The patient then remains at that pressure for a further 150 minutes, consisting of two periods of 15 minutes air/60 minutes oxygen, before the pressure is reduced to atmospheric over 30 minutes on oxygen.Vitamin E and selenium were proposed and later rejected as a potential method of protection against pulmonary oxygen toxicity. There is however some experimental evidence in rats that vitamin E and selenium aid in preventing in vivo lipid peroxidation and free radical damage, and therefore prevent retinal changes following repetitive hyperbaric oxygen exposures. Normobaric setting
Bronchopulmonary dysplasia is reversible in the early stages by use of break periods on lower pressures of oxygen, but it may eventually result in irreversible lung injury if allowed to progress to severe damage. One or two days of exposure without oxygen breaks are needed to cause such damage.Retinopathy of prematurity is largely preventable by screening. Current guidelines require that all babies of less than 32 weeks gestational age or having a birth weight less than 1.5 kg (3.3 lb) should be screened for retinopathy of prematurity at least every two weeks. The National Cooperative Study in 1954 showed a causal link between supplemental oxygen and retinopathy of prematurity, but subsequent curtailment of supplemental oxygen caused an increase in infant mortality. To balance the risks of hypoxia and retinopathy of prematurity, modern protocols now require monitoring of blood oxygen levels in premature infants receiving oxygen.
This has led to the current recommendation by the Diving Committee of the Undersea and Hyperbaric Medical Society that a diver should be raised during the seizures clonic (convulsive) phase if the regulator is not in the divers mouth—as the danger of drowning is then greater than that of AGE—but the ascent should be delayed until the end of the clonic phase otherwise. Rescuers ensure that their own safety is not compromised during the convulsive phase. They then ensure that where the victims air supply is established it is maintained, and carry out a controlled buoyant lift. Lifting an unconscious body is taught by most recreational diver training agencies as an advanced skill, and for professional divers it is a basic skill, as it is one of the primary functions of the standby diver. Upon reaching the surface, emergency services are always contacted as there is a possibility of further complications requiring medical attention. The U.S. Navy has procedures for completing the decompression stops where a recompression chamber is not immediately available.The occurrence of symptoms of bronchopulmonary dysplasia or acute respiratory distress syndrome is treated by lowering the fraction of oxygen administered, along with a reduction in the periods of exposure and an increase in the break periods where normal air is supplied. Where supplemental oxygen is required for treatment of another disease (particularly in infants), a ventilator may be needed to ensure that the lung tissue remains inflated.