The International System of Units (SI) is an extension of the metric system and was approved by the General Conference on Weights and Measures in 1960. The SI, expanded for the health professions, has been adopted by most European countries and is being adopted by Canada. Proponents of the SI for American medicine see intrinsic merit in its coherent units and believe international communication among physicians requires its adoption. Opponents fear that conversion to the SI is little more than "tinkering" and that any changes from the present system are potentially dangerous. Adoption of some of the less controversial portions of the SI has been recommended by the AMA Council on Scientific Affairs; consideration by the House of Delegates is anticipated.
Powsner ER. SI Quantities and Units for American Medicine. JAMA. 1984;252(13):1737–1741. doi:10.1001/jama.1984.03350130051034