OXYGEN THERAPY IN THE HOME OR EXTENDED CARE FACILITY
Distinguished
Professor of Plastic Surgery and
Professor
of Biomedical Engineering
University
of Virginia Health Systems
Charlottesville,
Virginia 22901
CHARLES
R. WOODARD, B.S.
Research
Associate
University
of Virginia Health Systems
Charlottesville,
Virginia
COLLEEN
M. NATARAJAN, B.S.N.
Research
Associate
University
of Virginia
Charlottesville,
Virginia
Long-term oxygen therapy (LTOT) is an effective prescription drug for patients with advanced chronic obstructive pulmonary disease (COPD) and chronic hypoxemia. When home oxygen therapy (HOT) is used in conjunction with pulmonary rehabilitation, it has improved the quality of patient life. Physiologic improvements may include amelioration of cor pulmonale, enhanced cardiac function, increased body weight, reversal of polycythemia, improved neuropsychiatric function and exercise performance, reduced pulmonary hypertension, improved skeletal-muscle metabolism, and possible reversal of sexual impotence.1 In addition, oxygen is the only drug proven to increase survival in COPD patients with hypoxemia.
Based on 1993 Medicare data, it is
estimated that 616,000 patients are receiving HOT, at an annual cost of $1.4
billion.2 This cost exceeds
the entire annual budget of the National Heart, Lung, and Blood Institute for
1993. Consequently, the Health Care
Financing Administration (HCFA, Baltimore, MD, 410-786-3000), which funds
Medicare, has attempted to develop stringent guidelines for reimbursement to
curb therapeutic abuse.
Oxygen is defined as a medication to correct hypoxemia by the healthcare industry. Currently, Medicare does not provide reimbursement for any outpatient medications, and therefore would not cover HOT as a medication. Instead, the HCFA classifies oxygen and oxygen delivery equipment as durable medical equipment (DME), which allows for patient reimbursement. The indications for physician prescribed HOT are similar to those used in the Nocturnal Oxygen Therapy Trial performed by the National Institutes of Health (NIH), and are as follows3:
Arterial partial pressure of oxygen (PaO2) equal to or less than 55 mmHg or arterial oxygen saturation (SaO2) equal to or less than 88% are the guidelines for LTOT. In addition, those patients with PaO2 56 to 59 mmHg, or SaO2 at 89% meet the criteria for LTOT with one of the following indications:
· Electrocardiographic evidence of cor pulmonale
· Edema due to congestive heart failure (CHF)
· Erythrocytosis greater than 56%
Oxygen may also be prescribed for patients with hypoxemia during exercise or sleep. During exercise, the patient must have a PaO2 equal to or less than 55 mmHg or SaO2 equal to or less than 88%. A sleeping patient must have a PaO2 equal to or less than 55 mmHg or SaO2 equal to or less than 88%, or a drop in PaO2 of more than 10 mmHg or in SaO2 of more than 5% with signs and symptoms of hypoxemia, including restlessness and insomnia.
Current Medicare requirements for
reimbursement of HOT include4:
1.
A
Medicare-certified laboratory must perform PaO2 or SaO2 measurement. This condition prevents a conflict of
interest, where an oxygen supplier or home health provider supplies and
certifies the need for HOT.
2.
Arterial
blood gases must be obtained following optimum medical management. Medicare acknowledges the need for oxygen
therapy for short-term clinically unstable patients. However, the diagnosis for LTOT should only occur after the
patient is stabilized and receiving appropriate therapy.
3.
A
physician or an employee of the physician must complete the Certification of
Medical Necessity (Form HCFA-484) and only the physician can sign the
form. Previously, the oxygen suppliers
completed the necessary forms and mailed them to a physician for
signature. Consequently, the physician
was unaware of the therapy being provided and had no records concerning the
therapy.
4.
Retesting
and recertification are required in 61 to 90 days if the initial PaO2 was
greater than 55 mmHg or SaO2 greater than 88%.
This recommendation is for short-term clinically unstable patients that
require reevaluation after 2 to 3 months to determine the need for LTOT. Therefore, the recommendation for reevaluation
should apply regardless of the initial PaO2 or SaO2.
5.
Recertification
(but not retesting) is required in all patients after one year. HCFA recognizes that once the need for LTOT
exists, retesting is unecessary.
However, documentation of patient compliance with therapy is required
after one year.
6.
After
the first year, recertification is necessary only if the oxygen prescription is
changed. Retesting of PaO2 or SaO2 is
not necessary, but may be justifiable to determine disease progression.
7.
