Rapid Response Team Activations in Oncologic Ambulatory Sites: Characteristics, Interventions, and Outcomes

PURPOSE:

Patients with cancer are vulnerable to clinical deterioration. Rapid response teams (RRTs) identify and manage patients with acute changes in clinical status. Although RRTs have been well studied in the hospital setting, there are limited data on patients who require support in the ambulatory or outpatient oncologic settings. Describe baseline characteristics, reasons for activations, interventions, and outcomes of ambulatory oncologic patients receiving RRT activation in a tertiary cancer center.

METHODS:

We conducted a retrospective review of adult (age ≥ 18 years) patients requiring RRT activation at multiple ambulatory sites between July 2020 and June 2021. Demographic and clinical data captured include age, sex, race, ethnicity, do not resuscitate status, vital signs, receipt of active cancer treatment within 30 days, and cancer type. Using Kaplan-Meier survival analysis and multivariable Cox proportion hazard ratio regression models, outcomes of 90-day mortality and hospitalization were assessed.

RESULTS:

There were 322 RRT activations among 427,734 visits to 10 ambulatory sites (0.75 RRTs/1,000 visits). The most frequent reasons were syncope (25.2%), fall (24.5%), and adverse reaction to cancer therapy or intravenous contrast (16.5%). One hundred thirty-seven (42.5%) required transfer to an emergency department, of which 81 (59.1%) required hospital admission. At 90 days, 51 (15.8%) had died, with 44 (86.3%) receiving comfort measures. Kaplan-Meier survival analysis and multivariable Cox proportional hazard ratio regression showed that heart rate > 100 at RRT presentation and hospitalization after a RRT event were significantly associated with 90-day mortality.

CONCLUSION:

Although uncommon, patients with cancer undergoing care at ambulatory sites can suffer acute clinical deterioration needing RRT review. The rates of hospitalization and mortality among such patients are high, suggesting the need for improved end-of-life care.

INTRODUCTION

Survival for patients with cancer has generally improved since the 1970s, largely because of advances in treatment protocols and development of targeted therapies.¹ Many cancer therapies are now taken orally at home or administered intravenously in an outpatient setting. As a result, much cancer care no longer requires inpatient admission, and many patients prefer to avoid interfacing with an acute care setting unless necessary.² An unintended consequence of these shifts is that patients may become acutely ill or suffer clinical deterioration during their outpatient visits, prompting activation of medical emergency response. Although the trends in cancer mortality has improved,¹ patients with cancer remain a vulnerable population, with higher risks for medical emergencies and mortality compared with patients without cancer.^3,4

Rapid response teams (RRTs) are used in both acute care and subacute hospitals to identify, evaluate, and triage patients for signs of clinical deterioration.^5,6 They serve as a safety net for patients who are acutely ill and have been associated with reductions in hospital cardiac arrest and mortality.^7-12 Although RRTs have been well studied in the hospital setting, little is known about patients who require such care in outpatient or ambulatory oncology settings.^13-15

To address this critical knowledge gap, we conducted a retrospective study of RRTs at Memorial Sloan Kettering Cancer Center (MSKCC) ambulatory sites. Focusing on adult oncologic patients who required RRT support in these ambulatory settings, we sought to describe patients' baseline characteristics, reasons for activation, interventions, and outcomes, including hospitalization and 90-day mortality.

METHODS

System Structure

MSKCC is a free-standing comprehensive multisite oncologic center, which includes a 500-bed acute care hospital, the Josie Robertson Surgery Center for short-stay surgical procedures, and the Koch Center, which primarily delivers outpatient care but also has capacity for 16 inpatient beds. Each of these sites have a dedicated 24/7 RRT available for acute patient issues or medical emergencies. Given the immediate availability of inpatient support, data from these sites were excluded.

Beyond the three core facilities, there are 10 ambulatory sites that provide additional geographic access to patients for routine outpatient visits and follow-up, urgent visits for symptom management, chemotherapy, radiation therapy, select invasive procedures, radiologic imaging, and transfusions. These ambulatory sites are free-standing and are not physically connected to a hospital with an emergency room or critical care support. They have limited hours of operation (typically 07:00-20:00) without any inpatient capacity or overnight observation. In addition, the RRT at these ambulatory sites are known as the Medical Emergency Response Team.

