This paper focuses on wireless sensor networks (WSNs) for healthcare and medical applications which aim to look after patients by monitoring vital signs, diagnostics and drug administrations. WSNs in such applications are usually composed of different types of small-size battery powered sensors. In fact, wearable sensors are used to collect information about the signs of a person that needs a medical care. Static sensors, deployed inside the hospital or the home building, are used to collect information about indoor environment. The collected data is then transmitted towards the sink. Since some patients can move, WSN topology is hybrid and composed of mobile and static nodes. Routing Protocol for Low Power and Lossy Networks (RPL), an IPv6 distance vector routing protocol designed for static wireless sensor network, can be adapted to our need. So in this paper, we propose to modify RPL in order to fit with an hybrid topology. The performance of the modified protocol is evaluated and compared with the existing RPL protocol. The results show that our protocol optimization for healthcare application offers better performance.