Portable
oxygen is covered if the patient is mobile in the home. The requirement specifies the need for
patient mobility within the home, but does not indicate the need or ability for
travel outside the home. Mobility is
defined as the patient frequently travelling beyond the limits of a stationary
system with 50 feet of tubing attached.
OxiScan™ (Airsep®,
Buffalo, NY) is an oximetry recording and reporting system used by physicians
and healthcare providers to determine whether a patient requires HOT. Designed for reliability, easy operation,
and patient comfort, the OxiScan™ utilizes the Delta Sleep Apnea Index (DSAI)
to measure variations between successive oxygen saturation data. This approach is useful for patients who experience
obstructive apneic episodes during sleep, as they do not have significant
desaturation, but have multiple occurrences.
Because patients with obstructive sleep apnea (OSA) do not desaturate in
a routine physical examination during the day, physicians do not consider them
candidates for oxygen therapy. This
new, innovative approach to oximetry provides accurate evaluation of these
patients in a nocturnal setting with a sensitivity of 98%. It is recognized that polysomnography
remains the “gold standard” as a diagnostic tool for COPD and OSA
patients. However, when it is used with
DSAI as a supporting parameter, physicians are able to identify potential sleep
disorders in patients who previously had seemingly normal pulse oximetry
recordings. Therefore, it is
recommended that polysomnography be used with the OxiScan™ to evaluate accurate
candidates for HOT.
Under a prospective payment system, all DME has been covered by the HCFA. Home oxygen represents 45% of the total cost of DME. The current Medicare reimbursement program considers all oxygen delivery systems to be therapeutically equal and “modality neutral.” Therefore, the reimbursement provided is a combination of the costs of liquid and gaseous systems with some adjustments for high (greater than 4 liter/minute) and low (less than 1 liter/minute) flow rates. This guideline has provided incentive to DME suppliers to supply the least expensive oxygen delivery devices for maximum profit without regard for the patient’s health. For example, a supplier in an underserved or rural area may legally refuse to supply anything other than an oxygen concentrator and heavy steel cylinders on wheels for a mobile patient, even though the physician may have requested something light and ambulatory that would facilitate rehabilitative therapy. The Medicare reimbursement for this situation is the same if the supplier issues the more expensive ambulatory unit or the less expensive, bulky “portable” unit.
Current studies have shown that 80%
of HOT patients are provided with the oxygen concentrators with heavy steel
cylinders.5 Consequently,
the HCFA believes that it is overpaying for HOT. Therefore, the HCFA has recommended a 40% reduction in
reimbursement for all supplied oxygen delivery systems. The implication of this proposal would be a
greater incentive for DME suppliers to provide the least expensive device to
maintain profitability. Several medical
societies including the American Thoracic Society, the American College of
Chest Physicians, and the National Association for Medical Direction of
Respiratory Care (NAMDRC), have recommended that the HCFA abandon this proposal
and recognize that there is a distinct difference in the cost and quality of
modern stationary, portable, and ambulatory oxygen systems. This recommendation by the medical societies
places the responsibility of determining need for a specific oxygen delivery
device on the physician rather than the supplier.
In the past, large gas cylinders were used for HOT. They were bulky and unattractive, requiring frequent replacement if used continuously. Because each cylinder lasted only 2 to 3 days, multiple cylinders had to be stored in the home. Today, the bulky cylinders have been replaced by more modern versions and are only used as back-up units in the event of power failure.
Currently, the most widely used
stationary systems concentrate oxygen with a molecular sieve that separates
nitrogen from oxygen. When first
introduced, the systems were noisy, heat-producing, and as large as a
refrigerator. Because of advances in
technology, today’s stationary concentrators average 40 lbs to 60 lbs and are
quieter, more efficient, and easier to maintain. These systems are also relatively inexpensive, and are therefore
used frequently by DME suppliers for a high rate of return. A 95% oxygen concentration at flow rates of
4 liters to 6 liters/minute can be achieved by modern concentrators. These devices also have alarms that sound
when the flow rate falls below a critical level, ensuring adequate oxygen
delivery. Unfortunately, the cost of
power to operate these devices is not reimbursable, and the concentrators are
inoperable in the event of a power failure.
The liquid oxygen is stored in large
insulated canisters weighing 60 lbs to 120 lbs. The reservoir requires frequent refilling. Although the cost of the liquid oxygen
remains relatively inexpensive, the delivery fees, especially to rural areas,
may be quite expensive and are not reimbursable. Oxygen venting into the surroundings occurs, even when the system
is not in use, reducing the overall efficiency of stationary systems.
