David R Drover1, S J Barker2,3. 1. Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University Medical Center, Stanford, CA, USA. 2. Professor Emeritus of Anesthesiology, University of Arizona, Tucson, AZ, USA. sbarker@masimo.com. 3. Masimo Corporation, Irvine, CA, USA. sbarker@masimo.com.