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Cultivating Quality

Implementation of a Warm Zone Model During the COVID-19 Pandemic

Omess, Sarah MSN, APRN, AGCNS-BC, AGPCNP-BC; Kaplow, Roberta PhD, APRN-CCNS, AOCNS, CCRN; Green, Alyson MS, APRN, AGCNS-BC, OCN; Kingsley-Mota, William MSN, RN, NEA-BC; Mota, Sérgio MSN, RN, CCRN-CSC, NE-BC; Paris, Lauren MSN, APRN, ACCNS-AG, AGPCNP-BC, CCRN; Wilson, Keisa MSN, RN, RN-BC

Author Information
AJN, American Journal of Nursing: January 2021 - Volume 121 - Issue 1 - p 48-54
doi: 10.1097/01.NAJ.0000731664.58705.c3
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In March 2020, Emory University Hospital, a Magnet-designated tertiary care facility and one entity of Emory Healthcare in Atlanta, received its first documented cases of coronavirus disease 2019 (COVID-19). The hospital's executive leadership and a senior nursing director assembled an interprofessional quality improvement (QI) team—comprising a clinical nurse specialist (CNS), two epidemiologists, and four infection preventionists—and tasked the team with identifying ways to improve staff and patient safety while caring for patients with suspected or confirmed COVID-19 infection. At the time, the hospital was placing patients who tested positive for COVID-19, as well as persons under investigation (PUIs) for COVID-19, on a designated acute care unit or ICU, a practice known as geographic cohorting. As the number of COVID-19 cases continued to rise, a secondary level of geographic cohorting was put into effect, resulting in unit populations consisting exclusively of confirmed COVID-19 patients. PUIs were placed on a separate inpatient unit or harbored in place if they became a PUI after admission to a non-COVID unit.

The QI team developed several innovative strategies focused primarily on staff safety. These strategies reduced the amount of time spent donning and doffing personal protective equipment (PPE) and improved the conservation of PPE; they also improved workflow efficiency and reduced the risk of self-contamination in the PPE doffing process. The increased risk of health care workers becoming contaminated while doffing PPE has been well-documented.1-3 For example, depending on the type of PPE (gowns, gloves) and the scenario in which it's used, researchers have found rates of self-contamination while doffing PPE to be between 46% and 90%.4-6

Statement of the problem. COVID-19 started to impact the United States in early 2020. By March, the first patients testing positive for COVID-19 presented in Georgia. By this time, some states were already facing PPE shortages among other equipment and staffing challenges. In light of the growing national shortage of PPE, the QI team was charged with ensuring that our institution could maintain staff safety.

Caring for patients who tested positive for COVID-19 required an extensive examination and modification of workflow and PPE practices. The QI team implemented a “warm zone model” to deliver care safely to this population, improve workflow, and conserve PPE. This article outlines the warm zone model from concept to implementation and evaluation in the care of patients with COVID-19.


In managing emergency responses to biological and chemical disasters, existing hospital infrastructure and patterns of movement of personnel often require modification from daily operations. One approach is the delineation of hot, warm, and cold zones.7 Hot zones are areas where the risk of contamination is highest. Warm zones are a transitional area between hot and cold zones, where the risk of contamination is moderate. Cold zones are areas free from contamination risk.

Another important asset in managing a biological disaster, such as an infectious disease outbreak, is the biocontainment patient care unit (BPCU). The BPCU is designed to reduce the risk of contamination and exposure to highly infectious pathogens.8 When biocontainment is required, it's also important to maintain a unidirectional flow of staff and equipment and a traffic pattern that mitigates the risk of contamination of the cold zone, where staff don clean PPE.8

Emory University Hospital's BPCU supported the treatment of a small number of patients who had Ebola in 2014. When these patients were admitted, the BPCU care team encountered challenges with traffic patterns. While a unidirectional flow of people and materials is optimal, the existing architectural infrastructure did not support this. The BPCU team had to establish a process to safely manage a warm zone that could also function as a cold zone. This need for a change in workflow led to the concept of a temporary warm zone. The BPCU team developed procedures to allow for removal of waste and materials from the hot zone through the warm zone, followed by decontamination of the warm zone, which removed contamination risk and reestablished the cold zone.

