A portable emergency respirator is disclosed. This respirator contains an electrical power supply, an air compressor, and a switch which allows one to produce three separate different types of pneumatic outputs from the air compressor. In one mode of operation, the output from the air compressor provides intermittent positive pressure ventilation to the patient. In a second mode of operation, the output from the air compressor is automatically synchronized with the patient breathing. In a third mode of operation, the output from the air compressor is manually controlled by an operator.