[Federal Register Volume 61, Number 167 (Tuesday, August 27, 1996)]
[Proposed Rules]
[Pages 44013-44019]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-21846]
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DEPARTMENT OF HEALTH AND HUMAN SERVICES
21 CFR Part 880
[Docket No. 85N-0285]
Medical Devices; Reclassification of the Infant Radiant Warmer
AGENCY: Food and Drug Administration, HHS.
ACTION: Proposed rule.
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SUMMARY: The Food and Drug Administration (FDA) is proposing to
reclassify the infant radiant warmer from class III (premarket
approval) into class II (special controls) based on new information
regarding the device. The infant radiant warmer is a device consisting
of an infrared heating element intended to maintain the infant's body
temperature by means of radiant heat. This document summarizes the
basis for the agency's findings that sufficient valid scientific
evidence is available to support reclassification of the infant radiant
warmer and to establish special controls to provide reasonable
assurance of the safety and effectiveness of the device. This action
implements the Medical Device Amendments of 1976 (the amendments) as
amended by the Safe Medical Devices Act of 1990 (the SMDA).
DATES: Written comments by November 25, 1996. FDA proposes that any
final rule based on this proposal become final 30 days after
publication in the Federal Register.
ADDRESSES: Submit written comments to the Dockets Management Branch
(HFA-305), Food and Drug Administration, 12420 Parklawn Dr., rm. 1-23,
Rockville, MD 20857.
FOR FURTHER INFORMATION CONTACT: Janet L. Scudiero, Center for Devices
and Radiological Health (HFZ-410), Food and Drug Administration, 9200
Corporate Blvd., Rockville, MD 20850, 301-594-1287.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Classification and Reclassification of Devices Under the Medical
Device Amendments of 1976
II. Reclassification Under the Safe Medical Devices Act of 1990
III. History of the Proceedings
IV. Device Description
V. Recommendation of the Panel
VI. Summary of the Reasons for the Recommendation
VII. Risks to Health
VIII. Summary of Data Upon Which the Recommendation is Based
IX. FDA's Tentative Findings
X. Environmental Impact
XI. Analysis of Impacts
XII. Paperwork Reduction Act of 1995
XIII. Request for Comments
XIV. References
I. Classification and Reclassification of Devices Under the Medical
Device Amendments of 1976
Under section 513 of the Federal Food, Drug, and Cosmetic Act (the
act) (21 U.S.C. 360c), as established by the amendments (Pub. L. 94-
295) and amended by the SMDA (Pub. L. 101-629), FDA must classify
devices into one of three regulatory classes: Class I, class II, or
class III. FDA's classification of a device is determined by the amount
of regulation necessary to provide reasonable assurance of safety and
effectiveness of a device. Except as provided in section 520(c) of the
act (21 U.S.C. 360j(c)), FDA may not use confidential information
concerning a device's safety and effectiveness as a basis for
reclassification of the device from class III into class II or class I.
Under the original 1976 act, devices were to be classified into
class I (general controls) if there was information showing that the
general controls of the act were sufficient to assure safety and
effectiveness; into class II (performance
[[Page 44014]]
standards) if there was insufficient information showing that general
controls themselves would ensure safety and effectiveness, but there
was sufficient information to establish a performance standard that
would provide such assurance; and into class III (premarket approval)
if there was insufficient information to support classifying a device
into class I or class II and the device was a life-sustaining or life-
supporting device or was for a use that is of substantial importance in
preventing impairment of human health.
Most generic types of devices that were on the market before the
date of the original 1976 amendments (May 28, 1976) (generally referred
to as preamendments devices) have been classified by FDA under the
procedures set forth in section 513(c) and (d) of the act through the
issuance of classification regulations into one of these three
regulatory classes. Under sections 513(c) and (d) of the act, FDA
secures expert panel recommendations on the appropriate device
classifications for generic types of devices. FDA then considers the
panel's recommendations and, through notice and comment rulemaking,
issues classification regulations.
For those devices introduced into interstate commerce for the first
time after May 28, 1976, the device is classified through the premarket
notification process under section 510(k) of the act (21 U.S.C.
360(k)). Those devices that FDA finds to be substantially equivalent to
a classified preamendments generic type of device are thereby
classified in the same class as the predicate preamendments device.
Reclassification of classified preamendments devices is governed by
section 513(e) of the act. This section provides that FDA may, by
rulemaking, reclassify a device (in a proceeding that parallels the
initial classification proceeding) based on ``new information.'' The
reclassification can be initiated by FDA or by the petition of an
interested person.
The term ``new information,'' as used in section 513(e) of the act,
includes information developed as a result of a reevaluation of the
data before the agency when a device was originally classified, as well
as information not presented, not available, or not developed at that
time. (See, e.g., Holland Rantos v. United States Department of Health,
Education, and Welfare, 587 F.2d 1173, 1174 n.1 (D.C. Cir. 1978);
Upjohn v. Finch, 422 F.2d 944 (6th Cir. 1970); Bell v. Goddard, 366
F.2d 177 (7th Cir. 1966).)
