check out this thread for websites linking to NANDA and other nursing diagnosis sites
you state hypertension so
Hint: When thinking of hypertension think of potential adverse outcomes i.e. renal failure, MI, stroke
Think too of the factors that cause it - i.e. high salt in diet, stress, cholesterol intake, renal impairment etc etc
One of the reasons why you are having trouble is that hypertension is a medical diagnosis - you have to focus on those things a nurse can do i.e. diet, stress reduction/management, medication compliance, education etc - I hope this helps.
However you included "decreased cardiac output" so did you mean hyper or hypotension???