Triage protocol for allocation of critical health resources during Covid-19 pandemic and public health emergencies. A narrative review
Triage protocol during the COVID-19 health emergency.
Keywords:
Triage, Resource Allocation, Pandemic, COVID-19, EthicsAbstract
Background and aim of the work. Triage during the Covid-19 pandemic can impose difficult allocation decisions when demand for mechanical ventilation or intensive care beds greatly exceeds available resources. Triage criteria should be objective, ethical, transparent, applied equitably and publically disclosed. The aim of this review is to describe the triage tools and process for critical care resources in a pandemic health emergency. Methods. A narrative review was conducted of the literature on five electronic databases, namely PubMed, CINHAL, Web of Science, Cochrane and Embase, searching for studies published from 2006 to June 2020. Results. The results describe different triage tools. A gold standard of triage does not exist for the adult or paediatric population. Using probability of short-term survival as the sole allocation principle is problematic. In general, each triage protocol should be applied with a specific ethical justification, including transparency, duty to care, duty to steward resources, duty to plan, and distributive justice. Conclusions. Clinical triage decisions based on clinical judgment alone are prone to inconsistent application by triage officers in a pandemic. An ethical framework can inform decision-making and improve accountability. It remains difficult to connect clinical criteria and ethical criteria, because of the models on offer for health services.
References
European Centre for Disease Prevention and Control. Situation update worldwide, as of 22 April 2020. Available from: https://www.ecdc.europa.eu/en/geographical-distribution-2019-ncov-cases. Accessed 02 July, 2020.
Piva S, Filippini M, Turla F, Cattaneo S, Margola A, De Fulviis S, et al. Clinical presentation and initial management of critically ill patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Brescia, Italy. J Crit Care, 2020 Apr 14; 58:29-33. doi: 10.1016/j.jcrc.2020.04.004.
Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet, 2020;395(10223):497-506. doi:10.1016/S0140-6736(20)30183-5.
Guan WJ, Ni ZY, Hu Y, Liang WH, Ou CQ, He JX, et al. China Medical Treatment Expert Group for Covid-19. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med, 2020 Apr 30;382(18):1708-1720. doi: 10.1056/NEJMoa2002032. Epub 2020 Feb 28. PMID: 32109013; PMCID: PMC7092819.
Grasselli G, Zangrillo A, Zanella A, Antonelli M, Cabrini L, Castelli A, et al. COVID-19 Lombardy ICU Network. Baseline Characteristics and Outcomes of 1591 Patients Infected With SARS-CoV-2 Admitted to ICUs of the Lombardy Region, Italy. JAMA, 2020 Apr 6. doi: 10.1001/jama.2020.5394.
Frolic A, Kata A and Kraus P. Development of a Critical Care Triage Protocol for Pandemic Influenza: Integrating Ethics, Evidence and Effectiveness. Healthcare Quarterly, 2009;12(4):54-62. doi:10.12927/hcq.2009.21054.
Gomersall CD, Joynt GM. What is the benefit in triage? Crit Care Med, 2011; 39(4): 911–2. 8.
Ontario Health Plan for an Influenza Pandemic 2013. Available from: http://www.health.gov.on.ca/en/pro/programs/emb/pan_flu/pan_flu_plan.aspx. Accessed 15 June, 2020.
UNC Center for Bioethics. State, National, and International Organization Guidelines. Available from: https://bioethics.unc.edu/state-national-and-international-organization-guidelines/. Accessed 03.06.2020.
International Society For Priorities In Health. Specific Guidelines And Protocols For Covid-19. Available From: https://prioritiesinhealth.org/guidelines. Accessed June 03, 2020.
UNESCO International Bioethics Committee (IBC) and the UNESCO World Commission on the Ethics of Scientific Knowledge and Technology (COMEST). Statement On Covid-19: Ethical Considerations From A Global Perspective. Available from: http://www.bioethics.net/wp-content/uploads/2020/03/UNESCO-2020-03-26-Statement-of-the-UNESCO-International-Bioethics-Committee-IBC-and-the-UNESCO-World-Commission-on-the-Ethics-of-Scientific-Knowledge-and-Technology-COMEST2.pdf?x41592, Accessed June 03, 2020.