Reevaluation of the data previously before the agency is an
appropriate basis for subsequent regulatory action where the
reevaluation is made in light of changes in ``medical science.'' (See
Upjohn v. Finch, supra, 422 F.2d at 951.) However, regardless of
whether data before the agency are past or new data, the ``new
information'' on which any reclassification is based is required to
consist of ``valid scientific evidence,'' as defined in section
513(a)(3) of the act and 21 CFR 860.7(c)(2). FDA relies upon ``valid
scientific evidence'' in the classification process to determine the
level of regulation for devices. For the purpose of reclassification,
the valid scientific evidence upon which the agency relies must be
publicly available. Publicly available information excludes trade
secret and/or confidential commercial information, e.g., the contents
of premarket approval applications (PMA's). (See section 520(c) of the
act, (21 U.S.C. 360j(c).)
II. Reclassification Under the Safe Medical Devices Act of 1990
The SMDA further amended the act to change the definition of a
class II device. Under the SMDA, class II devices are those devices for
which there is insufficient information to show that general controls
themselves will ensure safety and effectiveness, but there is
sufficient information to establish special controls to provide such
assurance, including the issuance of a performance standard, postmarket
surveillance, patient registries, development and dissemination of
guidelines, and other appropriate actions necessary to provide
reasonable assurance of the safety and effectiveness of the device.
Thus, the definition of a class II device was changed from
``performance standards'' to ``special controls.''
III. History of the Proceedings
In the Federal Register of August 24, 1979 (44 FR 49873), FDA
published a proposed rule to classify the infant radiant warmer into
class III. The preamble included the classification recommendation of
the General Hospital and Personal Use Devices Panel (the panel). The
panel's recommendation included a summary of the reasons why the device
should be subject to premarket approval and identified certain risks to
health presented by the device, including electrical shock, possible
eye damage due to long-term exposure to infrared radiation, patient
injury, hospital staff burns, insensible water loss, and hyperthermia
or hypothermia. The panel also recommended that a high priority for the
application of section 515(b) of the act (21 U.S.C. 360e)(premarket
approval requirement) be assigned to the infant radiant warmer.
In the Federal Register of October 21, 1980 (45 FR 69694), FDA
published a final rule classifying the infant radiant warmer into class
III (21 CFR 880.5130). Concern for possible long-term effects of
infrared radiation on the skin and eyes of infants was the sole reason
for classifying the device into class III. FDA believed that the other
risks to health identified in the proposed rule could be addressed by
labeling or by a standard.
In the Federal Register of September 6, 1983 (48 FR 40272), FDA
published a notice of intent to initiate proceedings to require
premarket approval of 13 preamendments class III devices assigned a
high priority by FDA for the application of premarket approval
requirements. Among other things, the notice described the factors FDA
considered in establishing priorities for initiating proceedings under
section 515(b) of the act for issuing final rules requiring
preamendments class III devices to have approved PMA's or product
development protocols (PDP's) which have been declared completed. Using
these factors, FDA concurred with the panel's recommendation that the
infant radiant warmer should be subject to a high priority for
initiating a proceeding to require premarket approval.
In the Federal Register of January 15, 1986 (51 FR 1910), FDA
published a proposed rule to require filing of a PMA or a notice of
completion of a PDP for the infant radiant warmer. In accordance with
section 515(b) of the act and 21 CFR 860.132, FDA also announced an
opportunity for interested persons to request a change in
classification of the device based on new information. FDA identified
the following potential risks to health associated with the use of
infant radiant warmers: Insensible water loss, special risk group
infants with very low birth weight, hypothermia and hyperthermia,
damage to the eyes and skin, increased oxygen consumption, operator
error, and other safety risks common to many devices (e.g., electric
shock, inadequate stability, and burns to the user).
On January 30, 1986, the Health Industries Manufacturers
Association submitted a petition (Ref. 1) to reclassify the infant
radiant warmer from class III into class II. The petition was submitted
under section 513(e) of the act. Consistent with the act and the
regulations, FDA referred the petition to the panel for its
recommendation on the requested change in classification.
[[Page 44015]]
On May 21, 1986, during a meeting by teleconference, the panel
unanimously recommended that the infant radiant warmer be reclassified
from class III into class II and that any change in classification not
take effect until the effective date of a performance standard for the
generic type of device established under section 514 of the act (21
U.S.C. 360d) (Ref. 2 at p. 75).
In the Federal Register of May 27, 1987 (52 FR 19735), FDA
published a notice of intent to initiate a proceeding to reclassify the
infant radiant warmer from class III into class II. Subsequent to that
notice, FDA determined that the deliberations of the 1986 panel were
incomplete and that another panel meeting was necessary to allow the
panel to address specific recommendations and issues concerning the
reclassification of the infant radiant warmer (Ref. 2 at pp. 54 and
65). This additional panel meeting was held on May 11, 1994. A summary
of the panel's recommendation is set forth below.
IV. Device Description
FDA is proposing the following device description based on the
panel's recommendation and the agency's review.
The infant radiant warmer is a device consisting of an infrared
heating element intended to be placed over an infant to maintain the
infant's body temperature by means of radiant heat. The device may also
contain a temperature monitoring sensor, a heat output control
mechanism, and an alarm system (infant temperature, manual mode if
present, and failure alarms) to alert operators of a temperature
condition over or under the set temperature, manual mode time limits,
and device component failure, respectively. The device may be placed
over a pediatric hospital bed or it may be built into the bed as a
complete unit.
