Improving patient comfort: Development and analysis of a hydraulic interconnected suspension for ambulance stretcher

Ambulances are essential in medical emergencies, but the movements and vibrations encountered during transit can pose significant risks to patients. Factors such as emergency braking, sharp steering, and uneven road surfaces can destabilize the stretcher, potentially leading to spikes in arterial pressure and increasing the risk of secondary injuries. While traditional trolleys cum stretcher (TCS) systems are compact, they are not sufficient in mitigating these risks during transportation. This study investigates patient transport on stretchers, with a particular focus on the impact of vertical vibrations from uneven roads and the roll and pitch motions induced by changes in acceleration. A passive secondary hydraulic interconnected suspension (PSHIS) system has been designed without making any changes to the TCS system. It reduces the stretcher’s vertical, roll, and pitch motions, thus improving ride comfort and patient stability during ambulance transport. A 14-DOF ambulance with an Anti-Roll Bar (ARB) and a 3-DOF stretcher model was developed to validate roll resistance, pitch resistance, and comfort levels. The model was evaluated under ISO 8608 D-class rough road conditions and ISO 3888 double lane change (DLC) maneuvers using the AMEsim environment. Additionally, the model incorporated the PSHIS system and employed genetic algorithm (GA) optimization techniques. The results demonstrated that this approach significantly outperformed traditional TCS systems in enhancing patient safety and comfort during transit.