Christian MD. Triage. Crit Care Clin, 2019 Oct;35(4):575-589. doi: 10.1016/j.ccc.2019.06.009.
World Health Organization. Ethics in epidemics, emergencies and disasters: research, surveillance and patient care: training manual. Available from: https://www.who.int/ethics/publications/epidemics-emergencies-research/en/. Accessed May 05, 2020.
De Panfilis L, Tanzi S, Costantini M. Il processo decisionale per le cure intensive in situazioni di emergenza: l’etica medica e le cure palliative ai tempi del covid-19 . BioLaw Journal, in press.
Christian MD, Hawryluck L, Wax RS, et al. Development of a triage protocol for critical care during an influenza pandemic. CMAJ, 2006;175(11):13771381.
Sprung CL, Zimmerman JL, Christian MD, Joynt GM, Hick JL, Taylor B, Richards GA, Sandrock C, Cohen R, Adini B. Recommendations for intensive care unit and hospital preparations for an influenza epidemic or mass disaster: summary report of the European Society of Intensive Care Medicine’s Task Force for intensive care unit triage during an influenza epidemic or mass disaster. Intensive Care Med, 2010;36:428–443 DOI 10.1007/s00134-010-1759-y.
Maves RC, Downar J, Dichter JR, Hick JL, Devereaux A, Geiling JA, et al. Triage of scarce critical care resources in COVID-19: an implementation guide for regional allocation An expert panel report of the Task Force for Mass Critical Care and the American College of Chest Physicians. Chest, 2020. https://doi.org/10.1016/j.chest.2020.03.063.
Christian MD, Sprung CL, King MA, Dichter JR, Kissoon N, Devereaux AV, Gomersall CD. (2014). Triage: care of the critically ill and injured during pandemics and disasters: CHEST consensus statement. Chest, 146(4), e61S-e74S.
Einav S, Hick JL, Hanfling D, et al. Surge capacity logistics: care of the critically ill and injured during pandemics and disasters: CHEST consensus statement. Chest, 2014;146(4 Suppl):e17S–43S. 37.
Adeniji KA and Cusack R. The Simple Triage Scoring System (STSS) successfully predicts mortality and critical care resource utilization in H1N1 pandemic flu: a retrospective analysis. Critical Care 2011,15:R39. doi:10.1186/cc10001.
Pollaris G, Sabbe M. Reverse triage: more than just another method. Eur J Emerg Med, . 2016;23(4):240-247. doi:10.1097/MEJ.0000000000000339.
Hick JL, O'Laughlin DT. Concept of operations for triage of mechanical ventilation in an epidemic. Acad Emerg Med, 2006;13(2):223-229. doi:10.1197/j.aem.2005.07.037
Armstrong JH, Hammond J, Hirshberg A, et al. Is overtriage associated with increased mortality? The evidence says "yes". Disaster Med Public Health Prep, 2008;2(1):4–5.
Thompson AK, Faith K, Gibson JL, Upshur RE. Pandemic influenza preparedness: an ethical framework to guide decision-making. BMC Med Ethics, 2006;7:E12. Published 2006 Dec 4. doi:10.1186/1472-6939-7-12
Christian MD, Joynt GM, Hick JL, Colvin J, Danis M, Sprung CL. Chapter 7. Critical care triage. Recommendations and standard operating procedures for intensive care unit and hospital preparations for an influenza epidemic or mass disaster. Intensive Care Med. 2010 Apr; 36 Suppl 1:S55-64. doi: 10.1007/s00134-010-1765-0.
State of New Jersey. Department of Health. Allocation of Critical Care Resources During a Public Health Emergency. (Adapted from the University of Pittsburgh Model Policy). April 11, 2020 Available from: https://nj.gov/health/legal/covid19/FinalAllocationPolicy4.11.20v2%20.pdf. Accessed June 08, 2020.
Rosenbaum L. Facing Covid-19 in Italy - Ethics, Logistics, and Therapeutics on the Epidemic's Front Line. N Engl J Med, 2020 Mar 18. doi: 10.1056/NEJMp2005492.
