Venturi mask
Encyclopedia
The venturi mask, also known as an air-entrainment mask, is a medical device
to deliver a known oxygen
concentration to patients on controlled oxygen therapy
. Venturi masks are considered high-flow oxygen therapy devices. This is because venturi masks are able to provide total inspiratory flow at a specified FiO2
to patients therapy. The kits usually include multiple jets in order to set the desired FiO2
which are usually color coded. The color of the device reflects the delivered oxygen concentration, for example: blue = 24%; yellow = 28%; white = 31%; green = 35%; pink = 40%; orange = 50%. The color however varies with different brands and the user must check the instructions to determine the correct color for the desired FiO2
. (In the UK, the colours and respective delivery concentrations are; Blue 24%, White 28%, Yellow 35%, Red 40%, Green 60%).
Other brands of masks have a rotating attachment that controls the air entrainment window, affecting the concentration of oxygen. This system is often used with air-entrainment nebulizers to provide humidification and oxygen therapy.
is increased, the air to oxygen ratio decreases. For example, for 30% the ratio is 8 parts air to 1 part oxygen. For 40% the ratio decreases to 3 to 1. Since the jets in venturi masks generally limit oxygen flow at 12 to 15 liters per minute the total flow decreases as the ratio decreases. At an oxygen flow rate of 12 liters per minute and a 30% FiO2
setting, the total flow would be 108 L/min. At a 40% FiO2
setting, the total flow would decrease to 48 L/min. As a rule of thumb, 60 L/min is considered the minimum flow rate to qualify as a high flow device.
Medical device
A medical device is a product which is used for medical purposes in patients, in diagnosis, therapy or surgery . Whereas medicinal products achieve their principal action by pharmacological, metabolic or immunological means. Medical devices act by other means like physical, mechanical, thermal,...
to deliver a known oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
concentration to patients on controlled oxygen therapy
Oxygen therapy
Oxygen therapy is the administration of oxygen as a medical intervention, which can be for a variety of purposes in both chronic and acute patient care...
. Venturi masks are considered high-flow oxygen therapy devices. This is because venturi masks are able to provide total inspiratory flow at a specified FiO2
Fraction of inspired oxygen
Fraction of inspired oxygen is the percentage of oxygen concentration participating in gas exchange in the alveoli.-Uses:The ratio between partial pressure of oxygen in arterial blood and FiO2 is used as an indicator of hypoxemia per the American-European Consensus Conference on lung injury. A...
to patients therapy. The kits usually include multiple jets in order to set the desired FiO2
Fraction of inspired oxygen
Fraction of inspired oxygen is the percentage of oxygen concentration participating in gas exchange in the alveoli.-Uses:The ratio between partial pressure of oxygen in arterial blood and FiO2 is used as an indicator of hypoxemia per the American-European Consensus Conference on lung injury. A...
which are usually color coded. The color of the device reflects the delivered oxygen concentration, for example: blue = 24%; yellow = 28%; white = 31%; green = 35%; pink = 40%; orange = 50%. The color however varies with different brands and the user must check the instructions to determine the correct color for the desired FiO2
Fraction of inspired oxygen
Fraction of inspired oxygen is the percentage of oxygen concentration participating in gas exchange in the alveoli.-Uses:The ratio between partial pressure of oxygen in arterial blood and FiO2 is used as an indicator of hypoxemia per the American-European Consensus Conference on lung injury. A...
. (In the UK, the colours and respective delivery concentrations are; Blue 24%, White 28%, Yellow 35%, Red 40%, Green 60%).
Other brands of masks have a rotating attachment that controls the air entrainment window, affecting the concentration of oxygen. This system is often used with air-entrainment nebulizers to provide humidification and oxygen therapy.
Flow problems
Air entrainment masks, although considered high flow systems, are not always able to guarantee the total flow with oxygen percentages above 35% in patients with high inspiratory flow demands. The problem with air entrainment systems is that as the FiO2Fraction of inspired oxygen
Fraction of inspired oxygen is the percentage of oxygen concentration participating in gas exchange in the alveoli.-Uses:The ratio between partial pressure of oxygen in arterial blood and FiO2 is used as an indicator of hypoxemia per the American-European Consensus Conference on lung injury. A...
is increased, the air to oxygen ratio decreases. For example, for 30% the ratio is 8 parts air to 1 part oxygen. For 40% the ratio decreases to 3 to 1. Since the jets in venturi masks generally limit oxygen flow at 12 to 15 liters per minute the total flow decreases as the ratio decreases. At an oxygen flow rate of 12 liters per minute and a 30% FiO2
Fraction of inspired oxygen
Fraction of inspired oxygen is the percentage of oxygen concentration participating in gas exchange in the alveoli.-Uses:The ratio between partial pressure of oxygen in arterial blood and FiO2 is used as an indicator of hypoxemia per the American-European Consensus Conference on lung injury. A...
setting, the total flow would be 108 L/min. At a 40% FiO2
Fraction of inspired oxygen
Fraction of inspired oxygen is the percentage of oxygen concentration participating in gas exchange in the alveoli.-Uses:The ratio between partial pressure of oxygen in arterial blood and FiO2 is used as an indicator of hypoxemia per the American-European Consensus Conference on lung injury. A...
setting, the total flow would decrease to 48 L/min. As a rule of thumb, 60 L/min is considered the minimum flow rate to qualify as a high flow device.