RRT Composition

The 10 free-standing ambulatory sites are located within New York (NY) and New Jersey (NJ) and have a delineated RRT response led by advanced practice providers who are nurse practitioners, physician assistants, or physicians for patients with acute issues or medical emergencies. In addition, the RRT is supported by a registered nurse as well as nursing and administrative leadership. The RRT's primary role is to stabilize acutely ill patients as needed and activate emergency medical services (EMS) for transfer to the closest emergency department (ED) for further care. Alternatively, if the RRT and primary providers resolve the acute problem, patients can be sent home with further follow-up. For critically ill patients, the standard response rendered is basic life support and pharmacological advanced cardiac life support by selected teams of providers while waiting for EMS. Since 2020, there has been focused effort to standardize and clearly define the RRT lead and team members across the ambulatory sites who will respond to medical emergencies. In 2020, a uniform RRT note was also instituted to streamline documentation for all critical events requiring RRT support.

Study Design

This was a retrospective study for all adult patients (age ≥ 18 years) who required RRT activation in the ambulatory sites of MSKCC between July 2020 and June 2021. RRT activations for visitors, family members, and employees were excluded. Demographic and clinical data included age, sex, race, ethnicity, do not resuscitate (DNR) status, COVID-19 status, receipt of active anticancer treatment within 30 days before the RRT, cancer type, and performance status using the Karnofsky Performance Status (KPS) or Eastern Cooperative Oncology Group (ECOG) scale. Performance status is presented on the ECOG scale, and KPS was converted to ECOG scale as previously published¹⁶ using the following interconversion scale of KPS to ECOG (proposed by the American Joint Committee for Cancer): 100 (ECOG 0), 80-90 (ECOG 1), 70 (ECOG 2), 50-60 (ECOG 3), and 10-40 (ECOG 4).

RRT data included reasons for activation, team structure (including leader type), and treatment(s) delivered. Medical charts were also reviewed for the following vital signs: systolic blood pressure (SBP) < 90 mmHg, heart rate (HR) > 100 beats/minute (bpm), respiratory rate > 22 breaths/minute, oxygen saturation < 90%, or temperature > 38°C. Immediate outcomes included transfer to an acute care hospital ED, hospital admission, and 30- and 90-day mortality. The study was granted a waiver of informed consent by the institutional review board (IRB Protocol no. 22-020).

Statistical Analysis

R-studio version 4 was used for the analysis. Descriptive statistics included counts (percentage) or median (interquartile range). Comparison of proportions was done using the chi-square tests and differences in distributed data with the Mann-Whitney U test. A two-sided P value < .05 was taken to indicate statistical significance.

A multivariable Cox model was created using a univariate screen and stepwise selection algorithm to identify significant factors associated with 90-day mortality (covariates were entered into the model if P < .1 and were retained in the final model if P < .05). Differences in survival rates between patients who required hospitalization or those who were discharged home after RRT activation, patients with solid tumors versus hematologic malignancies, and impact of abnormal vital signs at presentation were visualized using Kaplan-Meier curve and compared using a log-rank test. The results of Cox proportional hazard models were summarized using Wald asymptotic 95% CIs and given a normal distribution of deviance residuals.

RESULTS

Baseline Demographics

During the study period, there were a total of 427,734 patient visits in the ambulatory sites, of which 322 required RRT activations for 316 patients (0.75 RRTs/1,000 visits or one RRT/1,328 visits) (Appendix Table A1, online only). The median (interquartile range) age was 64 (57-74) years and 60.3% were female. The majority (276; 89.0%) of patients had solid tumors, and 34 (11.0%) had hematologic malignancies. More than half (198; 61.5%) had received recent anticancer therapy and 35 (10.0%) had received radiation therapy within 30 days of the RRT activation. Six patients had an active DNR documented at the time of RRT activation (Table 1).

TABLE 1.

