The concept of interdependence is implicit in the discussion of the organisational nature
of family systems. Individual family members and the subsystems that comprise the family
system are mutually influenced by, and are mutually dependent upon, one another (von
Bertalanffy, 1968; Whitchurch & Constantine, 1993). What happens to one family member,
Brigitte S. Cypress,'Patient-Family-Nurse Intensive Care Unit Experience' | 5
or what one family member does, influences the other family members because of the dynamic
relationship within the system. Thus, the hospitalisation of a family member during
critical illness in the ICU has an impact on the whole family system’s equilibrium. This is
one of the primary concepts embedded in clinical models emerging from a systems perspective.