It is a condition where the alveoli are deflated, as distinct from pulmonary consolidation. It is a very common finding in chest x-rays and other radiological studies. It may be caused by normal exhalation or by several medical conditions. Although frequently described as a collapse of lung tissue, atelectasis is not synonymous with a pneumothorax, which is a more specific condition that features atelectasis.
There are two types of portable oxygen concentrators available on the market today: Continuous flow oxygen concentrators and pulse dose, or intermittent flow, oxygen concentrators. These two types of oxygen systems have very different benefits and limitations and each is best suited for a specific type of patient.
Approved Portable Oxygen Concentrators List Up to 21. FAA's final rule adding seven models to the list will take effect Oct. 31. Oct 23, 2012; Airline passengers who require medical oxygen soon will have a total of 21 approved portable oxygen concentrator models from which to choose. Effective Oct. 31, a Federal Aviation Administration final rule adds seven portable oxygen concentrator models to the agency's approved list.