Increasing Exercise Tolerance in COPD Patients with Ambulatory Ventilation

A new ambulatory noninvasive ventilation device is proving effective at increasing exercise tolerance for patients with COPD, an important factor for improving patient outcomes and quality of life.

For many COPD patients, a simple walk from one room to the next can be exhausting. For respiratory therapists and pulmonary physicians, improving the exercise tolerance of COPD patients is key to improving their lives, since a chief complaint is often their inability to participate in everyday activities.

Many treatment options have been explored by clinicians and researchers over the years, including supplemental low-flow oxygen, high-flow humidified oxygen, heliox, bronchodilators, exercise training and pulmonary rehab, lung-volume reduction surgery, continuous positive airway pressure (CPAP), and noninvasive ventilation (NIV).1 Despite the fact that, in a research setting, NIV has shown improvements in exercise tolerance and an ability to unload respiratory muscles during exercise, devices have proved too heavy, intrusive, and uncomfortable for at-home use.2

However, a new ventilation device from Irvine, Calif-based Breathe Technologies is attempting to solve those design challenges and increase exercise tolerance for COPD patients. The Non-Invasive Open Ventilation (NIOV) system is a one-pound, wearable, ambulatory ventilation system for the treatment of symptoms associated with a variety of respiratory insufficiency diseases, including COPD, interstitial lung disease, neuromuscular conditions, and pre- and post-lung transplant patients.

The NIOV system is designed to be lightweight and uses a nasal pillow interface rather than a mask. Patients are thereby able to walk with the tank on their backs, not drag it behind them, and are not prevented from eating, drinking, or talking while wearing the device.

How It Works

NIOV is a palm-sized device with three activity-level settings that are customized for each patient: resting (low), moderate activity (medium), and exercise (high). A thin tube connects the oxygen tank and the ventilator, while another connects the ventilator to the nasal pillow.

Unlike a bi-level system, which provides a boost of pressure during both inhalation and expiration, NIOV is really not a pressure support system, said Lewis R. Kline, MD, pulmonologist at Associates in Respiratory Medicine, Pittsburgh: “Rather, it is a volume-cycled ventilator: a tidal volume is set to be delivered during inspiration” depending on the needs of the individual patient and activity level. “At highest output, it can generate about 18 cm H2O pressure, but clinically, it is more accurate to think about NIOV in terms of the tidal volume that is set.”

One of the two main differentiating technologies in the NIOV system is the patient-device interface. NIOV employs Venturi jet nozzles, which draw in room air along with high-pressure oxygen in order to significantly increase the patient’s tidal volume and provide mechanical ventilation, according to Breathe Technologies CEO Larry Mastrovich. A conventional nasal cannula rests inside the nose and delivers gas without providing pressure or tidal volume to the patient.

By contrast, the NIOV’s nasal pillow partially occludes the nose and provides a combination of oxygen and ambient air at a high pressure, increasing the patient’s tidal volume and thus reducing dyspnea and the effort required to breathe, said Mastrovich.

The other design difference is the device’s high-pressure oxygen source (50 psi), which drives a miniaturized flow valve, omitting the need for a blower motor. When sensors in the interface detect a patient’s effort to inhale, the flow valve delivers a set volume of gas, which combines with room air via the Venturi entrainment ports in the nasal pillow. The device is equipped with a 4-hour rechargeable battery, as well.

“The clever thing about this device is that most ventilators are big devices with big pumps connected to a sealed mask. This [setup] prevents the patient from talking, and it also requires a fair amount of pressure,” as well as oxygen tanks that can weigh between 10 and 15 pounds, said Richard Casaburi, MD, of the Rehabilitation Clinical Trials Center of the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center in Torrance, Calif. By contrast, “NIOV is very light and doesn’t have a huge pump. This is something you carry on your shoulder, not something you drag along behind you.”

Who Can Be Helped

According to an August 2013 study in the American Journal of Respiratory and Critical Care Medicine, NIOV demonstrated dramatic improvements in shortness of breath and exercise endurance for stage III and IV COPD patients.1 Researchers compared 15 men (65.5 ±9.1 years) who underwent four methods of ventilation assistance: unencumbered room air; NIOV + compressed air; NIOV + O2; and O2 via nasal cannula.

According to their findings, NIOV + O2 showed the following:

54% increase in exercise endurance;

28% reduction in Borg Dyspnea Scale (BDS), which measures shortness of breath;

46% reduction in accessory respiratory muscle activation; and

increased and maintained oxygen saturation levels during exercise from 92.7% to 98.5%.1

Prior to testing, patients inhaled two puffs of albuterol sulfate. Spirometry, body plethysmography, and diffusing capacity were recorded. Patients exercised on an ergometer, and shortness of breath was measured every 2 minutes using the Borg Dyspnea Scale, while ECG and heart rate were continuously monitored. All tests were performed to the patients’ limit of tolerance.

