MYRA ESTRIN LEVINE PPT

1. LEVINE’S
THEORY AND
IT’S
APPLICATION
PRESENTED BY:
MS. ANMOL RATTAN
MSC NURSING 1stYEAR
R.A.K.C.O.N

2. MYRA
ESTRIN
LEVINE
ONE OFTHE MOST INFLUENTIALTHEORIST

3. BACKGROUND OF THE THEORIST:
MYRA ESTRIN LEVINE (1920-1996) was born in Chicago. She was the oldest of three children.
 She had one sister and one brother with whom she shared a close relationship.
 She was also fond of her father, who was a hardware man. He was often ill and frequently
hospitalized with gastrointestinal problems. She thinks that this might have been why she had such
a great interest in nursing.
 Levine began attending the University of Chicago but choose to attend Cook Country School of
Nursing when she could no longer afford the university.
 She received her diploma from Cook Country in 1944.
 She later received her Bachelor of science degree from University of Chicago in 1949 and her master
of science in nursing fromWayne State University in 1962.

4. BACKGROUND OF THE THEORIST:
 She had clinical experience in the operating room and in oncology nursing.
 She was a civilian nurse at the Gardinar General Hospital, director of nursing at Drexal home in
Chicago and administrative supervisor at University of Chicago clinics and Henry Ford Hospital in
Michigan.
 She was chairperson of clinical nursing atCook County School of Nursing and a faculty member at
Loyola University, Rush University, and University of Illinois.
 She was a visiting professor atTel Aviv University in Israel and Recanti School of Nursing at Ben
Gurion University of the Negev in Beer Sheeva, Israel.
 She was professor emeritus in Medical Surgical Nursing, University of Chicago, a charter fellow of
the American Association of Nurses (FAAN), and a member of SigmaThetaTau International, from
which she received the Elizabeth Russell Belford Award as distinguished educator.

5. ACHIEVEMENTS
1 1973: Charter fellow of the American
Academy of Nursing.
2 1976: Honorary member of American
Mental Aid.
3
1977: Honorary recognition from Illinois
Nurses Association and first recipient of the
Elizabeth Russell Belford Award for excellence
in teaching from SigmaThetaTau.
5

6. CONTRIBUTIONS
She authored 77 published articles
which included "An Introduction to
Clinical Nursing’’ with multiple
publication years on 1969, 1973 and
1989.

7. INTRODUCING THE THEORY :
Levine told others that she did not set out to
develop a “nursing theory’’ but wanted to find a
way to teach the major concepts in medical-
surgical nursing and attempt to teach associate
degree students a new approach for daily nursing
activities. She also wrote a book: FOUNDATIONS
OF CLINICAL NURSING

8. FOUNDATIONS
OF CLINICAL
NURSING
 Levine's original reason for writing the book was to find a way to teach
the foundations nursing that would focus on nursing itself and was
organized in such a way of that students would learn the skill as well as
the rationale for skill. She felt that the nursing research was generally
ignored.
 Her intent was to bring practice and research together to establish
nursing as an applied science.
The nursing care chapters in her text focus on nursing care of the patient with:
1. Failure of the nervous system;
2. Failure of the integration resulting from hormonal imbalance;
3. Disturbance of homeostasis: fluid and electrolyte imbalance;
4. Disturbance of homeostasis: nutritional needs;
5. Disturbance of homeostasis: systemic oxygen needs;
6. Disturbance of homeostasis: cellular oxygen needs;
7. Disease arising from aberrant cellular growth;
8. Inflammatory problems;
9. Holistic response.

9. GOAL OF THE THEORY:
 To promote adaptation and to maintain
wholeness using the principle of
conservation.

10. MAJOR CONCEPT AND COMPOSITION THE
CONSERVATION MODEL:
Levine discusses adaptation, conservation and
wholeness. Adaptation is the process by which
conservation is achieved and the purpose of
conservation is integrity.The core of Levine’s
theory are her four conservation principles.

