Patent Application
20230173214
According to the World Health Organization (“WHO”) over two hundred fifty million (250,000,000) people world-wide suffer from chronic obstructive pulmonary disease (“COPD”) and other lung disorders. Patients with moderate to severe COPD are typically prescribed supplemental oxygen in order to raise the oxygen level in their blood. Long term administration of oxygen to patients with chronic respiratory failure has been shown to increase survival in patients with severe resting hypoxemia, which is a below-normal or low level of oxygen in the patient's blood stream.
Supplemental oxygen has been provided in the past by traditional pressurized oxygen cylinders and more recently by oxygen concentrator devices that generate ninety percent (90%) or greater purity of oxygen from ordinary or ambient air through the use of zeolites and a process called pressure swing adsorption. An example of such oxygen concentrator device is described in U.S. Pat. No. 8,894,751, titled “Ultra Rapid Cycle Portable Oxygen Concentrator.”
Portable supplemental oxygen allows patients to be mobile and receive the further benefit of exercise by facilitating patient exercise while carrying the portable oxygen concentrator. COPD, however, like many lung diseases is a progressive disease. Over time, patients will typically require more oxygen to maintain the appropriate blood oxygen saturation level. As more oxygen is required, the oxygen concentrators typically require larger and heavier sizes in order to generate the higher level of oxygen necessitated by the patient. Unfortunately, the higher levels of oxygen tend to be drier and cause greater irritation to the patient's respiratory tract when compared to lower levels of concentrated oxygen or no concentrated oxygen.
A recent study has shown that with certain patients, non-invasive ventilators can produce s higher fraction of inspired oxygen (“FiO2”) and increased tidal volumes compared to oxygen concentrators, both pulse dose and continuous flow. See McCoy, Robert, A Bench Study to Compare Portable Therapies for Respiratory Insufficiency: Continuous Flow Oxygen (CF), Intermittent Flow Oxygen (IF), and Non-Invasive Open Ventilation (NIOV) Valley Inspired Products. In the McCoy study, a non-invasive open ventilation (“NIOV”) system, from Breathe Technologies, Inc. provided higher FiO2 and higher tidal volumes than the oxygen concentrators used in the study. The NIOV system and its successor product, the LifeAir 2000, are pseudo-portable ventilator products. To be truly portable such ventilators should be capable of being non-electrically tethered for an extended period of time and be able to generate the necessary air and oxygen quantity and concentration via a portable power source such as a battery.
COPD is a group of progressive lung diseases. The most common are emphysema and chronic bronchitis. Many people with COPD have both of these conditions. Emphysema slowly destroys air sacs in your lungs, which interferes with outward air flow. Bronchitis causes inflammation and narrowing of the bronchial tubes, which allows mucus to build up.
The leading cause of COPD is tobacco smoking. Long-term exposure to chemical irritants can also lead to COPD. It's a disease that usually takes a long time to develop. Diagnosis usually involves imaging tests, blood tests, and lung function tests.
There is no cure for COPD, but treatment can help ease symptoms, lower the chance of complications, and generally improve quality of life for the COPD patient. Medications, supplemental oxygen therapy, and surgery are some forms of treatment that are utilized to ease symptoms. Untreated, COPD can lead to a faster progression of the disease, heart problems, and worsening respiratory infections. It's estimated that about thirty (30) million people in the United States have COPD. As many as half are unaware that they have it.
COPD is a leading cause of hospitalizations in industrialized countries. In the United States, COPD is responsible for a large amount of emergency department visits and hospital admissions. In the year 2000, it was noted that there were over seven hundred thousand (700,000) hospital admissions and approximately one and one-half million (1,500,000) emergency department visits associated with COPD. Among people with lung cancer, between forty and seventy percent (40-70%) also have COPD.
About one hundred twenty thousand (120,000) people die from COPD each year in the United States. It's the third leading cause of death in the United States. More women than men die from COPD each year. It's projected that the number of patients diagnosed with COPD will increase by more than one hundred fifty percent (150%) from 2010 to 2030. Much of that increase can be attributed to an aging population.
The lung damage that occurs with COPD can cause hypoxia if it becomes too severe. COPD can have harmful effects on the body when it interferes with oxygen levels. If hypoxia progresses too far, it can lead to disability and death.
Oxygen passes into the blood from lung tissue through the alveoli, or air sacs. Oxygenated blood then leaves the lungs and travels around the body to other tissues. Vital organs and systems, especially the brain and heart, need enough oxygen to survive. COPD damages the air sacs in the lungs and interferes with this process. If the damage reaches a critical point, a person may develop hypoxia. Hypoxia occurs when the blood does not deliver enough oxygen to the air sacs in the lungs.
A person's body can adapt to cope with lower oxygen levels than are usual. However, in people with COPD, hypoxia in the lungs means oxygen levels become extremely low. When oxygen levels reach an extremely low level, the organs in the body do not get enough oxygen and start to develop damage and injury. This is known as hypoxemia.
