Radiology Departments as COVID-19 entry-door might improve healthcare ecacy and eciency, and Emergency Department safety

Background Possible COVID-19 pneumonia (ppCOVID-19) patients generally overwhelmed EDs during the rst COVID-19 wave. Home-connement and primary care phone follow-ups was the rst-level regional policy for preventing EDs to collapse. But when ppCOVID-19 needed x-rays assessment, the traditional outpatient workow at the radiology department (RD) was inecient and raised concerns about potential interpersonal infections. We aimed to assess the eciency of a primary care high-resolution radiology service (pcHRRS) for ppCOVID-19 in terms of time consumed at hospital and decision’s reliability. Methods We assessed 849 consecutive ppCOVID-19 patients, 418 appointed by general practitioners to the pcHRRS (home-conned ppCOVID-19 cases with negative –group-1- and positive -group-2- x-ray results) and 431 arriving the ED by themselves (group-3). The pcHRRS provided x-rays and oximetry in an only-one-patient agenda for home-conned ppCOVID-19 patients. Radiologists made next-step decisions (group-1: pneumonia-, home-connement follow-up; group-2: pneumonia+, ED assessment) according to x-rays results. ANOVA and Bonferroni correction, t-student, Kruskal-Wallis, and Chi2 tests were used to analyse changes in the ED workload, time-to-decision differences between groups, and pcHRRS performance for discriminating need for admission.

with the arrival of the COVID-19 wave in February 2020, regional health authorities put forward a strategy based on primary care health centres GPs keeping patients with mild clinical presentation at home, similarly to the European recommendations [1]; at the Region of Murcia, they controlled more than 26,800 symptomatic cases suspected or diagnosed with COVID-19, and more than 34,600 asymptomatic contacts at home, only by close telephone follow-up [2]. But soon, dyspnoea, recommendations for thorax x-rays even in the more resource constrained scenario [3,4], the high volume of home-con ned patients, and the growing number of subjects asked by phone to go to the Emergency (ED) or the Radiology Departments (RD) at the referral hospital without previous warning, urged us to set up a secure primary care high-resolution radiology service (pcHRRS) in our health area, out of the ED. The pcHRRS operated with a speci c RD team 12-hours daily, being at the same time the ED entry-door when appropriated. It was designed to offer GPs prompt objective respiratory clinical information from their home-based patients; to immediately transfer patients with pneumonia to the ED; to avoid overwhelming arrivals of respiratory patients to the ED; and, nally, to pilot and export the idea to the other health areas. Assuming the potential infection risk at overcrowded environments [5], we hypothesized that the pcHRRS would provide a much more e cient safer care. For that purpose, we aimed to analyse the pcHRRS e ciency in terms of reduced ED workload, waiting-times, and admission triage through a simple radiology algorithm.

Methods
This cross-sectional study followed the SQUIRE guidelines and was approved by our hospital ethical committee (C.I. EST: 55/20). Patients' informed consent was waived.

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Our health area coped with the highest COVID-19 burden (26.4%) at the Region of Murcia. There were 233 con rmed SARS-CoV-2 infections, 4004 accumulated possible cases and 4687 contacts by April 17 th , 2020, when recruitment ended. In the same period, 152 COVID-19 patients were hospitalized, which was also the highest number in all health areas (23.4%).
Considering the usual number of patients seen in our ED before the pandemic start (e.g. 20-26 February: 1657 patients) and a ratio of respiratory/non-respiratory patients close to 1 (0.94,206/218,[20][21][22][23][24][25][26] during the rst epidemic week, we expected 118 [(1657/2)/7] or more daily respiratory emergencies during the epidemic wave. The average waiting time for patients with suspected respiratory infection at the ED during the epidemic wave was 5:48h. Despite the ED having established separated ways for respiratory and non-respiratory patients, COVID-19 infection risk would presumably increase if health care was provided through the usual indoors overcrowded ED environment with extended waiting-times [5].
Accordingly, we designed a straightforward speci c radiology algorithm trying to keep the vast majority of possible pneumonia (ppCOVID-19) patients out of the ED, through an individualised short-time service while being highly effective for triaging need for admission.

