Blood is the liquid connective tissue carrying the needed oxygen and nutrients throughout the body. Taking around 20 seconds for complete circulation, it is necessary for every biological function. Aiding in the circulation are various arteries, capillaries, and veins, which make up the blood vessels throughout the entire body. The circulatory system is a vast maze altogether around 60,000 miles long. As our heart pumps blood through these vessels, at 60-100 beats every minute, bringing life to organ systems, keeping us alive and functioning properly. Physicians and surgeons are acutely aware of the importance and function of blood, and, thus seek to preserve its vitality throughout medical procedures.

One of the greatest risks in surgery is blood loss, therefore, doctors are always searching for ways to prevent this. Hemostasis is an important part of surgical training and can be a challenge to the novice surgeon. There are various instruments surgeons utilize, such as: electrocautery, ultrasonic energy devices, lasers, and microwave tissue dissectors, just to name a few. Central to utilizing these devices is proper training. In addition, repeated practice of surgical procedures is vital for the acquisition and improvement of surgical dexterity among undergraduates and surgery professionals, which in many cases is accomplished using cadavers. While cadavers provide the closest representation of a living patient available, there are limits to the training achieved using a standard cadaver specimen. One of these limits is that once an individual has died their circulatory system ceases to function, therefore, when practicing medical procedures, or testing pharmaceuticals or devices on these cadavers a key function is missing which means the information gained will be limited. Also, there is limited availability of cadavers, undesirable changes in tissue texture in addition to the absence of bleeding resulting in numerous disadvantages of cadaver-based training compared to training in live patients.

According to the September 2013 Annals of Surgery, a survey done of 91 residency programs, “more than 62% of the surgeons were found to be involved in more than one patient risk incident.” That same survey indicated that these “risk incidents” could be attributed to the significant lack of competency present in these graduates. The data is as follows:

• 21% felt that fellows arrived unprepared to the OR
• 30% could not independently perform a laparoscopic cholecystectomy
• 66% were deemed unable to operate for 30 unsupervised minutes of a major procedure
• 30% could not atraumatically manipulate tissue
• 26% could not recognize anatomical planes
• 56% could not suture
• 28% were not familiar with therapeutic options
• 24% were unable to recognize signs of risk

This does not diminish the crucial role cadavers play in medical education, however, it has been a focus of some in the medical community to find a way of giving more “life” to these essential tools. Pumping systems have been developed which simulate the actions of the circulatory system, however, until recently, these devices have been very limited in their function only maintaining circulation for approximately 30 minutes before the cadaver begins to bloat and leak. This has all changed with the introduction of envivoPC.

EnvivoPC= Lifelike Reperfusion for Cadavers

EnvivoPC is the first device of its kind to be able to simulate the circulatory system for an extended period of time, approximately 10 hours, providing a “life-like” cadaver. As the creators of envivoPC, Maximum Fidelity Surgical Simulations, explains:

• The system enables a hyper-realistic “patient” by perfusing a cadaver with our patent pending solution using a pulsatile pump to mimic heart function. (The system has overcome bloating and leakage problems.)
• The key advantage of the envivoPC are life-like tissue integrity, with anatomic accuracy and a functional circulatory system, using a blood substitute that extends cadaver use over multiple days and multiple procedures.
• Our system includes a pulsatile pump, a reservoir and tubing, an optional heat exchanger and patent pending blood substitute that is vital to successful cadaver reperfusion. (Five patents pending to date)

This innovative technology removes the existing limitations in using cadavers, increasing physician competency, while decreasing risk of injury to the patient. In order to demonstrate the functionality of this innovative technology, envivoPC has incorporated the following labs:

• Boot camp for central line access, trocar, and laparoscopic surgery. This boot camp was for 1st year residents at LSU Medical and Ochsner. Dr John Morrison holds the boot camp for two main reasons. 1. He has noticed a significant drop in skill from residents and 2. Teach how to properly access the central line (according to Dr. Morrison, improper central line access is the second most litigated medical procedure). Without the proper pulse and blood flow, students aren't trained properly on the central line procedure.
• Vascular lab for Pedal/Pop Access and Ultrasound. This lab is produced by Dr. Malachi Sheahan. During this lab, a leg only is perfused for practice access using Cook Medical device and ultrasound. Dr. Sheahan was very pleased that he was only able to use the initial legs each day for all day access procedure without any edema and without having to use more legs.
• Vascular lab for Fundamentals of Vascular Surgery Symposium. This lab is produced by Dr Sheahan as well. He brings in a combination of over 30 fellows and residents to review fundamental vascular surgical procedures. Creating a realistic, life-like blood flow blew away the attendees.
• AAA Stent placement with C-arm viewing. Dr Joss Fernandez successfully tested a new fluid he has produced that allows visual viewing of vascular branches with the C arm when training AAA stent procedures with medical devices. A first for our market of perfusion.

