The Impact of a Pulmonary Embolism Response Team on the Efficiency of Patient Care in the Emergency Department

Abstract

Introduction:

The concept of a Pulmonary Embolism Response Team (PERT) is multidisciplinary, with the hope that it may positively impact patient care, hospital efficiency, and outcomes in the treatment of patients with intermediate and high risk pulmonary embolism (PE).

Methods:

Clinical characteristics of a baseline population of patients presenting with submassive and massive PE to URMC between 2014 and 2016 were examined (n=159). We compared this baseline population before implementation of a PERT to a similar population of patients at three-month periods, and then as a group at 18 months after PERT implementation (n=146). Outcomes include management strategies and efficiency of the emergency department (ED) in diagnosing, treating, and dispositioning patients.

Results:

Before PERT, patients with submassive and massive PE were managed fairly conservatively: heparin alone (85%), or additional advanced therapies (15%). Following PERT, submassive and massive PE were managed as follows: heparin alone (68%), or additional advanced therapies (32%). Efficiency of the ED in managing high risk PE significantly improved after PERT compared with before PERT; where triage to diagnosis time was reduced (384 vs. 212 minutes, 45% decrease, p=0.0001), diagnosis to heparin time was reduced (182 vs. 76 minutes, 58% decrease, p=0.0001), and the time from triage to disposition was reduced (392 vs. 290 minutes, 26% decrease, p <0.0001).

Conclusions:

Our analysis showed that following PERT implementation, patients with intermediate and high risk acute PE received more aggressive and advanced treatment modalities and received significantly expedited care in the ED.

Introduction

Venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), is the third leading cause of cardiovascular mortality and a major cause of morbidity, disability, health care cost, and economic consequences[1–5]. The mainstay of treatment for low risk patients with PE, whose three-month mortality is 1%, is anticoagulation, however the optimal therapy for patients with submassive and massive PE, whose three-month mortality is 22% and 58%, respectively, is uncertain[5].

An array of advanced therapies beyond anticoagulation has been developed, including thrombolytics, catheter-based techniques, surgical methods, and hemodynamic support devices. However, high quality data supporting the benefit of these therapies are either lacking, show underwhelming or inconsistent benefit, or demonstrate considerable risks[6,7]. As patients with submassive and massive PE represent a heterogeneous population, certain subgroups of patients may benefit from these aforementioned therapies. However, identifying the best treatment strategy for an individual patient remains a challenge, and may be best made in a multi-disciplinary and patient-centric approach – personalized for the individual patient. Furthermore, atypical or non-specific presentations often make the diagnosis of pulmonary embolism challenging, which, along with other barriers to efficient medical care, can cause delays in administration of appropriate treatment for these patients, which may be clinically detrimental when early administration of anticoagulation has been associated with a decrease in mortality[8].

The development of Pulmonary Embolism Response Team (PERT) has been proposed to address these limitations, and the institution of PERTs has been adopted by dozens of hospitals nationwide, many of whom collaborate in the PERT Consortium[9–11]. Differences in therapies provided have been reported by PERT institutions without a change in mortality[12]. However, to our knowledge, no controlled studies have demonstrated the effect of PERT on the efficiency of patient care in the ED. We hypothesized that implementation of a multidisciplinary PERT would positively impact the efficiency of care of patients with submassive and massive pulmonary embolism in the ED. To test this hypothesis, we evaluated patients presenting to the ED, before and after the implementation of a PERT, and examined their associated times to diagnosis, therapy, and disposition.

Methods

Study Design:

This study is a single-institution observational study, before-and-after chart review of adults with submassive and massive pulmonary embolism presenting to the emergency department before and after the initiation of a Pulmonary Embolism Response Team (PERT) at the University of Rochester Medical Center/Strong Memorial Hospital. The study was approved by the institution’s Research Subjects Review Board, which waived informed consent for enrolled patients given the observational nature of the study. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Patient Population:

We analyzed data from adults in the ED with acute massive PE (defined as having sustained hypotension with systolic blood pressure (BP) <90 mmHg, cardiopulmonary arrest, or dependent on inotropes) or submassive PE (evidence of RV dysfunction by imaging or elevated NT-proBNP, or myocardial necrosis by elevated cardiac troponin T without massive criteria) before and after the initiation of PERT on November 1, 2016. Excluded patients included those with low-risk PE (not meeting massive or submassive criteria), known or chronic VTE but the reason for presentation was not related, and transfers from an outside facility where the diagnosis of PE was made previously. The baseline (pre-PERT) patient cohort between May 22 2014 and December 31 2015 who received standard care for PE as prescribed at the discretion of the treating physician was used as a reference group in our institution. Eligible patients following PERT implementation were continuously and prospectively enrolled with management decisions determined by the multi-disciplinary PERT.

