Background: Patients who have a critical illness and a protracted admission to an intensive care unit (ICU) are known to develop muscle weakness and wasting. This can lead to increased length of stay in both the ICU and the hospital, and rehabilitation can also be prolonged. Admission of a family member to an ICU places heavy stress on a family, whereby the ongoing effects for the family and patient can take years to resolve, if ever. In the context of the patient and family centred care (PFCC) movement, family involvement in patient care, as a means of improving both patient and family outcomes, has been studied across multiple clinical contexts. However, a gap in knowledge is the impact of family assisting with passive exercises of unconscious patients in the ICU. Purpose: To investigate whether family assisted passive exercising of an unconscious patient can achieve better outcomes for the family, nurses, patient and healthcare system. Research design: A prospective, comparative, interventional study. The study was conducted between May 2015 and May 2016. The setting was two general ICUs in a publicly funded tertiary and quaternary referral hospital in Sydney, Australia. One unit was deemed the active unit, where family members delivered the passive exercises to the patient. The second unit was the control unit, where the patients received standard care with the direct care nurses performing the passive exercises. The quantitative approach was the dominant aspect of the study. Outcomes of family needs and satisfaction were measured by surveying the ICU families with the: 30-item Critical Care Family Needs Inventory (CCFNI) pre-test; and 30-item Needs Met Inventory (NMI) and, single item Family Feedback Survey (FFS) tool, post-test. The nurses were surveyed with the CCFNI pre- and post-test to assess their perception of family needs, and to ascertain if the intervention improved alignment between the nurses' and the families' perception of need. Outcomes for nurses' stress, and whether the intervention had any impact on these stressors, were measured using the modified Nursing Stress Scale (mNSS) pre- and post-test. The modification included four study specific questions in relation to teaching, talking and discussing clinical care with family members and delivering passive exercises to patients. Muscle mass measurement was the major clinical outcome for the patient and was evaluated using ultrasound technology and a tape measure. Organisational and clinical factors were evaluated to ascertain outcomes for the patient and the healthcare system. Information that was extracted from the ICU electronic medical record (EMR) and entered into the study specific family assisted passive exercise instrument (FAPEI), for this purpose, included: demographics of the patient and the family member; patient mortality; the number of hours the patient received mechanical ventilation; and, ICU and hospital length of stay. Three focus groups were conducted. Two groups were with nurses from the active and control units, and one with the ICU managers and educators. The focus groups triangulated the data obtained from the CCFNI, NMI, mNSS and FSS with professionals' perceptions of the impact of the study on the family, nurses, and patients. The quantitative data were analysed using descriptive and inferential statistics. The qualitative data from the focus groups used inductive content analysis. Results: In total 30 families and patients were initially enrolled into the study. After attrition 19 families and patients completed the study ‚Äö- 10 in the active unit and nine in the control unit. Pre-test, both the active and the control units responses to the CCFNI showed that nurses did not rank family needs as highly as the families regarding assurance, information and proximity domains. Post-test, the nurses' perception was more aligned with that of family, with greater improvement in the active unit. The level of improvement in the active unit was unmatched in the control unit. The comparison of the results of the CCFNI pre-test to the NMI post-test completed by the families showed that needs were met more in the active unit. This result was not matched in the control unit. The FSS was given a maximum score of 100, by five families in the active unit and four families in the control unit. The mNSS was completed pre-test by a majority of nurses from the active unit (n= 45; 80%) and the control unit (n=55; 82%). Similarly, a majority of nurses completed survey post-test in both the active unit (n=40; 69%) and control unit (n=40; 85%). Pre-test the results of the mNSS showed there was little difference between the units in regards to the highest and lowest scoring individual stressors. Both units scored the most stressful items from the death and dying and workload factors. Pre- to post-test there was greater improvement (a decrease) in the mean scores of these factors and the factor, conflict with other nurses, in the active unit. Again this was not matched in the control unit. The results across both units, demonstrated that there was a correlation between years of nursing experience and how stress was perceived. In the outcome of muscle mass measurement, the study did not detect any change in the units due to the intervention. Clinical and organisational outcomes showed no discernible patterns that could be specifically attributed to the intervention. The focus group nurses supported the importance of PFCC in the ICU. They highlighted the improvement in communication with families and the assurance for the families that resulted from the intervention. Conclusion: Family assisted passive exercise, designed and implemented with the principles of PFCC can enhance family and nurses satisfaction in the ICU. The intervention improved communication between the nurses and families helping address family needs and reducing nurses' stress levels. However, the intervention did not prevent muscle wasting in ICU patients. A significant study insight is that death and dying remains an on-going challenge in the ICU for both the families and the nurses. This has been identified as an area for service improvement and has led to enhanced communication training for the nurses. It has been identified that nursing stressors could be better managed when nurses interact with families, assisting them with passive exercises in ICU. This insight has not been previously reported. This thesis has also made methodological contributions through modification of the NSS and the study specific theoretical framework, therefore, uniquely contributing to the knowledge of the understanding of PFCC. In the outcome of muscle mass measurement, the study did not detect any change in the units due to the intervention. Clinical and organisational outcomes showed no discernible patterns that could be attributed to the intervention.