Baseline Demographics of 322 Ambulatory RRT Patients

Presentation

The majority of RRTs were advanced practice provider–led (230; 71.4%) followed by a MD (90; 28.0%) and by a registered nurse (2; 0.6%; Appendix Table A2, online only). The majority of the RRT activations were inside the facility, with 29 (9.0%) in an outdoor public space at the facility such as the parking lot. The most frequent reasons for RRT activation were syncope (25.2%), fall (24.5%) and adverse reaction (16.5%) to anticancer therapy or intravenous contrast (Table 2). Sixty-eight (21.1%) patients had SBP < 90 mm Hg and 112 (34.8%) had HR > 100 bpm. There were three activations for patients found to be in cardiac arrest, with a total of eight patients who suffered cardiac arrest during the RRT evaluation. Patients had varying underlying reasons for deterioration including 69 (21.4%) who were thought to be hypovolemic (Appendix Table A3, online only).

TABLE 2.

Encounter Reasons and Vital Sign Abnormalities

Treatment and Outcomes

The most common interventions (Table 3) by the RRT included administration of at least 1 L of intravenous fluid (133; 41.3%), followed by supplemental oxygen (92; 28.5%). Only 21 patients (6.52%) required epinephrine for anaphylaxis management. Of the eight RRT activations who suffered cardiac arrest, six (1.86%) required intravenous epinephrine and three (0.9%) required shock delivery. More than half of the patients (180; 55.9%) were able to return home, whereas 137 (42.5%) were sent to a local ED for further evaluation. Of these 137 transfers, 81 (59.1%) required hospital admission. Thirty (9.3%) patients died within 30 days, and 51 (15.8%) died within 90 days of RRT activation (Table 4).

TABLE 3.

Treatment Delivered During 322 Ambulatory RRT Calls in Oncology Patients

TABLE 4.

Disposition Outcomes of 322 Ambulatory RRT Calls in Oncology Patients

Subanalysis of Patients Who Died at 90 Days

Of the 51 patients who ultimately died within 90 days of RRT, two died shortly after transfer to the ED. After RRT, 15 (29.4%) received anticancer therapy and seven (13.8%) received radiation therapy. Although only 6 of the 51 patients (11.8%) were DNR before RRT, another 22 (43.4%) were made DNR after RRT. The majority (64.7%) died at home or inpatient hospice settings, and 86.3% died with comfort care measures in place. Patients who died were more likely to have a HR > 100 bpm (56.9% v 30.4%), SBP < 90 mmHg (27.5% v 19.6%), and respiratory rate > 22 breaths/min (15.7% v 4.8%) than patients who were alive at 90 days (Appendix Table A4, online only).

Performance Status

The total number of patients with available performance scores within the last 40 days before RRT activation was limited to 122. Median time from the date of performance score assignment to the RRT was 4 days. Kaplan-Meier survival analysis and multivariable Cox proportional hazard ratio regression model showed that ECOG scores showed statistically significant association with 90-day mortality, with higher ECOG scores and lower survival rate (Data Supplement, online only; P < .0001).

DISCUSSION

RRT activation for patients in ambulatory setting has been described to occur as many as 13%¹⁷ to 27.9%¹⁸ of encounters; however, in those studies, the nonhospitalized patients were physically connected to a hospital with ED and critical care resources. To our knowledge, there are limited data on RRT response in free-standing ambulatory sites and no prior studies have described RRT in an oncology population in the ambulatory setting. As cancer care evolves and moves increasingly to outpatient/ambulatory settings, so too does acuity and illness severity. Accordingly, providers who work in these areas must be able to respond to the unique acute problems that are more commonly seen in an inpatient setting. Our study offers novel insights into the frequency, characteristics, interventions, and outcomes of oncologic patients who require RRT activation in free-standing ambulatory sites.

Although DNR documentation was initially present in just 12% of the times for all the patients who died within 90 days, the overwhelming majority of them ultimately expired with comfort measures in place. According to literature, it has been reported that up to one third of the hospitalized patients prompting RRT are at end of life; and that RRT may be instrumental in initiating advance care planning for end of life.^19-21 We hypothesize that there may have been an opportunity to improve advance care and end-of-life care planning before the patients suffered clinical deterioration prompting RRT activation during their outpatient visits.

