In addition to limited energy resources in wireless sensor networks, failure of the nodes is a constraint to provide a reliable communication. As the failure of a node may have many reasons like mobility of the node and node or link failure, it is clear that in a real environment, we cannot control or reduce the number of failure in a network but it's possible to manage it. In this paper, we propose a technique to improve routing protocols by considering both energy and failure constraints and managing them. By using this technique, the routing protocols dynamically adapt to nodes' failure. The simulations results show the efficiency of this technique in two sample routing protocols.