To the Editor:
Classical teaching has been based on “see one—do one.” More recently, a stepwise teaching approach has been described that has four steps: demonstration, deconstruction, comprehension, and performance.1,2 The process of achieving competence includes structured skill training, not just doing the technique.3
Medical students have to learn to perform several procedures before the end of their medical school training. One of the competences that they need to acquire is the peripheral vein catheterization, which is the most common procedure performed in the emergency department and in the operating room. Many students have not placed even one intravenous cannula during their medical training because of lack of opportunity to practice. On the other hand, students rapidly improve their proficiency after only five attempts.4 Guidelines have been published regarding this skill acquisition, showing that the process of learning is complex, and simulators may be helpful.5
To try to help in this skill performance acquirement, simulators have been developed. Simulators for peripheral vein catheterization have limitations, and even the most complex are far from providing a sensation that mimics the real experience. For medical students, the transfer of procedural skills acquired in a laboratory into clinical practice has not been clearly established.6
We propose a cheap and realistic strategy: the human placenta as a model for vein catheterization. During a cesarean delivery, once the placenta is delivered and out of the surgical field, after the umbilical vessels have been clamped, the medical student is allowed several attempts at placental venous catheterization with intravenous 20-gauge or 18-gauge cannulas. As the umbilical vessels are clamped, some supra-atmospheric pressure is maintained inside the placental vascular bed. As soon as the cannula is inserted into the vein, the blood reflux is seen in the catheter, and the venous blood flows freely when the catheter is placed, as happens during routine peripheral vein catheterization in a real patient. It allows the student and the observer/supervisor (the staff) to confirm a successful venous cannulation.
One limitation of this model is that once a vein has been catheterized, the blood amount inside the placental field decreases, and sometimes big hematomas can develop in very few seconds, which decreases the availability of the same placental specimen for a new training attempt. This model has also strengths, and the main one is the high number of available placental specimens in a university hospital. Another advantage is that the placental simulator is a cheap model, and also it is safe for students, patients, and staff. We believe that this model can be one more helpful tool for training medical students and even nurses in this basic skill.
The authors declare no competing interests.