PERT Team as an Intervention:

Once PERT was initiated, our institution recommended that PERT be activated immediately by the ED physician, and immediate treatment prescribed by the ED physician if needed, when patients met criteria for submassive or massive PE. The PERT activation prompted an immediate evaluation and co-management by the inpatient cardiac care unit (CCU) and medical intensive care unit (MICU) physicians. The evaluating PERT team then involved other PERT physicians as needed: cardiac surgery, interventional radiology, and vascular surgery. Following PERT evaluation, the involved physicians and patient collaborated to determine the optimal treatment plan, including the assessment of the risks and benefits of therapeutic options including anticoagulation, systemic thrombolysis, percutaneous thrombolysis and thrombectomy, surgical embolectomy, hemodynamic support, and IVC filter placement. Unless contraindicated, low molecular weight heparin was recommended as the preferred initial anticoagulant due to the rapid onset of action and ability to reliably achieve a therapeutic effect. An inpatient pharmacist with experience in ED care was immediately available to facilitate prompt administration anticoagulation and intravenous thrombolysis, if needed. Once the treatment plan was established, the PERT facilitated admission to the appropriate inpatient unit. Educational sessions were held with the faculty and house staff reinforcing the important aspects of patients with intermediate and high risk PE and how PERT at the institution would become involved to facilitate patient care.

Data Collection and Outcomes:

Data were collected for patients in the pre-PERT and post-PERT cohorts via the electronic medical record. Baseline characteristics such as demographics and comorbid conditions, vital signs, laboratory and imaging findings were recorded. Data were collected regarding the details of inpatient management including time course in the ED and therapies received. Furthermore, clinical outcomes data including mortality, adverse events (such as bleeding and hemodynamic decompensation), length of hospitalization, and recurrent DVT/PE were collected. The primary outcomes for this study analysis include the time from ED triage to a time-stamped radiographic diagnosis of PE, time from diagnosis of PE to anticoagulation administration, and the time from ED triage to patient disposition to an admitting service. Study data were collected and managed using the secure REDCap electronic data capture tools hosted at the University of Rochester[13].

Statistical Analysis:

Dichotomous variables are presented as frequencies and continuous variables as mean with standard deviation (SD) unless otherwise stated. The distribution of data was interrogated for normality using the Shapiro–Wilk test which determined it to be non-Gaussian. For three or more group comparisons, the Kruskal–Wallis test followed by Dunn post-test was used. For two groups, the Mann-Whitney U test was used. Significance was reported if the P value <0.05. All data were analyzed with GraphPad Prism 7 (GraphPad Software, Inc, La Jolla, CA).

Results

Before PERT, 571 patients with ICD codes for PE were screened, 412 patients were excluded (due to absence of acute PE, unrelated admission, low-risk PE, or diagnosis made at an outside facility), 159 patients with acute submassive or massive PE evaluated in the ED were included in the analysis. After PERT was initiated, the team evaluated 188 patients, 29 were excluded (due to absence of acute PE or low-risk PE), and 146 patients with acute submassive or massive PE were included in the analysis. Baseline demographic information is demonstrated in Table I. The average patient age was 63 15 years before PERT and 63 16 (p=0.6679) after PERT. Before PERT, 52.8% of patients were female compared to 50.7% after PERT (p=0.708). Before PERT, 27% and 73% of evaluated patients had massive and submassive PE, respectively, compared to 19% and 8% after PERT (p=0.104). Figure 1 demonstrates the treatment modalities received by these patients. Patients were more likely to be treated conservatively before PERT, as 85% were treated with anticoagulation alone and 15% received advanced therapies. After PERT, patients were likely to be treated more aggressively, with 68% of patients treated with anticoagulation alone, and 32% receiving additional advanced therapies including systemic thrombolysis, extra-corporeal membrane oxygenation, surgical embolectomy, or catheter-directed procedures.

