THE INVENTION RELATES TO AN APPARATUS (2, 3), COMPRISING A MATING UNIT (20-1, 20-2) FOR RELEASABLY ATTACHING THE APPARATUS (2) TO A MEDICAL DEVICE (1) OR FOR RELEASABLY RECEIVING AT LEAST A PART OF THE MEDICAL DEVICE (1). THE APPARATUS (2, 3) FURTHER COMPRISES ONE OR MORE OPTICAL SENSORS (25, 26) AND/OR ONE OR MORE ACOUSTICAL SENSORS (27) FOR DETERMINING INFORMATION RELATED TO A CONDITION AND/OR USE OF THE MEDICAL DEVICE (1). THE INVENTION FURTHER RELATES TO A SYSTEM COMPRISING SUCH AN APPARATUS (2, 3) AND SUCH A MEDICAL DEVICE (1), TO A METHOD (500, 600, 700) AND A COMPUTER PROGRAM (61) FOR DETERMINING INFORMATION RELATED TO A CONDITION AND/OR USE OF SUCH A MEDICAL DEVICE (1), AND TO A COMPUTER-READABLE MEDIUM (60) STORING SUCH A COMPUTER PROGRAM (61). THE MOST ILLUSTRATIVE DRAWING ACCOMPANYING THE ABSTRACT: FIG. 4
