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Sleep apnea:
Characterized by disturbances or cessation in
breathing during sleep, obstructive sleep apnea (OSA),
the most prevalent form of apnea, is a condition
that affects millions of Americans. OSA episodes
result from partial or complete blockage of airflow
during sleep that lasts at least 10 seconds and
often as long as 1 to 2 minutes. In a given night,
people with moderate to severe apnea may experience
complete or partial breathing disruptions as high as
200 - 500 per night. Sufferers usually snore between
episodes, and then snort, gasp or choke when they
start breathing again. Because their slumber is
constantly disrupted, they are deprived of the
restorative sleep necessary for efficient
functioning of both body and mind. This major
medical disorder has been linked with hypertension,
depression, stroke, cardiac arrhythmias, myocardial
infarction and other cardiovascular disorders.
The need for at-home sleep assessment devices is
well recognized by sleep disorder community. Many
significant sleep pathologies, especially
sleep-related breathing disorders, are diagnosed by
clinical polysomnograms (PSGs) which cost about $600
- $3000. These tests require special hospital or
sleep disorder center over-night stays with
technicians present to monitor both the equipment
and the patient. Such intensive study provides the
best possible patient care and obtains the best
possible data for diagnosis of sleep disorders. Less
expensive alternatives however, using ambulatory
instruments and technician-free-home recording can
provide both a substitute for the clinical sleep lab
studies in certain situations, particularly for some
diagnoses of very severe disorder, and serve as
preliminary screening to determine the need for a
more complete test for other situations. Since Sleep
Medicine Centers are also not always affordable or
readily accessible to many patients, at-home or
ambulatory (portable) monitoring can considerably
reduce this problem by taking the sleep study to the
patient in his own environment. In addition to their
role in screening and diagnosis, ambulatory monitors
can also enhance evaluation of treatment efficacy
and compliance.
Patients with excessive sleepiness pose a
particularly significant clinical population whose
disorder is not only life threatening for the
patient but also, because of the increased risk of
injury or accidents by sleep-deprived drivers, both
private and commercial, threatens the lives of many
others. Estimated prevalence of patients with
chronic excessive sleepiness varies considerably but
the surveys which have specifically asked about
daytime excessive sleepiness estimate the prevalence
at about 4 -5% of the adult population.
The role of ambulatory recording for sleep apnea:
One of the primary functions of the sleep study for
evaluating patients with excessive sleepiness is to
determine the presence of a sleep-related breathing
disorder, particularly sleep apnea, which has to be
considered a possibility for essentially all of
these patients. Since there has been no biological
marker or wake time study developed that uniquely
characterizes sleep-related breathing disorders, a
sleep study detecting these events provides the
definitive diagnosis. An ambulatory screening device
for apnea such as the “SleepCheck” monitor developed
by IM Systems may now be used to detect sleep apnea
events with a reasonable degree of accuracy. The
device is also easy to use by the lay person with
minimum patient discomfort and is seen to be
particularly useful as part of the continuum of
diagnosis and care for the excessively sleepy
patient. This is also likely to apply to patients
who complain of insomnia characterized by very
interrupted sleep at night with loud snoring. The
perpetuity of care and treatment for sleep apnea
will be significantly enhanced by the addition of
the SleepCheck at-home monitoring device. In
particular, inexpensive ambulatory or at-home,
technician-free, patient self-recording for apnea
could be used to:
1. Reduce cost by substituting for a sleep lab study
in some situations.
2. Reduce cost by screening out patients who do not
need a full sleep study.
3. Increase accessibility to diagnostic sleep
studies.
4. Provide evaluation in the more natural home
setting.
5. Provide evaluation of treatment compliance and
treatment benefits.
6. Enable larger scale research studies including
epidemiological and clinical outcome studies.
The SleepCheck product:
IM Systems’ technologically advanced monitoring
device, "SleepCheck", was developed as a screening
device for use by those patients who may potentially
suffer from sleep apnea. This product is especially
designed for easy self-application by the patient.
SleepCheck detects all three types of apnea
(obstructive, central and hypopnea), is
sophisticated, affordable, convenient and
user-friendly. The device not only answers the need
for a simple, at-home screening method, but also has
application for determining the need for further
clinical evaluation by polysomnography (PSG).
At-home testing requires that the patient apply a
disposable airflow cannula to the upper lip (similar
to an oxygen cannula) and push the start button on
the unit. The pager size device can be clipped to
the patient’s bed clothing or placed next to a
pillow. SleepCheck measures the patients’
respiratory airflow pressure at the nose and mouth.
A unique feature is a LCD bar graph that follows the
breathing pattern. As the patient inhales and
exhales, the bar moves back and forth, verifying
proper cannula application and monitor operation.
