Part IV: Oxygen Delivery Methods
According to the American Thoracic Society, the method of oxygen delivery that’s best for you depends upon a number of factors, including your oxygen requirements, the efficiency, reliability and personal acceptance of the device, and how easy it is to use. First and second-line options are presented below:
When patients are relatively stable, first-line oxygen therapy options are generally the best choice and include:
- Standard nasal cannula – As mentioned previously, a standard nasal cannula works best for stable patients who need low-flow oxygen at low to medium concentrations. See nasal cannulas and nasal cannula accessories here.
- Venturi mask – A Venturi face mask mixes oxygen with room air, creating high-flow, enriched oxygen with pre-set concentrations. Venturi masks deliver oxygen at concentrations of 24-40 percent. Health care providers may opt for a Venturi mask if they’re concerned about a patient retaining carbon dioxide (CO2).
When patients need higher concentrations of oxygen at greater flow settings, the following second-line options are available:
- Simple face mask – A simple face mask delivers oxygen concentrations of 40-60% at 5-10 liters per minute. The face mask is well-suited for patients who are prone to nasal irritation and/or nosebleeds. Simple face masks are also used for patients who breathe strictly through their mouths. Keep in mind, however, that the simple face mask is obtrusive and sometimes uncomfortable. It also muffles communication, interferes with coughing, and prevents eating or drinking unless first removed.
- High-flow transtracheal catheter – Transtracheal catheters deliver high-flow oxygen directly into the trachea, or windpipe. They are believed to reduce the effort it takes to breathe and enhance the removal of CO2 from the lungs.
- Non-rebreather mask – The non-rebreather (NRB) mask is ideal for patients who are critically ill and require higher concentrations of oxygen. This type of mask delivers high-flow oxygen at concentrations of 40-90 percent. Its major drawback: the NRB mask must be tightly sealed against the face, which can be uncomfortable. It’s also associated with a higher risk of CO2 retention.
- Reservoir cannula – As mentioned previously, reservoir cannulas improve the efficiency of oxygen delivery saving two to four times the oxygen delivered via continuous flow.
- High-flow warmed and humidified nasal oxygen – For patients who need higher concentrations of oxygen at flow rates of 10-40 liters per minute. When warmed and humidified, high flow oxygen is more comfortable and better tolerated by patients,
surpassing the NRB mask at the same flow setting.
Non-Invasive Positive Pressure Ventilation (NIPPV)
NIPPV refers to a method of delivering oxygen without the use of a breathing tube and mechanical ventilator. There are two types of NIPPV:
- Continuous positive airway pressure (CPAP) – CPAP is a non-invasive breathing machine that’s used to treat a common sleep disorder known as obstructive sleep apnea (OSA). It’s also used in the treatment of COPD and overlap syndrome (a term used when OSA and COPD occur together). CPAP delivers a mixture of oxygen and/or room air from a machine through a plastic tube that’s connected to a face or nasal mask. It’s most commonly used at night when oxygen levels in the blood tend to drop more frequently, but can also be used during the day. CPAP helps people with OSA and/or COPD keep their breathing passages open by providing a continuous flow of air into their airways. The pressure level on CPAP is doctor-prescribed, single-level and constant, meaning there’s no difference in the pressures when breathing in or out. Because this may cause increased anxiety and shortness of breath in some COPD patients, bi-level positive airway pressure (see below) is often the preferred method of NIPPV for people with COPD and other breathing disorders.
- Bi-level positive airway pressure (BiPAP) – Similar to CPAP, BiPAP is a non-invasive breathing machine that can be used as an alternative in patients who find it difficult to breathe against the continuous pressure of the CPAP machine. Because BiPAP provides a higher pressure when breathing in and a lower pressure when breathing out, it’s easier for some people with COPD and other breathing disorders to tolerate.