Novel paediatric pericardiocentesis simulator: a collaboration between the Departments of Pediatrics and Biomedical Engineering

Introduction

Cardiac tamponade is a life-threatening compression of the heart due to accumulation of fluid surrounding the heart. It occurs in two out of 10 000 people annually and is universally fatal if the fluid is not timely drained.¹ The more rapidly accumulation occurs, the quicker the patient develops symptoms, including dyspnoea, fatigue and chest pain.² Vital sign changes include tachycardia, tachypnoea and hypotension with a narrow pulse pressure. Pericardiocentesis is the required treatment to drain this fluid improving cardiac output.³

Simulation is an adjunct education tool to practise rare but crucial procedures.¹ Current manikins do not have the capabilities to practise pericardiocentesis. Only torso task trainers are available.^{4 5} Our objective was to develop a pericardiocentesis trainer model that could both reliably recreate the procedure and be placed in a manikin, with no fluid leakage.

Methods

Model assembly and design

The Department of Biomedical Engineering collaborated with the Department of Pediatrics to build an inexpensive pericardiocentesis model with the following constraints:

1. Fit existing child simulators without significant chest wall distortion.

2. Have components to protect simulator both structurally and electronically from fluid spills using self-sealing technology.

3. Provide realistic fluid removal.

4. Have easily refillable fluid compartment that does not require direct access to task trainer.

5. Costs less than $500 budget.

The final design encompasses a two-piece tray system, a top and bottom tray, attached by a peg system made from acrylic. The bottom tray houses the pericardial sac which is made of self-sealing silicone and acrylic. The self-sealing material acts as a port allowing for repeated needle punctures during simulation of pericardiocentesis and as a gasket to seal off the pericardial sac. The pericardial sac contains coolant fluid that acts as the pericardial effusion fluid. Figure 1 shows three views using computer-aided design of the trainer. Refill and air release tubes, made of medical tubing, are attached to the silicone of the pericardial sac. The final cost of materials and fabrication was just over $300.

Figure 1.

Pericardial sac final design in exploded view. PVC, polyvinylchloride.

Simulation case

Audience and learning objectives

The intended learner audience are fellows and attendings, predominantly from paediatric critical care, emergency medicine and cardiology divisions. The learning objectives of the case are:

1. Recognise pericardial tamponade including the pathophysiologic changes that occur as the effusion enlarges.

2. Perform a bedside pericardiocentesis.

3. Recognise pericardial effusion as a potential cause of cardiomegaly on a chest radiograph.

Case details

A 10 year-old with new-onset primary mediastinal pre-B acute lymphocytic leukaemia presents with difficulty breathing and chest pain. Initial vital signs: heart rate (HR) of 125, blood pressure (BP) of 90/50, respiratory rate of 26, oxygen saturation of 92% and a temperature of 38.3°C. Over the next 10 min as learners are taking history and assessing the patient, the HR increases to 170, BP decreases to 60/40 with a narrowing of the pulse pressure. If the learners give the patient a fluid bolus, BP improves briefly but gradually falls back to prebolus level. The HR will continue to increase, and the BP will continue to fall. The patient gradually stops talking. If the learners provide oxygen the saturations will improve to 98%. If the learners intubate the patient without draining the effusion the patient goes into pulseless electrical activity (PEA) due to decreased preload. After 10 min if no correct interventions are made the patient will develop PEA requiring cardiopulmonary resuscitation and pericardiocentesis for recovery. If the learners recognise and drain the effusion, the patient improves reflected by improvement of tachycardia, BP and mental status.

Model evaluation

The Institutional Review Board at the University of Alabama at Birmingham approved this study. The model was tested repeatedly with paediatric critical care fellows and emergency medicine fellows using a simulation case over 2 years during our pre-existing critical care conferences. Our standard evaluation tool accessed performance of both task trainer and the simulated scenario.

Results

All of the fellows (12/12) who participated found the case realistic with the appropriate level of difficulty. Given the context of the patient becoming tachycardic and hypotensive in a background of malignancy, all groups initially thought of septic shock and gave fluids along with broad-spectrum antibiotics. When the chest radiograph was available each group was able to transition to a diagnosis of cardiac tamponade as the cause of shock. The attendings and fellows who have performed pericardiocentesis on actual patients found the pericardiocentesis trainer and the scenario accurate regarding the angle of entry, removal of fluid and clinical improvement following removal of pericardial fluid.

Discussion

We introduce the first insertable paediatric pericardiocentesis trainer in a high-fidelity manikin allowing trainees to practise this life-saving procedure in a realistic clinical context. The design of a tray within a tray model allows fluid to be safely contained, avoiding contamination of the simulator while the fluid is removed in real time during the procedure. Paediatric critical care fellows and attendings and emergency medicine fellows found the simulator effective. Also for those practitioners who had previously performed the procedure, they found the simulator realistic. Although task simulators are important in training, the ability of our device to be inserted under the chest skin of high-fidelity simulators allows the possibility to integrate the procedure within a cardiac tamponade scenario.

Our model, constructed for under $500, is cost-effective. The main obstacle encountered during development was designing a reliable self-sealing compartment for the pericardial fluid. Having this compartment within a tray gives a secondary back-up area to collect any drops of fluid if they were to leak.

There are some important limitations. We have used the simulator approximately 30 times during the scenario and afterwards as learners independently practised the procedure at the end of scenario. We do not have long-term durability. Also, the simulator has been tested with a limited number of learners from a single institution.

Conclusion

We have developed a novel pericardiocentesis simulator that can be inserted under the chest skin of most manikins to simulate pericardial tamponade. Prior to our project’s inception, leaders of the departments engineering and Pediatrics/Simulation Center met to establish clear terms of credit and costs. In general, everything was split evenly. This early planning has led to a productive relationship with this and other projects.