Optimize Infant Oral Feeding Outcomes with Zero-ResistanceTM Bottle System
A report on the difference between typical disposable feeding systems and Dr. Brown’s® vacuum-free, controlled-flow bottle system. Dr. Brown’s® bottle system with internal vent eliminates all sub-atmospheric pressure in the bottle during feeding.
In this research project, the Dr. Brown’s® Zero-ResistanceTM bottle system consistently measured no sub- atmospheric pressure. Widely-used bottle systems (Volufeed vessel and disposable nipples) in the hospital setting were tested indicating the existence of sub-atmospheric pressure during a 60-cc formula extraction using a breast pump.
As studies by Lau (2000) and Fucile (2009) have speculated, the presence of sub-atmospheric pressure in a bottle system may have negative effects on an infant’s feeding, which according to this report may validate that an infant will expend more energy making the feeding experience less efficient.
More testing will be required to evaluate an actual infant feeding vs. breast pump which was used for this research.
Figure 1. The chart above shows the calculations as mmHg pressure (sub-atmospheric) within the bottle type / nipple combination used. Dr. Brown’s® bottles were measured using the internal vent system. All disposable nipples were tested attached to a Volufeed as typical for a feeding tool in a NICU.
Figure 2. The chart above illustrates the average mmHg pressure (sub-atmospheric) within the bottle type /nipple by brand.
Questions answered by Lisa Kleinz, MA, SLP/L, CLC, CNT, Director of Education /Account Manager
Dr. Brown’s® Medical, a Division of Handi-Craft Company
1.Dr. Brown’s® bottle system with internal vent eliminates all sub-atmospheric pressure in the bottle during feeding. – what does this mean exactly and how does it do this? What is happening with other bottles without a vent system?
As you may know, when a typical bottle is assembled, and the collar is tightened, as the infant begins to suck, there is subatmospheric pressure that is created. This is because as liquid volume decreases, air volume increases. Due to Bernouli’s law, Volume and pressure are inversely related. So…..if air volume increases, pressure decreases, or in this case becomes negative, which is subatmospheric. This is the physics of bottle feeding which many feeders do not realize. This is also affected by how tight the collar is on. Nurses know this because they will release the collar a little when the flow seems too slow. Because of our internal venting system, there is a release of the pressure inside the bottle so this subatmospheric pressure does not occur. The venting system allows the bottle to remain positive or atmospheric pressure. We tested this and our white paper validates these values.
2. Presence of sub-atmospheric pressure in a bottle system may have negative effects on an infant’s feeding, which according to this report may validate that an infant will expend more energy making the feeding experience less efficient. Why exactly does an infant expend more energy with the volufeeders?
This effect of vacuum free is significant due to previous findings from Fucile and Lau. See articles attached. They found that with standard bottles, in order for the infants to overcome the resistance caused by negative pressures, the infants have to suck harder/ work harder. Their study found that these infants with a vacuum free bottle demonstrated greater overall transfer and rate of milk transfer, and more mature sucking stages. They speculated that oral feeding performance improves without significant change in sucking effort with vacuum free.
Interestingly, when we also tested other commercial ‘vented’ bottles (many have vents at the bottom, in the nipples etc as you know), there is still this development of negative pressure. Vented does not equal vacuum-free!
I hope this helps. I feel strongly that health care professionals and parents should more fully understand the physics of bottle feeding, especially in the fragile feeder population. Why are we creating an environment where premature and sick infants have to work harder to withdraw liquid (by using standard bottles)?
Original info for clearer picture of charts here: Dr. Brown’s Zero Resistance Bottle System Report 7.24.18_
Fucile S, Gisel E, Schanler RJ, Lau C. A controlled-flow vacuum-free bottle system enhances preterm infants’ nutritive sucking skills. Dysphagia 2009; 24:145-151.
Lau C, Schanler RJ. Oral feeding in premature infants: advantage of a self-paced milk flow. Acta Paediatrica 2000; 89: 453-9.Detailed Methodology is available upon request: firstname.lastname@example.org