Hypoxia and hypoxemia can also lead to other conditions, including neurocognitive dysfunction, pulmonary hypertension, secondary polycythemia, skeletal muscle dysfunction, and systemic inflammation, to name a few conditions.
Neurocognitive dysfunction. Hypoxia can cause injury to the brain and nerve cells. Hypoxia may trigger changes in brain function and thought processes. If COPD brings down brain oxygen levels too much, it can also reduce the number of neurotransmitters that the brain creates. Neurotransmitters are chemical messengers that ensure different parts of the brain and nervous system can communicate with each other. Sufficient oxygen is essential for creating these neurotransmitters and making sure they function correctly.
Pulmonary hypertension. Typically, the right side of the heart pumps low oxygen blood to the lungs. Once it reaches the lungs, blood can pick up oxygen from inhaled air. The oxygenated blood then returns to the left side of the heart, which pumps it throughout the body. A person with COPD can experience inflammation in the arteries that transfer blood from the right side of the heart to the lungs. This inflammation can cause high pressure to develop in these arteries, which is also known as pulmonary hypertension. This higher pressure means that the right side of the heart has to work harder to pump blood through those arteries. The over work of the heart can cause damage to the heart, making it weak.
Secondary polycythemia. Secondary polycythemia is the body's response to chronic hypoxia due to COPD. The body starts creating extra red blood cells to transport more oxygen. Extra blood cells mean that the blood is more prone to clotting. In people who have COPD, this condition can also increase the risk of abnormal heart rhythms, longer hospital stays, and more breathing complications.
Skeletal muscle dysfunction. People whose COPD has reached a more advanced stage can have difficulty engaging in physical exercise and activity. As a result, their muscles start to become weak. The weakened muscles are more easily fatigued, making it difficult for a person with COPD to exercise. Lack of exercise or the inability to exercise can exacerbate numerous conditions of the patient with COPD.
Systemic inflammation. A chronic lack of oxygen can cause inflammation in the body's tissues, which can lead to several conditions. Examples include atherosclerosis, which makes the arteries harden. Atherosclerosis increases the risk of heart disease, heart attack, and stroke.
If a person has severe hypoxemia due to COPD, a doctor will commonly recommend oxygen therapy. Oxygen therapy involves breathing in extra oxygen through a small, flexible tube, or nasal cannula, that fits in the nostrils. According to a 2019 study in the open access scientific journal PLOS One, long-term oxygen therapy may improve the quality of life for people with COPD hypoxemia by decreasing COPD flares and increasing tolerance to physical activity.
Current studies show that individuals with severe COPD are likely to benefit the most from oxygen treatment. However, not everyone with COPD is a good candidate for supplemental oxygen. It is advisable that a doctor carefully prescribes and closely monitors oxygen therapy. Too much oxygen can lead to higher carbon dioxide levels, although exercise can be challenging for people with COPD, physical activity can improve oxygen uptake in the lungs of a person with mild COPD and improve their breathing patterns. Those with more advanced hypoxia, however, may find any amount of physical activity difficult.
In addition to COPD, other diseases treated with supplemental oxygen include pulmonary fibrosis, pneumonia, cystic fibrosis, severe acute respiratory syndrome coronavirus (SARS-CoV-2 or COVID-19), and sleep apnea.
The average total lung capacity of a human male at sea level is about six liters (6 L) while the same for a female is about four and two tenths liters (4.2 L). Larger, more physically fit people and people living at higher altitudes typically have a larger total lung capacity. Tidal volume, the volume of air moved into or out of the lungs during quiet breathing for both sexes averages about five hundred milliliters (500 ml).
Air is a mixture of gases, primarily nitrogen (N2; 78.6 percent), oxygen (O2; 20.9 percent), water vapor (H2O; 0.5 percent), and carbon dioxide (CO2; 0.04 percent). In the body, oxygen is used by cells of the body's tissues and carbon dioxide is produced as a waste product. The ratio of carbon dioxide production to oxygen consumption is the respiratory quotient (“RQ”). RQ typically varies between seven tenths and one (0.7-1.0).
Each gas component of air mixture exerts a pressure. The pressure for an individual gas in a mixture is the partial pressure of that gas. As stated above, approximately twenty-one percent (21%) of atmospheric gas is oxygen. Carbon dioxide, however, is found in relatively small amounts, approximately four hundredths percent (0.04%). The partial pressure for oxygen is, therefore, much greater than that of carbon dioxide.
The RQ is used to calculate the partial pressure of oxygen in the alveolar spaces within the lung, the alveolar partial pressure of oxygen (“PO2”).
The structure of the lung maximizes its surface area to increase gas diffusion. Because of the enormous number of alveoli (approximately three hundred million (300,000,000) in each human lung), the surface area of the lung is very large, approximately seventy-five square meters (75 m2). Having such a large surface area increases the amount of gas that can diffuse into and out of the lungs.
