Oxygen is given to patients through a variety of methods, primarily utilizing either low-flow or high-flow systems.
Low-Flow Systems
Low-flow oxygen delivery systems provide oxygen at a rate that is lower than the patient's inspiratory flow rate. This means the patient also breathes in room air along with the supplemental oxygen. Examples include:
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Nasal Cannula: A common method involving prongs placed in the nostrils, delivering a low concentration of oxygen (typically 1-6 liters per minute).
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Simple Face Mask: This mask covers the nose and mouth and delivers a higher concentration of oxygen than a nasal cannula (typically 5-8 liters per minute).
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Reservoir Masks: These masks (partial rebreather and non-rebreather) have a reservoir bag that collects oxygen, allowing for a higher inspired oxygen concentration. A non-rebreather mask has one-way valves to prevent exhaled air from mixing with the oxygen in the reservoir, potentially delivering up to 90% oxygen.
High-Flow Systems
High-flow oxygen delivery systems provide oxygen at a rate that meets or exceeds the patient's inspiratory flow rate, ensuring a consistent and predictable oxygen concentration. These systems always require humidification due to the high flow rates which can dry out the airway. Examples include:
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Venturi Mask: This mask delivers a precise and controlled oxygen concentration, regardless of the patient's breathing pattern. Different colored jets regulate the amount of room air mixed with the oxygen.
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High-Flow Nasal Cannula (HFNC): This system delivers heated and humidified oxygen at high flow rates through a nasal cannula, providing respiratory support beyond just supplemental oxygen.
Humidification
Regardless of the delivery system (but especially with high-flow systems), humidification is essential to prevent drying of the airways, which can lead to discomfort and complications. The humidifier should be positioned lower than the patient's head to prevent water from draining back into the tubing.
System Selection
The choice of oxygen delivery system depends on several factors, including:
- Patient's oxygen needs: Measured by blood oxygen saturation (SpO2) and arterial blood gas (ABG) analysis.
- Patient's breathing pattern and respiratory rate.
- Patient's tolerance of the device.
- The desired oxygen concentration.
In summary, oxygen delivery to patients involves selecting the appropriate system (low-flow or high-flow) and ensuring proper humidification to meet their individual respiratory needs.
