Protocol
normocapnia
Subjects in both motion and low perfusion groups had three pulse oximeters placed on both a test hand (motion or low perfusion) and control hand (non-motion or normal perfusion). Pulse oximeters were randomly assigned to digits 2 to 5 on both test and control hands to mitigate for order bias.Subjects were administered air–nitrogen–carbon dioxide mixtures with a voluntarily increased minute ventilation, with carbon dioxide added as needed to maintain normocapnia. The test administrator adjusted the inspired air–nitrogen–carbon dioxide mixture breath-by-breath to achieve a series of stable SaO