Table 2.

The Abbott Aimplus infusion pump illustrates two common problems of number entry with its varied response to the single key sequence Embedded Image. Pressing Embedded Image on the Abbot (or pressing Embedded Image or equivalent on other devices) immediately before entering a number is crucial to the outcome. (a) When Embedded Image has just been pressed, the display is cleared, and Embedded Image can only mean one thing, although exactly what depends on which mode the pump is in. (b) If Embedded Image has not been pressed, the behaviour is almost arbitrary, and many values are possible depending on the user's prior keystrokes. Although the behaviour described in this table is specific to the Abbott Aimplus, like very many devices a display of ‘0 • ’ or ‘0 • 0’ is ambiguous, as it may be the result of pressing Embedded Image, which resets the display, or it may be the result of previous keystrokes (such as Embedded Image, say, which produce exactly the same display but has a different effect on subsequent number entry).

(a) mode Embedded Image pressedvaluerationale
µgm mL−1123decimal points are ignored
mL hr−11 • 2ignores anything after one decimal digit
time1.23 AM or 1.23 PMin some time modes, decimal points change AM/PM. Embedded Image resets the time to 0.00 but does not reset AM/PM
(b) mode Embedded Image not pressedpossible valuerationale
mgm mL−19999 • 9anything ignored unless Embedded Image pressed first
mL hr−10 • 1a user previously pressed, e.g. Embedded Image
mL hr−10 • 0a user previously pressed, e.g. Embedded Image
time0.00 AM or 0.00 PMit looks like Embedded Image was pressed, but pressing Embedded Image, etc., locks the display except for AM/PM, which still changes with the decimal point