Società Italiana di Anestesia Analgesia Rianimazione e Terapia Intensiva (SIAARTI). Raccomandazioni di etica clinica per l’ammissione a trattamenti e per la loro sospensione, in condizioni eccezionali di squilibrio tra necessità e risorse disponibili. Available from: http://www.siaarti.it/SiteAssets/News/COVID19%20-%20documenti%20SIAARTI/SIAARTI%20-%20Covid19%20-%20Raccomandazioni%20di%20etica%20clinica.pdf. Accessed May 12, 2020.
Truog RD, Mitchell C, Daley GQ. The Toughest Triage - Allocating Ventilators in a Pandemic. N Engl J Med, 2020;10.1056/NEJMp2005689. doi:10.1056/NEJMp2005689.
Rosoff PM, DeCamp M. Preparing for an influenza pandemic: are some people more equal than others? J Health Care Poor Underserved, 2011 Aug;22(3 Suppl):19-35. doi: 10.1353/hpu.2011.0098.
Cheung W, Myburgh J, McGuinness S, Chalmers D, Parke R, Blyth F, et al. Influenza Pandemic ICU Triage 3 study investigators; Australian and New Zealand Intensive Care Society Clinical Trials Group. A cross-sectional survey of Australian and New Zealand public opinion on methods to triage intensive care patients in an influenza pandemic. Crit Care Resusc, 2017 Sep;19(3):254-265.
Antommaria AH, Sweney J, Poss WB. Critical appraisal of: Triaging pediatric critical care resources during a pandemic: ethical and medical considerations. PediatrCrit Care Med, 2010 May;11(3):396-400. doi: 10.1097/PCC.0b013e3181dac698.
The National Institute for Health and Care Excellence (NICE). Care of dying adults in the last days of life. National Clinical Guidelines Centre NICE guideline [NG31]. Available from: https://www.nice.org.uk/guidance/ng31. Accessed May 13, 2020.
SICP-SIAARTI–FCP. Position paper. Le Cure Palliative nel trattamento dei malati COVID-19/SARS- CoV-2. Available from: https://www.fedcp.org/news/fcp-siaarti-e-sicp-le-cure-palliative-nel-trattamento-dei-malati-covid-19-sars-cov-2. Accessed May 13 2020.
Institute of Medicine 2012. Crisis Standards of Care: A Systems Framework for Catastrophic Disaster Response: Volume 1: Introduction and CSC Framework. Washington, DC: The National Academies Press. https://doi.org/10.17226/13351.
World Health Organization. Integrating palliative care and symptom relief into the response to humanitarian emergencies and crises: a WHO guide. Geneva: World Health Organization; 2018. Licence: CC BY-NC-SA 3.0 IGO.
Powell T, Christ KC, Birkhead GS. Allocation of ventilators in a public health disaster. Disaster Med Public Health Prep, 2008;2(1):20-26. doi:10.1097/DMP.0b013e3181620794.
D'Angelo D, Chiara M, Vellone E, et al. Transitions between care settings after enrollment in a palliative care service in Italy: a retrospective analysis. Int J Palliat Nurs, 2013;19(3):110-115. doi:10.12968/ijpn.2013.19.3.110.
Ornelas J, Dichter JR, Devereaux AV, Kissoon N, Livinski A, Christian MD. Methodology: care of the critically ill and injured during pandemics and disasters: CHEST consensus statement. Chest, 2014 Oct;146(4 Suppl):35S-41S. doi: 10.1378/chest.14-0746.
Nates JL, Nunnally M, Kleinpell R, Blosser S, Goldner J, Birriel B, Fowler CS, Byrum D, Miles WS, Bailey H, Sprung CL. ICU Admission, Discharge, and Triage Guidelines: A Framework to Enhance Clinical Operations, Development of Institutional Policies, and Further Research. Crit Care Med, 2016 Aug;44(8):1553-602. doi: 10.1097/CCM.0000000000001856.
Timbie JW, Ringel JS, Fox DS, Pillemer F, Waxman DA, Moore M, Hansen CK, Knebel AR, Ricciardi R, Kellermann AL. Systematic review of strategies to manage and allocate scarce resources during mass casualty events. Ann Emerg Med, 2013 Jun;61(6):677-689.e101. doi: 10.1016/j.annemergmed.2013.02.005.
Afessa B, Gajic O, Keegan MT, Seferian EG, Hubmayr RD, Peters SG. Impact of introducing multiple evidence-based clinical practice protocols in a medical intensive care unit: a retrospective cohort study. BMC Emerg Med, 2007 Aug 8;7:10.
