Editor’s  Note: PPP sponsors educational programming for its members and invites all interested parties to take part in our periodic Journal Club.  For those new to the format, a journal club is a gathering of medical professionals to discuss a scientific paper.  The paper under discussion is distributed prior to the meeting date, so that all participants can read it.  The club meeting begins with a member presenting a summary of the chosen paper.  Then the discussion begins, including questions about the study design, methods, results, and conclusions.  Finally, a consensus is rendered regarding the overall value of the paper. 

This blog entry introduces and summarizes our next Journal Club paper, so you’ll be ready for the discussion!

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January 22, 2020
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The Influence of Unit-Based Nurse Practitioners on Hospital Outcomes and Readmission Rates for Patients with Trauma

David S. Morris, MD, Patrick Reilly, MD, Jeff Rohrbach, MSN, Georgianna Telford, CRNP, Patrick Kim, MD and Carrie A. Simms, MD, MS


Is the care given by unit-based nurse practitioners (UBNPs) equal to that of resident-run (RR) services? 


At the time of this study, the study site, a hospital, had a unique model that utilized unit-based Nurse Practitioners (NPs) for most of their trauma patients. However, trauma patients who were admitted to other units, such as another surgical intensive care unit, were cared for by traditional resident-run (RR) teams. It is important to note that the trauma attending physician led both of these teams. The authors note that the involved NPs had, on average, 15.6 years of experience caring for trauma patients. The residents provided night coverage for the NP service and performed any required invasive procedures (i.e. chest tube placement).

The authors assert that patients were assigned to the trauma unit versus other units based primarily on bed availability. On the trauma unit at their hospital, the attending trauma surgeon and the NPs were involved in multidisciplinary rounds with bedside nurse, social workers, pharmacists, and physical and occupational therapists. However, the residents and attendings were not included on multidisciplinary rounds in other units. 

The authors use two trauma scores: the Injury Severity Score (ISS) and the Abbreviated Injury Scale (AIS) score. The ISS is one way to standardize the severity of injury based on six body systems: head and neck, face, chest, abdomen, external, and extremity. The AIS scores each body region on a 6 point scale, with 6 being untreatable and 1 being minor. 


A retrospective chart review was performed of all admissions to the trauma service from January 1, 2007 to August 31, 2010. The authors collected data including demographics, mechanism of injury, ISS and AIS scores, as well as co-morbidities. They also tabulated the following complications: pneumonia, deep vein thrombosis (DVT), pulmonary embolism (PE), acute renal failure (ARF), and surgical site infection (SSI). They also documented early re-admissions and discharge destination. 

The authors excluded the 196 patients who died, all of which whom died in the operating room or in the intensive care unit. They also excluded 97 patient who were discharged directly from the intensive care unit. 


Once the deaths were excluded, there were 3,859 patients included in the study with 2,759 admitted to the NP service and 1,100 admitted to the resident-run service. 

Baseline characteristics

There was no statistical difference between the two groups in terms of age, sex, race, or insurance status. The patients had similar co-morbidities (notably, diabetes, COPD, chronic kidney disease, heart failure, and coronary artery diseases) and mechanism of injury, ISS, as well as surgical procedures performed during admission. However, there was a statistically significant difference AIS score for abdominal (NP>RR, 0.6 vs 0.5) and face (NP<RR, 0.35 vs. 0.42) trauma. 

Hospital Complications

The overall rates of most complications were not statistically significantly different between the two groups. However, the patients on the NP service were more likely to be diagnosed with a DVT (4% vs. 2.5%, p=0.02). There was no statistically significant difference between the groups for length of stay. 

Discharge Destination

More patients on the NP service went home (67% vs. 60%, p=0.002), and more patients on the RR service were admitted to hospice (3% vs. 1%, p=0.04) or to a supervised residential facility such as an assisted living facility (1.6% vs. 1%, p=0.03). There were no differences in re-admission rates between the two groups. 

Authors’ Conclusions

The authors conclude that “care provided by [NPs] is equivalent to that provided by residents.” They go on to say that the difference in mean length of stay (0.5 days lower in the NP group), while not statistically significant, could be relevant to administrators who are looking to offset the cost of hiring more NPs.

PPP Initial Discussion/Critique

The NPs in the study had, on average, 15.6 years of experience caring for trauma patients. Residents have, by nature of residency, on average, 2.5 years, taking the simple average of a first-year resident to a senior resident. This is a significant point. Residents were able to achieve outcomes similar to those of the NP service despite having fewer years of experience, and while juggling the many duties of residency (surgery, lectures/didactics, studying). 

The statistically significant outcome measure was the DVT rate, which was lower for the RR service. The authors then go on to say that, despite the higher DVT rate, the length of stay was the same between the two groups. This should not be surprising, as DVT is not an indication for admission and can, in fact, be treated as an outpatient. 

While the authors looked at discharge destination, it is unclear what the recommended discharge destination would be for any given patient. For example, if a social worker recommends a patient go to an assisted living facility, but the patient instead goes home, is that considered “better”?  Similarly, if medical futility exists, and hospice is what is best for the patient, and the residents were able to deliver compassionate care that allowed that to happen, shouldn’t that be noted? 

The authors spend a great portion of the discussion focusing on the longer length of stay on the RR service, although there was no statistically significant difference (6.5 vs. 7 days). While they wax poetic about administrative implications, they fail to note that, statistically, one cannot make any statement regarding an actual difference in length of stay.  They do note that it takes longer to discharge a patient to a facility, as opposed to home, and the RR team discharged more of their patients to facilities that the NP teams did.

The authors recognize the limitations of the study, ignore the statistically significant findings as irrelevant, then use results that aren’t relevant to hammer home the point of equivalence. They conclude the care is equal, despite the evidence failing to support that conclusion.

Additional References: 

Injury Severity Score

Abbreviated Injury Scale


Discussion Questions
Please join us on Twitter #PPPJC @PPPforpatients, January 22, 9pEST

1) The authors assert that, because the trauma attending surgeon led both the NP and RR teams, the outcomes can be compared equally.  Does it matter that the resident-run teams had patients admitted to units outside of the usual trauma unit? 

2) Residents are involved in the NP service for overnight coverage and for invasive procedures but not vice versa. How is this a direct comparison of the two outcomes? 

3) The RR teams had lower rates of DVT occurrence. Why may this have occurred? 

4) Length of stay between the two groups was not statistically significantly different, although RR teams were less likely to discharge home. What are the implications of this? 

5) Why may have RR teams been less likely to discharge home? More likely to discharge to hospice? 

6) The authors conclude that care between the RR teams and the NP team were “equal.” Do you agree or disagree with this conclusion? 

7) Does this study support the independent practice of NPs?