Theories are the foundation for all professions. It provides set of concepts that make the basic knowledge of the specific discipline. Similarly, nursing theories define the basic concepts and principles of nursing profession in a scientific manner (Iskandarani et al., 2012). Nursing theories are considered as a tool to increase understanding of values and meanings of the nursing profession. It also helps to understand the role and position of nurses in the healthcare setting (Zamanzadeh et al., 2015). There is need of a strong theoretical background in leading nurses towards improved care delivery, enhanced critical thinking, and enriched decision making. Nursing theories are the basic foundations that help nurses in terms of determining the needs and achieve goals to advance nursing care and its delivery (Colley, 2003). Furthermore, its theories also provide opportunities in learning to give care in holistic manner. Nursing theories assist in learning assessment of patients, planning, implementing, and evaluating in a professional way (Karnick, 2014). Researchers endorsed the importance of implementation of nursing theories in the clinical practice in order to achieve high quality of care. Nursing theories provide a medium to rationalize the care provided by nurses. Moreover, it provides an identity to nurses that differentiates the nursing practice from the medical practice (Meleis, 2012). This paper highlights the importance of nursing theories as the foundation for nursing profession.

Any discipline is a basis on its knowledge development. Nursing discipline is also basis on its knowledge development through nursing theories. Lack of work on nursing theories and its elimination from practice and research will convert it from profession to the tasks needed by patients and their families.

There are different types of theories. In literature, all levels of nursing theories exist, such as meta-theory, grand theory, mid-range theory, and micro theory (Matney et al., 2016). In meta-theories, the subject matter is another theory. It provides a critical exploration of the theoretical frameworks. Grand theories contribute a broad perspective to define the purpose and structure of nursing practice. Most of the grand theories are developed between the 1960s and the 1980s. These theories help to differentiate between nursing practice and medical practice. On the other hand, middle range theories are categorized as having a set of ideas and variables that are narrower, but testable. Middle range theory proposes the specificity required for research and practice in the specific area. For this reason it starts a concept analysis leading towards development of a larger conceptual model (often called a construct). Micro theories develop specific concepts regarding nursing practices (Matney et al., 2016).

Han et al. (2017) have conducted a study to identify the current status of research and developmental trends of nursing theories in different parts of the world. To fulfill the aim of the research, they analyzed publications from the year 2005 untill 2014. The study stated that 1472 articles were included, having a basic theme, which were analyzed for analysis of nursing models. The researchers concluded that most of the work regarding nursing models and nursing theories are done in the United States. Furthermore, researchers highlighted that with the time the number of publications is continuously decreasing (Han et al., 2017). In the timeframe of 2005 and 2009, there were four research themes that are, nursing education and theoretical research, clinical nursing and psychological care, nursing administration, and models of nursing education. Whereas, in the time period of 2010 and 2014, there were five research themes: that were nursing theories and clinical nursing practice, nursing administration models and assessments of nurses' knowledge and skills, community nursing administration models, nursing human resource management, and nursing education models and approaches. In conclusion, nursing models are implemented in the broader view in most of the nursing profession in every aspect (Han et al., 2017). On the contrary, McCrae (2012) highlights the other aspect of the nursing theories and models. Researchers highlighted that there is a need to utilize nursing theories and models in research practice in order to bridge the gap between theory and practice (McCrae, 2012).