V. Recommendation of the Panel
In the public meeting held on May 11, 1994, the panel unanimously
affirmed its previous recommendation that the infant radiant warmer
should be reclassified from class III into class II (Ref. 3), and that
the appropriate special control is a voluntary standard. The panel
identified the Association for the Advancement of Medical
Instrumentation (AAMI) voluntary standard for infant radiant warmers as
the special control for the infant radiant warmer (Ref. 4).
The panel further recommended the following restrictions on the use
of the device: A prescription statement in the labeling of the device
that restricts the device to use only upon the order of a physician,
only in health care facilities, and only by persons with specific
training and experience in the use of the device.
VI. Summary of the Reasons for the Recommendation
The panel gave the following reasons in support of its
recommendation to reclassify the infant radiant warmer from class III
into class II:
1. General controls by themselves are insufficient to provide
reasonable assurances of the safety and effectiveness of the device.
2. There is sufficient publicly available information to establish
special controls to provide reasonable assurance of the safety and
effectiveness of the device for its intended use.
3. An existing voluntary standard (Ref. 4) is the special control
recommended by the panel.
4. There is sufficient publicly available information to
demonstrate that the device is not potentially hazardous to the life,
health, or well-being of the infant. The panel identified no new risks
to health associated with the use of the device and determined that
some of the previously identified potential risks to health are no
longer risks or are no longer serious risks (Ref. 3 at p. 225). Thus,
the probable benefits to health of the device outweigh any probable
risks to health.
The panel believes that the current and any subsequent
manufacturers of the infant radiant warmer can comply with this
voluntary standard, that FDA can ensure the safety and effectiveness of
the device made by new manufacturers through the premarket notification
procedures under section 510(k) of the act, and that a regulatory level
of class III is unnecessary.
VII. Risks to Health
When the infant radiant warmer was proposed for classification into
class III in 1979, the panel identified certain risks to health that
they believed the device presented. The risks to health were identified
as electrical shock, possible eye damage, patient injury, hospital
staff burns, insensible water loss, and hyperthermia or hypothermia (44
FR 49873 at 49874). When the device was classified into class III in
1980, FDA identified concern for possible delayed long-term effects of
infrared radiation on the skin and eyes of infants as the only risk to
health presented by the device. FDA also determined that the other
risks to health identified in the proposed rule could be addressed by
labeling or by a standard (45 FR 69694). Subsequently, in 1986, the
agency identified increased oxygen consumption as another potential
risk to health associated with the use of the device (51 FR 1910).
Based on the review of the new data and information contained in
the petition and the panel members' personal knowledge of and
experience with the device, the panel on May 11, 1994, agreed that all
the potential risks to health (insensible water loss; special risk
group, very low birth weight infants; hyperthermia and hypothermia;
possible eye and skin damage; and increased oxygen consumption)
associated with the use of the infant radiant warmer could be
controlled by special controls (Ref. 3). The panel also believed that
the general risks to health (operator error, electric shock, inadequate
device stability, and burns to operators) could also be addressed by
special controls.
On the basis of its review and the panel's recommendation, FDA now
believes that the use of the infant radiant warmer for maintaining an
infant's body temperature does not present a potential unreasonable
risk of illness and injury, and that special controls would provide
reasonable assurance of the safety and effectiveness of the device. In
addition to the AAMI standard, FDA has also incorporated the panel's
labeling recommendation as special controls for this device.
VIII. Summary of the Data Upon Which the Proposed Recommendation is
Based
A. Insensible Water Loss
An increased rate of insensible water loss is the principle, well-
documented risk to health associated with the use of infant radiant
warmers (Refs. 5 and 6). Insensible water loss is the continuous and
usually imperceptible loss of water, mainly from the skin, that occurs
to some extent in all newborn infants. It is a well recognized
condition of prematurity, its severity being inversely related to birth
weight (Ref. 7). Other factors that contribute to insensible water loss
in neonates include: Illness; environmental temperature and humidity;
and other therapies, especially phototherapy and respiratory support
(Ref. 5). Insensible water loss is also associated with the use of
incubators (Refs. 5 through 7).
Bell (Ref. 6) evaluated four studies (Refs. 8 through 11), which
reported increased rates of insensible water loss of 40 to 190 percent
during the use of radiant warmers compared to the use of incubators. He
determined that the variations in the increased rates of insensible
water loss are related to the experimental conditions of the
investigations (mainly the different
[[Page 44016]]
weighing methods used in the studies). Bell concluded that insensible
water loss in infants under infant radiant warmers without phototherapy
is 40 to 100 percent higher than in infants in incubators.
Increased insensible water loss places an infant at a risk of
dehydration and electrolyte imbalance and potentially interferes with
the infant's thermoregulation. Because both underestimation and
overestimation of fluid and electrolyte requirements can have serious
consequences to infants, especially to low birth weight infants,
guidance for parenteral fluid and electrolyte administration was
needed. Since the infant radiant warmer was classified in 1980, several
guidances which include recommendations for parenteral fluid and
electrolyte administration have been developed for premature and term
infants (Refs. 6, 12, and 13).
The use of plastic heat shielding with infant radiant warmers has
been reported to reduce insensible water loss (Refs. 14 through 17).
However, this practice is not without risks, including both
underheating and overheating of infants (Refs. 2 and 18). The panel
agreed that the use of heat shielding should be at the discretion of
the informed physician (Ref. 2).