Centers for Disease Control and Prevention. Pandemic Influenza Triage Tools: User Guide. Available from: https://www.cdc.gov/cpr/healthcare/pan-flu-app/files/PITA-UserGuide.pdf. Accessed May 11, 2020.
Lim W. Pandemic flu: clinical management of patients with an influenza-like illness during an influenza pandemic. Thorax, 2007;62(Suppl.1):1–46.
Rowan KM, Harrison DA, Walsh TS, McAuley DF, Perkins GD, Taylor BL, Menon DK. The Swine Flu Triage (SwiFT) study: development and ongoing refinement of a triage tool to provide regular information to guide immediate policy and practice for the use of critical care services during the H1N1 swine influenza pandemic. Health Technol Assess, 2010 Dec;14(55):335-492. doi: 10.3310/hta14550-05.
Khan Z, Hulme J and Sherwood N. An assessment of the validity of SOFA score based triage in H1N1 critically ill patients during an influenza pandemic. Anaesthesia, 2009; 64:1283–1288 doi:10.1111/j.1365-2044.2009.06135.x.
Vincent JL, Moreno R, Takala J, et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. On behalf of the Working Group on Sepsis-Related Problems of the European Society of Intensive Care Medicine. Intensive Care Med, 1996;22(7):707-710. doi:10.1007/BF01709751.
Domínguez-Cherit G, Lapinsky SE, Macias AE, Pinto R, Espinosa-Perez L, de la Torre A, Poblano-Morales M, Baltazar-Torres JA, Bautista E, Martinez A, Martinez MA, Rivero E, Valdez R, Ruiz-Palacios G, Hernández M, Stewart TE, Fowler RA. Critically Ill patients with 2009 influenza A(H1N1) in Mexico. JAMA, 2009 Nov 4;302(17):1880-7. doi: 10.1001/jama.2009.1536.
Zou X, Li S, Fang M, Hu M, Bian Y, Ling J, Yu S, Jing L, Li D, Huang J. Acute Physiology and Chronic Health Evaluation II Score as a Predictor of Hospital Mortality in Patients of Coronavirus Disease 2019. Crit Care Med, 2020 May 1. doi: 10.1097/CCM.0000000000004411.
Le Gall JR, Lemeshow S, Saulnier F. A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study. JAMA, 1993;270(24):2957-63.
Kądziołka I, Świstek R, Borowska K, Tyszecki P, Serednicki W. Validation of APACHE II and SAPS II scales at the intensive care unit along with assessment of SOFA scale at the admission as an isolated risk of death predictor. Anaesthesiol Intensive Ther, 2019;51(2):107-111. doi: 10.5114/ait.2019.86275.
Zhang X, Liu B, Liu Y, Ma L, Zeng H. Efficacy of the quick sequential organ failure assessment for predicting clinical outcomes among community-acquired pneumonia patients presenting in the emergency department.BMC Infect Dis, 2020 Apr 29;20(1):316. doi: 10.1186/s12879-020-05044-0.
Department of Health. Pandemic influenza: surge capacity and prioritisation in health services. London: Department of Health; 2008.
Leteurtre S, Duhamel A, Grandbastien B, et al. Paediatric logistic organ dysfunction (PELOD) score. Lancet, 2006; 367:897.
Pollack MM, Patel KM, Ruttimann UE: The Pediatric Risk of Mortality III–Acute Physiology Score (PRISM III-APS): A method of assessing physiologic instability for pediatric intensive care unit patients. J Pediatr, 1997; 131:575–581.
Duncan H, Hutchison J, Parshuram CS: The Pediatric Early Warning System score: A severity of illness score to predict urgent medical need in hospitalized children. J Crit Care, 2006;21:271–278.
Slater A, Shann F, Pearson G, et al: PIM2: A revised version of the Paediatric Index of Mortality. Intensive Care Med 2003; 29: 278–285.
Christian MD, Toltzis P, Kanter RK, Burkle FM Jr, Vernon DD, Kissoon N, & Task Force for Pediatric Emergency Mass Critical Care. Treatment and triage recommendations for pediatric emergency mass critical care. Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies, 12(6 Suppl), S109–S119. https://doi.org/10.1097/PCC.0b013e318234a656.
