Is the preferred crib mattress a breathable crib mattress or an air permeable crib mattress?
Many crib mattress companies are beginning to market their fiber filled or plastic filled crib mattress as being “breathable.” So what is the definition of breathable? When it comes to fiber and fabrics, the definition of breathable is admitting air to the skin and allowing sweat to evaporate.
The definition of air permeable when it comes to fibers and fabric is the rate of airflow passing perpendicularly through a known area under a prescribed air pressure differential between two surfaces of a material.
Many parents believe a breathable crib mattress is the same as an air permeable crib mattress. There are some similarities between a breathable crib mattress and an air permeable crib mattress; both admit air to the skin and both allow sweat to evaporate. However, the air permeable crib mattress is the only crib mattress that is recognized by medical professionals and safe sleep experts as addressing the risk factors associated with infant sleep related deaths and a breathable crib mattress is not.
AIR PERMEABLE CRIB MATTRESSES AND THE AAP
In fact, the SafeSleep® Breathe-Through Crib Mattress created by Safe Sleep Technologis, (formerly Secure Beginnings) is the only air permeable crib mattress on the market today that is approved and endorsed by leading American Academy of Pediatric (AAP) physicians as addressing the multiple risk factors associated with infant sleep related deaths (SIDS/SUID).
In 2011, Dr. Margie Andreae and her sister – the creator of the first commercially viable air permeable/breathe-through crib mattress – began to challenge the AAP’s Safe Sleep Task Force to include relevant test data proving the SafeSleep® air permeable crib mattress does reduce the many risk factors associated with infant health and safe sleep.
The pair used scientific literature supported rationale for to convince the Task Force to recognize the safety and health benefits of air permeable crib mattresses.
The AAP’s Task Force on Sudden Infant Death Syndrome technical report was originally published online October 17, 2011 in Pediatrics.
Dr Rachel Moon, the Chair of the Task Force, maintains that there was no data to support the use of breathable crib mattresses or air permeable crib mattresses to prevent SIDS/Suffocation at that time.
RELEVANT SCIENTIFIC TEST DATA
Relevant scientific test data shows the air permeable mattress by Safe Sleep Technologies:
- Reduces the risk of CO2 rebreathing compared to a fiberfill mattress,
- Eliminates the use of a crib sheet and potential for entanglement, and
- Reduces Staph aureus colonization by eliminating the fiber fill or plastic core.
CO2 RETENTION AND RISK OF REBREATHING
Prior to the publication of the AAP Task Force report, studies were available that clearly demonstrated that the risk of rebreathing of exhaled air (CO2) was lowest on air permeable crib mattresses and surfaces (Kemp 2000, Bar-Yishay 2011). In addition, Dr. Moon was provided with test data from Intertek, a CPSC accredited and recommended lab, showing significantly low risk hazard of rebreathing of an air permeable crib mattress (lower than the firm fiber fill crib mattress with tight fitting sheet). These data demonstrate that the air permeable crib mattress has significantly lower CO2 retention. All three reports used similar test methods and had similar results.
While the studies do not demonstrate a direct prevention of SIDS or suffocation, they rely on the hypothesis of rebreathing of CO2 as a potential contributor for these unexpected infant deaths. Indeed no studies have substantiated this hypothesis; however, this is the same hypothesis used by the AAP Task Force to support many of their recommendations including the following with quotes taken from the AAP Task Force report.
- Supine sleep position: “The prone or side sleep position can increase the risk of rebreathing expired gases, resulting in hypercapnia and hypoxia.”
- Room-Sharing Without Bed-Sharing Is Recommended: “Bed-sharing might increase the risk of overheating, rebreathing or airway obstruction, head covering, and exposure to tobacco smoke, which are all risk factors for SIDS.”
- It Is Prudent to Provide Separate Sleep Areas and Avoid Cobedding for Twins and Higher-Order Multiples in the Hospital and at Home: “Furthermore, there is increased potential for overheating and rebreathing while cobedding, and size discordance might increase the risk of accidental suffocation.”
- Pillows, Quilts, Comforters, Sheepskins, and Other Soft Surfaces Are Hazardous When Placed Under the Infant or Loose in the Sleep Environment: “However, such soft bedding can increase the potential of suffocation and rebreathing.”
- Avoid Overheating and Head Covering in Infants: “It is not known whether the risk associated with head covering is attributable to overheating, hypoxia, or rebreathing.”
AIR PERMEABLE SIDES IN BASSINETS
In addition, the Task Force recommends air permeable sides when bassinets are used. This recommendation is based on a retrospective review and analysis of infant deaths occurring in bassinets between June 1990 and November 2004 that were reported to the CPSC (Pike/Moon 2008). The authors identified at least six infants who were found with their “face wedged against the side of the bassinet.” While there was no mention of any bassinets having air permeable sides in the study, the study authors (including R Moon who is on the AAP Task Force) recommend “a bassinet with vertical sides of air-permeable material, such as mesh, may be preferable to one with air-impermeable sides.” The Task Force makes the recommendation for air permeable sides based on infants with face wedged against side of sleep environment but fails to recommend air permeable crib mattresses as being preferable air impermeable crib mattresses to address infants face-straight- down on firm mattresses despite the continued report of such deaths.
