Evaluating processes of care and outcomes of children in hospital (EPOCH): study protocol for a randomized controlled trial

Christopher S Parshuram, Karen Dryden-Palmer, Catherine Farrell, Ronald Gottesman, Martin Gray, James S Hutchison, Mark Helfaer, Elizabeth Hunt, Ari Joffe, Jacques Lacroix, Vinay Nadkarni, Patricia Parkin, David Wensley, Andrew R Willan, Canadian Critical Care Trials Group, Christopher S Parshuram, Karen Dryden-Palmer, Catherine Farrell, Ronald Gottesman, Martin Gray, James S Hutchison, Mark Helfaer, Elizabeth Hunt, Ari Joffe, Jacques Lacroix, Vinay Nadkarni, Patricia Parkin, David Wensley, Andrew R Willan, Canadian Critical Care Trials Group

Abstract

Background: The prevention of near and actual cardiopulmonary arrest in hospitalized children is a patient safety imperative. Prevention is contingent upon the timely identification, referral and treatment of children who are deteriorating clinically. We designed and validated a documentation-based system of care to permit identification and referral as well as facilitate provision of timely treatment. We called it the Bedside Paediatric Early Warning System (BedsidePEWS). Here we describe the rationale for the design, intervention and outcomes of the study entitled Evaluating Processes and Outcomes of Children in Hospital (EPOCH).

Methods/design: EPOCH is a cluster-randomized trial of the BedsidePEWS. The unit of randomization is the participating hospital. Eligible hospitals have a Pediatric Intensive Care Unit (PICU), are anticipated to have organizational stability throughout the study, are not using a severity of illness score in hospital wards and are willing to be randomized. Patients are >37 weeks gestational age and <18 years and are hospitalized in inpatient ward areas during all or part of their hospital admission. Randomization is to either BedsidePEWS or control (no severity of illness score) in a 1:1 ratio within two strata (<200, ≥ 200 hospital beds). All-cause hospital mortality is the selected primary outcome. It is objective, independent of do-not-resuscitate status and can be reliably measured. The secondary outcomes include (1) clinical outcomes: clinical deterioration, severity of illness at and during ICU admission, and potentially preventable cardiac arrest; (2) processes of care outcomes: immediate calls for assistance, hospital and ICU readmission, and perceptions of healthcare professionals; and (3) resource utilization: ICU days and use of ICU therapies.

Discussion: Following funding by the Canadian Institutes of Health Research and local ethical approvals, site enrollment started in 2010 and was closed in February 2014. Patient enrollment is anticipated to be complete in July 2015. The results of EPOCH will strengthen the scientific basis for local, regional, provincial and national decision-making and for the recommendations of national and international bodies. If negative, the costs of hospital-wide implementation can be avoided. If positive, EPOCH will have provided a scientific justification for the major system-level changes required for implementation.

Trial registration: NCT01260831 ClinicalTrials.gov date: 14 December 2010.

