Hey guys I know some are wary of medical devices, however, we are picking upo steam here with our wooden lung research. Problem is we need to build a simple but reliable pressure relief valve, capable of moving back and forth between positive and negative pressure 12 to 20 per minute for adults and 20 to 30 minutes for children. I have spent hours reading up on various valve set up. our mission is to use commonly available product found in hardware stores. This is a very important project, not for routine use if we ever get to this point GOD HELP US. The proposal is for worst case emergency operations as a bridging device for between 24-96 hours, until a modern vent can be procured. Wooden lungs were sucessfully used in the 1930-1950 however, much of the available technology and diagrams on how the flapper valve "the heart of the system" are missing. In some cases the flapper valve was operated manually one on one by volunteers during the polio epidemics.
Ideally we should be able to go to the local home depot or lowes purchase necessary supplies (plywood,etc) and build devices in hospital parking lot as needed. The vacuum component is easy, it is just how do we automated the pressure relief valve. The projects concept is basically using Katrina as a base line, where we can not get enough supplies from other parts of the country and need for ventilators exceed available modern ventilators on site.
"The Drinker and Shaw tank-type ventilator of 1929 was one of the first negative-pressure ventilators widely used for mechanical ventilation. This metal cylinder completely covered the patient up to the neck. A vacuum pump created negative pressure in the chamber that elevated the patient's chest. Better known as the iron lung, this device used negative pressure to cause a drop in the intrapulmonary pressure and to allow ambient airflow into the patient's lungs.
Upon termination of breath, the negative pressure applied to the chest dropped to zero and the elastic recoil of the chest and lungs permitted passive exhalation. This allowed ventilation of the patient without the placement of a tracheostomy or an endotracheal tube. Nevertheless, this mode of ventilation was cumbersome and led to patient discomfort and inaccessibility by health care providers. Because the negative pressure created in the chamber was exerted on the abdomen and chest, the patient tended to experience a decrease in cardiac output from the pooling of venous blood in the lower torso.
Concepts developed by the military regarding the delivery of oxygen and gas volume to fighter pilots operating at high altitude during World War II were incorporated into the evolution of the modern positive-pressure ventilator. This technology was matched by the development of safer, cuffed, endotracheal tubes, allowing positive-pressure ventilation to replace the iron lung. Today, negative-pressure ventilation is used only in certain situations."
Quote from
http://www.emedicine.com/med/topic3370.htm
Edited by - mattlott on Mar 15 2006 4:47 PM
Login
Register
FAQ
Search
