A breathing apparatus can take many different forms, but the primary purpose is to support the mechanical movement of air in and out of the lungs and the exchange of oxygen and carbon dioxide. Wearing a breathing apparatus allows you to enter into a hazardous environment, underwater and even resuscitate a person who is not breathing.
The Respiratory System
The respiratory system is responsible for delivering oxygen from the outside air to your body tissue for survival. This happens through two distinct yet interdependent processes called ventilation and oxygenation. Ventilation is the process of moving air from the atmosphere into your lungs, while oxygenation is the process of oxygen and carbon dioxide exchange in small sacs within the lungs called alveoli. A breathing apparatus acts as a mechanism to replace your respiratory system function under abnormal circumstances.
The Basic Apparatus
The basic apparatus assumes you are breathing on your own and simply provides the supplemental atmospheric content of air to accommodate oxygenation. For example, during an ambulance call an emergency medical technician will administer oxygen via a mask attached to an oxygen source if you are having difficulty breathing. Another example is the drop-down masks in an airplane in case of emergency. Another type of basic apparatus assumes the role of ventilation when you are unable to breathe called a bag-valve-mask (BVM). This oddly shaped device has a mask that fits over your mouth and a bag that the operator squeezes forcing air into your lungs. When the bag is released, air rushes out of your lungs and the process starts again. BVMs are designed to attach supplemental oxygen to them to provide a higher concentration to accommodate more efficient oxygenation.
Self Contained Apparatus
A Self-Contained Breathing Apparatus (SCBA) has many different applications in environments that do not support normal human respirations. The term self-contained means the device is not reliant on a stationary supply. One example of this type of apparatus is called a Self-Contained Underwater Breathing Apparatus used for diving underwater. According to Dave's Outdoor Adventure, scuba diving is taking a life-support system with you into an environment your body is not meant to survive. Scuba components consist of a high pressure tank, mouth piece and regulator that maintains breathing gas at a constant ambient pressure. Another type of SCBA is that used by firefighters to be able to enter the dangerous environment of burning buildings. Firefighters' SCBA are constructed closely like the scuba with only slight changes in the pressure regulator and the addition of a full face mask versus a mouth-piece. According to Fire and Smoke: Understanding the Hazards, fire generates the three hazards of heat, smoke and depletion of oxygen, and the contribution of each hazard is characteristic of the fire. Entering an environment like this without an SCBA would result in immediate death of the firefighters. A third type of SCBA is generically referred to as a gas mask. According to Brinkster.com, these air purifying respirators worn over the face pass contaminated air through some type of filtering element before it is inhaled. These devices have historic applications in firefighting, biological and chemical warfare and mining.
Assisting Devices
A Continuous Positive Airway Pressure (CPAP) device is a practical breathing apparatus that is used in a range of health care environments to treat sleep apnea and respiratory failure. According to Kaiser Permanente, CPAP gently splints the soft tissue in your airway open so that you breathe more regular, stop snoring and get a restful sleep. The CPAP machine works by providing a continuous flow of positive pressure to keep the pathway from the nose and mouth to the lungs open. CPAP also has application in emergency medical services treatment of congestive heart failure. The positive pressure forces excess fluids out of the alveoli and decreases blood return to your heart and lessening the workload.
Fully Powered Devices
The most advanced type of breathing apparatus is the mechanical ventilator because it supports the functions of ventilation and oxygenation using a variety of strategies. According to Emedicine, ventilator strategies have been developed to manage different disease and traumatic processes to protect lung tissue while maintaining adequate gas exchange, and are responsible for increased rates of survival. Strategies might include continuous ventilation which delivers an oxygen concentrated volume of breath in a preset cycle, or assist-controlled which works more in coordination with the person's spontaneous breathing efforts. Other adjustments include changing the concentration of oxygen, the volume delivered in one breath and the rate at which the breath is delivered.
References
- Dave's Outdoor Adventure: What is Scuba Diving?
- "Fire and Smoke: Understanding the Hazards"; Committee on Fire Toxicology, Board on Environmental Studies and Toxicology, Commission on Life Sciences, National Research Council; 1986
- Brinkster.com: The Invention of the Gas Mask
- Kaiser Permanente: How Does CPAP Work
- Emedicine: Ventilator Management
