PTF

Patient Treatment File Hospital data. (PTF)
The PTF files are analogous to hospital discharge abstracts and include basic demographic data as well as principal, primary, and nine secondary ICD-9-CM codes. In the VA, the primary diagnosis code refers to the condition that accounted for the majority of the hospital stay. The principal diagnosis code, which was added in FY1997, refers to the diagnosis that led to hospitalization. In addition to the main PTF file, surgeries and procedures files are also available. The surgeries file contains ICD-9-CM procedure codes for surgical procedures (e.g., coronary artery bypass surgery) performed in the operating room, whereas the procedures file includes codes (e.g., cardiac catheterization) for procedures performed outside the operating room. The surgeries file has an observation for each surgery performed during an episode of care, and up to five codes per surgery may be listed. The procedures file includes an observation for each day procedures occurred during the hospitalization, and up to five procedures may be listed. There is a maximum of 32 observations per hospitalization or episode of care resulting in a maximum of 160 procedure codes. In addition to hospital or acute care, the PTF includes extended care (VA nursing home), observation (outpatient surgery), and non-VA care (care provided in facilities with which the VA contracts).

Note: I don't think there is a maximum limit of observations (ie: 32) in a VistA system.