Payment calculations represent projected net revenue from the various payor sources. For example, projected payments from commercial insurers and self-pay patients equalled billed charges minus the Medical Centers average percentage of uncollectible debts. Fbr all other payors, payments were calculated as specified in contractual agreements between the payors and the Medical Center. Our methods for calculating Medicare payments have been described in detail previously. All calculations assume full reimbursement by patients for deductibles and co-payments.
For cost analyses, patients were grouped by certain clinical characteristics (mechanically ventilated vs not mechanically ventilated) and/or by financial considerations (primary payor source). To compare expenses between the MICU and the NRCU, we evaluated cost data from all patients who received mechanical ventilation first in the MICU, then in the NRCU during a single hospitalization within the 12-month study period.
Results
Patient Population
In 1988, a total of 136 patients were cared for in the NRCU (47 percent men, 53 percent women). More than half of the patients were 60 to 80 years of age (Fig 1).

Figure 1. Age distribution of patients admitted to the NRCU.