Using the Synergy Model to Link Nursing Care to Diagnosis-Related Groups

Critical Care Nurse, Vol. 20, No. 3, June 2000.

Rosemary K. Doble, RN, Martha A.Q. Curley, RN, PhD, CCNS , Eileen Hession-Laband, RN, MBA , Barbara L. Marino, RN, PhD , Susan M. Shaw, RN, MS

As we venture into the 21st century, we reflect on the changes in healthcare. The fee-for-service system has been replaced with managed care, and today healthcare systems across the United States are trying to maintain quality while struggling for fiscal survival. Even so, healthcare dollars account for a growing percentage of the gross domestic product. (1) Because nursing salaries account for a sizable part of healthcare costs, nurses are challenged to articulate their value as healthcare professionals in this cost-contained environment. Nursing, however, has yet to describe the experience of quality care or find a way to succinctly and reproducibly measure such care. (2) Now is the time to link nursing practice to patients' needs by using a language that is universally understood across the healthcare system, especially to payers of nursing services. In this article, we describe a project in which the Synergy Model was used to link nursing care to diagnosis-related groups (DRGs), the basis of the established method of reimbursement and the language used by payers.

Traditional Models

Nursing productivity is typically measured for staffing and budgetary concerns and to describe and quantify nursing practice and the outcomes of nurses' services. (3) Historically, nursing care has been prospectively measured by using one of several highly subjective systems for classifying patients. These tools typically describe the amount of time nurses spend on tasks; for example, time needed to complete a bed bath or to take vital signs. Not considered is the amount of time a nurse needs to get to know a patient in order to create a safe environment and plan the care that eventually becomes visible and thus measurable.

The Yale Project

In the late 1980s, researchers at Yale University School of Nursing evaluated the nursing intensity measures used in 9 hospitals. (4) Daily classifications of patients and DRG information accumulated over patients' entire length of stay (LOS) were considered. In cross-hospital comparison, the Yale researchers found wide variability in the nursing time attached to care of patients, but considerable consistency was apparent in the nursing intensity within each DRG. (4)

RIMS / Nursing Acuity Project

The work of the Yale study was expanded by the Resource Information Management System / Nursing Acuity Project. (5) Its purpose was to use existing data to develop a system for classifying patients' severity of illness that could be used in management decisions, such as resource allocations and staffing decisions. Diers and Bozzo (5) formed a panel of nurse experts from the varied disciplines at Yale New Haven Hospital. Because patients in intensive care units (ICUs) usually require more nursing resources and often experience longer LOS than do patients in other units, nurse experts were separated into an ICU group and a non-ICU group.

A list of DRGs was compiled from the medical records of patients discharged the previous year. The nurse experts assigned either a "high" or "not high" rating to each DRG, depending on nursing care requirements, and then sorted these 2 categories into 5 intensity clusters, with level 1 being the least intensive care and level 5 being the most intensive care. A sixth cluster was created for patients whose needs were extreme. (5) Then, an hour standard was attached to each level to indicate how much nursing time was required to meet the needs of the patients.

Nursing Resource Measurement Project

Children's Hospital in Boston went a step further in its Nursing Resource Measurement project by using the Synergy Model to give nursing experts a common language to describe patients' needs and the nursing competencies required by pediatric patients within each DRG. "The fundamental premise of [the Synergy Model] that patients' characteristics drive nurses' competencies. When patients' characteristics match and synergize, patients' outcomes may be optimized." (2, p64)

The Children's Hospital task force was charged with addressing the issue of measuring nursing intensity. Because the project would eventually describe patients' care needs across the healthcare system, broad representation on the task force was sought. A nurse researcher, several program directors, and advanced practice nurses brought their expertise in clinical measurement, management, and clinical practice; a nursing project manager brought database and informatics expertise; and the finance officer was asked to participate.

Once the task force had developed the framework of the project, the Nursing Resource Measurement group was formed with clinical experts in specialty areas: level 3 staff nurses or clinical coordinators. As with the earlier projects, an ICU group and a non-ICU group were formed. The ICU group included nurses from the multidisciplinary ICU, newborn ICU, cardiac ICU, and the bone marrow transplant unit. The non-ICU group consisted of representatives from all specialty inpatient units, including neurology, orthopedics, cardiology / cardiac surgery, general surgery, oncology, and general medicine.

