Good question. There is no change in the swallowing reflex with emphysema. However, if a person with emphysema is short of breath while eating, having trouble swallowing between breaths, it is conceivable that this might increase the risk of aspiration.
What you should do about it depends, in part, on whether the aspirated material was or was not immediately coughed-up. If not coughed-up, the aspirated food or liquid has the capacity to initiate the process of inflammation which, in turn, could lead to infection, bronchitis or pneumonia or even lung abscess. Unless coughed up immediately, the material is likely to remain in the lung, indefinitely and might only lead to infection after days or even weeks have passed.
It would be wise to consult with your doctor and have an x-ray performed. If you continue to cough after the aspiration, even in the absence of x-ray change, it might be necessary to remove the aspirated material, under direct vision, with an instrument called a bronchoscope.