Proven Benefits of Bleeding Simulation

Although this technology is new, various studies have been performed to test the benefits of perfusion systems on cadavers in training.

One such study was performed at the Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, Brazil. This study was performed using animal cadavers, which were embalmed and then “bright red and dark red surrogate solutions were infused through the arterial and venous system, respectively. Cannulated arteries were connected to a pump to replicate the arterial pulsatile flow.” When surgical procedures were performed on these cadavers, the simulating bleeding system “allowed proper identification and isolation of bleeding vessels, along with adequate training of preventive and control hemostatic techniques”. In addition, the concluding results showed an overall superiority in the enduring quality of the cadavers, which means more procedures can be done on a single cadaver limiting the number of cadavers needed. An increase in competency was also observed, as this simulation provided life-like conditions. Here is what the study concluded:

• This study combined a perfusion technique and a well-established cadaver preservation method (Silva et al., 2004, 2007). Tissue texture was maintained and cadavers could be used several times, thereby overcoming some of the limitations of formaldehyde preserved cadavers (e.g., unpleasant odor) and of fresh/cryopreserved specimens (e.g., single use). Overall reduction of the number of specimens required for training and less time-consuming cadaver preparation are further advantages of the combined method.
• Undergraduates trained in cadavers and artificial models that do not mimic live tissue texture and bleeding tend to be less confident in their skills due to limited exposure to the actual challenges inherent to the practice of surgery and may therefore hesitate to operate on live animals (White et al., 1992; Smeak et al., 1994). Artificial bleeding introduces a high-fidelity simulation training method to overcome the lack of familiarity of novices with basic surgical tasks.
• Technical errors during simulation are obviously devoid of clinical significance and morbid or lethal consequences. However, the practical experience gained with this method is a feasible alternative for replacement of live surgery in the beginning of the learning curve, and can certainly be applied in the operating room.
• Allowing the refinement of surgical competence and proficiency before the first experience on real patients, surgical interventions can be restricted to animals that would really benefit from such procedures and avoid using animals exclusively for learning purposes.

Why envivoPC is Superior

In line with the previous study, utilization of the envivoPC technology in cadavers extended the “life” of the cadaver to two weeks, which allows for more than 20 procedures to be performed on one cadaver. With limited supplies of cadavers, this is an effective way to decrease the number of cadavers needed.

Some of the features of envivoPC are:

• Continuous pulsatile flow mimics heart function
• Proprietary embalming fluid (patent pending)
• Proprietary blood substitute (patent pending)
• Arterial and venous flow capabilities.
• Heart rate 30-100 bpm
• Stroke Volume 10-80 ml
• Systolic Blood Pressure 40-200 mmhg
• Diastolic Blood Pressure 10-100 mmhg
• 50-75% diastolic time

The benefits of mimicking these life-like conditions in a cadaver are:

• Ability to control heart rate, volumes, and pressure.
• Ability to feel a pulse in the cadaver to find surgical landmarks, access points.
• Creates hyper-realistic “patient” cadaver which demands rigorous surgical techniques to prevent fluid (blood) loss.
• Surgical/bioskills can be practiced in a hyper-realistic setting without risk to live patients.

This innovative technology is advancing the learning experience of students and physicians, alike. The limitations once present with utilizing cadavers to prepare students and graduates for real world experience are now a thing of the past. EnvivoPC has made the “living cadaver” a reality.

The MARC Institute, Innovation in the Making

Leading the way in innovative technology for medical advancement is The MARC Institute. EnvivoPC is now available at The MARC Institute, where the following procedures can be performed using this technology:

• Stent and valve placement
• Central line access
• Trocar and laparoscopic surgery
• Pedal/pop access and ultrasound
• Multiple vascular procedures
• Plastic surgery/Vascularization of skin flaps
• Trauma situations
• Multiple cardiovascular procedures

The MARC Institute is leading the way in the use of fresh-frozen cadavers, they recognize that cadavers are an invaluable, and irreplaceable resource for the medical student and professional. Catering to the advancement of modern medicine they offer a variety of courses to healthcare professionals including: Spine, Orthopedics, Pain Management, Anatomy, Dental, Plastic Surgery, Dermatology, CMF, and, now, envivoPC. In addition, the facilities at The MARC Institute are designed to accommodate the student, practitioner, and researcher with advanced technologies and equipment, as well as, facilitating large and small groups for education or research purposes. We invite you to learn more about what we offer by visiting The MARC Institute either in person or online.