If you do not feel a thump against your fingers and do not see the chest rise or fall, what action should you take?

When assessing an unresponsive individual, the absence of a thump against your fingers, which indicates a pulse, along with the lack of visible chest rise or fall, suggests that the person is not breathing effectively or at all. In such situations, it is critical to initiate CPR immediately. CPR provides vital oxygen to the brain and other organs, which can be crucial in preventing irreversible damage or death.

This action is essential as it addresses the most immediate threat to life: the inability to circulate blood and oxygen throughout the body. Once CPR is started, it is important to call for emergency medical assistance to get advanced care.

Other actions, although they may seem beneficial, would delay critical intervention. Monitoring vital signs without initiating CPR provides no benefit if the individual has stopped breathing or has no pulse. Checking for obstructions in the airway might be necessary if there's a reason to suspect choking, but in the absence of breathing or pulse, starting CPR takes priority to maintain circulation and oxygenation. Administering oxygen may be helpful once basic life support measures are underway and if there’s an available source, but it does not replace the need for chest compressions and rescue breaths in a situation where the individual is not breathing.