Implementation of advance care planning in the routine care for acutely admitted patients in geriatric units: protocol for a cluster randomized controlled trial oleh Maria Romøren, Karin Berg Hermansen, Trygve Johannes Lereim Sævareid, Linn Brøderud, Siri Færden Westbye, Astrid Klopstad Wahl, Lisbeth Thoresen, Siri Rostoft, Reidun Førde, Marc Ahmed, Eline Aas, May Helen Midtbust, Reidar Pedersen