The nurse experts used an expanded model of the traditional DRG system to better include children and infants who require acute care - the All Patient Refined - DRG (APR-DRG) system - which addressed patients- severity of illness (the extent of physiological decompensation) and risk of mortality (the likelihood of dying). The APR-DRG system included 4 severity of illness / risk of mortality subclass ratings for each DRG: 1, minor; 2, moderate; 3, major; 4, extreme.

Data sheets for each level of each APR-DRG were designed to provide a profile of the group of patients being categorized (Table 1). Each data sheet included the number and name of the APR-DRG, levels 1 to 4, numbers of patients with that DRG over a year's time, percentage of patients who were cared for in the ICU, percentage who died, associated primary diagnoses and secondary diagnoses, primary and secondary procedures, age group, and mean and range for LOS.

Table 1 Data sheet for APR-DRG 001 for fiscal year 1997: craniotomy with intracranial hemorrhage and deep coma

Level 1 Level 2 Level 3 Level 4
Patients, no. 3 4 1 0
Patients with stay in intensive care unit, % 100 100 100 NA
Age of patients, no.

School Age 2 3 1 NA
< 1 year old 1 1 0
Patients who died, no. 0 0 0 NA
Average length (range) of stay, days 14 (3-21) 16 (7-34) 33 NA
Primary diagnosis, no. of patients Intracranial hemorrhage, 2
Subdural hemorrhage, 1
Cerebrovascular anomaly, 3
Subarachnoid hemorrhage, 1
Cerebrovascular anomaly, 1 NA
Secondary diagnosis, no. of patients Ventricular shunt status, 1 Intracranial hemorrhage, 2
Hemiplegia, 1
Brain conditions, 1
Convulsions, 1
Intracranial hemorrhage, 1
Obstructive hydrocephalus, 1
Struck by person / object, 1
Subdural hematoma, 1
Thrombocyto-penia, 1
Depressive Disorder, 1
Eating Disorder, 1
Hereditary hemolytic anemia, 1
Intracerebral hemorrhage, 1
Systemic lupus erythematosus, 1
Mean no. of secondary diagnoses per case 0.33 2.5 6 NA
Primary procedures, no. of patients Ventriculostomy, 2
Incision of cerebral meninges, 1
Other brain incision, 2
Intracranial vessel excision, 1
Other craniotomy, 1
Other brain excision, 1 NA
Secondary procedures, no. of patients Computed tomography of head, 3
Magnetic resonance imaging of brain and brainstem, 2
Ventriculostomy shunt - abdomen, 1
Contrast cerebral arteriography, 5
Computed tomography of head, 3
Magnetic resonance imaging, 2
Skull plate insertion, 1
Incision of cerebral meninges, 1
Intracranial vessel excision, 1
Cranial puncture, 1
Other brain excision, 1
Replace ventriculoperi-toneal shunt, 1
Mean no. of secondary procedures per case 2 4 0 NA
ADHD = attention-deficit hyperactivity disorder
APR-DRG = all patient refined diagnosis-related grouping
NA = not applicable

The Process

The concepts of DRGs and APR-DRGs were clarified as the tool for information review, and the Synergy Model was used as a conceptual framework. Nurse experts were then divided into ICU and non-ICU groups, and separate facilitators led the discussions on how much nursing care could be equated to each level of each APR-DRG.

Using the Synergy Model as a framework, DRGs were sorted into high and not-high categories relative to patients' needs (Table 2). Then the nursing competencies (Table 3) were used to designate clusters 1, 2, or 3 for not-high DRGs and 4, 5, or 6 for high DRGs. The following paragraphs are the actual discussion in which nurse experts from the ICU group described the nursing care for craniotomy with intracranial hemorrhage and deep coma (APR-DRG 001) and the facilitator helped to focus on experiential knowledge and empirical data.

