tamilia, Taffoni, et al., 2014). Researchers are also designing sophisticated equipment to measure nutritive sucking abilities in the infant (Cavaiola et al., 2014; Tamilia, Delafield, Fiore, & Taffoni, 2014). Using the available evidence, this review has focused attention on the need for this research. Additionally, this review has attempted to provide guidance for the bedside caregiver, focused on individualizing choices of bottle/teats to meet the needs of the infant. While the therapist may be limited in their choices of synthetic teats in the hospital, both hydrostatic pressure and vacuum effects may be manipulated to slow, or speed, the flow. Positioning the infant so that the bottle is horizontal to the mouth of the infant will mitigate the influence of hydrostatic pressure. Tightening the teat will slow the flow; loosening will increase the flow rate. When options are available, therapists may pick a teat that is more firm or that has a small hole to slow the flow.

Caregivers must understand how to pick bottles/teats based upon both infant and bottle factors — as many infants in the NICU setting lack the ability to easily adjust their sucking patterns to slow the flow and may be at risk for aspiration with larger bolus amounts. Every evaluation needs to begin with understanding the capabilities of the infant, and adjustments to the equipment should be based upon the behaviors of the infant. Additionally, feedings should focus on skill development and enjoyment, which naturally lead to improved volume intake. Focusing solely on increasing the volume taken during a feeding without also focusing on skill and enjoyment may lead to infants learning that eating is uncomfortable — which may be one reason why feedings often continue to be challenging after discharge.

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WRITTEN BY: Britt F. Pados, Jinhee Park, Suzanne M. Thoyre, Hayley Estrem, and W. Brant Nix

Feeding can be physiologically challenging for pre-mature and medically fragile infants who are learning to feed orally. Whereas breastfeeding may be the ultimate goal, most infants who are hospitalised will receive some bottle-feedings. Many variables contribute to an infant’s ability to bottle-feed safely and effectively, but one easily manipulated variable is the rate of milk flow from the bottle teat. Milk flow is defined as the rate of transfer of milk from the bottle into the mouth during sucking. The rate of milk flow can affect an infant’s ability to integrate fluid management with respiration, as well as the degree of ventilatory compromise associated with feeding (al-Sayed, Schrank, & Thach, 1994; Mathew, 1991a). When an infant swallows, the airway is closed for about 1 s to prevent aspiration of milk (Mathew, 1991b). As milk flow increases and requires increased swallowing frequency, ventilation is increasingly interrupted and respiratory rate decreases (al-Sayed et al., 1994). When milk flow slows, the swallow is delayed until a critical volume is accumulated (al-Sayed et al., 1994), allowing the infant to breath more frequently and better maintain physiologic stability during feeding.

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