The application of nursing theories in clinical practice varies in different settings. However, their goal is to provide quality care worldwide. There is scarcity of literature available regarding application of theory into practice in our clinical setting (Kim, 2010, 2012). To address gaps between theory and nursing practice, Ahtisham and Jacoline (2015) used Virginia Headerson's Need theory to explain the ways of application of nursing theory in the clinical area in order to provide effective care and reduce the gap between theory and practice. According to researchers, the need theory of Virginia Henderson is reflectings realism in care. It enables nurses to improve the standard of care by performing assessment and developing of a care plan in a realistic manner (Ahtisham & Jacoline, 2015). A qualitative study analyzed that nurses are less equipped to perform the role of researcher, due to which the fact that they are not able to justify their profession, with knlowledge of without the relationship between nursing theory and practice. Researchers highlighted the importance of balance between teaching and practice of research in nursing academia. They also wish to promote the development of models and theories in their own discipline (González, Badia, & Font, 2014). Evidences show that nursing process is using a tool for systematic clinical decision making. However, nursing students are facing challenges in its application. Therefore, researchers suggest utilizing qualitative studies to explore nursing students' experiences and view in this regard (Heidari & Hamooleh, 2016). Heidari conducted a qualitative study regarding nursing students' experiences in employing nursing process at the clinical arena. The results of the study identified that application of nursing process without proper direction leads to the decrease in performance in the clinical area, decreased critical thinking ability, and ultimately results in an increase of student's dissatisfaction level (Heidari & Hamooleh, 2016). Another qualitative study aimed to describe the perception of nurse managers after implementation of nursing philosophies in a ward setting and concluded that working according to nursing philosophy provides support to the nurse managers and nursing staff in their everyday work and in contributing and sharing values (Traav et al., 2014).

Researchers have highlighted in many research studies regarding the gap between theory and practice. They also discuss the role of nurse educators in defining the impact of knowledge of nursing theories in terms of practices and to observe outcome on patients’ outcomes (Hussein & Ousji, 2017). Researchers further highlighted that many of the researches studied now-a-days are based on implementation sciences to understand and progress towards the use of theoretical approaches in a better way (Nilsen, 2015). Nilsen classify theories, models, and frameworks according to simplicity in scientific approach in implementation, facilitation in selection, and relevancy with research and practice. Researchers classify them in three categories; however these categories are overlapping too. The most determinant frameworks provide limited support for carrying out implementation endeavors since the determinants usually are too generic to provide sufficient detail for guiding an implementation process. While the relevance of addressing barriers and enablers to translating research into practice is mentioned in many process models, these models do not identify or systematically structure specific determinants associated with implementation success. Furthermore, process models recognize a temporal sequence of implementation accomplishments, whereas determinant frameworks do not explicitly take a process perspective of implementation (Nilsen, 2015).

While performing literature reviews of the available literature, it was identified that many researchers have studied the effectiveness of some specific theory or framework in specific domains. Sell (2017) had discussed the background of Complexity Integration Nursing Theory (CINT), which consists of four grand nursing theories: that are human becoming nursing theory, theory of nursing knowledge and wisdom, the social entirely nursing theory, and theory of nursing practices. CINT is the unique way of presenting theories in a single metatheory. It incorporates nursing practices, nursing education, and nursing research too (Sell, 2017). On the contrary, it is stated that the understanding, implementation, and evaluation of complex theory are considered as the main problems for practicing nurses. Researchers should work on a foundational level in order to explain the concepts and constructs in a clear manner (May, 2013). A cross-sectional study was conducted in Parana, Brazil to identify the way of addressing nursing theories in undergraduate level. Researchers identified that nursing theories are taught in a fragmented manner in 35 courses, due to which it may lead to the inability of students to implement and understand the different aspects of a single theory in a professional manner (Matos et al., 2011).

