Sentence:  He's at the age where mucus is a daily companion, a culture of mucus among the old, mucus in a thousand manifestations, appearing in clots by total surprise on a friend's tablecloth, rimming his breath-passages at night in hard <WSD>venturi</WSD>, enough to darken the outlines of dreams and send him awake, pleading. 
Meaning of the word marked with <WSD> tags:  A constriction in the flow of air to lungs.