Final answer:
If gastric distension occurs during ventilation, adjust the person's head position and try to ventilate again, and if necessary, perform the Heimlich maneuver to resolve a blockage.
Step-by-step explanation:
If you notice gastric distension while providing ventilations, you should reposition the person's head to ensure proper airway alignment and attempt to ventilate again. If distension continues, it may be necessary to perform the Heimlich maneuver to clear a potential blockage. Gastric distension can occur when air enters the stomach instead of the lungs, causing the stomach to inflate; this can be reduced by ensuring that the ventilations are not too forceful or too rapid.