Device and method for monitoring an access to a patient

A device for monitoring an access to a patient of an apparatus by which a liquid is provided to the patient via a needle or cannula comprising:

• a needle or cannula comprising a narrowed cross-section comprising a constriction for flow to generate a pressure below atmospheric due to the liquid flowing through the needle or cannula, wherein cross-sections on both sides of the narrowed cross-section are wider than the narrowed cross-section, said narrowed cross-section having an opening, the opening entirely within a region of the narrowed cross-section, the opening comprising a through-hole or a milled aperture within the constriction of the needle or cannula, and the needle or cannula being configured such that, if the needle or cannula is out of the access then, due to the liquid flowing through the needle or cannula, the needle or cannula draws in air through the opening, thereby causing a sound to be generated;
• and
• an analyzing unit for sensing the generated sound, said analyzing unit being configured such that, when the generated sound is sensed, it is determined that the patient access is not in proper order.