Dear Andrew my apologies CAL Chronic Airway Limitation is one of those frustrating new acronyms that are used which has replaced COPD They all mean the same thing and this may seem trivial but it actually really important These days most UK Australian and increasingly many more US hospitals are using this as the default title in place of COPD or others haha Sorry to be fussy but I think it is very important to use up to date terms so that the article is easy to find and so that it uses the correct title Whatever that means haha best wishes Tom H see httpwwwabaccicomwikipediatopicaspxcurtitleChronicobstructivepulmonarydisease and httpwwwncahsnswgovauchronicdiseaseindexphppageidsiteid httpwwwerjersjournalscomcgicontentabstract