Warm zone model concept. One of the epidemiologists on the QI team had been vital in developing the BPCU's traffic pattern in response to Ebola. The QI team encountered similar traffic pattern challenges on the COVID-19 cohort unit. The unit infrastructure included patient rooms along two hallways that needed to function as both warm and cold zones. By extrapolating lessons learned from the BPCU during the Ebola outbreak, the QI team developed a process based on the warm zone concept and modified donning and doffing procedures to align with the BPCU's workflows of nurses and other members of the multidisciplinary team, including physicians, NPs, physician assistants, pharmacists, respiratory therapists, phlebotomists, and X-ray technologists. The updated procedures included double gloving and two gown-doffing procedures. One doffing procedure was used for disposable gowns; the other for gowns that could be sterilized and put back into circulation. Next, the QI team developed a procedure to safely guide staff to “bridge” (transition) between the rooms of patients with COVID-19.

The QI team also developed a buddy system that could involve two RNs or any combination of multidisciplinary care team members; one person stayed in the cold zone and the other stayed in the hot zone. Items such as equipment, supplies, and waste could be passed back and forth in either direction through the warm zone using an over-bed table. Waste was removed from the hot zone in a trash bag that was first wiped down with an antimicrobial wipe, then brought out of the hot zone and placed into a second trash bag before it was removed from the unit. The person in the hot zone would open the patient's room door and retrieve items from the over-bed table in the warm zone and then close the door. The person in the cold zone would then disinfect the over-bed table.

Before leaving a patient's room, the multidisciplinary care team member would doff the outer pair of gloves using the “beak method”—pulling one glove inside out over the hand, grasping the second glove at the wrist with the inside of the first glove and pulling it off, then removing the first glove using the clean-gloved hand (a method shown in this video:

The multidisciplinary care team member then exited the hot zone while still wearing a pair of inner gloves and the remaining PPE and performed hand hygiene on the inner gloves with alcohol-based hand sanitizer. Staying inside the warm zone, the team member moved toward the next patient's room, donned a new pair of outer gloves, and entered the room, another hot zone.

We followed the recommendations of the Centers for Disease Control and Prevention regarding hot zone PPE, which had to be donned before entering a patient's room and providing care.10


The QI team identified an acute care unit where implementation of the warm zone model could be piloted. The senior nursing director, who helped to assemble the QI team, formed an acute care clinical team that included the CNS from the QI team, another CNS, and an education coordinator. The clinical team was tasked with developing a transferrable process for setting up a warm zone model in acute care and providing education on the model for unit staff.

Before implementation of the warm zone model, every RN was required to doff all PPE after providing care to a patient who had tested positive for COVID-19 and don new PPE before providing care to the next patient who had COVID-19. This meant that on each 12-hour shift, an RN who cared for three COVID-19 patients would don and doff PPE an average of 18 times. The clinical team also conducted a time-in-motion study and found that, on average, donning PPE took one minute and 57 seconds, and doffing took two minutes and 35 seconds.

Implementation. The acute care clinical team identified the warm zone as half the width of the hallway outside patients' rooms; there were two such hallways on the unit. With the assistance of facilities management, the hallway floor was taped down the middle with red tape to denote the warm zone (see Figure 1). PPE caddies that had hung on patients' doors were relocated to the cold zone and hung on the wall opposite the patients' rooms. The warm zone was equipped with trash cans, gloves, and alcohol-based hand sanitizer. Signage was created to notify hospital staff of the warm zone and the risk of contamination. The clinical team provided staff education before implementation and real-time follow-up training as needed. The clinical team also created a resource binder for unit staff to reference. The warm zone model process was not expanded to the multidisciplinary care teams until unit-based staff had it mastered.

Figure 1.
Figure 1.:
Implementing the Warm Zone Model in the Acute Care Unit

Prior to the coronavirus pandemic, patient care assignments were based on acuity; but when the hospital began admitting patients with COVID-19, the clinical team had to modify assignments so that the patients assigned to one RN were located on the same hallway, or warm zone, while still factoring in patient acuity.

Acute care unit results. According to a recent study, frustration with frequent donning and doffing of PPE, especially when nurses realized supplies were needed after they had already entered a patient's room, was more likely to increase the risk of reduced adherence to best practices.11 Use of the warm zone model meant that the RN assigned to the patient (or the patient's medical provider or ancillary personnel) could remain in the warm zone, already donned in PPE, while the buddy RN obtained any medications or personal care items.

Clinical team members fine-tuned the warm zone implementation process through random observations and real-time feedback from the buddy teams as well as the multidisciplinary care team. The final warm zone model was consistently reported to have improved the workflow of the multidisciplinary care team. A decrease in mental and physical fatigue associated with the tedious process of donning and doffing PPE was also reported.

After warm zone model implementation, the clinical team conducted a second time-in-motion study. The team found that, on average, each RN now donned and doffed PPE five times per 12-hour shift, 72% less than before implementation of the warm zone model. This translated into a time savings of 58 minutes and 53 seconds and 13 fewer gowns used per RN per 12-hour shift.


