What is the recommended use of an oxygen conserving device (OCD) for patients requiring supplemental oxygen?

Oxygen Conserving Devices for Supplemental Oxygen

Oxygen-conserving devices should be used in home oxygen patients requiring high flow rates to extend cylinder duration, and should be considered for patients who are active outside the home following an ambulatory oxygen assessment. 1

Primary Indications

For patients requiring portable oxygen who are mobile and active outside the home, oxygen-conserving devices offer significant practical advantages by reducing total oxygen usage by approximately 50% compared to continuous flow systems. 1 This translates directly to:

• Extended cylinder duration, allowing patients greater mobility and independence 1
• Reduced frequency of home oxygen deliveries and associated costs 1, 2
• Improved portability for ambulatory patients 1, 3

Critical Pre-Implementation Requirements

Before prescribing an oxygen-conserving device, patients must undergo ambulatory assessment because these devices vary significantly in their ability to maintain oxygen saturation levels during exercise. 1 This assessment is essential because:

• Some patients, particularly mouth breathers, may struggle to trigger the demand-delivery mechanism 1
• Device specifications vary substantially between manufacturers and models, making them non-comparable 1
• Individual patient factors (respiratory rate, breathing pattern, exercise capacity) significantly affect device performance 1

Device Selection Algorithm

Start with nasal cannulae as first-line for home oxygen delivery, then consider oxygen-conserving devices based on specific patient characteristics: 1, 4

Consider oxygen-conserving devices when:

• Patient requires high flow rates (>4 L/min) and needs extended cylinder duration 1
• Patient is mobile and active outside the home 1
• Patient demonstrates ability to trigger the device during ambulatory assessment 1
• Patient is primarily a nasal breather 1

Avoid or use with caution when:

• Patient is a mouth breather 1
• Patient has high resting respiratory rate 1
• Patient has cognitive problems 1
• Nocturnal use is required (limited evidence for nighttime efficacy) 1

Important Performance Limitations

Oxygen-conserving devices were inferior to continuous flow oxygen in most measured variables when compared directly, despite reducing oxygen consumption. 1 Specifically:

• Demand oxygen delivery systems produced only small increases in walk distance without significant elevation of oxygen saturation 1
• Exercise performance may not improve despite adequate oxygenation 1
• Device effectiveness varies substantially between different models and manufacturers 1, 5

Patient Acceptance Issues

Compliance problems are common and should be anticipated, with studies showing up to 43% of patients discontinuing use before study completion. 2 Common complaints include:

• Bulkiness and poor fit (76% of patients) 2
• Ear discomfort (38% of patients) 2
• Nasal discomfort (29% of patients) 2
• Required nasal breathing (29% of patients) 2

Alternative Delivery Systems

For patients with hypercapnic respiratory failure or high resting respiratory rates, Venturi masks should be considered instead as they provide more precise oxygen delivery and avoid the triggering issues associated with conserving devices. 1

For patients requiring very high efficiency, transtracheal oxygen delivery can be considered but requires dedicated support from a trained team and carries risks of catheter displacement, mucous obstruction, and infection. 1

Nocturnal Use Caveat

Evidence for nocturnal oxygenation using pulsed-dose oxygen-conserving devices is limited, with studies showing no clinical difference between continuous oxygen and pulsed oxygen delivery at various settings. 1 Therefore, continuous flow should be preferred for overnight use unless specifically assessed and proven effective in the individual patient.

Cost-Effectiveness Considerations

In compliant patients, oxygen-conserving devices can achieve net savings of approximately $141 per patient per month through reduced liquid oxygen consumption (from 200 to 135 pounds/month). 2 However, this benefit is only realized in patients who maintain full compliance with device use. 2