When breathing decreases 50% or more for 10 seconds
or longer, this event is considered an apnea event
and tallied on the LCD readout.
SleepCheck is a miniature battery-powered unit that
is completely portable, allowing the patient total
freedom of movement while sleeping. It is the first
monitor for home use that directly counts and
displays a tally of apnea events and average events
per hour for the sleep night. All report data is
directly displayed on the unit’s LCD – no download
is required. Unlike other sleep monitoring
instruments, which traditionally require a
professional to attach an array of sensors and
electrodes to a bedside recorder, the unit is simple
to use and does not require technical assistance.
The novel feature of SleepCheck is that home
screening for sleep apnea is not only by unattended
means but also there is at no stage of the process,
technician involvement in obtaining the home
recording. The SleepCheck can be sent to the patient
through the mail or the patient can pick it up in a
doctor’s office. No sensors will be placed on the
patient by technicians, no units calibrated nor
instrument set-up required in the patient’s home.
The patient does not adjust the functioning of the
unit. Rather, the unit displays the breathing
pattern and amplitude as a seen by the moving bar
graph which notifies the patient if the signal that
is too low or if the application of the air cannula
is improperly placed or attached. Apnea data is
continually presented on the LCD display as the
sleep night progresses. All results are contained in
the SleepCheck unit and the data can then be read by
the physician simply by pressing the panel button to
view the displayed reports.
The accuracy of SleepCheck’s detection routines and
published results more than suffices for the
intended use of SleepCheck as an at-home screening
tool and it uses a simple approach easily understood
by clinicians and physicians. It should be noted
that the apnea detection algorithms (embedded
programs) are coded inside the monitor and the
detection process occurs in real-time, recording
each apnea event as it occurs during the sleep
night. Direct results are then provided on the LCD
readout and not by complex PC analysis on data
downloaded from bedside or PSG recorders.
SleepCheck’s features :
1) advanced airflow-pressure technology, 2) direct
readout on the LCD display, 3) displays average
hourly apnea events, 4) displays total nightly apnea
events, 5) displays apnea events per hour, 6)
provides a bar-graph breathing indicator to confirm
proper cannula attachment and operation, 7) features
nine-hour recording time to cover a full night’s
sleep period, 8) provides error detection, and 9) is
portable, self-contained and uses an easy to replace
AAA battery.
To verify the integrity of the monitoring process,
the error detection function reports the condition
of the cannula sensor during sleep. If the cannula
becomes displaced from the nose or mouth area or is
unable to sense adequate airflow for at least 15
minutes, an error message ("E") is indicated on the
LCD display for each hour of monitoring in which the
condition occurs. This feature provides an accurate
report of false negatives which is essential for
accurate monitoring of apnea events.
SleepCheck applications :
Besides testing and diagnosing patients for sleep
apnea at the standard sleep disorder center, sleep
professionals can now use SleepCheck to provide
inexpensive sleep apnea evaluations outside the
clinical or hospital setting. With SleepCheck, sleep
therapist, researchers, primary care physicians, GPs
and other medical specialists can easily and
inexpensively screen for the presence and severity
of apnea. Once a diagnosis has been made, an
appropriate treatment plan can be formulated.
Following treatment, SleepCheck can objectively
measure the effectiveness of treatment.
Furthermore, SleepCheck has major applications for
use by all medical professionals who have interest
in assessing sleep disordered breathing. Dentists
who treat sleep apnea patients with special
appliances are eager to measure apnea events
pre-appliance and post-appliance to verify the
effectiveness of their apparatus. Otolaryngologists
(head and neck surgeons), as well as plastic
surgeons who perform corrective procedures on the
throat or sinus cavities can assess the
effectiveness of their surgery or re-constructive
surgical procedures. The efficacy of surgical
adjustments to the throat, including uvula, soft
palate and tonsil infections, or corrective
procedures to the nasal cavities for polyps or a
deviated septum, can now be assessed using objective
measures rather than subjective reports by the
patient. Neurologist and sleep specialists can
evaluate the effectiveness of non-surgical methods
used to reduce apnea, and monitor the results of
their drug or behavioral therapies. Pulmonologists
can ascertain if a Continuous Positive Airway
Pressure (CPAP) mask is required and facilitate CPAP
management, which helps relieve breathing
obstructions and heavy snoring.
The introduction of SleepCheck to the sleep disorder
marketplace represents a major opportunity for an
apnea-screening product and has the potential for
strong market penetration and a substantial return
on investment. The field of medicine engaged in the
study and treatment of sleep-related disorders is
eager for home monitoring products that are proven,
inexpensive, simple to use, and will not only
facilitate accurate screening, but also can provide
definitive diagnosis and deliver follow-up
monitoring. SleepCheck fills all of these
requirements. It is ideally suited for use by
physicians who screen and treat patients who are
suspected of, or who are diagnosed with sleep apnea.