Although an increased rate of insensible water loss is a risk to
health in the use of the infant radiant warmer, it can be managed by
careful monitoring of the infant and administration of parenteral or
oral electrolyte therapy when necessary. The new parenteral fluid and
electrolyte therapy guidances minimize this risk to health and support
the use of infant radiant warmers in the management of critically ill
infants to whom continual access by health professionals is essential.
The panel believed that this risk to health is a well-understood
risk associated with the use of the infant radiant warmer and that it
is related to both the prematurity of the infant and the open bed
design of the device (Ref. 3). The panel agreed that this risk to
health is clinically manageable and that it could be controlled by
special controls.
B. Special Risk Group--Very Low Birth Weight Infants
To survive, very low birth weight infants, weighing 1,500 grams or
less, require aggressive diagnostic and therapeutic procedures, such as
emergency resuscitation, tracheal intubation, placement of catheters
and needles, and blood sampling (Ref. 1). The use of infant radiant
warmers has allowed essential access to the infants for the performance
of these necessary procedures while providing effective warming. This
is particularly important immediately after birth, during the first
days of life, and for the care of critically ill premature infants.
Very low birth weight infants are especially susceptible to
increased rates of insensible water loss because of their larger
surface area to mass ratio, higher body water content, and the thinner
epidermal barrier of their skin (Refs. 2 (at pp. 56 and 57), 5, and
13). The advances in parenteral fluid and electrolyte therapy since
1980 provide specific guidance to minimize this risk for very low birth
weight infants (Refs. 6, 12, and 13).
The panel believed that this potential risk to health is not a risk
related to the device, but that it is related to the prematurity of the
infants (Ref. 3). The panel stated that the use of the infant radiant
warmer has made the care of these infants more manageable, and the
panel commented that now even smaller premature infants than in 1986
are successfully treated in infant radiant warmers. The panel believed
that this risk can be controlled through special controls.
C. Damage to the Eyes
Infant radiant warmers operate by directing invisible infrared
radiation (IR) from an overhead heater to the infant's body. The
magnitude and spectral characteristics of the IR are controlled by the
design of the device and are important in assessing the potential risk
of exposure to IR.
During its classification deliberations in 1979, the panel
considered infant radiant warmer performance data developed for FDA
under a contract (Ref. 19). However, that data did not sufficiently
address the panel's concern about the possibility of adverse effects on
the eyes of infants resulting from long-term exposure to IR. The
petition reported new performance data on five radiant warmers (Ref.
1). The new data provided measurements for individual wavelength
regions of the electromagnetic spectrum, including the ultraviolet (200
to 400 nanometers (nm)), visible (400 to 760 nm), and IR-A (760 to
1,400 nm) wavelength regions, and for the 1,400 to 4,500 nm wavelength
region which includes the IR-B (1,400 to 3,000 nm) wavelength region
and the 3,000 to 4,500 nm portion of the IR-C wavelength region (the
IR-C wavelength region extends from 3,000 to 100,000 nm). The petition
also reported total irradiance, including irradiance for wavelengths
extending beyond 4500 nm obtained by another measurement method. The
IR-A wavelength region is associated with the potential for damage to
the lens and retina of the eye. The IR-B and IR-C wavelength regions
are associated with the potential for thermal damage to the cornea of
the eye.
All the infant radiant warmers emitted IR primarily in the IR-B and
IR-C wavelength regions (Ref. 1). No ultraviolet radiation and
negligible visible radiation (nondetectable to 0.026 milliwatt per
square centimeter (mW/cm2)) was detected. The range of maximum IR-
A irradiance was 0.103 to 3.463 mW/cm2, and the range of maximum
total irradiance was 39.2 to 60.3 mW/cm2. These maximum
irradiances were obtained at full power and at high line voltage (130
volts). At lower heater power levels, proportionately more of the IR is
from the IR-C wavelength region.
In clinical use, however, infant radiant warmers are rarely
operated at full power and at high line voltage (Ref. 1). The total
irradiances necessary to maintain the desired infant skin temperature
typically range from 12 to 25 mW/cm2, and typical IR-A irradiances
are less than 1.0 mW/cm2. Engel et al. reported mean total
irradiances of less than 10 mW/cm2 and 17.1 mW/cm2 for the
warming of two groups of critically ill premature infants (Refs. 20 and
21); in general, the smaller infants required higher irradiances. In
addition, the necessarily more frequent handling of critically ill
neonates, which may be as often as once every 10 minutes, may interrupt
delivery of a portion of the radiant heat to the infant and thus
increase the amount of radiant power required for heating (Ref. 2).
The petition also summarized published information that was not
reviewed by the classification panel when the infant radiant warmer was
classified. Both Sliney and Freasier (Ref. 22) and Sliney and Wolbarsht
(Ref. 23) reported that a safe chronic ocular exposure level to IR-A
was 10 mW/cm2. The petition reported that the maximum amount of
IR-A of the tested infant radiant warmers ranged from 0.24 to 3.5 mW/
cm2, and that in actual use, infant radiant warmers emit typically
less than 1 mW/cm2 of IR-A (Ref. 1). Thus, the potentials for
chronic injury to the lens and the retina are low because infant
radiant warmers emit significantly less IR-A radiation than the level
of IR-A radiation believed to be associated with injuries of the lens
and retina.
The cornea and aqueous humor absorb almost all of the IR from 1,400
to 1,900 nm; the cornea absorbs all the IR above 1,900 nm (Ref. 23).