The NewLife® Elite (AirSep®,
Buffalo, NY) oxygen concentrator is the optimal stationary oxygen delivery
system available on the market. Its
convenient patient controls and handles, safety features, and quieter operation
complement its aesthetically pleasing exterior design. A roller base design provides bilateral air
exhaust paths to lower internal temperatures and eliminate rain-out, thereby
extending the life of the unit. Its
spring-mounted compressor allows for quieter operation, as well as cooler operating
temperatures.
From a clinical prospective, the
NewLife® concentrator has several innovative features. Its Locking Flow feature protects CO2-retaining
patients from the dangers of higher liter flow. The built-in Flow Restrictor prevents overdrawing of oxygen by
the patient. Quieter operation allows
for unit placement directly next to the patient’s bed. The cool running of the concentrator reduces
the concern of heat exhaustion into the patient’ room. The concentrator’s efficiency may reduce
power consumption by 20% when compared to other marketed concentrators. This remains important to the patient, as
power expenses may not be reimbursable.
A long power cord facilitates easy movement around the house on its
built-in, protected wheels.
Several affordable options from AirSep®
increase the efficiency of the oxygen concentrator. The Ecocheck® oxygen monitor is a small electronic device
utilizing ceramic O2-sensing technology initially developed for the
military. The device immediately
responds to changes in oxygen purity, remaining insensitive to temperature and
barometric pressure changes. The
single-light system illuminates when the oxygen level is below 85%, sounding an
alarm if the condition continues for more than 15 minutes. The Air Outlet feature provides a source of
compressed air directly from the unit’s own internal compressor, permitting
nebulizer treatments simultaneously with oxygen therapy from the NewLife®
unit. The oxygen flows from the outlet
at 6 liters per minute at 12 psig with an easy-to-use on/off valve. This feature may prove invaluable with the
changing reimbursement on medication compressors as it performs a dual function
using only one piece of equipment. The
Dual 6 option increases the delivery of the concentrator to 6 liters per minute
of oxygen at 90% ± 3% purity. It shows
the system pressure digitally on a continuous pressure display (CPD), contains
a transducer to continually monitor pressure, and enables viewing of the diagnostic
indicators and CPD through the air intake opening on the back of the unit. This option is ideal when two patients in
the same home require oxygen therapy, because they may simultaneously use the
concentrator. It also remains an ideal
option if only one patient has insurance coverage for the device.
Most COPD patients with hypoxemia remain mobile and active within their homes. Therefore, there is a large demand for oxygen delivery systems that can accommodate the lifestyle of these patients, as well as increase the opportunity for rehabilitation. A portable system is defined as a system weighing more than 10 lbs designed to be transported, but not easily carried by the patient. An ambulatory system weighs less than 10 lbs when filled with oxygen, lasting for at least 4 hours at a flow equivalent to 2 liters/minute of continuous flow, and allows the patient unrestricted mobility with ease of transport.
Portable units provide some degree
of mobility, but are difficult to maneuver in and out of vehicles and require
transportation in a stroller. The power
source for these devices may either be a standard 12-volt battery or a
conventional AC electrical outlet.
Portable concentrators have been developed that weight only 15 lbs,
while delivering 30% to 40% oxygen.
However, higher flow rates to compensate for the low delivery of oxygen,
require that the systems be frequently refilled.
Ambulatory liquid oxygen delivery
systems represent a revolutionary advancement in the quality of HOT. These ambulatory devices are engineered to
flow on demand, by sensing the start of ventilation and delivering a pulse of
oxygen during early inspiration for effective gas exchange in the lungs. Current systems weigh approximately 5 lbs when
filled, last up to 8 hours at a flow rate of 2 liters/minute, and may be
carried in a small pack around the waist.
Ambulatory systems are pneumatically operated, eliminating the need for
an outside power source. To offset
maintenance costs, the system is used in conjunction with a stationary oxygen
concentrator.
Future investigations into the most
efficient and cost-effective systems are currently underway. To reduce costs, scientists are developing
transfilling devices that could store oxygen at lower pressures, thereby increasing
the amount stored in each tank. Also,
researchers are developing materials that would reduce the atmospheric venting
observed in the current oxygen delivery devices.
Oxygen-conserving devices reduce the need for frequent oxygen renewal. From a rehabilitative standpoint, this technology has reduced the overall weight of ambulatory devices. Because it is often difficult to maintain high oxygen concentrations that are needed for patients with refractory hypoxemia, oxygen-conserving devices allow these patients to receive HOT, rather than permanent care in a hospital setting.
