Emergency Medical Technician VII Progress Indicator: Question 1 of 20 1.  When delivering mouth-to-mask ventilations with supplemental oxygen: Choices: Deliver each breath for longer than 10 seconds. It is not necessary for the patient's chest rise to be visible. Provide a minimum flow rate of 10 to 12 L/min. Slow the ventilatory rate to 1 breath every 8 seconds.