Thus, most IR emitted by infant radiant warmers is absorbed by the
anterior structures of
[[Page 44017]]
the eye and is not transmitted to the lens and retina. Sliney and
Freasier (Ref. 22) and Sliney and Wolbarsht (Ref. 23) also reported
that the irradiance of 100 mW/cm2 was ``well below'' the threshold
irradiance level to prevent corneal injury. Thus, the potentials for
injury to the cornea and aqueous humor from exposure to IR emitted by
infant radiant warmers are low because the maximum irradiances of
infant radiant warmers range from 36.8 to 60.3 mW/cm2 and their
typical total use irradiances range from 12 to 25 mW/cm2 (Ref. 1).
For both the total irradiance and the IR-A irradiance, the margins for
safety are significant.
To put this irradiance information in perspective, it should be
noted that premature infants' eyes are rarely opened and that blinking
of the eyes when opened keeps the corneal epithelium from drying out
(Ref. 24). Thus, there is a low probability that a significant amount
of IR actually enters the eyes of premature infants.
There are two studies on the effects of IR on the eyes of neonates.
Johns et al. detected no adverse eye effects in infants warmed under
radiant warmers after followup times of up to 45 days (Ref. 25). This
study now has increased significance since Pitts and Cullen reported
that corneal damage heals rapidly (usually within 24 hours) and that
lens opacities formed within 24 hours after exposure heal earlier than
expected (usually within 1 month) (Ref. 26). Thus, any corneal or lens
effects, if present, would have been detected by Johns et al.
In 1993, Baumgart et al. (Ref. 27) reported a retrospective study
of critically ill premature infants treated under radiant warmers and
incubators with longer followup times of 30 days to 6 years. The mean
followup time for the radiant warmer group was 29 months, and the mean
IR irradiance of the infant radiant warmer group was less than 30 mW/
cm2. They found no long-term or short-term corneal or lens effects
in either group. The incidence of retinopathy of prematurity was higher
in the radiant warmer group, but this higher incidence was attributed
to prematurity and to the hospital's policy of placing the more
critically ill premature infants receiving oxygen in infant radiant
warmers rather than in incubators. It is noted that the incidence of
retinopathy of prematurity is associated with prolonged oxygen therapy
(Ref. 28).
There are few recommended IR exposure levels specifically intended
for infants under infant radiant warmers. The Emergency Care Research
Institute proposed that 0.3 W/cm2 (300 mW/cm2) was a
reasonable total irradiance limit for an infant under an infant radiant
warmer in 1973 and 1984 (Refs. 24 and 18, respectively) and that the
near IR range between 700 to 1,200 nm should be limited to 40 mW/
cm2. The 1994 International Electrotechnical Commission standard
for infant radiant warmers has irradiance limits of 100 mW/cm2 for
total IR irradiance and 10 mW/cm2 for IR-A (Ref. 29). The 1995
AAMI voluntary standard special control has irradiance limits of 60 mW/
cm2 for total IR irradiance and 10 mW/cm2 for IR-A (Ref. 4).
The maximum irradiances of currently marketed infant radiant warmers
meet the AAMI voluntary standard special control irradiance limits
(Ref. 3).
This new information concerning the IR irradiance characteristics
of infant radiant warmers and the irradiance levels associated with
acute and chronic injuries to the eyes have addressed the safety
concerns previously held about the unknown potential for IR-induced
long-term effects to the eyes of infants under infant radiant warmers.
The panel stated that in over 20 years of clinical use, there are no
reports in the literature of any adverse long-term effects to the eyes
of infants attributed to the IR radiation emitted by infant radiant
warmers (Ref. 3). They further commented that long-term developmental
health assessments of infants cared for in infant radiant warmers do
not mention any delayed eye conditions (Ref. 3, pp. 190 and 191). The
panel agreed that the potential risk to health of long-term damage from
overexposure of the eyes to total IR and IR-A could be controlled by
special controls.
D. Damage to the Skin
The IR emitted by infant radiant warmers is designed to be below
the threshold for thermal injury to the infant's skin (Ref. 24). The IR
is not of sufficient energy to cause photochemical reactions in the
skin. Most of the IR-A irradiance is reflected from the skin while IR-B
and IR-C irradiance are absorbed by the outer 1 millimeter of the skin
to accomplish the desired warming effect.
The panel commented that there are no published reports of skin
damage in infants attributed to the use of radiant warmers and that
long-term developmental health assessments of infants cared for in
infant radiant warmers do not mention skin conditions (Ref. 3). The
panel believed that the potential risk of overexposure of the skin to
IR could be controlled by special controls.
E. Increased Oxygen Consumption
Bell reviewed five studies (Ref. 6) that reported conflicting
results of statistically significant increased oxygen consumption rates
(Refs. 30 and 31) and unchanged oxygen or slightly increased
consumption rates (Refs. 11, 28, 32, and 33) in infants warmed under
radiant warmers compared to infants warmed in incubators. Because
increased oxygen consumption may be an indicator of a stress-related
increase in metabolism, these reports caused concern that the use of
infant radiant warmers stress the metabolism of infants.
