<qa>  What is the ISO 9919 standard published by the International Organization for Standardization?At present the FDA have adopted the standards published in 2005 by the International Organization for Standardization ISO, entitled ISO 9919. This is a set of technical specifications and guidelines for pulse oximeters, which share certain technical similarities to cerebral oximeters. In particular, Annex EE details the conduct of a controlled desaturation study for the calibration of pulse oximeter equipment. Specifically, the fraction of inspired oxygen delivered to test subjects is varied to achieve a series of targeted steady state saturation periods over a range of arterial oxygen saturation of 70 - 100. 