The biggest challenge in bag-mask ventilation is maintaining an open airway and a tight seal using one hand. If a second person is available, it is recommended that one person manages the mask and the airway, while the second person squeezes the bag to ventilate the chest. The person responsible for the mask stands at the head of the bed and places his thumbs on the top surface of the mask. The remaining fingers are then used to grip the mandible on either side. The mask is squeezed between the thumbs and the fingers to create a seal and at the same time the mandible is elevated to open the airway. This technique is considerably easier, but again, the physicians must be constantly checking that air is flowing easily into the patient and that the chest is rising and falling.