pcHRRS characteristics
The pcHRRS provided thorax x-rays and oximetry, making unnecessary a direct GP-to-patient contact. To be useful, the pcHRRS had to be 1) relevant: by deciding next steps; 2) accessible: available in less than 24 hours for any home-con ned patient; 3) swift: less than 15 minutes RD work ow without waiting time on an only-one-patient appointment and expedited electronic report for the GP or the ED; and 4) safe: by reducing risks of a) Staff infections: radiographers and nurses in charge of the oximetry and patient's navigation avoided close contacts with the available personal protective equipment; b) Patients infections: they knew in advance how to reach the radiology room limiting interactions with other patients; barrier and hygiene resources were always available; and c) Wrong communication with the ED: COVID-19 ED physicians were fully aware of patient's management through the pcHRRS .
2.2. pcHRRS resources ( g.1, Supplementary g.1) 1. General practitioners.Suspected or con rmed COVID-19 cases were interviewed by telephone every day. GPs had to rule out ppCOVID-19 if fever remained more than 6-7 days or persistent respiratory symptoms or worsening of respiratory or general condition at any time (especially dyspnoea). Those patients were appointed to the pcHRRS.
2. Speci c electronic agenda. GPs could schedule thorax x-rays into the radiological information system from 9:00 a.m. to 9:00 p.m., every 15 minutes Monday to Sunday, and every 30 minutes on weekends and holidays.
3. COVID-19 radiology room. Short street access room with a robotized x-ray digital 3D tomosynthesis (3DDT) and immediate PACS archiving, limiting any patient-to-patient and patient-to-staff interactions.
4. Radiology Department work ow a) Administrative staff. As soon a patient was appointed, a Radiology secretary phoned encouraging him to attend the appointment and giving instructions for a safe access to the radiology room (Supplementary g.2). A radiology resident played that role on weekends and holidays.
b) Reception. Upon arrival, the patient warned the reception staff that he was coming through the pcHRRS and was provided with a surgical mask. Relatives generally waited in the street to avoid person-to-person interactions. The reception staff checked that patients knew how to reach the radiology room, preventing random navigation through other areas.
c) Radiology Department radiographers and nurses. When arriving to the radiology room, the patient proceeded immediately when the door was open. They were instructed to clean their hands with hydro-alcoholic solution, alcohol or to put gloves on, depending on daily resources. Within the room they received remote instructions from the radiographer so as to do the posteroanterior and lateral thorax x-ray radiographs, or a lateral radiograph and 3DDT. Then, the nurse performed oximetry and informed the radiology resident. Once the radiologists assessed the x-rays and decided the next step, the nurse informed the patient and, when needed, went with him to the ED admission point, preventing him from accidentally leaving the pcHRRS or random navigations, and avoiding delays and x-rays repetitions. When occasional delays made an arriving patient to wait outside the room, the patient within stayed in the changing room while the radiographer cleaned every contacted element. Once the decision was made, the technical staff cleaned the changing room and started again. d) Radiologists. A resident and a staff radiologist worked close to the COVID-19 room, allowing a fast and direct communication always maintaining a safe distance with radiographers and nurses, and between themselves. The Radiology resident, who was the only additional pcHRRS personnel resource, 1) assessed thorax x-rays and was allowed to send the patient to the ED when sure about signs of pneumonia; abnormal x-ray with ndings different from pneumonia where handled as usual (Supplementary g.3); 2) drafted structured reports to be eventually validated by the radiologist; he used standardized radiology information according to scienti c recommendations [6], also including oximetry results and the patient's nal destination (Supplementary g.4); 3) phoned the ED COVID-19 physicians warning about abnormal x-rays; 4) recorded and followed up every case; 5) recorded every pcHRRS incident; and 6) played the administrative role on weekends and holidays, being the reason for the 30 minutes time slots on those days. The radiologist supervising the pcHRRS on weekdays was one of our regular on-duty emergency radiologists, and the on-call radiologist on weekends and holidays. They guaranteed a correct work ow, supervised the radiology resident, and validated radiology reports in nonconclusive and normal cases, and whenever requested by the resident.
5. Emergency Department. A COVID-19 physician evaluated every pcHRRS patient with radiological ndings of pneumonia. The work ow was streamlined since the patient didn't need a triage and had reported x-rays and oximetry.
6. Crisis committee. The Head of the RD, the Primary Care Network Director and the Medical Director of our health area, and one of the emergency radiologists met every day to know the number of involved patients, clinical results and incidents, so as to make changes on the y. When required, the RD Supervisor and the Administrative Coordinator, and the ED COVID-19 Medical Coordinator attended the initial meetings.
For our purposes, all consecutive pcHRRS and the ED patients with respiratory infection symptoms were retrospectively studied from 5 days before the pcHRRS started. All pcHRRS patients underwent conventional thorax x-rays with posteroanterior and lateral views. A systematic assessment by 3DDT and oximetry were implemented later in the pcHRRS.