Table 2 Dimensions or characteristics of patients
Stability Ability to maintain a steady-state equilibrium
Complexity Intricate entanglement of 2 or more systems (eg, body, family, therapies)
Vulnerability Susceptibility to actual or potential stressors that may adversely affect the patient's outcomes
Resiliency Capacity to return to a restorative level of functioning using compensatory mechanisms; ability to bounce back quickly after an injury
Predictability Summative characteristic that allows one to expect a certain trajectory of illness
Resource availability Extent of resources (eg, technical, fiscal, personal, psychological, social) that the patient, family, and community bring to the situation
Participation in care Extent to which the patient and family members engage in aspects of care
Participation in decision making Extent to which the patient and family members engage in decision making

Table 3 Dimensions or characteristics of nurses
Clinical Judgement Clinical reasoning, which includes clinical decision making, critical thinking, and a global grasp of the situation, coupled with nursing skills acquired through a process of integrating formal and experiential knowledge
Advocacy or moral agency Working on another's behalf and representing the concerns of the patient, family, and community; serving as a moral agent in identifying and helping to resolve ethical and clinical concerns within the clinical setting
Caring practices Constellation of nursing activities that are responsive to the uniqueness of the patient and family and that create a compassionate and therapeutic environment, with the aim of promoting comfort and preventing suffering; such caring behaviors include but are not limited to vigilance, engagement, and responsiveness
Collaboration Working with others (eg, patients, families, healthcare providers) in a way that promotes and encourages each person's contributions toward achieving optimal and realistic goals for patients
Systems thinking Body of knowledge and tools that allow nurses to appreciate the care environment from a perspective that recognizes the holistic interrelationship that exists within and across the healthcare system
Response to diversity Sensitivity to recognize, appreciate, and incorporate cultural or ethnic differences in the provision of care
Clinical inquiry or Innovator / Evaluator Clinical knowledge development by the nurse to promote the best outcomes for patients
Facilitator of knowledge Ability to facilitate learning by patients and their family members

ICU Nurse 1: What kind of care has to be done for a patient with a ventriculostomy? Is there an open area or...?
ICU Nurse 2: A [patient with a] ventriculostomy is a lot of work if it is externalized, if the patient has a CVD [cerebrovascular device]. If the patient has a ventricular [internal] shunt, there's a lot of teaching needed, and then for the first 24 hours, the patient needs close neurological observation to make sure the shunt is working. You have to get the patients up, ad lib activity, if they are tolerating the pressure changes. But a straightforward shunt is not a lot of work. If it's externalized, and the patient has a ventriculostomy, that's a lot of work.

Such discussion would continue with the nurse expert presenting the case to the group explaining why a particular APR-DRG level should be placed in the high or not-high category. Once the category was decided, the nursing characteristics from the Synergy Model were used to assign the patient to a cluster group.

Facilitator 1: So here you have on level 1 [APR-DRG] a patient who is school aged, with IVH [intraventricular hemorrhage], AV (arteriovenous] malformation, and probably a ventriculostomy whose LOS is 14 days. So from there, how stable are these patients, on average? How complex are they? What are their vulnerabilities? Resiliency? Predictability?
ICU Nurse 1: Moderately stable and minimally complex on our floor. But they are pretty vulnerable and must be watched in case of another bleed or a rebleeding. Their resiliency should be good. They should return to their original level of functioning. As for predictability? They're moderately predictable.
Facilitator 1: So given what you've said, would you put them in a high or low cluster?
ICU Nurse 1: Low, I guess.
Facilitator 1: So we call that patient group low. Now, if we look at the nursing competencies required to care for patients in the low category, would it be a 1, 2, or 3?
ICU Nurse 1: I think it would be a 3. The nurse needs to be able to make clinical judgements about how the patient is tolerating pressure changes in the brain. Is he stable enough to get out of bed or into a carriage? The nurse needs to recognize the family's cognitive abilities and formulate a teaching plan that meets the family's needs. The nurse has to do a lot of teaching about the shunt if there is a CVD. And [the nurse must] collaborate with a lot of disciplines, like neurology, neurosurgery, PT [physical therapy], OT [occupational therapy], and must organize the discharge. It requires a lot of collaboration.

And so the interactions would proceed: expert nurses articulating their practice and getting agreement form the group. Colleagues would listen and try to understand the similarities and differences among the patients in their own populations of concern.

