An automatic mechanical lockdown for releasably attaching a litter to a transportable life support system has a base having a recess formed therein and a generally arcuate latch typically attached to the base. The recess of the base is sized to receive a pole of a litter. The latch has open and closed positions with respect to the recess such that the latch is pushed from the closed position thereof to the open position thereof when a litter pole is moved toward the recess of the base. The latch returns and remains in the closed position thereof when a litter pole is disposed within the recess. A spring which is attached to the base and the latch biases the latch in the closed position thereof. The latch can be moved from the closed position to the open position thereof by a person's thumb while the person maintains his grasp upon a litter pole.