Nursing theories are considered as indicators of evidence based nursing practices; however, researchers claim that their application is missing from the practice area. A descriptive, analytical study was conducted to explore the barriers of nurses in the application of nursing theories. The data surround six types of barriers asked by the participants. These are personal barriers, educational barriers, personal theorist barriers, texts and documents related to the theory barriers, political and social adaptation barriers, and usefulness perceived barriers to the nursing theory. The results of the study identified that educational barriers and lack of text and documentation is identified as the important barriers in nursing theory application. It was recommended that there is need of training courses on the principles, rules and standards for nurses in dealing with patients will be able to modify and enhance nurses' attitudes and encourages nurses to use nursing theories (Mohammadib et al., 2015). Another study was conducted to explore the trends in nursing theories through the review of the last 10 years’ available literature. The researcher categorized findings into six themes: that are foci on specifics; coexistence of various types of theories; close links to research; international collaborative works; integration to practice; and selective evolution. Researchers recommended that continuous efforts are required to link research and practice of theories (Im & Chang, 2012). It has been identified that since the last three decades, nurses have been making efforts to upgrade the nursing education. They are until now succeeding in shifting the focus of nursing education from hospital services to the identification of other areas of nursing. Literature still claims the gap between classroom teaching and practices in the clinical area (Mensik et al., 2011; Im & Chang, 2012). Saifain, AbuRuz, and Masa’deh (2015) have used a qualitative approach to explore reasons for the gap present between nursing education and practice. The results of the study revealed three themes based on interesting facts about nursing educators. First, was the qualification of nurse educators. Second, was the lack of communication between theory and clinical teachers and last, but not least was the lack of support from educators to implement theory in the clinical area. The similar aim of the quantitative study was conducted in Riyadh, including nursing students and nursing staff, and it was discovered that 48% of the nurses thought that nursing theories are beneficial for nursing practices. However, 56% participants did not know that which theories are applicable in their working area. The study concluded that there is a lack of knowledge among the participants regarding nursing theories. It was further recommended that to advance the nursing profession, it is necessary that hospitals and nursing schools follow a theoretical model and link theories to practice (Saifan et al., 2015). Scholars recommended that through the use of nursing theories, nurses could improve nursing practices, and nursing education and could develop strong collaboration with other healthcare members (Brazil et al., 2005). Nurses are working very hard to upgrade their profession, but they are facing many challenges in today's world. One of the biggest challenges is the effective utilization of constructing theories by nurses in their practice area. The effective practice of nursing theory is the assurance of implementation of evidence-based practice in the clinical area. Florence Nightingale, the founder of modern nursing has given a format of documentation and suggested useful concepts of environment that could be applicable to provide agerm free environment to the patients (Idress, 2014). Similarly, Tonges and Ray (2011) apply the caring model for development of effective nursing care at Carolina Hospital. In this study, researchers further recommend the researchers to make associations between interventions and caring process in other parts of the world (Tonges & Ray, 2011). Zarzycka et al. (2013) have conducted a research in Poland to implement some theories in the clinical area. Researchers concluded that due to the complexity of nursing theories, its interpretation and application is difficult. Furthermore, there is a need to have command on theoretical background for proper implementation. The above mentioned factors become barriers for nurses to implement nursing theories in the required area (Zarzycka et al., 2013). Arora (2015) had written a paper to help nurses summarize some nursing theories with their historical background, classification, and purpose (Arora, 2015). The researchers highlighted that nurses should know about all the underpinnings of the theory for the purpose of application. In this way nurses could enrich self-sufficiency by understanding nursing theories focusing on independent functions (Arora, 2015; Tiwaken et al., 2015).

The findings of the review article identified that the nurses have developed many nursing theories in order to organize and improve the nursing practices. The paper highlights that many nursing researchers have tested those theories in their specific discipline as well. The findings of the study are endorsed by Arora, (2015); and Tiwaken et al., (2015). Furthermore, researchers are recognizing the importance of theory which demands for encouraging new projections in the practice of nursing services and researches (Arif & Nasir, 2019). There is an essential responsibility on nursing educators to ensure the implementation of nursing theories in the clinical area. They must reflect and highlight the challenges a student faces while per forming implementation. The effective implementation of nursing theories at the clinical area is the prime responsibility of nursing institutions and researchers for the improvement of nursing practices and betterment of the nursing profession (Arif & Nasir, 2019).

The researcher only selected those research articles that highlighted the overall nursing theories. The few articles selected, worked on any selected specific nursing theory in order to emphasize the phenomena of importance of the nursing theory in nursing profession.

In conclusion, nursing theories could be expressed as a systematic expression to formulate nursing profession. They provide a set of recommendations to improve the nursing profession. Nurses are on the verge of implementing nursing theories. They are facing many challenges and barriers in terms of understanding concepts, clarification of defined concepts for the implication, and also from the research point of view. These challenges create a gap between theories and its practical implications. Researchers recommend that distinct approaches are required to decrease the gap that exists between the academic and clinical component of nursing education. Furthermore, clinical instructors need to design strategies and new innovative ways for more effective clinical teaching. Finally, there is a need to facilitate a conducive learning environment to study nursing theories and to highlight their application in the specific field of nursing.