Table I:

Demographics and baseline data for each population

Clinical Characteristics	Pre-PERT	Post-PERT	p-value
Number of Patients (n)	159	146
Massive PE, % / Submassive PE, %	27/73	19/81	0.104
Aqe (mean, years)	63 ± 15	62 ± 16	0.667
Sex (female, % / male, %)	53/47	51/49	0.708
Race
White (%)	64.2	79.5	0.003
Black (%)	25.2	14.4	0.019
Hispanic (%)	1.3	1.4	0.932
Asian (%)	0.6	0.7	0.952
Other (%)	8.7	4.0	0.017

Figure 1. Treatment modalities for managing high risk PE before and following PERT.

Data are represented as therapies administered as a percentage of the population evaluated

Efficiency in the ED in managing submassive and massive PE significantly improved after PERT compared to before PERT. The time to PE diagnosis, anticoagulation administration, and patient disposition before PERT, were quantitatively evaluated (Figure 2). The median time from initial triage in the ED to the diagnosis of pulmonary embolism was reduced (384 before- PERT vs. 212 minutes after PERT, 45% decrease, p=0.0001). Once the diagnosis of PE was established, the median time from diagnosis to heparin infusion was reduced (182 vs. 76 minutes, 58% decrease, p=0.0001). Lastly, the median time from triage to patient disposition to an admitting service was reduced (392 vs. 290 minutes, 26% decrease, p <0.0001).

Figure 2. Imporvement in ED metrics following PERT Implementation.

A. The time from patient triage to PE diagnosis. B. The time from PE diagnosis to heparin infusion. C. The time from triage to patient admission. Each metric was evaluated before PERT and after initiation of PERT implementation. Data are represented as median (horizontal bar). ¶P <0.0001 pre-PERT vs. post PERT. The improvement in metric after PERT implementation is noted as percent change below each graph.

Discussion

The efficiency of patient care in the ED following PERT implementation significantly decreased the time to diagnosis, treatment, and disposition of patients with PE. A previous investigation suggested that a decreased time from diagnosis of PE to anticoagulation administration was associated with improved clinical outcomes [8]. Future studies will evaluate morbidity and mortality and which clinical variables collected for our patients evaluated by PERT impact such clinical outcomes. We anticipate that prompt evaluation by a multidisciplinary collaborative PERT determining the most appropriate treatment plan and the activation of the pharmacy prioritizing administration of anticoagulation are responsible for the marked decrease in time from diagnosis to treatment of PE in our ED. Parenthetically, the collaborative nature of PERT was viewed positively by our ED physicians which may positively impact patient care transitions in general, not only for patients with a diagnosis of acute PE.

The time taken to diagnose PE was significantly decreased, given that the PERT is activated for a patient with an established diagnosis of PE. We believe our institution-wide educational efforts emphasizing the importance of identifying patients who are at high risk of complications due to PE increased awareness of PE in general, and so the diagnosis was established more promptly. The time from patient triage to admission decreased at a magnitude similar to the decrease in time from triage to diagnosis, emphasizing an early diagnosis of PE is key to mobilizing patients from the ED to the inpatient units.

There are limitations to the present study. The before-and-after design like other observational studies is a source of potential bias. The single institution study conveniently serves as its own control since careful analysis of the patient population with PE was conducted in the several months prior to initiating a PERT, but PERT as an interventional tool was not delivered in a randomized, controlled manner. We therefore cannot exclude that there may have been confounding factors impacting patient outcomes, including contemporaneous changes in ED work-flow and in radiographic image interpretation during the same time period independent of the effects of PERT. This appears to be most pertinent to the improvement in time to diagnosis of PE, however we maintain that the benefits of our PERT at an institutional level extend beyond the impact the team has once it has been activated for a diagnosed PE.

Conclusions

This single-center observational study before and after implementation of a multidisciplinary PERT activated by ED physicians demonstrated improved efficiency of care of patients with submassive and massive PE by decreasing the times to diagnosis of PE, treatment with anticoagulation, and patient disposition after PERT. Future studies are required to determine if those metrics or other aspects of PERT translate to an improvement in clinical outcomes.

Key Points.

• Patients with submassive and massive pulmonary embolism carry a high mortality.

• The optimal therapy for these patients is not yet established. Efficiency of care is suggested as a way to improve patient outcomes.

• We demonstrated that implementation of a PERT was associated with significantly improved times to diagnosis, treatment, and disposition for patients in the emergency department.

• Future studies are required to determine the effect of PERT on other outcomes and if this improvement in the efficiency of care affects mortality.