Final answer:
The first action a rescuer should take when dealing with gastric distention during positive-pressure ventilation is to ensure proper tidal volume for visible chest rise, which helps in preventing air from entering the stomach.
Step-by-step explanation:
If gastric distention occurs in a victim as a result of positive-pressure ventilation, the first action the rescuer should take is to ensure proper tidal volume for visible chest rise. Gastric distention can be caused by too much air entering the stomach instead of the lungs during artificial respiration. This may result from air being delivered too quickly or with too much force. To reduce the likelihood of gastric distention, it's essential to provide breaths that are not too forceful and to allow enough time for the air to enter the lungs, monitoring chest rise to confirm correct ventilation. This helps to prevent air from being diverted into the stomach, which can reduce the effectiveness of breaths and increase the risk of regurgitation and aspiration.
If adjusting the tidal volume does not remedy the situation, rechecking the head tilt and chin lift positioning can help ensure the airway is properly opened for breaths to reach the lungs. In cases where the person requires CPR, recall that delivering compressions at a depth of at least 5 cm and at a rate of 100 compressions per minute is vital. Additionally, the rescuer should keep up to date with CPR guidelines, as these may change periodically based on the latest scientific research and expert consensus.