In the lungs, oxygen diffuses out of the alveoli and into the capillaries surrounding the alveoli. Oxygen (about ninety-eight percent (98%)) binds reversibly to the respiratory pigment hemoglobin found in red blood cells (RBCs). RBCs carry oxygen to the tissues where oxygen dissociates from the hemoglobin and diffuses into the cells of the tissues. More specifically, alveolar PO2 (“PalvO2”) is higher in the alveoli (PalvO2=100 mm Hg) than in blood PO2 (40 mm Hg) in the capillaries. Because this pressure gradient exists, oxygen diffuses down its pressure gradient, moving out of the alveoli and entering the blood of the capillaries where O2 binds to hemoglobin. At the same time, alveolar partial pressure of carbon dioxide (“PCO2”) is lower PalvO2=40 mm Hg than blood PCO2=(45 mm Hg). CO2 diffuses down its pressure gradient, moving out of the capillaries and entering the alveoli.
The result of breathing increased partial pressures of oxygen is hyperoxia, an excess of oxygen in body tissues. Hypercapnia is when a patient has too much carbon dioxide (CO2) in their bloodstream. Excess CO2 usually happens as a result of hypoventilation, or not being able to breathe properly and get oxygen into the lungs. Chronic Restrictive Diseases such as pulmonary fibrosis, Infant Respiratory Distress Syndrome and pneumothorax cause a reduction in lung volume capacity. Chronic Obstructive Diseases such as asthma, COPD, and emphysema do not result in decreased lung capacity, but flow rates are impeded.
The gas exhaled from a human is approximately four to five percent (4-5%) by volume of carbon dioxide, about a one hundred (100) fold increase over the inhaled amount. The volume of oxygen is reduced by a small amount, four to five percent (4-5%), compared to the oxygen inhaled. See table 1.
Average lung volumes and capacities of an average adult male are as follows (Table 2)
One reason a ventilator may be better than supplemental oxygen in raising a patient's blood oxygen saturation level has to do with a patient's inspiration abilities and their lung oxygen and carbon dioxide exchange/transfer effectiveness.
Schematic A shows a typical human pulmonary circuit, including partial pressures of oxygen and carbon dioxide in ambient air, arterial blood, and venous blood. If a patient has poor inspiration capabilities, elevating the oxygen concentration through supplemental oxygen improves oxygen and carbon dioxide exchange in the lungs but the patient will likely have difficulty exhaling carbon dioxide as the tidal volume will not be enough to provide the pressure needed for proper gas exchange. By Henry's law, the solubility of a gas in a liquid is directly proportional to the pressure of that gas above the surface of the solution. This applies to mechanical or noninvasive ventilation in that increasing positive end-expiratory pressure (“PEEP”) increases the pressure in the system. This, in turn, increases the solubility of oxygen and its ability to cross the alveolocapillary membrane and increase the oxygen content in the blood.
Table 3 reflects measurements of oxygen concentration for patients with various tidal volumes at various supplemental oxygen levels.
PEEP is a mode of therapy used in conjunction with mechanical ventilation. At the end of mechanical or spontaneous exhalation, PEEP maintains the patient's airway pressure above the atmospheric level by exerting pressure that opposes passive emptying of the lungs. This pressure is typically achieved by maintaining a positive pressure flow at the end of exhalation. This pressure may be measured in centimeters of water.
PEEP therapy can be effective when used in patients with a diffuse lung disease that results in an acute decrease in functional residual capacity (“FRC”), which is the volume of gas that remains in the lung at the end of a normal expiration. FRC is determined by primarily the elastic characteristics of the lung and chest wall. PEEP is typically utilized for acute respiratory failure syndrome (“ARFS”) to allow reduction in the level of oxygen being given. Extrinsic PEEP can be used to increase oxygenation.
Extrinsic PEEP can also be used to improve ventilation-perfusion (“VQ”) mismatches. The application of positive pressure inside the airways can open or “splint” airways that may otherwise be collapsed, decreasing atelectasis, improving alveolar ventilation, and, in turn, decreasing VQ mismatch.
The application of extrinsic PEEP will, therefore, have a direct impact in oxygenation and an indirect impact on ventilation. By opening up airways, the alveolar surface increases, creating more areas for gas exchange and somewhat improving ventilation. Nevertheless, extrinsic PEEP should never be used for the sole purpose of increasing ventilation. If a patient needs to clear CO2 by improving ventilation, the patient should receive some level of pressure support for ventilation, either via bilevel positive airway pressure (“BPAP”) or invasive ventilation.
Extrinsic PEEP also significantly decreases the work of breathing. This is especially important for stiff lungs with low compliance. In intubated patients with low compliance, work of breathing can represent an important part of their total energy expenditure (up to thirty percent (30%)). This increases CO2 and lactate production, both of which may be problems of their own. By decreasing work of breathing, CO2 and lactate production decreases, decreasing the need for high minute ventilation (to correct the hypercapnia and acidosis) and thereby decreasing respiratory drive and further decreasing the work of breathing needed by the patient in a positive-effect loop. An article by Carpio titled, “Positive End-Expiratory Pressure” describes PEEP and reviews the indications, contraindications, complications and other elements of the use of PEEP related to the care of patients requiring ventilation.