References

    1. 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;21:271–8. doi: 10.1016/j.jcrc.2006.06.007.
    1. Suominen P, Olkkola KT, Voipio V, Korpela R, Palo R, Rasanen J. Utstein style reporting of in-hospital paediatric cardiopulmonary resuscitation. Resuscitation. 2000;45:17–25. doi: 10.1016/S0300-9572(00)00167-2.
    1. Reis AG, Nadkarni V, Perondi MB, Grisi S, Berg RA. A prospective investigation into the epidemiology of in- hospital pediatric cardiopulmonary resuscitation using the international Utstein reporting style. Pediatrics. 2002;109:200–9. doi: 10.1542/peds.109.2.200.
    1. Tibballs J, Kinney S. A prospective study of outcome of in-patient paediatric cardiopulmonary arrest. Resuscitation. 2006;71:310–8. doi: 10.1016/j.resuscitation.2006.05.009.
    1. Gillis J, Dickson D, Rieder M, Steward D, Edmonds J. Results of inpatient pediatric resuscitation. Crit Care Med. 1986;14:469–71. doi: 10.1097/00003246-198605000-00007.
    1. Nadkarni VM, Larkin GL, Peberdy MA, Carey SM, Kaye W, Mancini ME, et al. First documented rhythm and clinical outcome from in-hospital cardiac arrest among children and adults. JAMA. 2006;295:50–7. doi: 10.1001/jama.295.1.50.
    1. Meert KL, Donaldson A, Nadkarni V, Tieves KS, Schleien CL, Brilli RJ, et al. Multicenter cohort study of in-hospital pediatric cardiac arrest. Pediatr Crit Care Med. 2009;10(5):544–53. doi: 10.1097/PCC.0b013e3181a7045c.
    1. Doherty DR, Parshuram CS, Gaboury I, Hoskote A, Lacroix J, Tucci M, et al. Hypothermia therapy after pediatric cardiac arrest. Circulation. 2009;119:1492–500. doi: 10.1161/CIRCULATIONAHA.108.791384.
    1. van Litsenburg R, de Mos N, Edgell D, Gruenwald C, Bohn DJ, Parshuram CS. Resource use and health outcomes of paediatric extracorporeal membrane oxygenation. Arch Dis Child Fetal Neonatal Ed. 2005;90:F176–F7. doi: 10.1136/adc.2003.047779.
    1. de Mos N, van Litsenburg RR, McCrindle B, Bohn DJ, Parshuram CS. Pediatric in-intensive-care-unit cardiac arrest: incidence, survival, and predictive factors. Crit Care Med. 2006;34:1209–15. doi: 10.1097/01.CCM.0000208440.66756.C2.
    1. Ebrahim S, Hutchison J, Parshuram C. Pediatric Academic Societies Annual Meeting. Baltimore, MD: Pediatric Academic Societies; 2009. Neurocognitive and quality of life outcomes following in-hospital resuscitation.
    1. Lacroix J, Hebert PC, Hutchison JS, Hume HA, Tucci M, Ducruet T, et al. Transfusion strategies for patients in pediatric intensive care units. N Engl J Med. 2007;356:1609–19. doi: 10.1056/NEJMoa066240.
    1. Hutchison JS, Ward RE, Lacroix J, Hebert PC, Barnes MA, Bohn DJ, et al. Hypothermia therapy after traumatic brain injury in children. N Engl J Med. 2008;358:2447–56. doi: 10.1056/NEJMoa0706930.
    1. Zaritsky A, Nadkarni V, Getson P, Kuehl K. CPR in children. Ann Emerg Med. 1987;16:1107–11. doi: 10.1016/S0196-0644(87)80465-1.
    1. Morris MC, Wernovsky G, Nadkarni VM. Survival outcomes after extracorporeal cardiopulmonary resuscitation instituted during active chest compressions following refractory in-hospital pediatric cardiac arrest. Pediatr Crit Care Med. 2004;5:440–6. doi: 10.1097/01.PCC.0000137356.58150.2E.
    1. Samson RA, Nadkarni VM, Meaney PA, Carey SM, Berg MD, Berg RA. Outcomes of in-hospital ventricular fibrillation in children. N Engl J Med. 2006;354:2328–39. doi: 10.1056/NEJMoa052917.