FIBERFILL MATTRESS VS. AIR PERMEABLE MATTRESS
Further the Task Force’s accompanying policy statement (AAP, 2011) recommends the following sleep surface: “Use a firm sleep surface—A firm crib mattress, covered by a fitted sheet, is the recommended sleeping surface to reduce the risk of SIDS and suffocation.”
Here the authors are stating that the firm crib mattress reduces the risk of SIDS. Even though they list this recommendation as Level A, they fail to provide the citations that support this recommendation in the policy statement. In referring back to the technical report, the authors rely on the CPSC recommendations to support their recommendation for the firm crib mattress:
“Cribs should meet safety standards of the CPSC, Juvenile Product Manufacturers Association, and the ASTM International (formerly the American Society for Testing and Materials), including those for slat spacing, snugly fitting and firm mattresses, and no drop sides.121”
This citation [121 US Consumer Product Safety Commission. Crib Safety Tips: Use Your Crib Safely. Washington, DC: US Consumer Product Safety Commission. CPSC document 5030] is a tip sheet written for parents and caregivers. It is not a well-conducted case-control study, a systematic review, or a meta-analysis. No other citation is provided. The citations for this recommendation do not meet the Level A requirements.
DR. JAMES KEMP AND COLLEAGUES
Dr. James Kemp and colleagues were some of the first to study the potential for various sleep surfaces to prevent infant rebreathing (Kemp 2000). They found that the firm mattress and four of the five surfaces designed to prevent rebreathing consistently allowed lethal rebreathing of CO2. Only one product—an air permeable crib mattress—was able to maintain CO2 levels below this threshold. The authors go on to say that “even firm crib mattresses could pose a rebreathing threat when vulnerable infants sleep prone.” They refer to studies showing that unaccustomed prone sleepers, including infants who are placed supine and roll prone have an increased risk of SIDS (L’Hoir 1998 and Mitchell EA 1999). These studies and others have shown that nearly half of SIDS victims unaccustomed to prone sleep, were discovered in the face-straight-down position. Many of these infants were found on a firm crib mattress. Dr. Kemp’s data supports that if vulnerable infants were placed on an air permeable crib mattress or surface, they would experience less risk of rebreathing should they inadvertently roll prone. There is no reference to breathable crib mattresses reducing CO2 levels or reducing risks.
DR. EPHRAIM BAR-YISHAY AND COLLEAGUES
Dr. Ephraim Bar-Yishay and colleagues provided the second study on CO2 accumulation and rebreathing on six infant sleep surfaces—an air permeable crib mattress, two conventional firm crib mattresses and three mattresses with an additional layer or topper designed to improve air flow similar to the toppers on current crib mattresses claiming to be “breathable crib mattresses”. (Bar-Yishay 2011). The air permeable crib mattress had a significantly faster rate of CO2 elimination and only the air permeable mattress was able to prevent CO2 accumulation with maximal CO2 levels significantly lower than that of the other crib mattresses. They concluded that the air permeable crib mattress exhibited significantly better aeration properties compared to the other five mattresses including the firm crib mattresses. the crib mattresses with “breathable” toppers to improve airflow – now being marketed as breathable crib mattresses – actually had higher rates of CO2 than the conventional crib mattress with no breathable cover.
SAFE SLEEP TECHNOLOGIES
Finally a US manufacturer of an air permeable crib mattress contacted the CPSC for recommendations on an accredited independent lab to conduct similar tests on aeration properties on their product. Intertek was recommended because they use a similar mechanical model and methods as designed by Dr. Kemp. The lab compared CO2 elimination on four different surfaces—an air permeable mattress, a firm mattress with tight fitting sheet, sheepskin, and a bean bag chair. The latter two are known high risk hazards for rebreathing (Kemp 1991, Kemp 1993) and have been implicated in a significant number of SIDS fatalities. Just as in the studies by Kemp and Bar-Yishay, the air permeable crib mattress showed significantly less CO2 retention than the firm crib mattress and the high hazard comparators. Intertek concluded that the air permeable crib mattress represents a significantly lower risk hazard for rebreathing than the firm crib mattress. They also compared the air permeability of the air permeable crib mattress to a firm crib mattress using the ASTM-D737-04 standard test method of air permeability of textiles. Based on the test data, the air permeable crib mattress has an air permeability rate over 330 times greater than the firm crib mattress.
These two well-designed, well-conducted case controlled studies along with the independent CPSC testing lab results strongly support a recommendation for use of an air permeable crib mattress. Just as the Task Force’s five Level A recommendations listed above are all based in some part on risk of rebreathing, it stands to reason that the Task Force would recommend the air permeable crib mattress with its significantly lower risk of rebreathing than the firm crib mattress with tight fitting sheet.
