The simulation of vibration at the supine patient’s body in HEMS

The associated risk for a patient taking advantage of Helicopter Emergency Medical Services (HEMS) mainly relates to vibrations. To this aim, especially in case of trauma and serious illness and long travels, aspects related to the vibrations effects on the patient needs to be properly investigated, taking into account the particular features of the helicopter used for HEMS. The purpose of this paper is the integrated simulation of vertical vibration at the supine patient’s body, lying down on a rescue litter, in HEMS. Here, a 3D structural model of a reference helicopter, the Aerospatiale Gazelle, has been developed in ABAQUS and integrated with a dynamic model where aerodynamic forcing functions due to rotor are modelled. The accelerations at the litter location in the helicopter structural model are recorded and used as inputs to the supine patient’s body model in MATLAB. The Multi-Body (MB) model of the patient’s body consists of three interconnected masses of the head-neck, torso-arms and pelvis-legs. The simulation is carried out for single manoeuvre and the vibration information is extracted at the three body segments. This predictive approach of integrated simulation of the helicopter-patient is an effective tool in investigating of biodynamic response of the patient in HEMS. The benefits of this approach are reducing the risk and costs of running the experiments, providing suggestions on redesigning of litters and controlling the vibration on the litters in HEMS.