Previous chapters have considered the challenge presented when caring for acutely unwell patients, and the many decisions made each day which impact on patient outcome. Patients who are acutely unwell present in a variety of healthcare settings and good clinical reasoning skills are needed in order to make sense of the care required in a range of different situations. Uncertainties exist in nursing practice; if the risk of patient deterioration is to be reduced, then the nurse must apply knowledge and make clinical judgements. An assessment is made, and then decisions as to the problem and required action. Planning follows and goals established to achieve the desired outcomes (Figure 53.1). This is a dynamic process and critical thinking is required so that the nurse is able to identify possible options based on evidence.