The new edition of the OHAM is a very welcome revision indeed. The first edition was starting to feel rather dated.
For the most part is extremely comprehenisive, covering everything for altitude sickness to COPD exacerbations. The information is always well presented and reasonably succinct. It really does follow on nicely from the OHCM.
Of course there are problems- the text has become more prose-like and less bullet pointy. This means that whilst it is a 'pocketbook', it really is best read at home before and after the event to dissect out what may/went wrong. Nevertheless it is useful in making sure you haven't forgotten anything during an on-call.
The book includes a section of respiratory support- this is esentially principle based and is of little use in an actual emergency. The practical management information the book provides would be enough for an SPR who was not working in their chosen field i think. Obviously each hospital has its own guidelines which no doubt deviate from this text.
The main book to compare it with is the 'Acute Medicine: A Practical Guide to the Management of Medical Emergencies'
Overall, the OHAM is more detailed and comprehensive, HOWEVER - the other book is far more practical and offers extremely valuable management algorithms.
In short, you must use BOTH books........