Step-Down Unit Acuity

We are discussing acuity based staffing on our unit, and whether we should be considered ‘step down’, particularly in regards to some of the specialty patients we accept. We are officially deemed ‘med-surg’, except when residents sign their notes as ‘ICU’ (confusing, huh?). We take as little as POD#1 CABG/Valves/heart transplants, PA catheters (Swan-gantz catheters), post-Cath lab (including TR bands and femoral sheath pulls), an array of cardiac drips including remodulin, NTG and dopamine, and LVAD patients. We all take a critical care course and are ACLS cerified. We are fairly strict about a 4:1 ratio, with hardly any deviation from this ratio (never 5:1, basically never 3:1 unless you just had a discharge). We only have one mandatory assessment charted per day. We are trying to argue that some of these patients, particular fresh open hearts and SWANs would be on true ‘step down’ units or the ICU at other hospitals. Do any other facilities take these patients outside the ICU, and if so, what are your ratios? Do you think those ratios are safe at your own facilities? Any information or input is appreciated, as well as any literature references. I can find very few scholarly articles and very little consistency about the definition of a ‘step down’ unit, the types of patients that should be on them, and the recommended nurse:patient ratio on these units. Thank you!