While managing hemorrhage is a basic surgical skill, our malpractice claim data suggests that uncontrolled hemorrhage is a leading adverse event in surgery. Practicing hemorrhage control skills and teamwork during massive surgical blood loss situations is an important simulation exercise. We have previously described an inexpensive device made from readily available materials that allows a learner to practice careful dissection, hemostasis, tying off blood vessels with suture in deep locations, and control of massive hemorrhage.1 The device is based on the concept of a generic vascularized growth in a non-specific tissue medium that requires resection. This system used a plum or pluot threaded with thin-walled silicone tubing to represent blood vessels embedded within colored gelatin to represent a tumor in a generic tissue bed. We now describe a highly engineered version of this open surgical model that can be used repeatedly and reliably for either surgical skills simulation or team training exercises. We have used the open surgical simulator for interprofessional team training approximately ten times with substantial engagement of the surgical team and successful simulation of uncontrolled hemorrhage.
The new version replaces the fruit with a reusable, permanently mounted silicone tumor, with barbed fittings allowing for easy replacement of the silicone vessel segments. Using 3-D printer technology a module containing the tumor and associated plumbing was designed to replace the abdominal insert of a Laerdal manikin or used stand-alone. A portable suction canister stand is used as a simulated blood reservoir (7500cc) and for housing electronics. Submersible pumps provide controllable blood pressure for three vessels and two sources of occult bleeding; in-line pressure sensors detect loss of hemostasis, and measure blood loss; a force-sensitive resistor detects application of direct pressure to control hemorrhage. An Arduino microcontroller is used to control the fluidic systems; Bluetooth wirelessly links the Arduino to a GUI application running on an Android tablet that provides controls for pumps and valves and provides gages showing blood volume, blood loss and pressure/force values to the instructor. A foil plate at the base of the gelatin layer provides a means to connect an electrosurgery return cable and permit the use of cauterization. We are developing image analysis tools to evaluate the quality of dissection and utilization of hemorrhage control skills.
This simulated tumor system allows repeatable simulations to measure surgical skills or for use in teamwork simulations requiring surgery. We have used the device primarily for the later purpose. The device provides a considerable challenge for even experienced surgeons allowing a simulation scenario to develop over 20 minutes. This system can produce bleeding over a range from easily manageable to uncontrollable. Hemorrhage control skills such as appropriate use of electrosurgery, point pressure, vessel ligation with suture or clips, and packing can be used with this model. Combined with a manikin simulator, scenarios requiring massive intraoperative transfusion can be simulated for operating room teams. We plan to develop the surgical skills assessment aspect of this simulator by defining visual measures of the quality of dissection and use of hemorrhage control skills. Modifications to improve performance and allow this device to be commercially produced are under way.
1. Berry W, Raemer D. The Tumor: A Simulator for Open Surgery. Simul Healthc. 2006;1(2):115.
Gregory Loan is a consultant for the Medicines Company. Mark Ottensmeyer is involved in corporate sponsored research funded by Lantos Technologies, is a consultant for SImQuest Solutions, Inc., and is employed by Massachusetts General Hospital, which receives patent royalties from CAE Healthcare.