Bell evaluated these studies taking into account differences in the
various study parameters used, including differences in the
servocontrol skin temperatures and the humidity in the neonatal
nurseries (Ref. 6). He determined that only a small increase in oxygen
consumption (4 kilocalories per kilogram per 24 hours additional energy
expenditure) occurs in the infants under infant radiant warmers
compared to infants in incubators. Bell agreed with Wheldon and Rutter
(Ref. 31) that the net total heat loss of infants under radiant warmers
to the environment due to evaporation, convection, radiation, and
conduction does not exceed that of infants in incubators. He concluded
that the increased oxygen consumption of infants in infant radiant
warmers is of unknown clinical significance. Subsequently, Marks et al.
reported that premature infants under infant radiant warmers
experienced no short-term metabolic complications or adverse effects on
growth even though they had a 10 percent higher oxygen consumption
compared to infants in incubators (Ref. 34).
The panel acknowledged that although oxygen consumption may be
greater in infants cared for in infant radiant warmers than in
incubators, the clinical significance of this, if any, is unknown (Ref.
3). They noted that other factors unrelated to the device can also
cause increased oxygen consumption. The panel agreed this potential
risk could be controlled by special controls.
F. Hypothermia and Hyperthermia
The risks to health of hypothermia and hyperthermia are low during
proper use of the device (Ref. 1). Infant radiant warmers are used to
treat and to prevent hypothermia. Both hypothermia and hyperthermia can
result from malfunctioning alarms and radiant heater components, and
hyperthermia can result from detachment of the skin temperature probe
from the infant. The device's temperature and failure alarm system is
designed to prevent
[[Page 44018]]
hypothermia and hyperthermia by alerting operators of unsafe
temperature conditions, skin temperature probe detachment from the
skin, probe failure and device failure. The petition (Ref. 1), current
device labeling (Ref. 3), the AAMI voluntary standard special control
(Ref. 4), and accepted medical practice (Refs. 1 and 3) all recommend
frequent monitoring of infants under infant radiant warmers. They also
recommend that infant radiant warmers should be operated in the skin
temperature servocontrol mode rather than the manual mode to further
reduce the risks of both hypothermia and hyperthermia (Refs. 1 and 4).
The panel agreed that this risk to health could be controlled by
special controls.
G. Other Risks
Four other potential risks associated with the use of infant
radiant warmers are electrical shock due to improper design or
construction of the device, injury due to instability of the device,
burns to the operator if the device is constructed of materials that
absorb radiant heat, and operator error. Operator error can be
minimized by appropriate training and comprehensive device labeling.
The panel agreed that these are well-known risks that are generic to
many neonatal devices and that they can be controlled by special
controls (Ref. 3).
H. Benefits of the Device
The infant radiant warmer has the unique benefit of providing
greater accessibility to the infant than do incubators during routine
nursing and intensive care procedures without interrupting the delivery
of heat. Infant radiant warmers can also heat an infant faster than an
incubator. Ahlgren reported that only 5 to 10 minutes are required to
warm the infant's skin to the preset skin temperature with the infant
radiant warmer as compared to 45 to 50 minutes for the incubator (Ref.
35). Infant radiant warmers are recommended for the care of newborn
infants who lose large amounts of heat through evaporation of amniotic
fluid from their skin in the delivery room (Ref. 27). It is estimated
that 80 percent of all infants are placed under infant radiant warmers
at some time during their hospital stay (Ref. 1). Many practitioners
consider infant radiant warmers to be the only way of warming some very
low birth weight and critically ill infants (Refs. 3 and 6).
The panel believes, based on publicly available, valid scientific
evidence, that the infant radiant warmer can be regulated as a class II
device (general and special controls) to reasonably assure the device's
safety and effectiveness (Ref. 3).
IX. FDA's Tentative Findings
FDA tentatively concurs with the recommendation of the panel that
infant radiant warmers should be reclassified into class II. The agency
believes that ``new information'' in the form of publicly available,
valid scientific evidence exists to establish special controls to
provide reasonable assurance of safety and effectiveness of the infant
radiant warmer for its intended use. The agency further identifies the
AAMI voluntary standard and labeling as the special controls. Moreover,
existing devices, within the generic type, have established a
reasonable record of safe and effective use. Consistent with the
purpose of the act, class II controls as defined by section
513(a)(1)(B) of the SMDA would provide the least amount of regulation
necessary to reasonably assure that current and future infant warmers
are safe and effective.
X. Environmental Impact
The agency has determined under 21 CFR 25.24(e)(2) that this action
is of a type that does not individually or cumulatively have a
significant effect on the human environment. Therefore, neither an
environmental assessment nor an environmental impact statement is
required.
XI. Analysis of Impacts
FDA has examined the impacts of the proposed rule under Executive
Order 12866 and the Regulatory Flexibility Act (Pub. L. 96-354).
Executive Order 12866 directs agencies to assess all costs and benefits
of available regulatory alternatives and, when regulation is necessary,
to select regulatory approaches that maximize net benefits (including
potential economic, environmental, public health and safety, and other
advantages; distributive impacts; and equity). The agency believes that
this proposed rule is consistent with the regulatory philosophy and
principles identified in the Executive Order. In addition, the proposed
rule is not a significant regulatory action as defined by the Executive
Order and so is not subject to review under the Executive Order.
