There is so much work and research on leadership in healthcare most NHS organisations will refer to the healthcare leadership framework http://www.leadershipacademy.nhs.uk/...hip-framework/
It's difficult to say that any one style is correct, and good leaders will be able to adapt their style depending on the situation. So in an emergency you may take on a direct managerial approach, giving instructions and directing your staff but if managing change work from within the team to encourage ownership and sustainable.
Respect is a massive part of leadership, without it your team just won't follow so gaining respect, credibility and loyalty is vital to being allowed to lead.
Take a look at some of the tools in the framework it should help