SleepCheck recording method:
An FDA Cleared 3-port oxygen oral/nasal cannula is
connected to the SleepCheck which contains a
solid-state air pressure transducer to measure the
airflow signal. This configuration allows monitoring
the inspiration and expiration function during the
breathing cycle. By measuring the airflow-pressure
signal, the SleepCheck monitor transforms the
changes captured by the oral/nasal cannula into
electrical signals, thus providing an accurate
analog representation of the breathing pattern. The
pressure range for the SleepCheck monitor fully
encompasses human breathing which typically ranges
from ±0.5 to +2 cm H2O(4 torr) for quiet breathing
with maximums to –6 cm H2O with increased
inspiration driving pressure.
Accuracy of SleepCheck :
Clinical results published in the Journal of SLEEP,
presented at a number of sleep medicine conferences,
and submitted to both NIH and the FDA, have shown
that the single measure of oral/nasal airflow is an
accurate means for detecting and screening for apnea
events. Data from these studies has been compared
with the gold-standard polysomnography (PSG -
polygraph studies) performed in a clinical sleep
laboratory. Compared with clinical PSG, SleepCheck
correlates at 97% overall and 94% point to point for
identifying apnea events. See the six clinical
testing studies listed below.
FDA -510k Clearance #K022294
SleepCheck received pre-market approval for sale
and distribution on April 25, 2003. The details of
this approval process are described below:
Patent award:
A U.S. patent for the SleepCheck technology entitled
"Non-Tethered Apnea Screening Device", was awarded
to Krausman and Allen and Assigned to IM Systems
November 7, 2000. US patent # 6,142,950.
Home-recording units commonly used for evaluation
of sleep apnea:
Current portable PSG systems share common
less-than-desirable features for home recording. (1)
Their use is complex, the equipment is expensive and
a technician usually must be involved for its set-up
and sometimes for disconnecting the system. (2) The
data collected must be subjectively analyzed in
detail by well-trained sleep technicians or
professionals, although usually with some computer
assistance. (3) They are usually designed for
measuring ventilating airflow by temperature changes
and not air pressure. (4) Their use requires
patients to be outfitted with an array of tethered
electrode wires and sensors for connection to bulky
body-worn monitors or tabletop console recording
systems. (5) The size, weight and tethered sensors
do not allow the patient to be fully ambulatory.
This limits the accuracy of diagnosis and treatment
evaluation for conditions where the sleep disorder
usually leads to frequent periods out of bed,
periods of sleep during normal wake times, and
patients who may not be compliant with difficult
instructions or movement restrictions. (6) The costs
are too high to produce any significant savings for
the health-care system. Thus, with present
state-of-the-art equipment for recording apnea and
sleep-related events, the patient is unable to
self-apply the apparatus and is generally unable to
freely move about unencumbered once the apparatus is
applied.
Patient Reimbursement:
As the cost of health care continues to rise and
reimbursement becomes more difficult, lower cost
alternatives to the high cost of sleep studies will
undoubtedly become more attractive. Presently, some
insurance companies have reimbursed for unattended
home testing for sleep apnea using CPT code #
95806-52. On a State-by-State basis, a few insurance
providers and Medicare have begun to pay for at-Home
Sleep Studies. However, program standards have not
been established and reimbursement may not always be
approved. Although there is no guarantee for
reimbursement from HMOs, Medicare or other
providers, the climate is shifting and unattended
at-home testing is gaining acceptance. Many
physicians are now looking to move screening and
other forms of testing from the laboratory to the
home environment. Technological advances for
technician-free home-based monitoring is seen as a
major step forward for providing a simple and
convenient method for diagnosing sleep disorders,
especially for the various forms of apnea and sleep
disordered breathing. SleepStrip has reported that
the above CPT reimbursement code has been
successfully used by physicians to bill the
patient’s insurance company, HMO, or Medicare for an
overnight sleep test using the SleepStrip product.
If approved or allowed, the suggested billing for
SleepCheck would be in the $100 range per sleep
night.
The price for the SleepCheck, represents a
significant decrease form the clinical sleep lab
testing enabling for the first time accurate and
cost-effect screening. The SleepCheck monitor is
sufficiently inexpensive and easy to use that is
should dramatically reduce current reimbursement
barriers. The potential significance of this access
for the family doctor or sleep medicine specialist
deserves special recognition as result of the
innovation in this screening product. SleepCheck
offers for the first time a potential clearly
cost-effective device for screening the sleep apnea
patients. |