The use of extrinsic PEEP is tricky, and although it may be beneficial, it has to be guided by good clinical sense. In cases of dynamic flow obstruction, especially in COPD where there is alveolar collapse, (Note: This does not include asthma where there is inflammation of the airway but not necessarily airway collapse.) the application of extrinsic PEEP will splint the airways open, permitting this way for air to be flushed from alveolar pouches and decreasing auto-PEEP. Extrinsic PEEP will also decrease work of breathing in the appropriate setting. Nevertheless, when applied in the wrong setting, like in patients without dynamic airflow obstruction, the application of extrinsic PEEP will generate back pressure that will prevent air from getting out of the lungs, worsening air trapping. It is also important to understand that the extrinsic PEEP initially will add to the auto-PEEP, increasing the intrathoracic pressure. When used, it is recommended to maintain extrinsic PEEP below seventy-five to eighty-five percent (75-85%) of the auto-PEEP. Again, the use of extrinsic PEEP to treat auto-PEEP is driven by strong clinical sense as not all patients will benefit from it and others will be harmed. A practical way to assess the effects of extrinsic PEEP in auto-PEEP is to apply small increments of extrinsic PEEP and check the static pressures in the lungs. If the static pressures do not increase, then applying extrinsic PEEP may benefit the patient, but if the pressures increase, then it is time to back down on this strategy.
Another factor in designing respiratory treatment devices is understanding that breathing is dynamic, both breath rate and duration change with activities. Oxygen and tidal volume assist are typically correlated to the patient's requirements. Table 4 shows a typical COPD patient's breathing patterns.
When treating a patient needing supplemental oxygen it is important to understand the different blood oxygen saturation levels required for non-COPD patients compared to COPD patients. For non-COPD patients, the respiratory therapist should aim for a saturation between ninety-four to ninety-eight percent (94-98%). Contrary to what may have been practiced in the past, too much oxygen can be harmful. If a patient has a saturation level of one hundred percent (100%) oxygen, the amount of oxygen should be decreased as it creates to high partial pressure of oxygen.
Patients with COPD should have eighty-eight to ninety-two percent (88-92%) saturation levels as their target. The reason to target lower oxygen saturation levels is because COPD patients typically retain too much CO2. Reasons for retaining CO2 include severe obstructive lung disease such as bronchiectasis or cystic fibrosis or severe restrictive lung diseases such as those caused by neuromuscular diseases, severe kyphoscoliosis and severe obesity.
Patients with COPD optimize their gas exchange by hypoxic vasoconstriction leading to altered alveolar ventilation-perfusion ratios (“V/Q”). Excessive oxygen administration overcomes this, leading to increased blood flow to poorly ventilated alveoli, increasing the V/Q mismatch and therefore increasing physiological dead space. This increase in V/Q mismatch occurs in both CO2 retainers and non-retainers but the difference seems to be more profound in certain patients. Another reason too much oxygen can be bad for COPD patients is due to the Haldane effect. Deoxygenated hemoglobin (Hb) binds with CO2 with greater affinity than oxygenated hemoglobin (HbO2). Oxygen, therefore, induces a right shift of the CO2 dissociation curve, which is called the Haldane effect. In patients with severe COPD who cannot increase minute ventilation, the Haldane effect accounts for about twenty-five percent (25%) of the total PaCO2 increase due to O2 administration.
One way to deliver increased oxygen flow and pressure to create PEEP while not providing too much oxygen is to use a venturi mask or nasal cannula.
Typical low-flow oxygen systems provide supplemental oxygen often less than the patient's total minute ventilation. Because the patient's minute ventilation exceeds flow, the oxygen delivered by the device will be diluted with ambient air and thus the inspired oxygen delivery is less than anticipated. Low-flow oxygen delivery systems consist of nasal cannula, nasal catheters, and transtracheal catheters.
The standard nasal cannula delivers an FiO2 of twenty-four to forty-four percent (24-44%) at supply flows ranging from one to eight liters per minute (1-8 LPM). A general formula is FiO2=twenty percent (20%)+(4×oxygen liter flow). The FiO2 is influenced by breath rate, tidal volume and pathophysiology. The slower the inspiratory flow, the higher the FiO2; the faster the inspiratory flow, the lower the FiO2. Since the delivered oxygen percentage is very inconsistent during respiratory distress, a nasal cannula is not recommended for acute severe hypoxemia or patients that breathe on a hypoxic drive where too high of an oxygen concentration may lead to respiratory depression. A nasal cannula utilizes no external reservoir of oxygen and relies on the patient's upper airway as an oxygen reservoir. A humidification device is recommended for flows greater than about four liters per minute (4 LPM) to ensure humidification of the dry inspired gas. Even with humidity, added flows of six to eight liters per minute (6-8 LPM) can cause nasal dryness and bleeding. The best clinical indications for the nasal cannula are for patients who have a relatively stable respiratory pattern, who require low oxygen percentage, or who need supplemental oxygen during an operative or diagnostic procedure, or for chronic home care.
