The Hewlett-Packard 1000--Vitalmetrics VM220 connection: a description of the automated ultrasonic urine output measurement system in the CICU of Genolier Clinic.

After over eighteen years experience using an automated weighing technique to monitor the urine output, we have changed our system in favor of the Vitalmetrics VM220 ultrasonic urine/bladder temperature measurement devices. Last year we began with one VM220 interfaced directly to the Hewlett-Packard 1000 computer's standard ASCII circuit card (H-P 12966A ASCII BACI). We found that we could read and interpret the ASCII string transmitted by the VM220; then started a search for a suitable multiplexing device through which we could manage all six of our VM220's with only one interface card. Perhaps there are many more, but we found two which we shall discuss in this report: 1. The Baytech Associates model 528-B 8 channel switching device and 2. the SEA Corporation signal distribution controller (also known as the cluster controller) which has 16 channels. In our post-operative cardiovascular intensive care unit (CICU), we have used the Baytech 528-B multiplexer to monitor the urine output for over 250 open heart surgery patients. Later this year, we acquired a cluster controller from SEA Corporation in Birmingham, Alabama (USA). We have written software for testing and incorporating this application into a Hewlett-Packard Patient Data Management System (PDMS).