    1. Berg MD, Nadkarni VM, Berg RA. Cardiopulmonary resuscitation in children. Curr Opin Crit Care. 2008;14:254–60. doi: 10.1097/MCC.0b013e3282fa6fec.
    1. Moler FW, Meert K, Donaldson AE, Nadkarni V, Brilli RJ, Dalton HJ, et al. In-hospital versus out-of-hospital pediatric cardiac arrest: a multicenter cohort study. Crit Care Med. 2009;37:2259–67. doi: 10.1097/CCM.0b013e3181a00a6a.
    1. Nance ML, Nadkarni VM, Hedrick HL, Cullen JA, Wiebe DJ. Effect of preextracorporeal membrane oxygenation ventilation days and age on extracorporeal membrane oxygenation survival in critically ill children. J Pediatr Surg. 2009;44:1606–10. doi: 10.1016/j.jpedsurg.2008.10.048.
    1. Sutton RM, Niles D, Nysaether J, Abella BS, Arbogast KB, Nishisaki A, et al. Pediatrics: quantitative analysis of CPR quality during in-hospital resuscitation of older children and adolescents; 2009. Quantitative analysis of CPR quality during in-hospital resuscitation of older children and adolescents. Pediatrics. 2009;124(2):494–9. doi: 10.1542/peds.2008-1930.
    1. Topjian AA, Nadkarni VM, Berg RA. Cardiopulmonary resuscitation in children. Curr Opin Crit Care. 2009;15:203–8. doi: 10.1097/MCC.0b013e32832931e1.
    1. Perondi MB, Reis AG, Paiva EF, Nadkarni VM, Berg RA. A comparison of high-dose and standard-dose epinephrine in children with cardiac arrest. N Engl J Med. 2004;350:1722–30. doi: 10.1056/NEJMoa032440.
    1. Srinivasan V, Morris MC, Helfaer MA, Berg RA, Nadkarni VM. Calcium use during in-hospital pediatric cardiopulmonary resuscitation: a report from the National Registry of Cardiopulmonary Resuscitation. Pediatrics. 2008;121:e1144–51. doi: 10.1542/peds.2007-1555.
    1. Parshuram CS. Risk-adjusted intensive care unit outcomes and admission from our backyard*. Pediatr Crit Care Med. 2008;9:118–9. doi: 10.1097/01.PCC.0000298651.33662.2D.
    1. VandenBerg SD, Hutchison JS, Parshuram CS. A cross-sectional survey of levels of care and response mechanisms for evolving critical illness in hospitalized children. Pediatrics. 2007;119:e940–6. doi: 10.1542/peds.2006-0852.
    1. Chapman SM, Grocott MP, Franck LS. Systematic review of paediatric alert criteria for identifying hospitalised children at risk of critical deterioration. Intensive Care Med. 2009;36:600–11. doi: 10.1007/s00134-009-1715-x.
    1. Bellomo R, Goldsmith D, Uchino S, Buckmaster J, Hart GK, Opdam H, et al. A prospective before-and-after trial of a medical emergency team. Med J Aust. 2003;179:283–7.
    1. Buist MD, Moore GE, Bernard SA, Waxman BP, Anderson JN, Nguyen TV. Effects of a medical emergency team on reduction of incidence of and mortality from unexpected cardiac arrests in hospital: preliminary study. BMJ. 2002;324:387–90. doi: 10.1136/bmj.324.7334.387.
    1. DeVita MA, Braithwaite RS, Mahidhara R, Stuart S, Foraida M, Simmons RL. Use of medical emergency team responses to reduce hospital cardiopulmonary arrests. Qual Saf Health Care. 2004;13:251–4. doi: 10.1136/qshc.2003.006585.
    1. Daly FF, Sidney KL, Fatovich DM. The Medical Emergency Team (MET): a model for the district general hospital. Aust N Z J Med. 1998;28:795–8. doi: 10.1111/j.1445-5994.1998.tb01556.x.
    1. Bristow PJ, Hillman KM, Chey T, Daffurn K, Jacques TC, Norman SL, et al. Rates of in-hospital arrests, deaths and intensive care admissions: the effect of a medical emergency team. Med J Aust. 2000;173:236–40.