A nasal catheter is a soft paste tube with several holes at the tip. The nasal catheter is inserted into a nare or nostril, which typically needs to be changed every eight hours. The nasal catheter device has been replaced by the nasal cannula in certain situations but can be used for a patient that is undergoing an oral or nasal procedure.
Transtracheal catheters deliver oxygen directly into the trachea. There are washout and storage effects that promote gas exchange, as well as provide high-flow oxygen. High-flow transtracheal catheters may reduce the work of breathing and augment CO2 removal in the chronic oxygen user. Transtracheal oxygen therapy improves the efficiency of oxygen delivery by creating an oxygen reservoir in the trachea and larynx. Consequently, mean oxygen savings amount to approximately fifty percent (50%) at rest and thirty percent (30%) during exercise. Transtracheal oxygen reduces dead space ventilation and inspired minute ventilation while increasing alveolar ventilation slightly, which may result in a reduction of the oxygen cost of breathing. As a result, patients using this device may experience improved exercise tolerance and reduced dyspnea. This delivery device is best used for home care and ambulatory patients who require long periods of mobility and do not feel comfortable wearing a nasal cannula.
Air Entrainment Devices include venturi masks and nasal cannulas. With a traditional Venturi mask system, oxygen inflow is connected to a specific color-coded entrainment device at the base of the mask that provides a set oxygen inflow rate. Various entrainment devices can provide a flow of oxygen from twenty-four hundredths to one-half (0.24-0.5), with an oxygen inflow of four to fifteen liters per minute (4-15 L/min) and a total flow delivered to the patient (including entrained air) of thirty-five to forty-five liters per minute (35-45 L/min). If the patient's peak inspiratory flow exceeds this total flow, a lower flow of oxygen is inspired. A venturi mask can be very beneficial for a patient with COPD who has a low to moderate oxygen requirement but is at risk for hypercarbia with uncontrolled oxygen therapy.
Schematic B shows the fluid dynamics of a venturi device. For a venturi mask or cannula, the gas source is concentrated oxygen, typically greater than ninety-five percent (>95%) oxygen purity. The negative pressure caused by the accelerating oxygen passing through the gas injector and into the larger cannula “pulls” gas, in this case, ordinary air through the narrowed cannula. The effect being a larger volume of “mixed” air and oxygen is delivered to the patient.
Currently, different colored venturis correspond to different flow rates. Blue is typically used with a flow rate of two to four liters per minute (2-4 L/min) and delivers approximately twenty-four percent (24%) O2. White typically corresponds to four to six liters per minute (4-6 L/min) and twenty-eight percent (28%) O2. Yellow typically corresponds to eight to ten liters per minute (8-10 LP/min) and thirty-five percent (35%) O2. Red typically corresponds to ten to twelve liters per minute (10-12 L/min) and forty percent (40%) O2 and Green typically corresponds to twelve to fifteen liters per minute (12-15 L/min) and sixty percent (60%) O2.
Prior art ventilators, except as described below, are designed for hospital or home use with little to no consideration given for portability as the patient is typically not mobile and the equipment requires a stationary power source, i.e., wall socket or is extremely heavy and cumbersome even if a portable power source could be utilized.
Two pseudo portable ventilators are described herein. The first is the VOCSN by Ventec Life Systems. The VOCSN is a combination ventilator, supplemental oxygen, suction, cough assist and nebulizer device that weighs over eighteen pounds (18 lbs.). The VOCSN claims to be portable, but it is hardly wearable and can be difficult for patients with breathing issues to transport.
The second device is the Life2000 ventilation system by Breathe Technologies. The Life2000 ventilator claims to be only one pound (1 lb.) and is wearable, however, the Life2000 ventilator must be connected to an oxygen source or compressor in order to provide ventilation to a patient. The Life2000 compressor is powered via a 110/220 power outlet. Alternatively, an oxygen metal cylinder can be used as a source of oxygen to drive the ventilator to provide oxygen or mixed air and oxygen to a patient. The oxygen cylinder, unlike an oxygen concentrator has a finite supply of oxygen, can be relatively heavy and creates a potential combustion hazard.
Ventilators contribute energy to the respiratory system in the form of pressure assist and/or increased oxygen content of the breathing air. Physicians often prescribe both pressure assist and oxygen therapy together.
The preferred present invention addresses the deficiencies of prior art devices to provide portable ventilation to patients that require supplemental oxygen and prefer to maintain mobility, which often has beneficial effects for the patient.
