A portable pump for negative pressure wound therapy for drawing a vacuum from a wound site via a tube, the portable pump comprising: an inlet configured to attach the tube from the wound site; a canister in fluid communication with said inlet for collecting fluids drained from the wound site; a pressure sensor for sensing a pressure level in said canister; a manually-actuated pump mechanism for creating the vacuum, the manually-actuated pump mechanism comprising: a vacuum chamber in fluid communication with said canister, a piston disposed in said vacuum chamber, and a pump handle coupled to said piston so as to move said piston in said vacuum chamber between a first position and a second position so as to create the vacuum, the pump handle moving between a retracted position and an extended position, wherein said piston is in the first position when said pump handle is in the retracted position and is in the second position when said pump handle is in the extended position, wherein upon manually pumping said pump handle, said piston creates a vacuum so as to create the vacuum at the wound site and to draw any fluids from the wound site into said canister; a pressure selection input mechanism for allowing a target pressure level to be selected from one of a plurality of different target pressure levels; a controller coupled to said pressure sensor and said pressure selection input mechanism for prompting the user to manually actuate said pump mechanism when the sensed pressure level is below the selected target pressure level; and an automatic lock/release mechanism for selectively locking said pump handle in the retracted position and releasing said pump handle such that said piston may be moved into the second position and hence said pump handle is moved into the extended position, wherein said controller is coupled to said automatic lock/release mechanism for prompting the user to manually pump said pump handle by releasing said pump handle when the sensed pressure level is below the selected target pressure level. an inlet configured to attach the tube from the wound site; a canister in fluid communication with said inlet for collecting fluids drained from the wound site; a pressure sensor for sensing a pressure level in said canister; a manually-actuated pump mechanism for creating the vacuum, the manually-actuated pump mechanism comprising: a vacuum chamber in fluid communication with said canister, a piston disposed in said vacuum chamber, and a pump handle coupled to said piston so as to move said piston in said vacuum chamber between a first position and a second position so as to create the vacuum, the pump handle moving between a retracted position and an extended position, wherein said piston is in the first position when said pump handle is in the retracted position and is in the second position when said pump handle is in the extended position, wherein upon manually pumping said pump handle, said piston creates a vacuum so as to create the vacuum at the wound site and to draw any fluids from the wound site into said canister; a vacuum chamber in fluid communication with said canister, a piston disposed in said vacuum chamber, and a pump handle coupled to said piston so as to move said piston in said vacuum chamber between a first position and a second position so as to create the vacuum, the pump handle moving between a retracted position and an extended position, wherein said piston is in the first position when said pump handle is in the retracted position and is in the second position when said pump handle is in the extended position, wherein upon manually pumping said pump handle, said piston creates a vacuum so as to create the vacuum at the wound site and to draw any fluids from the wound site into said canister; a pressure selection input mechanism for allowing a target pressure level to be selected from one of a plurality of different target pressure levels; a controller coupled to said pressure sensor and said pressure selection input mechanism for prompting the user to manually actuate said pump mechanism when the sensed pressure level is below the selected target pressure level; and an automatic lock/release mechanism for selectively locking said pump handle in the retracted position and releasing said pump handle such that said piston may be moved into the second position and hence said pump handle is moved into the extended position, wherein said controller is coupled to said automatic lock/release mechanism for prompting the user to manually pump said pump handle by releasing said pump handle when the sensed pressure level is below the selected target pressure level.