Once the warm zone model was deemed successful in the acute care unit, members of the ICU clinical team started preparations to adopt it in the critical care setting. The ICU clinical team anticipated that implementing the warm zone model would result in an even greater conservation of PPE, considering that an ICU presents a more frequent need for additional therapies. On average, an RN working in the ICU would use 40 disposable gowns in a 12-hour shift before implementation of the warm zone model. A time-in-motion study showed that for each patient, RNs spent nearly five minutes donning and doffing PPE (an average of two minutes donning and two minutes and 48 seconds doffing).

Implementation. In preparing to implement the warm zone model in ICUs, the critical care team acknowledged that several adaptations to the acute care unit process were necessary. It was important to evaluate the differences in the two environments and workflows. Two floors of the COVID-19–designated ICU have a catwalk design, a hallway that wraps around the unit, forming the perimeter of the ICU. Each patient room has two doors: one that opens onto the catwalk and one that opens onto a central care team station. When these units don't host COVID-19 patients, families use the doors along the catwalk to enter patients' rooms, while the care team station is used only by staff members. The lack of family presence and social distancing were important strategies to help minimize the risk of COVID-19 exposure and spread. With family visitation restrictions in place, the critical care team designated the catwalk area as the warm zone; patients' rooms were hot zones, and the care team station in the center of the unit was the cold zone.

Two additional COVID-19–designated pop-up ICUs were created in response to the volume of patients that required a level of care that could be provided only in an ICU. In the pop-up ICUs, the layout was similar to that of the acute care unit, and the warm zones were modeled after their acute care counterparts.

The same bridging process was performed in the warm zone catwalk area outside the patients' rooms. Gloves and hand sanitizer were placed next to each patient's door. The PPE storage unit remained in the cold zone. One difference was that the warm zone and cold zones were not adjacent to one another, as they had been on the acute care unit. The critical care team developed three strategies to improve workflow in the ICU warm zone model: modifying the staffing matrix; improving communication; and increasing telemedicine support.

Modifying staffing. The COVID-19–designated ICUs revised their staffing matrices to allow for one extra resource RN, who functioned as a buddy for all nurses on the unit. The addition of the resource RN allowed for the RN-to-patient ratio to remain 1:2 in the ICU. On the two floors of the COVID-19–designated ICU (seven beds on each floor), there were nine nurses; four on each floor had patient assignments and one resource RN served as a buddy or resource for both floors. (In the ICU, the resource RN or buddy can go into hot zones to help with patient care, including with turning and bathing, and in emergencies.) The resource RN was assigned specific tasks, which included assisting with procedures such as intubation, bronchoscopy, tracheotomy, and obtaining vascular access; helping with transport of patients for procedures off the unit; initiating patient turns; coordinating baths with the patient care assistant (PCA); replenishing supplies in collaboration with the PCA; and acquiring medications, supplies, and equipment while in the cold zone. If the resource RN was busy, any member of the multidisciplinary team at the care team station was expected to support staff members who were in the hot zone. A charge nurse who didn't have a patient assignment was also available to support the team.

Improving communication. In addition to the existing call-light system, audio-only baby monitors were made available both inside and outside patients' rooms so that doors could remain closed while communication with nurses was enhanced.

Increasing telemedicine support. The use of telemedicine has expanded to the ICU, where it's referred to as tele-ICU, and expert critical care nurses and physicians provide continuous surveillance, monitoring, and patient care.12 At Emory Healthcare, the program is referred to as the Emory e-ICU Center.13

At Emory University Hospital, nurses and providers partnered with the e-ICU team in selected COVID-19 ICUs to add new functions and enhance existing ones. These functions included remote co-signature of blood products prior to administration; an increase in remote rounds from once per shift to every 30 minutes or one hour, depending on patient acuity; notification when continuous drips are low on volume and coordination of refills with pharmacy; and monitoring of dialysate and effluent in patients on continuous renal replacement therapy. In March 2020, when the first Emory University Hospital ICU began caring for patients who had COVID-19, the number of e-ICU sessions increased by approximately 400% (see Figure 2).

Figure 2.
Figure 2.:
Number of e-ICU Telehealth Sessions Before and After the ICU Began Caring for COVID-19 Patients

Going live. One week prior to beginning implementation of the warm zone model, the ICU CNS provided education in small groups to the entire nursing team. Reminders were provided via huddle. Multidisciplinary care team members also received education from their respective leaders.

