What should be the head of bed angle to prevent shear in patients?

Maintaining the head of the bed at an angle of 30 degrees or less is recommended to prevent shear in patients. This position helps to minimize the risk of pressure injuries by reducing the forces acting on the skin, particularly over bony prominences. When the head of the bed is elevated, especially beyond 30 degrees, the body tends to slide down due to gravity, which causes the skin to stretch and shear, increasing the likelihood of tissue damage. By keeping the bed angle lower, the risk of friction and shear is significantly diminished, thus protecting the patient's integrity of the skin and underlying tissues.

In contrast, higher angles such as 45 degrees or 90 degrees can exacerbate shear forces, leading to a higher risk of skin breakdown. A flat position may reduce the risk of shear but does not appropriately account for the need for head elevation for certain conditions such as respiratory distress. This makes 30 degrees an optimal angle to balance patient safety and comfort while minimizing the risk of shear.