Side effects associated with hyperbaric oxygen therapy include mild fatigue and ear discomfort (similar to the sensation of taking off or landing in an airplane). More severe complications are rare but can include oxygen poisoning, lung or sinus damage, fluid buildup in the middle ear or changes in vision. In order to avoid complications and side effects, you should not receive HBOT if you have recently had ear surgery, suffered an ear injury, have a collapsed lung, have a severe cold or fever, suffer from certain types of lung disease or have extreme claustrophobia.