Facilitator 1: So even though it's the same, almost the same LOS, 2 more days. Same age group. Just looking at the content in those 4 categories [primary / secondary diagnoses / procedures], the patient's complexity has increased dramatically. So, you went through that process of evaluating stability, complexity, and vulnerability for level 1. Contrast that now to level 2. [These were the severity levels attached to the APR-DRG profiles.]
ICU Nurse 1: Well, with their secondary diagnoses - the seizures and hemiplegia - they're much less stable, more complex, highly complex if they've got hemiplegia and seizures and a bleed. Highly vulnerable.
Facilitator 1: So stop right there. You don't have to go down the whole list. You put the first one in the low pile. This one would go...
ICU Nurse 1: the high pile.
Facilitator 1: Yes, in the high pile. All right, now go to the third, level 3. Contrast level 2 to 3.
ICU Nurse: High.
Facilitator 1: So you've got one low and 2 highs. Now flip over to the nurse characteristics. Level 1 is in a low pile, now you need to go 1, 2, or 3. What about clinical judgement?
ICU Nurse 1: It would be 2, in between. The advocacy and moral agency piece...
Facilitator 1: How much of a voice do you have to be for this patient?
ICU Nurse 1: Three.
Facilitator 1: Okay. Caring practices - to me - is the vigilance. How vigilant do you have to be for this patient?
ICU Nurse 1: With a recent bleed, you have to be pretty vigilant.
Facilitator 1: Okay, so higher?
ICU Nurse 1: Four. And collaboration - there will be a lot of services: PT, OT, social work...
Facilitator 1: More than a 1 or 2 or 3?
ICU Nurse 2: Probably neurosurgery, and then PT, OT, and social work.
Facilitator 1:: So more than one service would be involved?
ICU Nurse 1: Yeah.
Facilitator 1: Okay, so we'll do more than just low level.
ICU Nurse 1: Systems thinking - that would be like a 2. These patients are not that complex.
Facilitator 1: Are you thinking about discharge planning?
ICU Nurse 2: You need to coordinate to home, to rehab, to pulling services together.

In some cases, the experts were challenged to rethink their placement of a patient if the group did not reach a clear consensus. The nurse expert would then offer more details, as in this discussion about a patient on the ENT [ear / nose / throat] service in for a routine tonsillectomy. It would have seemed that such a patient would have had fewer requirements, but the nurse expert explained that the secondary diagnoses revealed a complex syndrome.

Facilitator 2: Can you help me understand why this patient would be a level 4?
General Surgery floor nurse: Because of these secondary diagnoses. I think the need for clinical judgement goes up because these kids need multiple systems. They have medical issues that affect other systems, and because of that, they are probably known to the system. They may have many services involved and you will have to advocate for them. The collaboration requires a nurse who has a lot of experience in coordinating complex cases.
Medical floor nurse: He didn't go to the ICU.
General Surgery floor nurse: I know, but he has other issues that require expertise. Like a seizure disorder, developmental delay, hearing and sight impairments. He needs a lot of vigilance. If his parent can't be at the bedside, he needs more attention. He needs to be fed fluids and eventually food, and you need to observe closely how well he tolerates oral intake. He is at high risk for aspiration. He also may bleed and be unable to alert the nurse.


The language of the Synergy Model gave voice to nursing's work and was essential to the calibration of the entire project. The model was used to define patients' characteristics and nursing care requirements for a vast array of patients within one acute care hospital. The Children's Hospital project will continue, and the panel of nurse experts who categorized each DRG will reconvene to determine the hour standard, which could markedly affect staffing plans and thus a unit's budget. The most important outcome of the project is that patients' needs and nursing care were articulated in a meaningful language to payers.


The authors thank these nurse experts for their clinical wisdom and spirit of collegiality: Patti Mantell, Ellie Hartfield, Susan Baccari, Mindy Doherty, Lisa Whalen, Regina Band, Ellen Sullivan, Anne Marie King, Judy Mahoney, Kathy Houlahan, Susan Reidy, Caroline Costello, Anne Cormier, Marguerite Davoren, and Jean White.


1. Health Care Financing Administration. National Health Expenditures. Available at: Accessed July 25, 1999.
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3. Bowles KH, Naylor MD. Nursing intervention classification systems. Image J Nurs Sch. 1996;28:303-308.
4. Thompson JD, Diers D. Management of nursing intensity. Nurs Clin North Am. 1988;23:473-491.
5. Diers D, Bozzo J. Nursing resource definition in DRGs. Nurs Econ. 1997;15:124-137.
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