Final answer:
The most effective ventilation device for a patient during single-rescuer CPR is a BVM without oxygen, as it provides adequate oxygen delivery and ease of use compared to NRBs, FROPVDs, or pocket masks with oxygen.
Step-by-step explanation:
During single-rescuer CPR, the most effective device for ventilating a patient would be a bag-valve-mask (BVM) without oxygen. While the BVM can be enhanced with supplemental oxygen, it can still provide adequate ventilation on its own due to its design, which allows for the delivery of high concentrations of oxygen and positive pressure ventilation. Devices such as Non-Rebreather masks (NRBs) and Flow-Restricted, Oxygen-Powered Ventilation Devices (FROPVDs) are more complex and typically require more than one rescuer to operate effectively, making them not the most suitable for single-rescuer scenarios. A Pocket mask with oxygen could be effective but is less efficient in terms of oxygen delivery and ease of use compared to the BVM. The BVM is a preferred choice due to its ability to maintain an open airway and provide adequate tidal volumes for the patient.