Bilevel Positive Airway Pressure (BiPAP) therapy is a form of noninvasive ventilation that helps people with respiratory conditions breathe more easily. The machine delivers air pressure through a mask, using a higher pressure during inhalation (IPAP) and a lower pressure during exhalation (EPAP). This bi-level support makes it easier to breathe out compared to continuous positive airway pressure (CPAP) and helps keep the airways open. BiPAP is often used for conditions like chronic obstructive pulmonary disease (COPD), central sleep apnea, or other conditions causing hypoxemia or hypercapnia. Supplemental oxygen is sometimes required when pressure support alone is insufficient to maintain adequate blood oxygen levels. Combining these two therapies is a common strategy for individuals experiencing severe hypoxemia.
Essential Equipment for Combined Therapy
Integrating oxygen delivery with a BiPAP machine requires specific components for proper function and safety. Essential items include the BiPAP machine, the prescribed mask, the flexible tubing, and an oxygen source, typically a stationary concentrator or a large tank for continuous flow.
The component that joins the two systems is the oxygen enrichment adapter, also known as a bleed-in adapter. This small accessory fits seamlessly into the BiPAP air circuit and features a separate, L-shaped port where the oxygen supply tubing connects. The adapter introduces the prescribed flow of pure oxygen into the main stream of pressurized air. Some specialized BiPAP masks have a dedicated oxygen port built in, eliminating the need for an external adapter.
Step-by-Step Oxygen Connection Guide
Before connecting, ensure both the BiPAP machine and the oxygen source are powered off to prevent accidental pressure or flow delivery. Prepare the oxygen source by connecting the long, thin oxygen tubing to the outlet port of the concentrator or the humidifier bottle attached to the tank. If a humidifier is used with the oxygen source, fill it with sterile or distilled water.
Connecting the Adapter
The most common method involves placing the oxygen bleed-in adapter at the air outlet port of the BiPAP machine. First, detach the main BiPAP tubing from the machine’s air outlet. Securely attach the adapter to the machine’s outlet, then reconnect the main BiPAP tubing to the opposite end of the adapter. This places the adapter directly in line with the pressurized airflow. The oxygen tubing from the concentrator is then firmly inserted onto the adapter’s protruding port.
Alternative Placement and Startup
An alternative connection point is placing the adapter closer to the mask, between the main tubing and the mask connection. This placement is sometimes preferred for higher oxygen needs. Regardless of the connection site, check all joints for a secure, airtight fit to prevent air leaks that compromise pressure therapy. Once connections are complete, turn on the BiPAP machine first, followed by the oxygen concentrator, and then put on the mask to begin therapy.
Setting and Monitoring Oxygen Flow Rates
It is important to understand the distinct roles of the two machines. The BiPAP unit controls the pressure, while the oxygen concentrator controls the flow rate. The BiPAP machine delivers air at two pressure levels, IPAP and EPAP, measured in centimeters of water (\(\text{cmH}_2\text{O}\)), which are set to manage breathing mechanics and keep the airway open. The oxygen concentrator provides a continuous flow of pure oxygen, measured in Liters Per Minute (LPM).
Oxygen Dilution
The high airflow generated by the BiPAP machine causes a significant dilution of the supplemental oxygen introduced into the circuit. If the concentrator is set to 2 LPM, the actual percentage of oxygen delivered to the patient (known as \(\text{FiO}_2\)) is much lower than the 100% oxygen leaving the concentrator. The final oxygen concentration is affected by the BiPAP pressure settings, the patient’s breathing pattern, and any leaks in the mask or circuit. Higher BiPAP pressures and higher leak rates tend to dilute the oxygen more, resulting in a lower delivered \(\text{FiO}_2\).
Monitoring Effectiveness
For therapeutic effectiveness, the oxygen flow rate must be set precisely according to a medical prescription. Users should never adjust the LPM setting on the oxygen concentrator without instruction from their healthcare provider. The effectiveness of the combined therapy is monitored using a pulse oximeter, a device that measures the patient’s blood oxygen saturation (\(\text{SpO}_2\)). The \(\text{SpO}_2\) reading helps the clinician determine if the current BiPAP settings and oxygen flow rate are achieving the desired oxygenation goals.
Safety and Long-Term System Maintenance
Introducing pressurized oxygen into the home requires strict safety protocols due to the increased risk of fire. Oxygen is not flammable, but it significantly supports and accelerates combustion, meaning a small spark or flame can quickly become a serious fire hazard. All oxygen equipment, including the concentrator and tubing, must be kept a safe distance away from open flames, gas stoves, burning candles, and heat sources. Smoking is prohibited in any area where oxygen is used or stored.
Tubing Management
The tubing should be routed carefully to avoid kinks, crushing, or becoming a tripping hazard. Damage to the oxygen tubing can impede the prescribed flow or lead to unintended oxygen leaks, which increases the fire risk in the immediate area.
Maintenance and Humidification
Regular maintenance involves distinct cleaning protocols for the combined system. The oxygen supply tubing and bleed-in adapter are consumable, single-use devices and should be replaced according to manufacturer recommendations or when they show signs of wear. The oxygen tubing must be kept clean and dry, separate from the standard BiPAP tubing.
Adding supplemental oxygen can exacerbate the drying effect on the airways, making proper humidification even more important. If the BiPAP machine has a heated humidifier, it should be used and filled daily with distilled water to prevent mineral buildup. The humidifier chamber should be cleaned regularly, and the BiPAP filters should be checked weekly and replaced as directed to ensure the machine is drawing in clean air.