Introduction
Point-of-Care Ultrasound (POCUS) is currently used through all stages of surgical care including resuscitation, preoperative diagnosis, surgery, and intensive care [
1,
2]. It is a
Physiological
On spot clinical decision tool which is used as an extension of the
Clinical examination in a
Unique and
Safe way for managing critically ill patients [
3‐
5]. Understanding its principles and limitations is the first step towards mastering this diagnostic tool and avoiding its pitfalls. Nevertheless, POCUS is operator dependable and needs proper training to reach its required level of competency. That is one of the hallmarks for a successful use of POCUS in managing critically ill patients [
6‐
8]. Therefore, POCUS training given for undergraduate medical students is recommended [
9].
Globally, there are huge differences in economical status, educational, technical, and health care facilities between different countries which will definitely impact training in acute care surgery and critical care medicine. The annual gross national income (GNI) per capita is less than 1000 US dollars for low-income countries and more than 12,000 US dollars for high-income countries [
10]. These differences lay heavy burdens on educators who work in settings having few resources. Knowledge and understanding of the local facilities and their needs will help in developing educational methods that are tailored to the income of these countries.
The World Society of Emergency Surgery advocates developing clinical guidelines that are accepted globally including low-income countries [
11]. Furthermore, it is developing surgical programs that aim at helping low- and middle-income countries. We have recently developed an efficient, simple, and cheap simulator that can be used for teaching POCUS globally. This stemmed from more than 30 years of intense experience in both clinical and educational POCUS activities. We aim in this communication to describe how to build up and use this simulator so as to help our colleagues in low- and middle-income countries who want to teach POCUS and do not have enough resources to purchase expensive mannequins and computer-based simulators.
Discussion
We have developed a cheap useful simulator using the Kunafa knife and play dough to teach POCUS for undergraduate medical students. We think that this portable simulator is a simple, valid, and cost-effective educational tool that may help colleagues in low-income countries in teaching POCUS.
We have recently reported our prospective global study on the management of acute appendicitis (MAGIC study) which included 4271 consecutive patients. There was significant variation in the radiological workup of patients depending on the GNI per capita [
14]. CT scan was done in less than 8% in the low-middle income countries compared with 38% in high-income countries. In contrast, ultrasound was done in more than 70% in the low-middle income countries compared with 60% in the high-income countries. The recent guidelines of the World Society of Emergency Surgery for the management of acute left colonic diverticulitis support the use of ultrasound as an initial diagnostic tool [
15]. The major two limitations for using ultrasound globally are availability and training.
During 2017, the annual GNI per capita for different countries ranged globally between 290 dollars and 82,650 US dollars [
16]. This has major impact on health care and educational resources. There have been great examples of innovative successful cheap clinical solutions in low-income countries like using a sterilized mosquito mesh in hernia repair instead of the expensive commercial mesh [
17]; and using a sterile soup ladle, kitchen funnel, sterile gauze, and a glass bottle to collect patient’s own blood for auto-transfusion [
18]. A similar approach should be adopted to develop educational methods for teaching POCUS in low- and middle-income countries. These should be innovative and stemming from deep understanding of the needs and problems encountered.
To develop this model, there was a need for in depth knowledge of the basic physics of ultrasound combined with considerable practical experience on teaching POCUS. The first author (FAZ) had been involved in developing complex animal models for teaching POCUS besides using human models in different POCUS courses in different countries for almost two decades [
6‐
8]. The simulator was built up based on the basic principles of ultrasound imaging in a cheap and practical way. The basic mode which is commonly used to perform POCUS is the two-dimensional (2D) brightness (B) mode [
19,
20]. Abdominal ultrasound examination for detecting free intra-peritoneal fluid, pleural fluid and peri-cardiac fluid is performed using the small print convex array probe (3–5 MHz) [
19]. This probe gives wider and deeper views [
12,
21] and its sections are very similar to the Kunafa knife blade. The ultrasound operator should have a clear three-dimensional mental anatomical map when performing the ultrasound study.
In 2009, we were astonished to find how a knife and an apple were very useful in teaching echocardiography views when used as a simulator in a low-middle income country [
22]. In comparison and 10 years later, we have used the Kunafa knife in the current simulator. Kunafa (or Kanafeh) is a common traditional dessert of the Middle East which is made from thin noodle-like pastry, soaked with sugar-based syrup, and layered with cheese [
23]. It is cut using the Kunafa knife into square pieces [
24]. Observing the similarity between the Kunafa knife and the small print convex array probe gave us the idea of using it as a simulator to teach POCUS. This idea stemmed from familiarity with the ultrasound probe and its function. The simple idea went into different stages of development, trial, and refinement during 2 years to reach the current reported form.
In a systematic review, we have recently compared different teaching focused assessment sonography for trauma (FAST) models including computer simulators [
25]. Computer simulators were used in 15% of the reported studies. They produce patients’ three-dimensional ultrasound images that are reconstructed in real time when scanning a mannequin. This makes POCUS teaching and assessment more objective. The mentor can select normal or abnormal images as he/she wishes [
26]. Those who are trained on simulators can properly identify pathological ultrasound images similar to those who are trained on real patients. This reduces the need for clinical patients, allows for safe training [
26,
27], and affords a standardized learning experience [
26‐
28]. Furthermore, they can be used for mastery training in which a predetermined level is designed. The learners continue practicing till they reach that level with little involvement of mentors [
29,
30]. Nevertheless, this training method has certain limitations. First, the fine manual practical skills which are needed in real ultrasound scanning, like avoiding the rib shadow artifacts by fanning or shifting, are difficult to teach by using a computer simulator. Second, the qualities of ultrasound images of intra-abdominal organs that vary with human or animal body built are difficult to mimic [
8]. Third, they may be expensive and may not be affordable by many institutions. Fourth, the critical decision-making using POCUS in sick patients is best taught bedside in the real life.
Limitations
It is important to highlight that this study has certain limitations. First, it may be argued that the reported method is just a personal experience and not an educational outcome study. Personal educational experience is a well-accepted subjective educational research method. Educationist when merged in their educational experience sense what works and what does not work by comparing their recent experience with their previous ones. We may be biased towards our new teaching model. Nevertheless, we think and hope that our simulator will support teaching POCUS globally especially in low- and middle-income countries. This opinion is stemming from more than 30 years deep interest and personal experience in this area.
Second, our simulator will not replace or produce ultrasound images. We think that the cost of expensive computer simulators should be invested in buying portable ultrasound machines that can be used directly on bedside for clinical care, education, and research at the same time. Ultrasound is very safe, and students can directly practice ultrasound on real patients following understanding its principles. That is different from training on invasive procedures like laparoscopy which has risk on patients. We have been using this approach for teaching POCUS, and we find it useful, feasible, and practical. This gives us the advantage of applying POCUS to solve clinical problems and show students how this works in real life as an on spot critical decision tool.