Statistical analysis
Patients were strati ed in: Group 1 (G1: pcHRRS; normal x-rays; returning home); Group 2 (G2: pcHRRS; xrays pneumonia ndings; referred to the ED); and Group 3 (G3: ED; respiratory infection symptoms according to the ED physician). For G1, the process length was the period between the pcHRRS appointment time and the radiology report validation time; if any patient arrive at hospital before the appointment time, the process length was considered the period between the exam acquisition and the radiology report validation time; for G2 and G3, it went from the arrival time to the ED to the clinical report signature time. Any G1 patient deciding to seek medical advice at the ED after leaving the pcHRRS was included in G3. Patients leaving or requesting voluntary medical discharge were included in the number of patients attended, but excluded from the time analysis, as this variable was lacking.
Patients' in ow was represented by daily absolute and relative frequencies, and the total accumulated frequency for all groups, and the daily ratio of hospitalized patients for groups 2 and 3.
Komogorov-Smirnov test was used to assess the normal distribution of the quantitative variables. The Kruskal-Wallis, Mann Withney U and Chi 2 tests were applied when appropriate. Qualitative variables are shown as absolute and relative frequency. Quantitative variables as mean ± standard deviation, median and interquartile range in square brackets or 95% con dence interval (95%CI), as appropriate Statistically signi cant differences were assumed when P <0.05. The analysis was performed with the IBM Statistics SPSS 20 software. Precise p values could not be extracted for the non-parametric tests using SPSS. For graphs, we also used the Excel Microsoft O ce 365 software.

Results
A top of 1494 con rmed and 5010 possible cases/week was reached in March 23-29 th , 2020, with a maximum of 119 con rmed cases/day on March 25 th , 2020. We considered that day to be the peak of the epidemic wave. The pcHRRS started on March 26 th , 2020 and has been active since then. From March 26 th to April 17 th , 2020, 418 and 431 respiratory infection patients were seen through the pcHRRS and the ED, respectively. Ten scheduled patients did not attend the pcHRRS appointment. Those 418 patients accounted for 9.86% of the active con rmed or possible accumulated cases (233 and 4004 patients, respectively) followed-up by telephone in that period of time, and 0.16% of our health area population (265.842 people).
After starting the pcHRRS, the number of patients/day in the ED gradually decreased ( g.2 When we began to write this manuscript, we had all radiological and laboratory data records for the rst 212 consecutive patients, all with conventional thorax radiographs and 73 with additional 3DDT. Their mean age was 46.75 ± 13.93 years, 87 (41%) men. Forty-eight (22.64%), 148 (69.81%) and 16 (7.54%) had abnormal, normal and questionable radiographs, respectively. All 48 patients with abnormal radiographs were referred to the ED, as well as 2 patients with normal radiographs and 4 patients with questionable radiographs in whom 3DDT brought out signs of pneumonia (6/54, 11.1%). These 54 patients (G2) were older (50.46 ± 15.73 years) than G1 patients (45.41 ± 13.01 years; P = 0.019), men showing a trend to be more frequently referred to the ED than women (29/87, 33.33% vs. 27/115, 23.48%; P = 0.057) due to radiological abnormalities.
SARS-CoV-2 infection was con rmed by reverse transcription polymerase chain reaction (PT-PCR), serology, or both in 37/212 (17.45%) and ruled out in 77/212 patients. In 87/212 patients the infection was ruled out, though results are now under review. We have no data to date on 11/212 patients.

