The administration of oxygen at higher levels than are normally found in the atmosphere to patients needing enhanced tissue oxygen uptake. Oxygen can be administered via nasal cannulae, Venturi masks, nonrebreathing masks, continuous positive-pressure ventilation devices, endotracheal tubes, or in airtight or hyperbaric chambers, depending on the needs of the patient. Each of these modes of therapy has its own benefits and limitations. Nasal cannulae facilitate speaking and eating but can deliver oxygen in concentrations only up to 40%. Venturi masks can deliver more oxygen (approx. 50%) more precisely than nasal devices, but they interfere with some communication and oral intake. The highest levels of noninvasive oxygen therapy are delivered by nonrebreather masks (approx. 90%). One hundred percent oxygen can be given through endotracheal tubes, but patients are often uncomfortable or hemodynamically unstable with these devices and may need sedation or paralytic or pressor drugs to support them. Continuous positive-pressure ventilation devices can be used to administer oxygen, but they are not tolerated by some patients because of claustrophobia and poor adaptation to the fit of the mask. Supplemental oxygen is also available for home use through an oxygen concentrator that uses a molecular sieve to remove nitrogen from room air.
SEE: hyperbaric oxygen; SEE: oximeter
Inhalation of high concentrations of oxygen, esp. at pressures of more than one atmosphere, may produce deleterious effects such as irritation of the respiratory tract, reduced vital capacity, and, sometimes, neurological symptoms. Serious eye defects may result if premature infants are exposed to a high concentration of oxygen as part of their therapy. Because oxygen provides a perfect environment for combustion, it should not be used in the presence of oil, lighted cigarettes or open flames, or where there is the possibility of electrical or spark hazards.
There's more to see -- the rest of this topic is available only to subscribers.