However, accumulation of carbon dioxide (described above) would remain the limiting factor. Apneic oxygenation is more than a physiologic curiosity. It can be employed to provide a sufficient amount of oxygen in thoracic surgery when apnea cannot be avoided, and during manipulations of the airways such as bronchoscopy, intubation, and surgery of the upper airways. However, because of the limitations described above, apneic oxygenation is inferior to extracorporal circulation using a heart-lung machine and is therefore used only in emergencies, short procedures, or where extracorporal circulation cant be accessed. Use of PEEP valves is also an accepted alternative (5 cm H2O in average weight patients and 10 cm H2O significantly improved lung and chest wall compliance in morbidly obese patients).In 1959, Frumin described the use of apneic oxygenation during anesthesia and surgery. Of the eight test subjects in this landmark study, the highest recorded PaCO2 was 250 millimeters of mercury, and the lowest arterial pH was 6.72 after 53 minutes of apnea. Apnea scientific studies
Studies found spleen volume is slightly reduced during short breath-hold apnea in healthy adults. Apnea test in determining brain death
A recommended practice for the clinical diagnosis of brain death formulated by the American Academy of Neurology hinges on the conjunction of three diagnostic criteria: a coma, absence of brainstem reflexes, and apnea (defined as the inability of the patient to breathe unaided: that is, with no life support systems like ventilators). The apnea test follows a delineated protocol.
Immersion may refer to:

The arts
"Immersion", a 2012 story by Aliette de Bodard
Immersion, a French comic book series by Léo Quievreux
Immersion (album), the third album by Australian group Pendulum
Immersion (film), a 2021 Chilean thriller film
Immersion (series), a webseries which test the concepts of video games in real life, created by Rooster Teeth Productions
Immersion journalism, a style of journalism

Science and technology
Immersion lithography or immersion microscopy, optical techniques in which liquid is between the objective and image plane in order to raise numerical aperture
Immersion (mathematics), a smooth map whose differential is everywhere injective, related to the mathematical concept of an embedding
Immersion (virtual reality), the perception of being physically present in a non-physical world, created by using VR

Other uses
Immersion baptism, a type of baptism whereby the subject is immersed in water
Immersion Corporation, a haptic technology developer
Immersion heater, a kind of water heater
Immersion therapy, overcoming fears through confrontation
Language immersion, a method of teaching a second language in which the target language is used for instruction