System for treating a wound with suction and method of detecting a loss of suction

A system for applying suction to a wound, comprising:

• a portable positive displacement pump for providing suction to a conduit operatively associated with the wound to communicate suction to the wound, the pump being capable of operation at variable speed;
• a vent in fluid communication with the conduit to provide a reference airflow into the conduit when the system is in operation, such that a loss of suction at the wound is indicated by deviation from the reference airflow;
• a flow rate monitor to monitor airflow through the conduit and to indicate reference airflow and deviation above and below the reference airflow;
• and
• a pressure transducer for detecting pressure at the pump, wherein the pump speed is controlled to maintain the pressure sensed by the transducer based on a pressure setting;
• wherein the airflow is determined by counting pump revolutions over a period of time.