The preferred invention combines oxygen delivery functions into a portable and preferably carriable unit, even more preferably carriable by a patient with a breathing ailment. The preferred unit or system is preferably carriable by ordinary or average patients with COPD or other lung diseases and preferably allows the patient mobility. A lightweight, preferably less than eight pound (8 lb.), portable ventilator device or system is designed for portability and to provide concentrated oxygen to the patient. To be portable the ventilator is battery operated and able to generate its own oxygen. In addition, the preferred device is scalable and configurable to decrease the weight and cost of the device to the patient, as their disease progresses, or oxygen needs change due to exercise or environment.
Briefly stated, the preferred device is directed to a portable oxygen delivery system including an oxygen concentrator having a housing, a compressor mounted inside the housing, a removably mounted cartridge located within the housing and in fluid connection with the compressor, the cartridge containing a zeolite for removing Nitrogen from air through a pressure swing adsorption process for creating concentrated oxygen, a power source attached to the housing and an oxygen controller device for electronically controlling the pressure swing adsorption process. The portable oxygen delivery system also preferably includes a blowing apparatus fluidly connected to the oxygen concentrator having a blower housing, a blower motor mounted inside the blower housing, a blower fan connected to the blower motor, a second power source attached to the blower housing and a blower controller device for electronically controlling the blower.
The preferred system may be utilized with portable oxygen concentrators described in U.S. Pat. Nos. 8,888,902; 8,894,751; 9,199,055; 9,492,781; and 9,993,765, as well as International Patent Application Publication No. WO 2018/226532, the contents of which are incorporated herein by reference in their entirety. These portable oxygen concentrators may be employed with the preferred system described therein to provide a source of portable concentrated oxygen to address the patient's COPD or other breathing disease.
The foregoing summary, as well as the following detailed description of preferred embodiments of the device, system and method of the present application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the portable ventilator, system and method, there are shown in the drawings preferred embodiments. It should be understood, however, that the application is not limited to the precise arrangements and instrumentalities shown. In the drawings:
Certain terminology is used in the following description for convenience only and is not limiting. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. The words “right,” “left,” “lower” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” or “distally” and “outwardly” or “proximally” refer to directions toward and away from, respectively, the patient's body, or the geometric center of the preferred portable ventilator system and related parts thereof. The words, “anterior”, “posterior”, “superior,” “inferior”, “lateral” and related words and/or phrases designate preferred positions, directions and/or orientations in the human body to which reference is made and are not meant to be limiting. The terminology includes the above-listed words, derivatives thereof and words of similar import.
It should also be understood that the terms “about,” “approximately,” “generally,” “substantially” and like terms, used herein when referring to a dimension or characteristic of a component of the preferred invention, indicate that the described dimension/characteristic is not a strict boundary or parameter and does not exclude minor variations therefrom that are functionally the same or similar, as would be understood by one having ordinary skill in the art. At a minimum, such references that include a numerical parameter would include variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.
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The basic design of the first preferred portable ventilator system 100 includes a portable oxygen concentrator 1, an air and oxygen flow controller or blowing apparatus 3 and a patient interface 5. The air and oxygen controller or blowing apparatus 3 can be remote to the portable oxygen concentrator 1, as shown in the embodiment of
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The zeolite material 1b is used as an ion-exchange bed in domestic and commercial water purification, softening, and other applications. In chemistry, the zeolite material 1b is used to separate molecules (only molecules of certain sizes and shapes can pass through), and as traps for molecules so they can be analyzed. The zeolite materials 1b are also widely used as catalysts and sorbents. Their well-defined pore structure and adjustable acidity make them highly active in a large variety of reactions. The zeolite materials 1b have the potential of providing precise and specific separation of gases, including the removal of water (H2O), carbon dioxide (CO2) and sulfur dioxide (SO2) from low-grade natural gas streams. Other separations include noble gases, nitrogen (N2), oxygen (O2), freon and formaldehyde. As described in WO-532, zeolites are used to remove Nitrogen through a pressure swing adsorption (“PSA”) process. A high-pressure valve 1c is shown at a distal end of a concentrated oxygen conduit 1d extending from the cylinder 1e of the sieve module 1a. Through the PSA process, ordinary air has Nitrogen molecules temporarily bonded to the zeolite material 1b and then evacuated from the cylinder 1e. The remaining concentrated oxygen is forced out of cylinder 1e into the tube 1d.
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To maximize performance and minimize the size and energy use of the turbine or blower fan 21 in the reservoir or blowing apparatus 3, it is desirable to locate the blower fan 21 generally proximate the patient interface 5. Referring to
The effects of mechanical ventilation with positive pressure on the venous return may be beneficial when used in patients with cardiogenic pulmonary edema. In these patients with volume overload, decreasing venous return will directly decrease the amount of pulmonary edema being generated, by decreasing right cardiac output. At the same time, the decreased return may improve overdistension in the left ventricle, placing it at a more advantageous point in the Frank-Starling curve and possibly improving cardiac output.