11. ADAPTATION
Adaptation is the life process by which people maintain their wholeness or integrity as they respond to
environmental challenges; it is the consequences of interaction between the person and the
environment. Successful engagement with the environment depends on adequate store of adaptation.
Every individual has unique range of adaptive response.These responses will vary based on heredity,
age, gender or challenges of an illness experiences.
Levine speaks of three characteristics of adaptation:
1.Historicity
2.Specificity
3.Redundancy

12. • Adaptation is a historical process; responses are based on
past experiences, both personal and genetic. Each
individual genetic pattern is unique which is further
developed by the individual experience.
HISTORICITY
• Adaptation is also specific. Each system has very specific
responses. Particular response are called into action by a
particular challenge; responses are task specific.
SPECIFICITY
• It represent the fail-safe option available to individual to
ensure adaptation. Levine believed that health is
dependent on the ability to select from redundant options.
• Loss of redundant option choices through trauma, age,
disease or environmental condition makes it difficult for
the people to maintain life.
REDUNDANCY

13. CONSERVATION
 Conservation is from Latin word conservationem, which means to
keep together.
 The product of adaptation is conservation.Through conservation,
individuals are able to confront obstacles, adapt according, and
maintain their uniqueness.
 Conservation describes how complex systems continue to
function in the face of challenges; it provide not only for current
survival but also for future vitality through facing challenges in the
most economical way possible

14. LEVINE’S LAW OF CONSERVATION :
WHOLE
PERSON
ENERGY
SOCIAL
INTEGRITY
PERSONAL
INTEGRITY
STRUCTURAL
INTEGRITY

15. • The individual requires a balance of energy and a
constant renewal of energy to maintain life activities.
Processes such as healing and aging challenge that
energy.This second law of thermodynamics applies to
everything in the universe, including people.
• Illness increases energy demand and that increased
energy demand can be measured by the level of fatigue.
• Energy is measured in everyday nursing practice via body
temperature, blood gases, pulse and blood pressure,
fluctuations determine either energy expenditure or
conservation.
• The balance is brought by proper rest, adequate
hydration ,inhalation of clean air ,nutrition.
Conservation
of energy :

16. • Healing is the process of restoring structuring and functional
defense in wholeness. Nurses can limit the amount of tissue
involved in disease by early recognition of functional changes.
• Refers to maintaining or restoring the structure of body
preventing physical breakdown and promoting healing.
• Changes in structure ultimately affect function that structural
integrity may be compromised by pathophysiological processes,
and that healing restores structural integrity.Therefore, to
regain structure and function, the body needs to restore
structural integrity through repair and healing.
• Nursing intervention aims in helping the individual to prevent
skin breakdown and limiting the amount of the tissue involved
in infectious disease.
• Examples:
Maintenance of clean, dry wrinkle-free linen.
Regular turning of patient side-to-side every 2 hours to
patients who are bedridden.
Maintenance of patient's personal hygiene.
Conservation
of Structural
Integrity:

17. • Self-worth and a sense of identity are important.This begins with
erosion of privacy and creation of anxiety.
• A client is a person with dignity sense of identity and self-worth.
• Individual strives for recognition ,respect, self-awareness, self-
hood and self-determination.
• Illness and hospitalization compromise personal integrity, self-
identity and self-respect.
• Person’s integrity is compromised when the individual becomes
dependent.
• Nursing interventions include protecting and respecting patient's privacy,
possessions, and defense mechanisms and supporting personal choice
• Examples include:
Expression of patient's feelings.
Involvement of patient in plan of care
Focus on self-aspect by not comparing to others. Reinforce positive
traits.
Promote socialization in such a way that the patient can develop positive
self-esteem.
Conservation
of Personal
Integrity:

18. • Life gains meaning through social communities and health is
socially determine. Nurse fulfill professional roles, provide for
family members, assist with religious need and use of
interpersonal relationships to conserve social integration.
• Individuals are recognized by social responsibilities,
traditional customs and spiritual group.Their behavior is
influenced by the ability to relate in various social groups,
families often are affected by an individual illness, and
hospitalization results in social isolation.
• Nursing intervention helping the individual to preserve his
or her place in the family, community and society.
• Examples:
In the case of a pregnant woman scheduled for cesarean
operation, her support system is very important both
before and after the operation.
Position patient in bed to foster social interaction with
other patients.
Promote patient's use of newspaper magazines, radio,TV,
Provide support and assistance to family.
Conservation
of Social
Integrity:

19. WHOLENESS
• Wholeness is based on Erikson's (1964) description of wholeness
as an open system: "Wholeness emphasizes a sound, organic,
progressive mutuality between diversified functions and parts within
an entirety , the boundaries of which are open and fluid".
• Levine (1973) stated that "the unceasing interaction of the
individual organism with its environment does represents an ‘open
and fluid’ system, and a condition of health, wholeness, exists
when the interaction or constant adaptions to the environment,
permit ease- the assurance of integrity in all dimensions of life.’’