The Regulatory Flexibility Act requires agencies to analyze
regulatory options that would minimize any significant impact of a rule
on small entities. Because of the potential costs to comply with the
provisions of premarket approval (class III) by each manufacturer, the
agency believes that the economic impact to comply with special
controls (class II) would likely be less. Therefore, the agency
certifies that the proposed rule will not have a significant economic
impact on a substantial number of small entities. Therefore, under the
Regulatory Flexibility Act, no further analysis is required.
XII. Paperwork Reduction Act of 1995
FDA tentatively concludes that the labeling requirements in this
proposed rule are not subject to review by the Office of Management and
Budget because they do not constitute a ``collection of information''
under the Paperwork Reduction Act of 1995 (Pub. L. 104-13). Rather, the
proposed labeling statements are ``public disclosure of information
originally supplied by the Federal Government to the recipient for the
purpose of disclosure to the public'' (5 CFR 1320.3(c)(2)).
XIII. Request for Comments
Interested persons may, on or before November 25, 1996, submit to
the Dockets Management Branch (address above) written comments
regarding this proposal. Two copies of any comments are to be submitted
except that individuals may submit one copy. Comments are to be
identified with the name of the device and the docket number found in
brackets in the heading of this document. Received comments may be seen
in the office above between 9 a.m. and 4 p.m., Monday through Friday.
XIV. References
The following information has been placed on display in the Dockets
Management Branch (address above) and may be seen by interested persons
between 9 a.m. and 4 p.m., Monday through Friday.
1. Health Industry Manufacturers Association Petition with
incorporated errata, volumes 1 to 5, Washington, DC, 1986 (submitted
January 30, 1986; revised April 15, 1986).
2. Transcript, General Hospital and Personal Use Devices Panel
(telephone conference call), May 21, 1986.
3. Transcript, General Hospital and Personal Use Devices Panel
with the attached general device classification questionnaire and
supplemental data sheet, May 11, 1994.
4. Association for the Advancement of Medical Instrumentation,
Infant Radiant Warmers (draft standard), May 1995.
5. Baumgart, S., ``Radiant Energy and Insensible Water Loss in
the Premature Newborn Infant Nursed under a Radiant Warmer,''
Clinics in Perinatology, 9:483-503, 1982.
6. Bell, E. F., ``Infant Incubators and Radiant Warmers, Early
Human Development,'' 8:351-375, 1983 (included in Ref. 1).
[[Page 44019]]
7. Baumgart, S., W. D. Engel, W. W. Fox, and R. A. Polin,
``Radiant Warmer Power and Body Size as Determinants of Insensible
Water Loss in the Critically Ill Neonate,'' Pediatric Research,
15:1495-1499, 1981 (included in Ref. 1).
8. Williams, P. R., and W. Oh, ``Effects of Radiant Warmers on
Insensible Water Loss in Newborn Infants,'' American Journal of
Diseases in Childhood, 128:511-514, 1974 (included in Ref. 1).
9. Wu, P. Y. K., and J. E. Hodgemen, ``Insensible Water Loss in
Preterm Infants. Changes with Postnatal Development and Non-Ionizing
Radiant Energy,'' Pediatrics, 54:704-711, 1974 (included in Ref. 1).
10. Bell, W. F., M. R. Weinstein, and W. Oh, ``Heat Balance in
Premature Infants: Comparative Effects of Convectively Heated
Incubator and Infant Radiant Warmer, with and without Heatshield,''
Journal of Pediatrics, 96:460-465, 1980 (included in Ref. 1).
11. Jones, R. W. A., M. J. Rochefort, and J. D. Baum,
``Increased Insensible Water Loss in New Born Infants Nursed under
Radiant Heaters,'' British Medical Journal, 1:1347-1350, 1976
(included in Ref. 1).
12. Baumgart, S., C. B. Langman, W. W. Fox, and R. A. Polin,
``Fluid, Electrolyte, and Glucose Maintenance in the Very Low Birth
Weight Infant,'' Clinical Pediatrics, 32:199-206, 1982 (included in
Ref. 1).
13. Costarino, A. T., and S. Baumgart, ``Controversies in Fluid
and Electrolyte Therapy for the Premature Infant,'' Clinical
Perinatology, 15:863-878, 1988.
14. Marks, K. H., Z. Freidman, and M. B. Maisels, ``A Simple
Device for Reducing Insensible Water Loss in Low-Birth Weight
Infants,'' Pediatrics, 60:223-226, 1980 (included in Ref. 1).
15. Baumgart, S., W. D. Engel, W. W. Fox, and R. A. Polin,
``Effect of Heat Shielding on Convective and Evaporative Heat Losses
and on Radiant Heat Transfer in the Premature Infant,'' Journal of
Pediatrics, 99:948-956, 1981 (included in Ref. 1).
16. Baumgart, S., W. W. Fox, and R. A. Polin, ``Physiologic
Implications of Two Heat Shields for Infants under Infant Radiant
Warmers,'' Journal of Pediatrics, 100:787-790, 1982 (included in
Ref. 1).
17. Fitch, C. W., and S. B. Korones, ``Heat Shield Reduces Water
Loss,'' Archives Disease in Childhood, 59:886-888, 1984 (included in
Ref. 1).
18. Emergency Care Research Institute, ``Evaluation: Infant
Warmers,'' Health Devices, 13:119-145, 1984.
19. Emergency Care Research Institute, ``The Development of a
Standard for Infant Warmers and Incubators,'' final report, FDA
Contract No. 223-75-5012, Plymouth Meeting, PA, 1976.
