Final answer:
To monitor technique and placement after verification of a ventilatory device like a bag-valve mask, observe the chest rise and fall and check for adequate oxygenation and ventilation along with monitoring vital signs.
Step-by-step explanation:
After verifying the technique and placement of a ventilatory device such as a bag-valve mask, ongoing monitoring is crucial to ensure its effectiveness. One way to monitor technique is to observe the chest rise and fall with each ventilation, ensuring that the mask is properly sealed and delivering sufficient air volume. Placement can be monitored by checking for adequate oxygenation and ventilation of the patient, as well as by monitoring the patient's vital signs such as heart rate, blood pressure, and oxygen saturation levels.