Oxygen Therapy and Devices Flashcards

A patient with COPD is being discharged on long-term oxygen therapy. As a COPD educator, you review the GOLD guidelines to confirm the qualifying criteria. Which of the following findings in a stable patient on optimal medical therapy meets the criteria for initiating long-term oxygen therapy to improve survival?

Answer: PaO2 ≤ 55 mmHg or SpO2 ≤ 88% at rest.

According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, long-term oxygen therapy (LTOT) has been shown to improve survival in patients with severe, resting hypoxemia. The established criteria for initiating LTOT are an arterial oxygen tension (PaO2) of 55 mmHg or less, or a pulse oximetry saturation (SpO2) of 88% or less, confirmed twice over a three-week period in a stable patient.

A patient with COPD is admitted with an acute exacerbation and is noted to be a CO2 retainer. The physician orders oxygen to maintain a specific, controlled saturation level and wants to deliver a precise fraction of inspired oxygen (FiO2) of 28%. Which of the following oxygen delivery devices is most appropriate for this patient?

Answer: Venturi (air-entrainment) mask

A Venturi mask, also known as an air-entrainment mask, is a high-flow device specifically designed to deliver a precise and fixed concentration of oxygen (FiO2), regardless of the patient's breathing pattern. This is crucial for patients with COPD who are at risk for hypercapnic respiratory failure, as it prevents over-oxygenation while ensuring adequate oxygenation. Other devices like nasal cannulas and simple masks are low-flow systems where the FiO2 can vary significantly with the patient's respiratory rate and depth.

A COPD educator is providing critical safety instructions to a patient and their family before the delivery of home oxygen equipment. Which of the following points is the MOST important to emphasize to prevent a fire-related accident?

Answer: Strictly prohibit smoking and keep oxygen at least 10 feet away from any open flame or heat source.

While all options are valid safety points, the most critical instruction is related to fire prevention. Oxygen itself is not flammable, but it vigorously supports combustion, causing other materials to ignite more easily and burn much faster. Prohibiting smoking and maintaining a safe distance from any source of flame or high heat is the single most important rule to prevent a catastrophic fire.

A patient using portable compressed oxygen cylinders for ambulation complains that the tanks run out too quickly, limiting their time away from home. Which of the following devices is specifically designed to deliver oxygen more efficiently and extend the duration of a portable oxygen supply?

Answer: An oxygen-conserving device (OCD)

An oxygen-conserving device (OCD) is designed to prolong the use of portable oxygen cylinders. Instead of providing a continuous flow of oxygen, it delivers a pulsed dose only when the patient inhales. This method reduces oxygen waste during exhalation and can extend the life of a tank by a factor of 3 to 5, significantly increasing the patient's mobility and time away from home.

A COPD educator needs to calculate the approximate duration of a portable E-cylinder for a patient. The tank pressure gauge reads 1800 psi, the prescribed flow rate is 3 L/min, and the tank factor for an E-cylinder is 0.28. How many minutes will the oxygen supply last?

Answer: 168 minutes

The formula to calculate the duration of an oxygen cylinder is: Duration (in minutes) = [(Cylinder Pressure in psi - Safe Residual Pressure) × Cylinder Factor] / Flow Rate (L/min). While some calculations omit the safe residual pressure (typically 200 psi) for estimation, the standard formula is (Pressure × Factor) / Flow. Using the simplified formula: (1800 psi × 0.28) / 3 L/min = 504 / 3 = 168 minutes. This calculation is a critical skill for educators to teach patients for managing their portable oxygen supply.

Which of the following oxygen systems is generally preferred for a highly active COPD patient who requires continuous oxygen at a high flow rate (e.g., 4-5 L/min) and prioritizes longer duration and lighter carrying weight for extended periods away from home?

Answer: A portable liquid oxygen system

For patients requiring continuous, high-flow oxygen (above 2-3 L/min) during activity, a portable liquid oxygen system is often superior. Liquid oxygen is much more concentrated than compressed gas, allowing a larger supply to be carried in a smaller, lighter-weight portable unit that lasts longer than similarly sized gas cylinders. While portable oxygen concentrators (POCs) offer unlimited oxygen with a power source, most pulse-dose models have limitations at higher continuous-flow equivalent settings, and continuous-flow POCs are typically heavier and have shorter battery lives.