Ohmeda Slide Rule for Pressures and Volumes

For decades, clinicians have appreciated shortcuts for calculating numbers and for converting units of measure. In both surgical and critical care suites, some “seasoned” anesthesiologists and intensivists appreciated using handy slide rules for a host of patient- and apparatus-related tasks. Assisted by this Ohmeda slide rule (upper image), one learned that 150 mmHg equals 20 kPa. On the back (lower image), a tidal volume of 700 ml at a respiratory rate of 10 per min was slide rule –calculated as having a 7 l/min minute volume. The Cleveland-based company founded in 1910 as “Ohio Chemical” shifted its corporate headquarters to Madison, Wisconsin, in 1946. Yet, starting in 1967, the firm still called itself Ohio Medical Products. By 1984 the Wisconsin-based company finall y shelved the name “Ohio” and rebranded itself as “Ohmeda.” And by then, calculators, computers, and digitization had combined to make handheld slide rules, like this one, largely obsolete. (Copyright © the American Society of Anesthesiologists’ Wood Library-Museum of Anesthesiology.)
Source: Anesthesiology - Category: Anesthesiology Source Type: research