SUFFOCATION/ENTANGLEMENT IN BEDDING: RISK OF CRIB SHEETS
The AAP Task Force concurs with the CPSC that all loose bedding should be removed from the infants sleep environment. The CPSC and the AAP issued an alert in 2001 warning parents and pediatricians of the “hidden hazard in babies’ cribs” of loose crib mattress sheets based on death reports of infants who suffocated or strangled when they became entangled in their crib mattress sheet. Two of the deaths involved fitted sheets. The CPSC now requires that all crib mattress sheets carry a warning that the sheet should not be used if it doesn’t fit properly. CPSC pushed the sheet-making industry to improve the fit of crib sheets on mattresses. However deaths from sheet entanglement remain a risk for infants. In the CDC’s multistate SUID Case Registry, the mechanism most frequently reported for possible and explained suffocation deaths was soft bedding which the registry defines as soft or loose bedding (Shapiro-Mendoza 2014). The loose bedding is not further defined but could be a blanket or fitted sheet that became loose.
Crib mattress manufacturers are not sheet manufacturers. The CPSC defines the industry requirements for mattress size based on ASTM standards. Their length and width requirements are consistent but their requirement for height is six inches or making mattress sizes inconsistent. Because there are no crib sheets made for a given mattress, the crib sheet remains a hazard. The design of the air permeable crib mattress eliminates this risk because no sheet or other bedding is used. Breathable crib mattresses still use a sheet.
The same data used by the Task Force in its recommendation against the use of soft or loose bedding, also supports a recommendation against the use of a crib mattress sheet when possible.
ROLE OF BACTERIA AND THE RISK OF FIBER FILL
A recent review article attempts to establish bacterial infection as having a major role in the pathophysiology of SIDS (Goldwater 2013). The authors debunk the respiratory physiology model both as being unproven and inconsistent with the most plausible physiological events that take place during a SIDS death.
A recent study showed SIDS victims, especially those found prone, are more often colonized with S. aureus than living control subjects (Highet 2014). Studies have demonstrated colonization of traditional fiber filled crib mattresses with Staph aureus (Sherburn 2007) suggesting a source for acquiring these bacteria. While no studies are available measuring colonization of air permeable crib mattresses, the surface is designed to be removed and laundered. The SafeSleep® by Safe Sleep Technologies, recommends regular cleaning of the surface in a conventional washer and dryer. Breathable crib mattresses still have fiber or other fills that can become contaminated.
Based on the bacterial infection hypothesis, it stands to reason the Task Force should consider recommending regular washing of infant sleep surfaces and removal of fillers from crib mattresses to reduce exposure to these pathogens.
In summary, the 2016 Safe Sleep Technical report now recognizes the safety advantages of air permeable crib mattresses to reduce the risk of unexpected suffocation/entanglement and other hazards that may be associated with SIDS.
The AAP does not recommend the use of “breathable” crib mattresses to reduce the risk of SIDS and other infant sleep related deaths.
For more information on air permeable crib mattress versus breathable crib mattresses please visit Compare to “Breathable” Crib Mattresses
Patrick L. Carolan, MD; William B. Wheeler, MD; James D. Ross, RRT, RCP; and James S. Kemp, MD, (2000), Potential to Prevent Carbon Dioxide Rebreathing of Commercial Products Marketed to Reduce Sudden Infant Death Syndrome Risk, Pediatrics, 105:4 774-779
Edwin A. Mitchell, BSc, MBBS, DCh, FRACP, FRCPCH, DSc; Bradley T. Thach, MD; John M. D. Thompson, PhD; Sheila Williams, BSc; for the New Zealand Cot Death Study, Changing Infants’ Sleep Position Increases Risk of Sudden Infant Death Syndrome. Arch Pediatr Adolesc Med. 1999;153:1136-1141.
American Academy of Pediatrics Task Force on Infant Positioning and SIDS. SIDS and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment, Pediatrics; originally published online October 17, 2011; TASK FORCE ON SUDDEN INFANT DEATH SYNDROME DOI: 10.1542/peds.2011-2284
Carrie K. Shapiro-Mendoza, PhD, MPHa, Lena Camperlengo, DrPHa, Rebecca Ludvigsen, MPHb, Carri Cottengim, MAc, Robert N. Anderson, PhDd, Thomas Andrew, MDe, Theresa Covington, MPHf, Fern R. Hauck, MD, MSg, James Kemp, MDh, and Marian MacDorman, PhDd. Classification System for the Sudden Unexpected Infant Death Case Registry and its Application. J Pediatr. Jun 2014; DOI: 10.1542/peds.2014-0180
Amanda R. Highet, Anne M. Berry, Karl A. Bettelheim, Paul N. Goldwater. Gut microbiome in sudden infant death syndrome (SIDS) differs from that in healthy comparison babies and offers an explanation for the risk factor of prone position. International Journal of Medical Microbiology. Jul 2014; Volume 304, Issues 5–6, July 2014, Pages 735–741; DOI: 10.1016/j.ijmm.2014.05.007