Two different approaches have been
used in oxygen-conserving devices. The
first employs a mechanical or increased anatomical reservoir that fills with
100% oxygen prior to exhalation. The
entire amount of oxygen then empties into the lungs during early
inspiration. Examples of the mechanical
reservoir include the nasal cannula and pendant reservoir cannula. Both systems make use of a collapsible
chamber that fills during exhalation and empties during inspiration, in a 20 mL
bolus of 100% oxygen. The nasal cannula
is more comfortable with a secure fit, but is not aesthetically pleasing, while
the pendant cannula has the advantage of being less conspicuous. One example of an expanded anatomical
reservoir is a transtracheal oxygen system.
The second and most widely used
oxygen-conserving system, due to its efficiency, delivers a pulsation of a
bolus of oxygen during the first one fourth to one half of inspiration. In this case, most of the oxygen is directly
delivered to the oxygen exchanging area of the lungs with little lost in the
anatomical dead space. In addition,
COPD patients inhale for approximately one part of the breathing cycle, while
exhaling for three to five parts. This
mechanism would eliminate oxygen flow during expiration that would otherwise be
wasted. The overall reliability,
safety, and efficacy of these devices have been proven, with noise being the
only complaint from some patients.
AirSep® has combined the pulse flow/every
breath and pulse flow/intermittent breath in their revolutionary Impulse™
Select oxygen-conserving device.
Because both systems have their own advantages, the Impulse™ Select allows
the physician to choose the optimal setting for their patients. The device has an easy-to-adjust internal
switch that allows the provider to select an appropriate pulse mode for a
particular patient. One mode maximizes
ambulation time, while the other maximizes oxygen output. The flow selector provides 1-6 liters per
minute in oxygen output. The Impulse™
Select uses one ‘D’ size battery and contains an audible and visual alarm when
the power source is depleted. Because
the device weighs between 5.4-6.2 lbs, it is easily transported in its
convenient carrying case. Consequently,
this oxygen-conserving device is optimal for any ambulatory patient, regardless
of prescription.
Transtracheal oxygen (TTO) systems deliver oxygen directly through a catheter inserted into the cervical trachea. Experience and training in this technique are required for proper and effective placement. The SCOOP™ catheter (Transtracheal Systems, Englewood, CO, 800-527-2667) and the Heimlich Microtrach™ catheter (Life Medical Technologies, Salt Lake City, NV, 801-972-1900) have a similar introduction pathway. The SCOOP™ system has a four-phase process: (1) patient evaluation, education, and device selection, (2) catheter insertion with stent placement, (3) in-place catheter cleaning through the immature tract, and (4) catheter removal for cleaning once the tract has become mature. The Heimlich Microtrach™ follows a similar protocol, except it does not use a stent, and utilizes oxygen only after the wound has healed. The Cook ITOC™ (Cook Inc, Critical Care Division, Bloomington, IN, 800-457-4500) surgically tunnels under the skin from the lower thorax to the neck before insertion into the cervical trachea.
A TTO system may be used in conjunction with a demand-flow ambulatory device to reduce further oxygen consumption, increasing the longevity of the ambulatory device. Studies have shown that the TTO system enhances patients’ adherence to therapy. Consequently, exercise tolerance is increased, and the work of breathing is decreased. A reduction in hospitalization of patients employing both systems in conjunction has been documented.
High cost and risk of infection are two major disadvantages of the TTO system. Accumulation of mucus balls, causing tracheal obstruction, is the most common complication and may be avoided with routine cleaning. Detailed patient education, support from healthcare personnel, and careful device selection all contribute to patient acceptance and a reduction in complications.
SHORT-TERM OXYGEN THERAPY
Due to the high cost of in-patient care, there is increased pressure for early discharge of patients with acute illness, even before the illness has resolved. Many COPD patients may require oxygen to leave the hospital, but may be taken off oxygen therapy once the acute episode resolves. If LTOT is not documented before hospital admission, then the patient requires a reevaluation 2 to 3 months after discharge for determination of LTOT necessity. Because LTOT is a lifetime commitment, proper documentation of a need is necessary.
BIBLIOGRAPHY
1. O’Donohue WJ. Advanced lung disease: Home oxygen therapy. Clin Chest Med 1997;18:535-45.
2. O’Donohue WJ, Pplummer AL. Magnitude of usage and cost of home oxygen therapy in the United States. Chest 1995;107:301-2.
3. Nocturnal Oxygen Therapy Trial Group. Continuous or nocturnal oxygen therapy in hypoxemic chronic obstructive lung disease: A clinical trial. Ann Intern Med 1980;93:391-8.
4. Conference Report. New problems in supply, reimbursement and certification of medical necessity for long-term oxygen therapy. Am rev Respir Dis 1990;142-721-4.
5. Weg JG, Haas CF. Long-term oxygen therapy for COPD: Improving longevity and quality of life in hypoxemic patients. Postgrad Med 1998;4(103).