A low air loss mattress is a powered air mattress designed to prevent and treat pressure injuries (bedsores). It actively manages the environment immediately surrounding the patient’s skin. This technology provides therapeutic benefits for individuals who are immobilized or spend extended periods in bed, where constant pressure and moisture can compromise skin integrity. Low air loss mattresses are widely used in hospitals, long-term care facilities, and home care settings.
The Mechanism of Low Air Loss Technology
The function of a low air loss mattress centers on managing the skin’s “microclimate,” which refers to the temperature and humidity level at the interface between the body and the mattress surface. This system utilizes an air pump to continuously circulate a low volume of air through the mattress structure. The air moves through tiny perforations, often located in the individual air cells or within the vapor-permeable cover that encases the mattress.
This continuous airflow wicks away excess moisture and dissipates heat that builds up against the skin. By reducing heat and humidity, the mattress prevents the skin from becoming macerated. Maintaining a dry and cool surface is crucial because moist skin is more vulnerable to the damaging effects of friction and shear forces.
The air cells themselves are inflated to a specific pressure, which ensures the patient’s weight is distributed evenly across a large area. This flotation-like effect reduces peak pressure points, especially over bony prominences like the heels, hips, and sacrum. The combination of microclimate control and pressure reduction creates an environment that supports tissue health and minimizes the factors that lead to skin breakdown.
Clinical Applications and Benefits
Low air loss mattresses are used for the prevention and treatment of pressure injuries in individuals with limited mobility. Regulating the skin’s microclimate directly addresses a major contributing factor to injury development: excessive heat and moisture. When the skin is constantly damp, it loses structural integrity and becomes less tolerant of mechanical loading.
The continuous airflow keeps the surface dry, which reduces the risk of skin maceration. This is particularly beneficial for patients prone to excessive sweating, fever, or incontinence. The flotation provided by the air-filled cells also redistributes body weight, reducing intense pressure that can impede blood flow to underlying tissues.
These support surfaces are often indicated for patients categorized as having a high risk of skin breakdown or those with existing Stage I or Stage II pressure injuries. They are also recommended for specialized populations, such as burn patients, where managing wound exudate and maintaining a dry surface is paramount for healing. Clinical studies show that using these mattresses can lower the incidence of pressure ulcers.
Low Air Loss vs. Other Powered Support Surfaces
Low air loss (LAL) systems are often confused with other powered types, particularly alternating pressure (AP) systems. LAL systems prioritize microclimate and moisture control through continuous airflow. This continuous flow regulates temperature and humidity at the skin interface, which is the fundamental difference.
Alternating pressure mattresses, by contrast, focus on active pressure relief by cyclically inflating and deflating a series of air cells. This inflation and deflation sequence constantly shifts the pressure points on the patient’s body, which helps stimulate circulation and prevents any single area from sustaining pressure for too long. While LAL systems offer pressure redistribution through immersion, AP systems provide dynamic pressure point shifting.
Another distinct type is the lateral rotation (LR) system, which physically turns the patient side-to-side on a timed schedule. LR systems are primarily used to reposition the patient to prevent pulmonary complications and pressure injuries. Many modern medical mattresses are now designed as hybrid systems, combining the microclimate control of low air loss with the circulatory benefits of alternating pressure.