According to the AJRCCM study, patients exercising with NIOV + O2 saw an average 6.1-minute increase in the length of time they could exercise before having to stop due to dyspnea, compared to oxygen delivered by conventional nasal cannula [17.5 vs 11.4 minutes (P<0.001)]: a “highly statistically significant” increase.1

Casaburi and his fellow researchers observed, however, that at the limits of tolerance, the patients’ perceived shortness of breath ratings were similar across all four test conditions. In short, once the patient “hits the wall,” the experience is the same regardless of the method of ventilation, or lack thereof.

“When those with lung disease exercise, they work a lot harder than healthy people do,” said Casaburi. “Their respiratory muscles are stressed. This device takes the stress off the respiratory muscles,” so that oxygen can be used to supply other muscles, primarily in the legs.

Mastrovich said the NIOV system can be used for congestive heart failure and cardiac rehab patients too. He pointed out the potential cost savings of employing it in “an institutional setting to facilitate early ambulation, helping a patient who’s in the ICU get up and get moving,” thereby aiding the hospital-to-home transition.

“This device goes well beyond the results seen with drugs or conventional oxygen therapy,” said Kline, who has tested the NIOV device on 16 of his patients.

One such patient with a genetic protein deficiency known as Alpha-1 Antitrypsin (AAT) showed significant improvement when the NIOV system was implemented, Kline said. AAT, which affects approximately 3.4 million persons worldwide, is an inherited disorder that may lead to COPD, with respiratory symptoms of frequent lower respiratory tract infections, diminished exercise tolerance, and shortness of breath.

Previously, Kline’s patient had been using pulsed-dose oxygen at a setting of four, with exercise limited to 20 minutes on a treadmill at 1.5 mph and a score of 6-7 on the Borg Dyspnea Scale during exercise. The patient had experienced “recurrent lung infections, emphysema, and bronchitis,” according to Kline. However, once he began using the NIOV system, the patient can now exercise for 30 minutes, reaching 2.2 mph on the treadmill, with a BDS score of 3-4.3 “Since he began wearing the NIOV full time, I haven’t heard anything from him. No emergencies. No hospitalizations,” Kline said.

Another of Kline’s patients who now uses NIOV full-time is a 61-year-old with stage IV COPD who was “in and out of the hospital seven times since the last influenza season,” Kline said. During the 3 months the patient has been using NIOV, he has not been hospitalized once.

Looking Forward

In 2011, 12.7 million US adults were estimated to have COPD,4 although more than twice that number show evidence of diminished lung function, indicating underdiagnosis.5 These statistics point to the large number of Americans who could be helped by a portable ventilation device that has proved highly effective in clinical studies and anecdotally in home use.

“Some insurance companies are paying” for the device, said Kline. “Once they can see how readmit rates plummet with its use, they’ll jump to cover it.” Medicare, however, is not yet on board. “I wish I could bring the Medicare folks into my clinic to see my patients,” said Kline. “I’ve not seen something like this in 31 years of clinical practice. It’s always the same story: A patient can walk maybe 50 feet with oxygen before he’s gasping, he’s fitted with this device, and he can walk 350 feet. His oxygen level doesn’t drop, and his heart rate stays in the 90s.”

Since up to a third of cardiac output needs to be devoted to breathing, in some COPD patients, “they become very ‘medicalized,’ tied to nebulizers, tied to supplemental oxygen,” Kline said. “This device frees them up.”

Casaburi and Kline both see this device as a means to enhance quality of life and prevent recurrent hospitalizations for COPD patients. If patients were sent home from the hospital with NIOV following an acute episode, future readmissions could be prevented, they said. Instead of calling 911, the patient could adjust the tidal volume on the device as high as 250 mL, as Kline’s two long-term-use patients have done to avoid ER visits, he said.

Moreover, increased exercise for anyone, COPD patient or not, has numerous benefits, including improved outlook, the ability to participate in social functions, and greater willingness to take better care of one’s health, said Casaburi. Some patients even use the device 24/7 rather than CPAP at night. Since NIOV unloads the respiratory muscles, these patients have fewer interruptions in their breathing and so are able to enjoy restorative deep sleep, added Kline.

The NIOV is FDA-approved for adult use, but following some changes in the interface and the software, Breathe Technologies is prepared to make a submission to the FDA for pediatric applications, Mastrovich said, which could open up the benefits of the device to children with pulmonary complications, the number one cause of mortality in children with neuromuscular disease.

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