Self-care theory defines self- care as work. It was first developed by Dorothea Orem. It is work required by or for every person to maintain life and health as well as to promote development. When persons are unable to provide the quantity and quality of self- care required, they need assistance. If this assistance is beyond the common sense knowledge acquired by the family or other lay caregivers in any society, the assistance of specially prepared caregivers is required (Taylor & Gebhardt, 2011).
These categories of specialized caregivers are known by the specialized services they provide. From the self- care deficit nursing theory perspective, the care or assistance provided by the nurse is associated with health- related actual or potential self- care deficits of persons, individually or collectively. Self- care occurs within the broad life situation of the individual, such as family, occupation, education, household, and care and guidance of dependent family members and others (Wills & McEwen, 2002).
The nursing theory is based upon the philosophy that all “patients wish to care for themselves”. They can recover more quickly and holistically if they are allowed to perform their own self- cares to the best of their ability. It is the job of the Registered Nurse to determine these deficits, and define a support modality. In caring the patients, they have to know what and when to eat, when and where to sleep and the eventual responses from the patients.
Environmental theory is a theory developed by Florence Nightingale and explored the nurse working environment. Unhygienic conditions are hazardous to the patient. These conditions include: light, effluvia, noise warmth and ventilation while external conditions can promote, reduce or prevent disease or death (Kathleen, 2013). It’s thus the duty of the nurse to provide a desirable nursing environment to meet its purposes.

Figure 1 showing the interrelationship between nursing theories and how they contribute to effective patient care

References
Kathleen, M. (2013). Role Development in Professional Nursing Practice. London: Jones & Bartlett Publishers
Taylor, S. & Gebhardt, K. (2011). Self-Care Science, Nursing Theory and Evidence-Based Practice, Springer Publishing Company, LLC.
Wills, M. & McEwen, M. (2002). Theoretical Basis for Nursing. Philadelphia. Lippincott Williamsand Wilkins.