op nurse:patient ratio

Our cath lab recently opened a seven bed outpatient unit. This unit is staffed by cath lab RN, RT and a NA/Ward Clerk. Recently we had a day when our patient load was low. Our department manager sent everyone home except one Rn to take care of one patient who had received Versed and Fentanyl for a pacemaker generator replacement. The staff of the cath lab feels that this was not safe. What is your opinion? Do you have a policy regarding staffing in an outpatient setting?