You are ventilating an apneic adult with a bag-valve-mask device and high-flow oxygen. Her pulse rate is 130 beats/min and she has cyanosis to her face and chest. The MOST reliable indicator of adequately performed ventilations in this patient is:
A) Pulse rate of 130 beats/min
B) Cyanosis to face and chest
C) Capillary refill time
D) Blood pressure of 120/80 mm Hg