LCSU 4, Laerdal Compact Suction Unit || The LCSU 4 is a portable, electrically powered, medical suction device intended for field and transport use. It is intended for intermittent operation to remove secretions, blood or vomit from a patient s airway to allow ventilation. Higher vacuum levels are generally selected for oropharyngeal suction, and lower vacuum levels are usually selected for tracheal suctioning and the suctioning of children and infants.