20. Health
Health is a state of being whole not just absence of illness or disease.
Health and disease are patterns of adaptive change. From a social
perspective, health is the ability to function in social roles.
Health is an individual response that may change over time in response to
new situations, new life challenges, and aging, or in response to social,
political, economic, and spiritual factors. Health is implied to mean unity
and integrity.
The goal of nursing is to promote health.
Person
Person is described as a holistic being; wholeness is integrity.
Integrity means that the person has freedom of choice and movement.
The person has a sense of identity and self-worth. Levine also
described person as a "system of systems, and in its wholeness
expresses the organization of all the contributing parts."
Person experience life as change through adaptation with the goal of
conservation. According to Levine, “the life process is process of
changes.’’
Nursing:
Levine stated following about nursing: “nursing is a human
interactions’’ rooted on the organic dependency of an
individual as well as communication with other human being.
The goal of nursing is to promote wholeness.
“Wholeness” can be achieved through the use of therapeutic
and supportive aspect of caring.
Environment
Environment is "where we are constantly and
actively involved the person and his or her
relationship to the environment is what counts.’'.
NURSING PARADIGM

21. ENVIRONMENT CONTD.
 Levine also views each individual as having his or her own environment, both internally and externally.
 Nurses can relate the internal environment as the physiological and pathophysiological aspects of the patient.
Levine uses Bates' definition of the external environment' and suggests three levels:
(1) perceptual,
(2) operational,
(3) conceptual.
These levels give dimension to the interactions between individuals and their environments.
 The perceptual level includes the aspects of the world that individuals are able to intercept and interpret with their sense organs.
 The operational level contains things that affect individuals physically although they cannot directly perceive them such as
microorganisms.
 At the conceptual level, the environment is constructed from cultural patterns, characterized by a spiritual existence and
mediated by the symbols of language, thought, history.

22. Fighting Right Mechanism
Most primitive response .
Hospitalization illness and new
experiences trigger a response.An
individual may turn away, “flight’ or
face his condition. "Fight” to assure
his safety and well-being.
Inflammatory immune Response
A way of healing, a defense
mechanism to protect self from
insult in a hostile environment.
Stress response
According to Selye, stress response
syndrome is a predictable non -
specifically induced organisimic
changes.
PerceptualAwareness
Information seeking response used
by the individual to seek and
maintain safety for himself. It
includes the basic orienting,
synaptic, auditory, visual, and taste
smell system.
INDIVIDUALS RESPOND TO THE ENVIRONMENTAL
CHALLENGES BY MEANS OF FOUR INTEGRATED
PROCESSES :

23. THEORETICAL
ASSERTIONS
Levine's work was intended to provide an organizational structure for teaching medical-surgical nursing rather than to develop
theory; Therefore she did not explicitly identify theoretical assertions. Although many theoretical assertions can be generated
from her work, the four major assertions follow:
1. "Nursing intervention is based on the conservation of the individual patient's
energy"
2. "Nursing intervention is based on the conservation of the individual patient's
structural integrity "
3. " Nursing intervention is based on the conservation of the individual patient's
personal integrity."
4. "Nursing intervention is based on the conservation of the individual patient's
social integrity."

24. USE OF NURSING PROCESS ACCORDING TO LEVINE:
PROCESS APPLICATION OFTHE PROCESS
ASSESSMENT
COLLECTION OF PROVOCATIVE
FACTSTHROUGH INTERVIEW AND
OBSERVATION OF CHALLENGES
TO ENVIRONMENTS,WITH
CONSIDERATION OF CONSER-
VATION PRINCIPLES
1. ENERGY CONSERVATION
2. STRUCTURAL INTEGRITY
3. PERSONAL INTEGRITY
4. SOCIAL INTEGRITY
Collection of provocative facts through observation and interview of challenges to
the internal and external environments.
The nurse observes the patient for organismic responses to illness, reads medical
reports evaluates results of diagnostic studies, and talks with patients and their
families (support persons) about their needs for assistance.
The nurse assesses for physiological and pathophysiological challenges to the
internal environment and the factors in the perceptual operational and conceptual
levels of the external environment that challenge the individual.
TROPHICONOSIS
NURSING DIAGNOSIS GIVESTHE
PROVOCATIVE FACTS MEANING
Nursing diagnosis gives provocative facts meaning.
The nurse arranges the provocative facts in a way that provides meaning to the
patient's predicament.

