Decades of research have resulted in the identification of PI risk factors, interventions to reduce such risk, and evidence-based treatment plans for those who unfortunately develop PIs. Complex system characteristics, including variability of individual and environmental factors, multiple feedback and process loops, and multiple levels of contributing factors, lead to the difficulty in accurate prediction of PI risk. Successful attempts to model the complexity of PI risk remains elusive. For this reason, the purpose of this study was the development of a conceptual model of pressure injury risk for hospitalized patients based on a synthesis of present PI models and recent research on hospitalized patients.
Methods: Walker and Avant’s (2005) theory development methods were used as a guide for this project. Initial work included review and synthesis of current PI models. In order to identify potential conceptual gaps in the models, a literature review was undertaken with a primary aim of identifying and categorizing predictive variables used in recent studies on PIs. PubMed and CINAHL indexes were searched, first for conceptual models (non-limited by date) and then for pressure injury research conducted on hospitalized patients within the period 2006-2016. A total of 5 PI conceptual models and 59 English language studies were reviewed and synthesized. The final step in theory synthesis, organization of concepts and statements into an integrated representation, included a review of each of the concepts identified in the conceptual model synthesis and empirical evidence, followed by the development of a graphical representation encompassing all relevant factors associated with development of PIs.
Results: During the conceptual model synthesis phase, several similarities in concepts associated with PI development were identified, including pressure, tissue tolerance, and shear. Primarily concepts associated with PI were represented via one-directional relationships despite the complexity and dynamic nature of PI risk. Empirical evidence supported the inclusion of many of the focal concepts found in the current PI models, but several concepts remained absent from current models. Pressure and tissue tolerance—as measured through various concepts and sub-concepts—continue to be supported as predictors of PI development. Factors associated with increased pressure for longer durations of time (e.g. immobility, pain, devices) result in greater risk for PI. Factors negatively affecting tissue tolerance, including poor oxygenation, limited perfusion, or excessive moisture, also contribute to PI risk. Shear, although less studied, similarly has evidence to support its relationship to PIs. There is also empirical evidence that new constructs are strong predictors for PI development among hospitalized patients. These constructs include additional patient demographic variables, environmental characteristics, and episode of care factors (Corniello, Moyse, Bates, Karafa, Holis, & Albert,2014; Tschannen, Bates, Talsma, & Guo, 2012). A complete understanding of the risk for PIs requires that these additional concepts be explored and integrated into PI risk models and assessments. For this reason, a new conceptual framework, the Pressure Injury Prediction Model, was developed.
The Pressure Injury Prediction Model accounts for the complex and dynamic nature of pressure injury risk and addresses new patient, contextual and episode of care process influences. A total of six primary constructs emerged. Pressure, tissue tolerance, and shear and friction align with earlier models. New constructs include patient, environment, and episode of care. The design of the model—which includes concentric circles—represents the dynamic and multi-level nature of patient, episodic, and environmental factors within the hospital stay that could change the level of PI risk for a patient.
Conclusion: Accurate risk assessment is essential for providing effective nursing care for the prevention of pressure injury. The development and testing of new interventions that address the complexity of contextual and process factors is vital for reducing this intractable problem. The Pressure Injury Prediction Model is a step forward for improved PI risk identification. Future research is needed to test the model so that targeted, evidence-based pressure injury prevention interventions, specific to a more precise patient risk profile, will improve patient outcomes and limit unwarranted and unnecessary care.