Proper management of mechanical ventilation also involves an understanding of lung pressures and lung compliance. Normal lung compliance is around one hundred (100) ml/cmH2O. This means that in a normal lung the administration of five hundred milliliters (500 ml) of air via positive pressure ventilation will increase the alveolar pressure by five centimeters per water column (5 cm/H2O). Conversely, the administration of a positive pressure of five centimeters per water column (5 cm/H2O) will generate an increase in lung volume of five hundred milliliters (500 mL). Because ventilators are not always used on normal lungs, compliance may be much higher or much lower. Any disease that destroys lung parenchyma like emphysema will typically increase compliance and any disease that generates stiffer lungs (ARDS, pneumonia, pulmonary edema, pulmonary fibrosis) will typically decrease lung compliance.
The problem with stiff lungs is that small increases in volume can generate large increases in pressure and cause barotrauma. This generates a problem in patients with hypercapnia or acidosis as there may be a need to increase minute ventilation to correct these problems. Increasing respiratory rate may manage the increase in minute ventilation, but if increased respiratory rate is not feasible, increasing the tidal volume can increase plateau pressures and create barotrauma.
There are two main pressures in the system to be aware of when mechanically ventilating a patient: (a) peak pressure is the pressure achieved during inspiration when the air is being pushed into the lungs and is a measure of airway resistance; and (b) plateau pressure is the static pressure achieved at the end of a full inspiration. To measure plateau pressure, an inspiratory hold on the portable ventilator 100 is formed to permit for the pressure to equalize through the system. Plateau pressure is a measure of alveolar pressure and lung compliance. Normal plateau pressure is below thirty centimeters per water column (30 cm/H2O), and higher pressure can generate barotrauma.
Providing ten to twenty centimeters per water column (10-20 cm/H2O) is normally sufficient for ventilators delivering a tidal volume between ten and fifteen milliliters per kilogram (10-15 mL/kg). Most modern ventilators can deliver flow rates between sixty and one hundred twenty liters per minute (60-120 L/min) with a peak flow rate of approximately sixty liters per minute (60 L/min) being adequate for most patients.
The oxygen concentrator 1 output is delivered to an inlet 3a of the blowing apparatus 3 and the blower fan 21 via the concentrated oxygen delivery tube 10. The length, size and composition of the concentrated oxygen delivery tube 10 generally determines how much oxygen flow is decreased to the blowing apparatus 3. The oxygen flow from the oxygen concentrator 1 through the concentrated oxygen delivery tube 10 adds additional energy to the blower fan 21 via a turbine inlet venturi 23, which raises the turbine inlet pressure. A blower motor 21a is mounted inside the blower housing 3b to drive and control the blower fan 21 during operation under direction of the blower controller device 9b. When a patient begins to inhale at the patient interface 5, the vacuum is sensed by a pressure sensor 5a, which can be incorporated into the patient interface 5 or located upstream of the cannula connector 10d along the gas pathway but downstream of the blower fan 21. The pressure sensor 5a preferably sends a signal to the blower controller device 9b, which sends a signal to the blower fan 21 to generate a predetermined volume of air that is delivered to the patient interface 5. At the same time the concentrated oxygen delivery tube 10 in the blower inlet venturi senses a negative pressure, the blower controller device 9b sends a signal to the oxygen controller device 9a and activates the oxygen concentrator 1 to deliver a bolus of O2 as a result of the concentrator pressure sensor 5a sensing an inspiration event at the patient interface 5. The oxygen concentrator 1 may be adjacent to the ventilator, the blowing apparatus 3, or fluidly connected with a tube of up to fifty feet (50 ft) in length. The turbine or blower fan 21 can also be programmed such that PEEP can be maintained in the patient's lungs after each exhalation.
The blower controller device 9b is also preferably configured to increase or decrease the speed of the blower fan 21 based on the sensed pressure at the pressure sensor 5a. The blower controller device 9b is preferably able to control the speed of the blower fan 21 to match the breath pressure requirements of the patient and is able to change and adapt the speed of the blower fan 21 as the patient's breath pressure requirements change and shift with activity or for other reasons. The blower controller device 9b may be designed and configured to speed up and slow down the blower fan 21 so the pressure at the patient interface 5 generally follows the patient's breathing patterns and may be able to replace the valves 14a, 14b, 14c by controlling the speed fo the blower fan 21.
The outlet flow of the blower fan 21 can be controlled with the piezo valves 14, turbine motor speed control, or a combination of both that are directed by the blower controller device 9b. As with the first embodiment, different oxygen concentrator capacities can be used to achieve increased O2 levels. Referring to
The piezo valves 14, 15 can be a better alternative to conventional solenoid valves, especially in applications requiring directly controlled proportional valves. The piezo valves 14, 15 provide relatively gentle and safe speed control for pneumatic cylinders, and work well in medical applications, laboratory automation, manufacturing, and even motor vehicles.
Referring to
This third preferred system 1x does, however, reduce the modularity described in the first and second preferred embodiments of
Referring to
In the event of a power failure, the cylinder 29 of pressurized oxygen of the second preferred embodiment may be used in place of the concentrator 1 and oxygen pressure may be used to cause air to be entrained into the venturi 23 and then flow through the blower 21 to the patient interface or mask 5. Given sufficient pressure from the oxygen cylinder 29, sufficient flow and positive pressure can be developed to provide the patient with positive pressure air.