25. HYPOTHESIS
DIRECTTHE NURSING
INTERVENTIONSWITHTHE
GOAL OF MAINTAINING
WHOLENESSAND
PROMOTINGADAPTATION
Direct the nursing interventions with the goal of maintaining wholeness
and promoting adaptation: nurse seeks validation of the patient's
problems with the patient or support persons.
The nurse then proposes hypotheses about the problems and the
solutions, such as eight glasses of water a day will improve bowel
evacuation.These become the plan of care
INTERVENTION Test the hypotheses. Nurses use hypotheses to direct care.The nurse tests
proposed hypotheses. Interventions are designed based on the
conservation principles: conservation of energy, structural integrity,
personal integrity, and social integrity.
Interventions are not imposed but are determined to be mutually
acceptable.The expectation is that this approach will maintain wholeness
and promote adaptation.

26. EVALUATION
Observation of
organismic response
to interventions
Observation of organismic response to interventions.
The outcome of hypothesis testing is evaluated by assessing for
organismic response that means the hypotheses are supported or not
supported.
Consequences of care are either therapeutic or supportive
therapeutic measures improve the sense of well-being supportive
measures provide comfort when the downward course of illness
cannot be influenced.
If the hypotheses are not supported, the plan is revised and new
hypotheses are proposed.

27. EXAMPLE OF NURSING PROCESS ACCORDING TO
LEVINE’S MODEL:
Mona, wife of an abusive husband, underwent a radical hysterectomy Postoperatively had pain,
weight loss, nausea, inability to empty bladder. Patient had history of smoking and stayed in house
which had no hygiene.
1. Assessment
Challenges to the internal environment of weight loss, nausea, loss of reproductive ability
Challenges to the external environment of abusive husband, unhygienic conditions at home.
 Energy conservation:Weight loss, nausea, pain.
 Structural integrity: Threatened by surgical procedure, inability to pass urine.
 Personal integrity: Not able to give birth to more children
 Social integrity: Strained relationship with husband.

28. EXAMPLE OF NURSING PROCESS ACCORDING TO
LEVINE’S MODEL:
2.Trophicognosis:
• Inadequate nutritional status.
• Pain
• Potential for wound and bladder infection .
• Need to learn self- catheterization.
• Decreased self-worth
• Potential for abuse.

29. EXAMPLE OF NURSING PROCESS ACCORDING TO
LEVINE’S MODEL:
3.Hypothesis
• Nutritional consultation
• Teaching and return demonstration of urinary
catherization.
• Care of surgical wound.
• Exploring concern regarding hysterectomy.

30. EXAMPLE OF NURSING PROCESS ACCORDING TO
LEVINE’S MODEL:
4. INTERVENTIONS
• Energy Conservation
• Providing medication for pain and nausea
• Allowing rest period.

31. EXAMPLE OF NURSING PROCESS ACCORDING TO
LEVINE’S MODEL
 Structural Integrity
Administering antibiotic for wound.
Teaching self-catheterization.
 Personal Integrity
Exploring her feeling about uterus removal while respecting her privacy.
 Social Integrity
Assess potential abuse from husband.
Support to family.

32. LEVINE'S WORK AND CHARACTERISTICS OF THEORY
Theories can interrelate concepts in such a way as to create a different
way of looking at a particular phenomenon.
- Levine has incorporated concepts of adaptation, conservation, integrity in a
way that provide a different nursing view.
Theories must be logical in nature.
-Levine's work is logical. One thought or idea flows from the previous one
and into the next.

33. LEVINE'S WORK AND CHARACTERISTICS OF THEORY
Theories should be relatively simple yet generalizable.
-There are only three concepts in Levine's theory.This is the essence of simplicity.
-The theory is generalizable as it can be used in any setting with any human
assistance from a nurse.
Theories can be the bases for hypotheses that can be tested.
-Levine's idea can be tested. Hypothesis can be derived from them
-Research have been conducted to test this hypothesis.
Theories contribute to and assist in increasing the general body of knowledge within the discipline trough
research implemented to validate them.
-Research has been conducted using Levine’s theory that has contributed to the general body of knowledge.