Discussion
During the rst COVID-19 epidemic wave, respiratory patients were managed signi cantly faster through the pcHRRS, regardless they returned home or were admitted. The pcHRRS contributed to halve the number of patients arriving to the ED for respiratory symptoms, triaging effectively the need for admission out of the ED.
The screening strategy recommended by the American College of Radiology and the Society of Thoracic Radiology for SARS-CoV-2 infection [7], based on RT-PCR and serology tests, has been applied in some countries [8]. But resources for laboratory tests in suspected SARS-CoV-2 infection were scarce and urged us to manage patients as potential infections in most occasions. Whatever the clinical setting, the RD was strategic when SARS-CoV-2 pneumonia had to be ruled out because hospital admission was then usually warranted [9]. Moreover, providing care for all suspected cases on a hospital basis may likely increase the number of infections in an already overwhelmed health system [8]. Therefore, according to our experience, a radiology entry-door may play a central role in ongoing waves of COVID-19 as our RD provided a faster and more e cient management, that was potentially safer [5].
The RD role to assess need for hospital admission in con rmed or possible COVID-19 patients has been a key innovative e cient strategy but it was applied without a speci c referral from the primary care network, and used CT as imaging technique [10]. Accordingly, the way home-con nement patients were managed and the straightforward imaging assessment are important differences in our case. Potential reduction of infection spread with our pcHRRS might have been achieved by keeping ppCOVID-19 outpatients with respiratory infection isolated in a speci c route from the beginning [11,12]. But, not less important, a personalised agenda contributes to clear facilities [13], guaranteeing a safe environment both for patients and health workers [10,12,[14][15][16]. Risk contacts were signi cantly reduced through our pcHRRS by providing an extremely quick response in terms of speci c appointments, safer x-ray technology and oximetry for decision making, and expedited information transmission, always out of the ED. At the same time, it safely discriminated patients needing admission from those still ready to be managed at home. More than ¾ of ppCOVID-19 patients managed through the pcHRRS returned home and only 12% of those cases needed further x-rays assessment, who never showed radiological worsening. ppCOVID-19 patients seen through the pcHRRS and the ED routes were discharged in 77% and 52%, respectively, but the pcHRRS route was 5.2 times faster. Moreover, it had a remarkably high performance for discriminating ppCOVID-19 patients needing hospital admission, as over 90% of those referred to the ED were admitted. Some authors have agreed on the discriminating potential of thorax radiography as an independent factor for hospital admission [9]. In our case, that performance remained at the same level both at the epidemic peak and while it was declining.
Following our legal obligation [17], we have to keep a safe speci c route for patients potentially infected by SARS-CoV-2, which necessarily needs x-ray assessment. We think that our RD work ow for ppCOVID-19 outpatients is this study's main strength as we haven't found reported a similar approach. Furthermore, the characteristics of age, gender and oximetry of our G2 patients were similar to those previously reported [9,18], and the way both cohorts were nally built up within a strict home-con nement regional strategy reproduces a real setting whose results might be used as a model in ongoing pandemic waves. Furthermore, we believe that the higher pcHRRS discriminative performance makes bene cial to maintain and expand the RD entry-door role in the long term to be prepared for future COVID-19 waves or other similar pandemics. But we also acknowledge some weaknesses. We have now complete clinical and radiological follow-up data in 212 patients, so many nal outcomes are still under assessment. But when patients returned home, GPs closely followed them up and we can assume that pcHRRS decisions were safe. Furthermore, a retrospective assessment of the pcHRRS x-rays exams by independent staff radiologists is still waiting. But the radiological reports were always validated by board-certi ed radiologists in patients without pneumonia ndings, who never needed admission regardless they were occasionally reassessed. Finally, we couldn't compare the economic issues at this moment, but, in principle, only a resident without any additional income was required in the pcHRRS, while patients navigating through the ED would normally increase expenses due to other laboratory analysis and medical variability.

Conclusion
In summary, a RD positioned as a COVID-19 entry-door may be e cient in an epidemic setting to decrease respiratory patients at the ED, while potentially reducing infection hazards through safe and expedited decisions.