Biddison LD, Berkowitz KA, Courtney B, De Jong CMJ, Devereaux AV, Kissoon N, ... & Powell T. (2014). Ethical considerations: care of the critically ill and injured during pandemics and disasters: CHEST consensus statement. Chest, 146(4), e145S-e155S.
Shahpori R, Stelfox HT, Doig CJ, et al: Sequential organ failure assessment in H1N1 pandemic planning. Crit Care Med, 2011; 39:827–832 91.
Papadimos TJ, Marcolini EG, Hadian M, Hardart GE, Ward N, Levy MM, Stawicki SP, Davidson JE. Ethics of Outbreaks Position Statement. Part 1: Therapies, Treatment Limitations, and Duty to Treat. Crit Care Med, 2018 Nov;46(11):1842-1855. doi: 10.1097/CCM.0000000000003416.
Eitel DR, Travers DA, Rosenau AM, Gilboy N, Wuerz RC. The emergency severity index triage algorithm version 2 is reliable and valid. Acad Emerg Med,. 2003;10(10):1070-1080. doi:10.1111/j.1553-2712.2003.tb00577.x.
Bostick NA, Subbarao I, Burkle Jr FM, Hsu EB, Armstrong JH, & James JJ. Disaster triage systems for large-scale catastrophic events. Disaster Med Public Health Preparedness, 2008;2(Suppl 1), S35–S39.
Sprung CL, Danis M, Iapichino G, Artigas A, Kesecioglu J, Moreno R, Lippert L, Randall Curtis J, Meale P, Cohen SL, Levy MM, Truog RD. Triage of intensive care patients: identifying agreement and controversy. Intensive Care Med, 2013. DOI 10.1007/s00134-013-3033-6.
University of Pittsburgh. Allocation of Scarce Critical Care Resources During a Public Health Emergency. Executive Summary. April 15, 2020. Available from: https://ccm.pitt.edu/sites/default/files/UnivPittsburgh_ModelHospitalResourcePolicy_2020_04_15.pdf. Accessed June 04, 2020.
Devereaux AV, Dichter JR, Christian MD, Dubler NN, Sandrock CE, Hick JL, et al. Task Force for Mass Critical Care. 2008. "Definitive Care for the Critically Ill during a Disaster: A Framework for Allocation of Scarce Resources in Mass Critical Care From a Task Force for Mass Critical Care Summit Meeting, January 26-27, 2007, Chicago, IL." Chest, 133(5): 51-66S.
Iowa Department of Public Health. An Ethical Framework for Use in a Pandemic (2007), Available from: http://publications.iowa.gov/17889/1/panflu_ehtical_guidelines_manual.pdf, Accessed June 3, 2020.
Persad G, Wertheimer A, Emanuel EJ. Principles for allocation of scarce medical interventions. Lancet, 2009;373:423-31
Emanuel EJ, Persad G, Upshur R, et al. Fair Allocation of Scarce Medical Resources in the Time of Covid-19. N Engl J Med, 2020;382(21):2049‐2055. doi:10.1056/NEJMsb2005114.
Hick JL, Hanfling D, Wynia MK, Pavia AT. Duty to plan: health care, crisis standards of care, and novel coronavirus SARS-CoV-2. NAM Perspectives. Available from: https://nam.edu/duty-to-plan-health-care-crisis-standards-of-care-and-novel-coronavirus-sars-cov-2/. Accessed March 5, 2020
Neuberger J, Adams D, MacMaster P, Maidment A, Speed M. Assessing priorities for allocation of donor liver grafts: survey of public and clinicians. BMJ 1998;317(7152):172–5.
Louisiana Department of Health & Hospitals ESF-8 Health & Medical Section State Hospital Crisis Standard of Care Guidelines in Disasters. Version 1.2 September, 2011. Available from: https://cdn.ymaws.com/www.lhaonline.org/resource/resmgr/imported/Louisiana%20CSOC%20Guidelines%20in%20Disasters.pdf. Accessed 03 June, 2020.
Guidelines for Ethical Allocation of Scarce Medical Resources and Services During Public Health Emergencies in Michigan - State Of Michigan Department of Community Health Office of Public Health Preparedness, Version 2.0, 2008.