20. Engel, W. D., S. Baumgart, W. W. Fox, and R. A. Polin,
``Effect of Increased Radiant Power Output on State of Hydration in
the Critically Ill Neonate,'' Critical Care Medicine, 10:673-676,
1982 (included in Ref. 1).
21. Engel, W. D., S. Baumgart, J. G. Schwartz, W. W. Fox, and R.
A. Polin, ``Insensible Water Loss in the Critically Ill Neonate,''
American Journal of Diseases in Children, 135:516-520, 1981
(included in Ref. 1).
22. Sliney, D. H., and B. C. Freasier, ``Evaluation of Optical
Radiation Hazards,'' Applied Optics, 12:1-24, 1973 (included in Ref.
1).
23. Sliney, D., and M. Wolbarsht, ``Safety with Lasers and Other
Optical Sources,'' Plenum Press, New York, 1980, pp. 144-149.
24. Emergency Care Research Institute, ``Evaluation: Infant
Warmers,'' Health Devices, 3:4-25, 1973.
25. Johns, R., D. Schaffer, and G. Peckham, ``Evaluation of the
Effects of Infrared Radiation on the Eyes of Infants under Radiant
Warmers,'' Unpublished, 1977 (included in Ref. 1).
26. Pitts, D. G., and A. P. Cullen, ``Determination of Infrared
Radiation Levels for Acute Ocular Cataractogenesis,'' Albrecht von
Graefes Archives Klinische Ophthalmologie, 217:285-297, 1981
(included in Ref. 1).
27. Baumgart, S., A. Knauth, F. X. Casey, and G. E. Quinn,
``Infrared Eye Injury Not Due to Radiant Warmer Use in Infants,''
American Journal of Diseases in Childhood, 147:565-569, 1993.
28. American Academy of Pediatrics and American College of
Obstetricians and Gynecologists, Guidelines for Perinatal Care,
Evanston and Washington, DC, respectively, 1983 (included in Ref.
1).
29. International Electrotechnical Commission, ``Medical
Electrical Equipment, Part 2: Particular requirements for the safety
of infant radiant warmers'', 1994.
30. LeBlanc, M., ``Relative Efficacy of Radiant and Convective
Heat in Incubators in Producing Thermoneutrality for the
Premature,'' Pediatric Research, 18:426-428, 1984 (included in Ref.
1).
31. Wheldon, A. E., and N. Rutter, ``The Heat Balance of Small
Babies Nursed in Incubators and under Radiant Warmers,'' Early Human
Development, 6:131-143, 1982 (included in Ref. 1).
32. Marks, K. H., R. C. Gunther, J. A. Rossi, and M. J. Maisels,
``Oxygen Consumption and Insensible Water Loss in Premature Infants
under Radiant Heaters,'' Pediatrics, 66:228-232, 1980 (included in
Ref. 1).
33. Darnall Jr., R. A., and R. L. Ariagno, ``Minimal Oxygen
Consumption in Infants Cared for under Overhead Radiant Warmers
Compared with Conventional Incubators,'' Journal of Pediatrics,
93:283-287, 1978 (included in Ref. 1).
34. Marks, K. H., E. E. Nardis, and M. N. Momin, ``Energy
Metabolism and Substrate Utilization in Low Birth Weight Neonates
under Radiant Warmers,'' Pediatrics, 78:465-472, 1986.
35. Ahlgren, E. W., ``Environmental Control of the Neonate
Receiving Intensive Care,'' International Anesthesiology Clinic,
12:173-215, 1974 (included in Ref. 1).
List of Subjects in 21 CFR Part 880
Medical devices.
Therefore, under the Federal Food, Drug, and Cosmetic Act and under
authority delegated to the Commissioner of Food and Drugs, it is
proposed that 21 CFR part 880 be amended as follows:
PART 880--GENERAL HOSPITAL AND PERSONAL USE DEVICES
1. The authority citation for 21 CFR part 880 continues to read as
follows:
Authority: Secs. 501, 510, 513, 515, 520, 701 of the Federal
Food, Drug, and Cosmetic Act (21 U.S.C. 351, 360, 360c, 360e, 360j,
371).
2. Section Sec. 880.5130 is revised to read as follows:
Sec. 880.5130 Infant radiant warmer.
(a) Identification. The infant radiant warmer is a device
consisting of an infrared heating element intended to be placed over an
infant to maintain the infant's body temperature by means of radiant
heat. The device may also contain a temperature monitoring sensor, a
heat output control mechanism, and an alarm system (infant temperature,
manual mode if present, and failure alarms) to alert operators of a
temperature condition over or under the set temperature, manual mode
time limits, and device component failure, respectively. The device may
be placed over a pediatric hospital bed or it may be built into the bed
as a complete unit.
(b) Classification. Class II (Special Controls). (1) Association
for the Advancement of Medical Instrumentation (AAMI) Voluntary
Standard for Infant Radiant Warmers; (2) prescription statement in
accordance with 21 CFR 801.109 (restricted to use by or upon the order
of qualified practitioners as determined by the States); (3) labeling
for use only in health care facilities and only by persons with
specific training and experience in the use of the device.
Dated: August 1, 1996.
D. B. Burlington,
Director, Center for Devices and Radiological Health.
[FR Doc. 96-21846 Filed 8-26-96; 8:45 am]
BILLING CODE 4160-01-F
