Human Patient Simulator

The human patient simulator (HPS) is designed to mimic the responses of a patient to a variety of medical interventions. A computer is programmed with over 450,000 lines of computer code and 500 mathematical models of physiologic systems. A number of preprogrammed scenarios enable instructors to test students on their ability to manage a variety of diseases, from asthma to treating ARDS to ACLS scenarios. The pace of each scenario may be controlled by the instructor. In addition, instructors and students can depart from the preprogrammed scenario by using any medical intervention that they choose from an intervention "menu". These interventions include altering the simulator's compliance, increasing urine output, or administering a medication. An almost infinite array of conditions and interventions can be constructed. In addition, the latest software versions (v 5.0 and greater) allow users to edit and even author their own scenarios. In addition to providing instructors with the ability to tailor learning experiences for their students, the scenario editor is easy to use.

The simulator is attached to the Merlin® Monitoring System manufactured by Hewlett Packard. This sophisticated monitoring system enables the user to monitor the "patient's" ECG, arterial blood pressure, pulmonary artery pressures, arterial saturation via pulse oximetry, and end-tidal CO2 levels via a mainstream capnograph.

The Merlin® Monitoring System also allows the user to calculate numerous hemodynamic parameters.

The HPS operates in the following fashion (please consult graphic shown below).


The operator selects a baseline patient from a menu of possible patients. These patients are in various states of underlying health (or sickness). The operator then selects a scenario to "overlay" on the baseline patient. These scenarios could cause the patient to develop an ischemic heart, low lung compliance, or high airway resistance. There are numerous scenarios for allied health sciences and anesthesia that come with the simulator (including ACLS scenarios). Each of the scenarios is composed of two or more states which are composed of events and transitions. Events could be an altered airway resistance, high pulmonary vascular resistance, an ischemic heart, or laryngospasm. Transitions allow the simulator to move from state to state when a particular medication is delivered (detected by a bar-code reader) or any predetermined option occurs (time in state, for example). Conversely, the operator may move from state to state as he or she determines appropriate.

Practitioners can administer medications. A bar code on a syringe is scanned with a bar code reader. The medication (it is actually tap water) is then "injected" into the simulator. In reality, the amount of medication administered is weighed by a sensitive scale and the physiologic response is then calculated.

Since the simulator is attached to a carbon dioxide tank to simulate the production of carbon dioxide, the simulator can be attached to a main stream capnograph.

The HPS is a marvelous addition to the tools available for teaching respiratory care, cardiopulmonary technology, EMS, and nursing students.