Hyperbaric Oxygen means delivering the oxygen above atmospheric pressure which is 760 mmHg (or 1 atm). Special hyperbaric chambers are made for providing hyperbaric Oxygen, which are very expensive.
Hyperbaric Oxygen Uses
- Carbon monoxide poisoning (half life of CO at 1 atm is 214 minutes which can be reduced to 19 minutes at 2.5 atm).
- Cyanide poisoning.
B. Gas bubble diseases:
- Decompression sickness.
- Air embolism.
- Crush injuries.
- Ischemic ulcers.
- Radiation necrosis.
- Refractory osteomyelitis.
- Oxygen support during lung lavage.
- Cerebral edema.
Hyperbaric Oxygen Toxicity
1. Pulmonary: ARDS
2. CNS: Seizures preceded by facial numbness, twitching, unpleasant olfactory or gustatory sensations at common in Hyperbaric Oxygen toxicity.
3. Eye: Myopia, nuclear cataract and retrolental fibroplasia (in neonates)
4. Avascular necrosis of bone.
Safe Levels of Hyper baric Oxygen and Therapy Schedule
Hyperbaric Oxygen Toxicity depends on 3 factors:
ii. Time of exposure and
iii. Oxygen concentration.
Pulmonary effects can be seen at 2 atm while CNS symptoms manifest above 2 atm.
• Patients with chronic diseases are usually given 2 hours at 2 atm once a day
• Patients with decompression sickness are given 100% oxygen at 2-8 atm followed by 1-9 atm interspersed by periods of 5-15 minutes of air breathing.
• Gas embolism patients can be given air at 6 atm followed by 100% oxygen at2-8 and 1-9 atm. The exact safe levels of hyperbaric oxygen are not defined but not more than 2-8 atm should be used with 100% oxygen but with air (21 %021 up to 6 atm can be used safely and one therapy schedule at a time should be of less than 2 hours.