34. THE ASSUMPTIONS AND VALUES RELATED TO
MODEL :
1.The person is viewed as a holistic being: "The experience of wholeness is the foundation of all
human enterprises"
2.Human beings respond in a singular yet Integrated fashion.
3. Each individual responds wholly and completely to every alteration in his or her life pattern.
4.Individuals cannot be understood out of the context of their environment.
5."Ultimately, decisions for nursing care are based on the unique behavior of the individual
patient.... A theory of nursing must recognize the importance of unique detail of care for a single
patient within an empiric framework which successfully describes the requirements of all
patients".

35. THE ASSUMPTIONS AND VALUES RELATED TO
MODEL
6 "Patient-centered care means individualized nursing care. It is predicated on the reality of
common experience: every man is a unique individual, and as such requires a unique
constellation of skills, techniques, and ideas designed specially for him".
7 "Every self-sustaining system monitors its own behavior by conserving the use of resources
required to define its unique identity".
8The nurse is responsible for recognizing the state of altered health and the patient's
organismic response to altered health.
9 Nursing is a unique contributor to patient care.
10.The patient is in an altered state of health. A patient is one who seeks health care because
of a desire to remain healthy or one who identifies a known or possible risk behavior.

36. VALUES
1.All nursing actions are moral actions.
2.Two moral imperatives are the sanctity of life and the
relief of suffering.
3.Ethical behavior is the day-to-day expression of one's
commitment to other persons and the ways in which human
beings relate to one another in their daily interactions.
4. A fully informed individual should make decisions
regarding life and death in advance of the situations. These
decisions are not the role of the health-care providers or
families.
5 Judgments by nurses or doctors about quality of life are
inappropriate and should not be used as a basis for the
allocation of care.
6 "Persons who require the intensive interventions of
critical care units enter with a contract of trust. To respect
trust... is a moral responsibility"

37. APPLICATIONS :
1. Practice
Levine helps define what nursing is by identifying the
activities it encompasses and giving the scientific
principles behind them. Conservation principles as a
framework are not limited to nursing care in the
hospital, but can be generalized and used in every
environment, hospital, or community.

38. APPLICATION
Conservation principles, levels of integration, and other concepts can be used in numerous contexts.
 Hirschfeld has used the principles of conservation in the care of the older adult. Savage used the Conservation Model
to establish a plan of care for infants.
 Dever based her care of children on the Conservation Model.
 Roberts, Fleming, andYeates-Giese designed interventions for women in labor on the basis of the Conservation Model.
 Pond used conservation model for guiding the nursing care of homeless at a clinic, shelters or streets:-
a) Used with patients across the lifespan, from the neonate to the elderly patient.
b) Used as a framework for many purposes, such as wound care, development of nursing diagnoses, care of intravenous sites, and care of
patients undergoing cancer treatment.
c) Influences the interventions undertaken by nurses, with them recognizing that the interventions should be related to the adaptive pathways,
while remembering that each pathway is influenced by historicity, specificity, and redundancy.
d) Applied in rendering comprehensive nursing care incorporated in the nursing process.

39. APPLICATION
2. Education
 Levine wrote Introduction to Clinical Nursing," a textbook for beginning students that introduced
new material into the curricula. She presented an early discussion of death and dying and believed
that women should be awakened after a breast biopsy and consulted about the next step."
 Introduction to Clinical Nursing provides an organizational structure for teaching medical-surgical
nursing to beginning students. Provides a student friendly nursing theory.This reflects simple yet
complete and concise nursing theory
 Used as a curriculum model and is a part of both undergraduate and graduate curricula.
 Provided an organizational structure for teaching medical-surgical nursing and stimulus for theory
development. She aimed to move away from a procedurally oriented educational process and
instead sought to teach the major concepts of medical-surgical nursing as generalized content.