Oxygen therapy and intravenous fluid therapy have been described as common intervention for ambulatory patients requiring RRT.^13,14,17,18 In our oncologic ambulatory patients, almost half of the RRT activations required at least 1 L of IV fluid, suggesting that the patients were found to be hypovolemic at the time of assessment. In addition, almost a quarter of the patients also required supplemental oxygen and 6.5% required administration of epinephrine for serious adverse reactions, suggesting the need to provide life-sustaining interventions while waiting for EMS.

One quarter of the RRT patients ultimately required hospitalization, and one in six were at end of life. We believe that the RRT response provided a safety net for this vulnerable population by providing an organized response for triaging and stabilizing patients requiring hospitalization for further management. It also provided a structured approach with skilled staff to respond to these relatively rare events. In addition, they provided assurance for patients who were well enough to be sent home.

The strengths of our study include the multicenter design, novel approach to evaluating a diverse set of events occurring under RRT response in the outpatient setting, evaluation of dedicated teams, and identification of the need to initiative goals of care in declining patients.

Despite this, our study has several limitations, mostly because of the retrospective nature of the study and the small sample size. There were a number of cases where patients' COVID-19 status and vital signs were unknown. The study could have also potentially missed a small number of RRT encounters for which a structured RRT note was not completed. In addition, we cannot comment on patients who had management of acute illness or deterioration during their oncology visits through mechanisms independent of a RRT activation. Thus, our findings are most applicable to the RRT model of care in this context.

Unfortunately, our study could not analyze data by cancer type for the 427,734 patient visits to understand the full impact of cancer or its severity on patients most likely to suffer clinical deterioration in the outpatient setting. Performance status scores close to the time of RRT activation was infrequently documented. Future study should be prospective and should account for cancer type, severity, and calculating performance scores closest to the time of RRT activation to fully understand the association with predicting mortality.

We are also not able to comment on the differences in the function of RRT between the ambulatory sites that could have affected the number of RRT activations and its outcomes. For example, some sites had higher rate of RRT activation compared with another site. This could have been due to the difference in threshold set for trigger or the culture surrounding RRT activation, differences in patient characteristics (including cancer type), or patient acuity.

For future research, we would like to perform a prospective study consisting of a larger sample size that would compare interventions and outcomes of RRT at one site versus another to understand what is the best model of RRT for oncology patients who suffer clinical deterioration at the ambulatory sites.

In conclusion, although uncommon, oncologic patients who present to the ambulatory sites can suffer clinical deterioration activating RRT. We felt, the RRT team provided a safety net for oncologic patients who suffered acute clinical deterioration after presenting to an outpatient setting. Although the majority of the patients who died were not DNR at the time of initial RRT activation, most ultimately died with comfort measures, suggesting the importance of initiating palliative care of the highly vulnerable patients. Further research is required to evaluate the generalizability of our findings in other settings, and further optimize processes and elements of this critical component of patient care.

APPENDIX

TABLE A1.

Patient Volume and RRT Calls by Sites

TABLE A2.

RRT Number According to Member Composition and Team Leader

TABLE A3.

Underlying Reasons for Deterioration

TABLE A4.

Associations With Mortality at 90 Days

AUTHOR CONTRIBUTIONS

Conception and design: Jibran Majeed, Sanjay Chawla, Susan Chimonas, Steven C. Martin, Daryl Jones

Administrative support: Maryellen O'Sullivan

Collection and assembly of data: Jibran Majeed

Data analysis and interpretation: Jibran Majeed, Sanjay Chawla, Ellen Bondar, Susan Chimonas, Daryl Jones

Manuscript writing: All authors

Final approval of manuscript: All authors

Accountable for all aspects of the work: All authors

AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

Rapid Response Team Activations in Oncologic Ambulatory Sites: Characteristics, Interventions, and Outcomes

The following represents disclosure information provided by authors of this manuscript. All relationships are considered compensated unless otherwise noted. Relationships are self-held unless noted. I = Immediate Family Member, Inst = My Institution. Relationships may not relate to the subject matter of this manuscript. For more information about ASCO's conflict of interest policy, please refer to www.asco.org/rwc or ascopubs.org/op/authors/author-center.

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