Because each patient room in the ICU had two doors, in ordinary circumstances, patient rooms could be entered from both the central care team station and the catwalk that defined the perimeter of the unit. On units where patients with COVID-19 were cared for, signs were placed on the outside of both doors to identify that such a patient was in the room. The doors that opened onto the catwalk (the warm zone) from these rooms were locked from the inside; entry to these rooms was possible only from the central care team station (a cold zone). Just-in-time education was presented to the staff as a final step prior to going live with the warm zone model.

Another challenge was that ancillary staff, such as respiratory therapy and radiology providers, also had to use the warm zone model workflow to access patients' rooms. Patients who are ventilated and sedated also require more frequent evaluation and may develop complications that require more interventions.14 With the majority of the COVID-19 ICU patients requiring mechanical ventilation, the ICU team worked with ancillary staff to provide education on the proper use of the warm zone model by multiple teams.

Critical care results. After implementing the warm zone model in the ICU, the use of gowns decreased from an average of 40 to 22 per RN per 12-hour shift. This resulted in a total of 86 minutes saved on donning and doffing PPE per shift.

As expected after the implementation of the warm zone model, RNs reported greater satisfaction as a result of increased efficiency in their workflow. Considering the number of times health care providers in an ICU must enter a patient's room on one shift, the time saved with the adoption of the warm zone model translates into additional time to spend delivering direct or indirect patient care as well as for important self-care, including more frequent bathroom and meal breaks and time spent not wearing PPE.


Staff members who worked on both acute and critical care COVID-19 cohort units were surveyed on their perceptions of PPE procedure, the time consumed in donning and doffing PPE, and the risk of self-contamination. Responses were given according to a 5-point Likert scale, with 1 = strongly disagree and 5 = strongly agree. An additional question was included for any staff members who had previous experience working in warm zones to determine their perception of reduced risk of self-contamination. Out of 100 RNs, 42 completed the survey, 31 of whom had experience working on a warm zone model unit. Among the staff members surveyed, 86% (n = 36) agreed or strongly agreed that donning and doffing was time consuming and 93% (n = 39) agreed or strongly agreed that a specific protocol for donning and doffing PPE was important. A total of 36% (n = 15) agreed or strongly agreed that they felt at risk for self-contamination during the doffing process. Similarly, of those staff who had previously worked on a warm zone model unit, 48% (n = 15) agreed or strongly agreed that they felt a reduced risk of self-contamination while doffing in a warm zone model (see Table 1).

Table 1. - PPE Survey Responses from Nurses on COVID-19 Cohort Units
Statement RN Responses (N = 42)
Strongly disagree (1) Disagree (2) Neither agree nor disagree (3) Agree (4) Strongly agree (5) Mean
Donning and doffing PPE according to a specific protocol is important. 3 0 0 2 37 4.67
Donning and doffing PPE is time consuming to my daily workflow. 1 1 4 17 19 4.24
I feel at risk for self-contamination when I doff PPE. 2 14 11 13 2 2.98
I felt a reduced risk of self-contamination with the warm zone model (n = 31).a 0 4 12 10 5 3.52
PPE = personal protective equipment.
aThe number of respondents was 31 because only staff who had previous experience with the warm zone model were asked to respond to this statement.


Interprofessional collaboration was paramount to the success of this project. Future considerations include sharing lessons learned with other teams within other Emory Healthcare entities as well as the community at large.

The often conflicting imperatives of maintaining employee safety as well as the availability of PPE amid the COVID-19 pandemic resulted in the need to redesign our care delivery model. It was of the utmost importance not to compromise staff safety. Experiential and published evidence guided the development of the warm zone model at Emory University Hospital. Prior to the implementation of the warm zone model, we observed that staff working on COVID-19 cohort units had a high rate of PPE use, primarily of disposable gowns. After implementation of the warm zone model on an acute care unit, the ability to “bridge” between patients without removing the gown resulted in a 72% reduction in gown usage. In the ICU, where there was a complex infrastructure layout, implementation of the warm zone model resulted in a 45% reduction in gown usage. Because of the immediate reduction in PPE during a time of nationwide supply chain issues, the warm zone model has now been implemented on all acute care and ICU COVID-19 cohort units within the hospital. Additionally, all hospitals within the Emory Healthcare system have adopted the warm zone model as a best practice model on the COVID-19 cohort units. Comparison data on PPE usage for all participating units are currently being collected and analyzed. To ensure ongoing success in reducing the use of PPE supplies while maintaining the safety of the multidisciplinary care team—as well as timely and efficient patient care—the QI team will continue to make improvements to the warm zone model.


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    coronavirus; COVID-19; personal protective equipment; warm zone

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