Abstract: A device for the aspiration of an air pocket surrounding a collapsed lung. The device includes a needle to be inserted into the cavity surrounding the collapsed lung, through the ribs of the patient. The needle is connected to a suction pump by means of a hose. A float-type flow-meter is provided to measure the air flow rate through the hose and the suction pump and to transmit an electrical signal which is indicative of the flow rate to an electronic controller which calculates and displays the total volume of the air that has flowed through the sensor. A vent line is provided between the suction pump and the flow-meter to prevent sudden increases in flow rates through the needle, and a three-way valve is provided to control flow through the vent line.