单词pack-year
网络: 吸烟的包装年；吸烟指数
He states that he has had the cough "for quite some time" and attributes it to his 40-pack-year history of smoking cigarettes.
系统回顾时患者提及偶发干咳。患者咳嗽很有一段时间了，并将其归咎于既往40年的吸烟史。