Abstract: An angle indicator incorporated in a siderail of a bed for maintaining a patient in horizontal position includes a light source connected to a processor unit. The processor unit processes signals from sensors of the bed, such as a patient support height sensor, a weight sensor, an accelerometer, a siderail position sensor, an external power sensor, a brake sensor or a monitor of vital signs, and evaluates the predefined states of these sensors by switching off, changing color or adjusting the intensity of backlight of the angle indicator. The angle indicator provides hospital staff with information of inclination of a movable section of the bed according to a horizontal plane. The staff can easily position the bed, for example, at a 30° angle, when positioning the patient in the cardiac position.