Robotic sock helps prevent blood clots

26 February 2015 | Research
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(From left) Department of Medicine Research Fellow Dr Liu Yuchun modelling the robotic sock, Asst Prof Yeow and Fanzhe

NUS researchers have invented a wearable robotic sock that promotes blood circulation and reduces the risk of deep vein thrombosis (DVT) for bedridden or immobile patients.

The team comprising Department of Medicine Assistant Professor Lim Jeong Hoon, Department of Biomedical Engineering Assistant Professor Raye Yeow Chen Hua and PhD student Low Fanzhe, fashioned the robotic sock's "push and pull mechanism by mimicking the extension-contraction tentacle movements of corals.

DVT refers to the formation of blood clots along the lower veins of the legs which can be fatal if the clot reaches one's heart or lungs. This risk can range between 13 per cent and 18 per cent for bedridden patients who cannot move their limbs.

The design uses a cotton sock linked to soft, lightweight silicon rubber actuators or motors integrated with a programmable pneumatic pump-valve control system. The invention stimulates ankle joint motions to facilitate blood flow in the leg. Soft components were chosen to increase patient comfort during use, hence minimising the risk of injury from excessive mechanical forces, explained Fanzhe.

Currently, anti-coagulation drugs are used to treat DVT but these have detrimental side effects such as increased risk of excessive bleeding which can be fatal, especially for haemorrhagic stroke patients. Existing mechanical compression devices and compression stockings also show no significant reduction in DVT risk. The new innovation will thus help address these issues.

"Given its compact size, modular design and ease of use, the soft robotic sock can be adopted in hospital wards and rehabilitation centres for on-bed applications to prevent DVT among stroke patients or even at home for bedridden patients, said Asst Prof Yeow.

To test the efficacy of the robotic sock, the team will be conducting pilot clinical trials with about 30 patients at the National University Hospital between March and August. Similar trials will subsequently be conducted across different local hospitals for further evaluation.

The feedback obtained during the trials will help the researchers improve the device's design and capabilities, and plan for commercialisation in future.

Robotic sock - 2

A close-up view of a prototype of the robotic sock