A device according to an aspect of the invention includes an air escapement conduit having an inlet port providing air communication with a chest cavity and an outlet port providing air communication with a vacuum source, the conduit allowing an air flow from the inlet port to the outlet port in response to a pressure differential between the ports, and a detector responsive to the air flow that provides a signal related to the air flow. The device may include an indicator device operable to provide evacuation information in response to the signal. The air escapement conduit may include a bubble chamber or a valving mechanism. The detector may be a pressure differential sensor operable to detect a difference in air pressure between the inlet port and the outlet port, and generate a signal related to the difference.