With renowned respiratory physician Thomas L. Petty, MD, on board, Denver oxygen patients took their portable oxygen concentrators on a ride in the Rockies to further knowledge about oxygen therapy at altitude.
On August 26, 2006, the first anniversary of the 6th Oxygen Consensus Conference in Denver, 13 adventurous long-term oxygen therapy (LTOT) patients embarked on a journey to further our knowledge of oxygen therapy at higher altitudes. With the recent success of portable oxygen concentrators (POCs) being approved for use during commercial flights, more LTOT patients will be traveling with less cost and, ideally, with fewer complications.
Even though the approved POCs have passed tests related to their operation at elevated altitudes, there has been little research on what effects the patient experiences while using these different POC devices at those same altitudes. Recommendations for use of POCs for specific patients at altitude have not been identified.
Many patients will simply use a POC at higher altitudes, or during airline travel, at the same setting as their home portable oxygen system, which may or may not sufficiently meet their oxygen needs. With this in mind, Thomas L. Petty, MD, organized a team of LTOT patients and clinicians to take an “altitude adventure.”
The Plan Denver offers an environment where travel to altitude does not require the use of an airplane. There are many locations where it is possible to drive to more than 10,000 feet and simulate the cabin pressure of most commercial airliners (approximately 6,000 feet to 8,000 feet). The idea behind the altitude adventure was to charter a bus and take a scenic drive to 10,000 feet, turn around, then come back to 7,000 feet for lunch and the return to Denver.
The goal was to make this a fun trip for LTOT patients, allowing them to join together with other patients and return home with a better understanding of their physiological response to altitude. Behind the scenes, the medical team would be monitoring the patients, adjusting oxygen settings, recording data, and ensuring the patients’ safety.
We recruited oxygen patients from the Denver area and offered them an opportunity to learn more about using their oxygen therapy at altitude. These patients were the adventurous type and jumped at the chance to be monitored while enjoying a scenic trek around the mountains. Many of these patients had concerns about flying to visit far-away relatives, so this opportunity gave them a chance to learn more about oxygen system capabilities while having the “safety net” of a team of clinicians close by with backup equipment. All patients signed informed consents and were assigned data sheets to record the time, altitude, oxygen setting, oxygen saturation, heart rate, and any pertinent comments related to how they felt during the journey.
Backup Equipment • CAIRE L 45 liquid oxygen (LOX) system • CAIRE L 10 LOX system • Spirit 300 • Stroller • Stroller high flow
At the beginning of the trip, each patient had a baseline oxygen saturation measured on their existing oxygen equipment, and then the same saturation was established with the POC. Oxygen settings would be adjusted as necessary during the trip to maintain similar oxygen saturation. Back-up oxygen equipment was on the bus to respond to any needs beyond the capabilities of the POC, and a chase car was stocked with additional equipment.
The Journey The journey began on Saturday, August 26, 2006, at the Colorado branch of the American Lung Association (CALA) office in Greenwood Village, a suburb of Denver. The CALA graciously provided a meeting point for the patients, room to set up equipment, and shared their time on this busy Saturday morning. The bus arrived at 8 am, the patients shortly thereafter.
Organizers set up equipment, readied patients for monitoring, and served a light breakfast. Dr Petty gave an overview of the plan for the day, and the bus left the CALA parking lot around 9:30. While the day was overcast and rainy, the patients seemed to enjoy the camaraderie of the group and you could sense the excitement for the trip.
At specific altitudes, as instructed by the clinicians, patients recorded oxygen saturations on their data sheets. Clinicians moved about the bus asking the patients how they felt, checked the oxygen equipment, conducted spot checks for oxygen saturations, and answered questions.
Many of the patients required an increase in their oxygen setting as the altitude increased. One patient was not able to maintain acceptable saturation levels on the POC and was switched to a LOX portable system at a setting of 6 lpm. Several of the clinicians checked their own oxygen saturation levels at 10,000 feet and found that they themselves were in the mid 80s for saturation. Both patient and clinician oxygen saturation levels dropped with activity such as moving around the bus and, for some patients, using the bus’s restroom facilities.
