Disclosed is a method of regulating fluid flow for a targeted lung region. The method comprises injecting a therapeutic agent into the targeted lung region. The therapeutic agent induces a reaction in lung tissue of the targeted lung region or in a collateral pathway to the lung region to reduce collateral fluid flow into the targeted lung region. In one aspect, the method additionally comprises deploying a bronchial isolation device in the direct pathway to regulate fluid flow to the targeted lung region through the direct pathway. The therapeutic agent can comprise, for example, a sclerosing agent that induces a reaction that causes sclerosis in the lung tissue.