40. APPLICATION
3. RESEARCH
Fitzpatrick and Whall state, "All in all, Levine's model served as an excellent beginning. Its contribution has added a great deal
to the overall development of nursing knowledge."
Enhances the foundation of nursing practice and nursing education. Hypotheses have been developed from Levine's theory,
and research has been conducted to test these hypotheses.
 Studies conducted by Wong (1989) andWinslow, Lane, and Gaffney (1985) support the importance of energy conservation for patients with
myocardial infarctions.
 Pappas (1990) investigated the relationship between nursing care and anxiety in patients with sexually transmitted diseases and found significant
relationships between constructs of nursing and components of anxiety
 Foreman (1987) found that variables that represented the four conservation principles were more important in combination than separately when
used to diagnose confusion in hospitalized elderly patients.
 MacLean (1987) used the principles of conservation of energy and conservation of structural integrity in identifying cues in that nurses use to
diagnose activity intolerance

41. CRITIQUING
THE THEORY 1
Clarity
Levine's model possesses clarity. Fitzpatrick and Whall believe
that Levine's work is both internally and externally consistent.
Fawcett states that "Levine's Conservation Model provides
nursing with a logically congruent, holistic view of the person."
The model has numerous terms; however, Levine adequately
defines them for clarity.
2 Simplicity
Although the four conservation principles appear
simple initially, they contain sub concepts and
multiple variables. Nevertheless, this model is still
one of the simpler ones that have emerged.
3
Generality
The four conservation principles can be
used in all nursing contexts.

42. LIMITATIONS
Limited attention can be focused on health promotion and illness prevention.
Nurse has the responsibility for determining the patient's ability to participate in
care, and if the perception of nurse and patient about the patient ability to
participate in care do not match, this mismatch will be the area of conflict.
The major limitation is the focus on individual in an illness state and on the
dependency of patient.

43. REASEARCH ARTICLE :
The effects of nursing care based on Levine's Conservation Model on fatigue, depression,
perceived social support, and sleep quality in infertile women: A randomized controlled trial.
Nurcan Kirca et al. Int J Nurs Knowl. 2022.
Purpose:The purpose of this study was to investigate the effects of nursing care based on the Levine's
Conservation Model on depression caused by infertility, fatigue, perceived social support, and sleep
quality levels.

44. REASEARCH ARTICLE
Methods:This study includes randomized controlled trial that was
conducted from July 2019 to April 2020, with 65Turkish women with
infertility (experimental group: 34, control group: 31).We collected data
using theVisual Similarity Scale for Fatigue, the Pittsburgh Sleep Quality
Index, the Beck's Depression Inventory, and the Multidimensional Perceived
Social Support Scale.The experimental group received nursing care based on
the Levine's Conservation Model. Data were analyzed using t-tests and χ2
tests analyses.

45. RESEARCH ARTICLE
Findings: As a result of the measurements made, it was found that the
experimental group had a lower fatigue level than the control group, with a
statistically significant difference between the groups (p < 0.001). It was also
found that the experimental group had higher energy and perceived social
support scores than the control group after the practice, with a statistically
significant difference between the groups (p < 0.001). As a result of the
measurements made after the practice, it was found that the experimental
group had a lower depression level than the control group, with a
statistically significant difference between the groups (p < 0.001).

46. RESEARCH ARTICLE
Conclusions: Nursing care based on the Levine's
Conservation Model decreased fatigue and
depression in women receiving infertility treatment
and increased perceived social support and sleep.

47. CONCLUSION:
Myra Levine’s nursing theory views the client as an integrated being who interacts with and adapts
to environment.
Levine expressed the view that within the nurse-patient relationship.The patient's state of health is
dependent on the nurse-supported process of adaptation.This guides nurses to focus on the
influences and responses of a client to promote wholeness through the Conservation Principles.
The goal of this model is to accomplish this through the conservation of energy, structural,
personal and social integrity.The goal of nursing is to recognize, assist, promote, and support
adaptive processes that benefit the patient.

50. REFERENCES :
1.Book
 BRAR N.P, RAWAT HCTEXTBOOK OF ADVANCED NURSING PRACTICE, JAYPEE
PUBLICATIONS, 1st EDITION. Page No. 605-614.
 TOMEY MARRINERANN, ALLIGOOD KAILL MARTHA'S NURSINGTHEORY
UTILIZATION & APPLICATION, 5th EDITION, MOSHY, page no.212-219
 MARILYN E. PARKAR NURSINGTHEORIES AND NURSING PRACTICE, 2nd EDITION,
Page no. 94-124.
 POTTER A. PATRICIA , PERRY GRIFFIN ANNE, FUNDAMENTALS OF
NURSING,MOSBY,5TH EDITION,PAGE NO .94-96