By 11:00 am, they reached 10,700 feet and began the journey back down the mountain. At 11:30 am, at an elevation of approximately 7,000 feet, the bus stopped at a local restaurant. Lunch was served, and the patients and clinicians openly discussed their trip, how they felt during their journey, and generally got to know one another better.
By 2:00 pm, they returned to CALA and each patient switched back to their own portable oxygen system. Data logs were collected, recording oximeters were returned, and patients had another opportunity to ask questions about oxygen therapy at altitude. In the following days, clinicians downloaded each patient’s oximeter stored data and reviewed the information to determine how the patients tolerated the trip.
Variables Associated with POCs In short, we wanted to understand how oxygen therapy with POCs affected patients at altitudes and air pressures similar to air travel. LTOT patients have actually been traveling by commercial air for many years. However, the airline usually provided the oxygen equipment—compressed gas cylinders delivering continuous flow oxygen.
Since there has not been a standard prescription for oxygen delivery with air travel, we do not know if patients maintain their proper oxygen saturation during air travel. Some patients might use their exercise prescription as a dose setting, while others might simply use their resting oxygen setting as their setting. Now, with the approval of POC systems as an alternative to compressed gas systems, more variables are present.
One variable is battery life. POCs need an AC or DC power source to produce their oxygen. Batteries for POCs allow for easier mobility but operate for a variable amount of time. The type of battery, the device’s flow setting, and the patient’s breathing rate are the main factors contributing to battery life. Another variable is oxygen production. Currently approved POCs for airliner use are capable of producing at least 750 mL of oxygen per minute, and each POC device has different capabilities (the POC used we used produced up to 3,000 mL of oxygen per minute).
Each POC’s built-in oxygen conserving technology provides a different dose volume per setting. Some devices vary their dose based on the patient’s breath rate. Also, oxygen provided by POCs is not 100% pure oxygen; it is a blend of gasses, with oxygen generally comprising 93% +/- 3% of the dose. This level of oxygen purity is variable based on several factors, including a patient’s breath rate.
All current POCs generate oxygen continuously but do not store any of this manufactured oxygen. With oxygen-conserving technology built in to all current POCs, continuous flow oxygen is generally not an option (only one POC on the market currently offers continuous flow capabilities). As technology advances, this may change. So if a patient’s POC malfunctions, she needs to immediately switch to a different oxygen system.
With the multitude of variables presented with the use of new oxygen systems like POCs, it is important for clinicians to understand the capabilities of the oxygen delivery system, the patient’s needs, and the environment in which the oxygen system and the patient will be breathing in. Monitoring a patient’s oxygenation at all levels of activity is a challenge, yet not knowing these important values may put patients at risk. Oxygen therapy is more than a setting on a dial. The clinician needs to be involved to determine the optimal device and setting for each patient at a specific activity level or environment such as air travel.
One of the recommendations from the 6th Oxygen Consensus Conference was to increase the research related to LTOT and to educate all associated with LTOT. The altitude adventure was a step in that direction. Even though this was not an official controlled clinical study, it is hoped that the findings will raise questions that will lead to controlled clinical studies. These controlled studies can provide more evidence about the need for improved delivery and monitoring of LTOT patients in all environments.
Robert McCoy, RRT, FAARC, is managing director of Valley Inspired Products Inc, Apple Valley, Minn. McCoy can be reached via e-mail: bmccoy@inspiredrc.com.
Even though the approved POCs have passed tests related to their operation at elevated altitudes, there has been little research on what effects the patient experiences while using these different POC devices at those same altitudes. Recommendations for use of POCs for specific patients at altitude have not been identified. 
Many of the patients required an increase in their oxygen setting as the altitude increased. One patient was not able to maintain acceptable saturation levels on the POC and was switched to a LOX portable system at a setting of 6 lpm. Several of the clinicians checked their own oxygen saturation levels at 10,000 feet and found that they themselves were in the mid 80s for saturation. Both patient and clinician oxygen saturation levels dropped with activity such as moving around the bus and, for some patients, using the bus’s restroom facilities. 
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