An apparatus for applying negative pressure to a wound, the apparatus comprising: a negative pressure source configured to couple via a fluid flow path to a wound dressing and provide negative pressure to the wound dressing; a sensor configured to monitor pressure in the fluid flow path; characterized by a controller configured to: determine that the wound dressing is coupled to a wound from a change in a magnitude of pressure in the fluid flow path over a time duration by comparing the change in the magnitude of pressure to an irregular pattern indicative of a chaotic condition while the negative pressure source maintains negative pressure in the fluid flow path within a target pressure range, output a first indication denoting that the wound dressing is coupled to the wound, determine that the wound dressing is not coupled to the wound from the change in the magnitude of pressure in the fluid flow path over the time duration by comparing the change in the magnitude of pressure to a regular pattern indicative of a steady state condition while the negative pressure source maintains negative pressure in the fluid flow path within the target pressure range, and output a second indication different from the first indication denoting that the wound dressing is not coupled to the wound. a negative pressure source configured to couple via a fluid flow path to a wound dressing and provide negative pressure to the wound dressing; a sensor configured to monitor pressure in the fluid flow path; characterized by a controller configured to: determine that the wound dressing is coupled to a wound from a change in a magnitude of pressure in the fluid flow path over a time duration by comparing the change in the magnitude of pressure to an irregular pattern indicative of a chaotic condition while the negative pressure source maintains negative pressure in the fluid flow path within a target pressure range, output a first indication denoting that the wound dressing is coupled to the wound, determine that the wound dressing is not coupled to the wound from the change in the magnitude of pressure in the fluid flow path over the time duration by comparing the change in the magnitude of pressure to a regular pattern indicative of a steady state condition while the negative pressure source maintains negative pressure in the fluid flow path within the target pressure range, and output a second indication different from the first indication denoting that the wound dressing is not coupled to the wound. determine that the wound dressing is coupled to a wound from a change in a magnitude of pressure in the fluid flow path over a time duration by comparing the change in the magnitude of pressure to an irregular pattern indicative of a chaotic condition while the negative pressure source maintains negative pressure in the fluid flow path within a target pressure range, output a first indication denoting that the wound dressing is coupled to the wound, determine that the wound dressing is not coupled to the wound from the change in the magnitude of pressure in the fluid flow path over the time duration by comparing the change in the magnitude of pressure to a regular pattern indicative of a steady state condition while the negative pressure source maintains negative pressure in the fluid flow path within the target pressure range, and output a second indication different from the first indication denoting that the wound dressing is not coupled to the wound. <EOS>