When the battery 25 becomes discharged to the point that it can no longer support the operation of the blower 21, an alarm is delivered and the blower 21 is shut off. Limited, but sufficient battery power then remains to operate the valves 14, 15 so that inspiration causes its operation and air/oxygen delivery is sustained for several hours.
Referring to
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Alternative preferred embodiments of the medicant delivery apparatus 32 include a small electronic atomizer, nebulizer or vaporizer 37 that generates a medical aerosol simultaneously with the flow of gas from the blower fan 21 to be delivered to the patient. Depending on the required medications of the user, different medications may be provided in medicant delivery apparatus 32. In one preferred embodiment, the atomizer 37 is releasably received in a receiving port 36. The receiving port 36 is electrically connected to the batteries 25 and the blower controller device 9b. The receiving port 36 is connected to the medicant delivery apparatus 32 through a one way valve that allows medication from the atomizer 32 to be delivered into the delivery apparatus 32 as determined by the blower controller device 9b. Alternatively, the delivery apparatus 32 or the atomizer 37 may be quick connected to the cannula connector 10d or may be integrated into the patient delivery tube 10b. In this alternative preferred embodiment, the delivery apparatus 32 or atomizer 37 is preferably mounted in the concentrated oxygen stream outside of the housing 50 and blower housing 3b such that the delivery apparatus or atomizer 37 may be quickly and easily removed and replaced such that the user is able to quickly add or remove medication or other therapeutics depending on patient needs or prescriptions.
In another preferred embodiment, an ozone generator (not shown) is located adjacent the venturi 23. Ozone is an oxidizer that has been shown to kill bacteria and mold. An ozone generator will produce ozone by adding energy to oxygen molecules (O2), which cause the oxygen atoms to part ways and temporarily recombine with other O2 molecules creating ozone (O3). The ozone generator creates ozone by introducing concentrated oxygen from the concentrator 1 into a high voltage chamber that creates ozone through a process known as Corona Discharge. In one preferred embodiment, the blower fan 21 and tubing from the blower fan 21 through to the patient interface 5 is sanitized by ozone by generating ozone at the ozone generator and then blowing the ozone through the blower fan 21 and tubing to the interface 5. Recognizing the dangers of a patient inhaling large amounts of ozone, the system 1 preferably includes a safety mechanism preventing use of the interface while ozone cleaning is occurring. For example, the interface 5 would have to be secured to a tray or receiving cartridge in order for ozone generation to occur. The ozone generator is preferably located adjacent to the venturi 23 or alternatively as a component of the oxygen concentrator 1 (see U.S. Pat. No. 9,492,781, which is incorporated herein by reference in its entirety, see also, for example, FIG. 17 and claim 17).
In another preferred embodiment, a pulse oximeter (not shown) is connected to a patient's finger, neck, wrist, ear lobe or other acceptable location for measuring blood oxygen saturation levels. The pulse oximeter is preferably, wirelessly connected to the oxygen controller device 9a or the blower controller device 9b. The preferred pulse oximeter could be a traditional finger secured unit such as the MightySat from Masimo or the AppleWatch from Apple. Such wireless connection between a pulse oximeter and the oxygen controller device 9a or the blower controller device 9b can be a passive connection where information received from the pulse oximeter is used by a caregiver or the patient to adjust a patient's air and oxygen flow or the connection can be an active connection where the pulse oximeter information or collected data is used to automatically adjust the patient's oxygen and air flow settings to achieve a desired blood oxygen saturation level. In a further preferred embodiment, the pulse oximeter is connected to the oxygen or blower controller device 9a, 9b and a remote computer such as a laptop or phone which contains additional memory storage options, settings, controls, web-based information such as temperature, location, speed, altitude, humidity and pressure. Such additional factors can be used to further adjust a patient's oxygen and air flow while also creating a history of such information for a caregiver to review. It is further contemplated, for example, that such historical data related to the patient's oxygen saturation levels, could be used to pre-empt blood oxygen saturation levels from dropping if historical data shows a pattern that can be anticipated. In one preferred embodiment, a cell phone with a global positioning system (“GPS”) tracker creates a historical map of a travel path of the patient. In one such situation, the patient has historically shown a drop of blood oxygen saturation level upon walking up an incline known on the map. To pre-empt the patient from becoming desaturated below a preferred level, the phone sends a command to the oxygen or blower controller device 9a, 9b to increase oxygen and air flow in anticipation of the incline.
Referring to
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It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the present description.
The present application claims the benefit of U.S. Provisional Patent Application No. 62/989,159, filed Mar. 13, 2020 and titled, “Portable Ventilator,” the entire contents of which are incorporated herein by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US21/22133 | 3/12/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62989159 | Mar 2020 | US |