Smith M, & Upshur R. Pandemic Disease, Public Health, and Ethics. In The Oxford Handbook of Public Health Ethics, eds Mastroianni, 2019, AC, Kahn JP, and Kass NE. DOI: 10.1093/oxfordhb/9780190245191.013.69.
Comitato Nazionale di Bioetica (CNB). (2020). COVID-19: La Decisione Clinica In Condizioni Di Carenza Di Risorse E Il Criterio Del “Triage In Emergenza Pandemica”. Available at: http://bioetica.governo.it/media/3997/p136_2020_covid-19-la-decisione-clinica-in-condizioni-di-carenza-di-risorse-e-il-criterio-del-triage-in-emergenza-pandemica.pdf. Accessed July, 05, 2020
SICP, SIAARTI, FCP. (2020). Le Cure Palliative nel trattamento dei malati COVID-19/SARS- CoV-2. Milano. Available at: https://www.fedcp.org/news/fcp-siaarti-e-sicp-le-cure-palliative-nel-trattamento-dei-malati-covid-19-sars-cov-2. Accessed July, 05, 2020.
Koonin LM, Pillai S, Kahn EB, Moulia D, Patel A. Strategies to Inform Allocation of Stockpiled Ventilators to Healthcare Facilities During a Pandemic. Health Secur, 2020;18(2):69-74. doi:10.1089/hs.2020.0028.
Kain T and Fowler R. Preparing intensive care for the next pandemic influenza. Critical Care, 2019;23:337 https://doi.org/10.1186/s13054-019-2616-1.
Ventilator Allocation Guidelines - New York State Task Force on Life and the Law New York State Department of Health, November, 2015.
Rosenbaum SJ. Ethical Considerations for Decision Making Regarding Allocation of Mechanical Ventilators during a Severe Influenza Pandemic or Other Public Health Emergency. Centers for Disease Control and Prevention, Office of the Associate Director for Science (SOAS) Ethics Subcommittee. Available from: https://www.cdc.gov/os/integrity/phethics/ESdocuments.htm#considerations. Accessed July 01, 2020.
Levin D, Cadigan RO, Biddinger PD, Condon S, Koh HK; Joint Massachusetts Department of Public Health-Harvard Altered Standards of Care Working Group. Altered standards of care during an influenza pandemic: identifying ethical, legal, and practical principles to guide decision making. Disaster Med Public Health Prep, 2009;3 Suppl 2:S132-S140. doi:10.1097/DMP.0b013e3181ac3dd2
Leider JP, DeBruin D, Reynolds N, Koch A, Seaberg J. Ethical Guidance for Disaster Response, Specifically Around Crisis Standards of Care: A Systematic Review. Am J Public Health, 2017;107(9):e1-e9. doi:10.2105/AJPH.2017.303882.
Wagner JM, Dahnke MD. Nursing ethics and disaster triage: applying utilitarian ethical theory. J EmergNurs. 2015;41(4):300–306.
Federazione Nazionale Ordini delle Professioni Infermieristiche. Codice Deontologico delle Professioni Infermieristiche 2019 Il testo approvato dal Consiglio Nazionale. Available from: https://www.fnopi.it/archivio_news/attualita/2629/Il%20testo%20definitivo%20Codice%20Deontologico%20degli%20Ordini%20delle%20%20Professioni%20Infermieristiche%202019.pdf. Accessed August 03, 2020.
Pena ME., Irvin CB, Tafcla RB. Ethical Considerations for Emergency Care Providers during Pandemic Influenza - Ready or Not.... Prehospital and Disaster Medicine, 2009;24(2):115-119.
World Health Organization. (2008). Addressing ethical issues in pandemic influenza planning: Discussion papers. Geneva: World Health Organization Available from: https://apps.who.int/iris/bitstream/handle/10665/69902/WHO_IER_ETH_2008.1_eng.pdf;jsessionid=B015FB7F0B9E95AF3DA6EE1473617372?sequence=1. Accessed August 03, 2020.
Downloads
Published
Issue
Section
License
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Transfer of Copyright and Permission to Reproduce Parts of Published Papers.
Authors retain the copyright for their published work. No formal permission will be required to reproduce parts (tables or illustrations) of published papers, provided the source is quoted appropriately and reproduction has no commercial intent. Reproductions with commercial intent will require written permission and payment of royalties.