    1. Salamonson Y, Kariyawasam A, van Heere B, O’Connor C. The evolutionary process of Medical Emergency Team (MET) implementation: reduction in unanticipated ICU transfers. Resuscitation. 2001;49:135–41. doi: 10.1016/S0300-9572(00)00353-1.
    1. Parr MJ, Hadfield JH, Flabouris A, Bishop G, Hillman K. The Medical Emergency Team: 12 month analysis of reasons for activation, immediate outcome and not-for-resuscitation orders. Resuscitation. 2001;50:39–44. doi: 10.1016/S0300-9572(01)00323-9.
    1. Hillman K, Chen J, Cretikos M, Bellomo R, Brown D, Doig G, et al. Introduction of the medical emergency team (MET) system: a cluster-randomised controlled trial. Lancet. 2005;365:2091–7. doi: 10.1016/S0140-6736(05)66733-5.
    1. Brilli RJ, Gibson R, Luria JW, Wheeler TA, Shaw J, Linam M, et al. Implementation of a medical emergency team in a large pediatric teaching hospital prevents respiratory and cardiopulmonary arrests outside the intensive care unit. Pediatr Crit Care Med. 2007;8:236–46. doi: 10.1097/01.PCC.0000262947.72442.EA.
    1. Sharek PJ, Parast LM, Leong K, Coombs J, Earnest K, Sullivan J, et al. Effect of a rapid response team on hospital-wide mortality and code rates outside the ICU in a Children’s Hospital. JAMA. 2007;298:2267–74. doi: 10.1001/jama.298.19.2267.
    1. Hunt EA, Zimmer KP, Rinke ML, Shilkofski NA, Matlin C, Garger C, et al. Transition from a traditional code team to a medical emergency team and categorization of cardiopulmonary arrests in a children’s center. Arch Pediatr Adolesc Med. 2008;162:117–22. doi: 10.1001/archpediatrics.2007.33.
    1. Tibballs J, Kinney S. Reduction of hospital mortality and of preventable cardiac arrest and death on introduction of a pediatric medical emergency team. Pediatr Crit Care Med. 2009;10:306–12. doi: 10.1097/PCC.0b013e318198b02c.
    1. Zenker P, Schlesinger A, Hauck M, Spencer S, Hellmich T, Finkelstein M, et al. Implementation and impact of a rapid response team in a children’s hospital. Jt Comm J Qual Patient Saf. 2007;33:418–25.
    1. Kotsakis A, Lobos AT, Parshuram C, Gilleland J, Gaiteiro R, Mohseni-Bod H, et al. Implementation of a multicenter rapid response system in pediatric academic hospitals is effective. Pediatrics. 2011;128:72–8. doi: 10.1542/peds.2010-0756.
    1. Chan PS, Jain R, Nallmothu BK, Berg RA, Sasson C. Rapid response teams: a systematic review and meta-analysis. Arch Intern Med. 2010;170:18–26. doi: 10.1001/archinternmed.2009.424.
    1. Feudtner C, Hays RM, Haynes G, Geyer JR, Neff JM, Koepsell TD. Deaths attributed to pediatric complex chronic conditions: national trends and implications for supportive care services. Pediatrics. 2001;107 doi: 10.1542/peds.107.6.e99.
    1. Joffe AR, Anton NR, Burkholder SC. Reduction in hospital mortality over time in a hospital without a pediatric medical emergency team: limitations of before-and-after study designs. Arch Pediatr Adolesc Med. 2011;165:419–23.
    1. Monaghan A. Detecting and managing deterioration in children. Paediatr Nurs. 2005;17:32–5. doi: 10.7748/paed2005.02.17.1.32.c964.
    1. Edwards ED, Powell CV, Mason BW, Oliver A. Prospective cohort study to test the predictability of the Cardiff and Vale paediatric early warning system. Arch Dis Child. 2009;94:602–6. doi: 10.1136/adc.2008.142026.
    1. Haines C, Perrott M, Weir P. Promoting care for acutely ill children-development and evaluation of a paediatric early warning tool. Intensive Crit Care Nurs. 2006;22:73–81. doi: 10.1016/j.iccn.2005.09.003.
    1. Tibballs J, Kinney S, Duke T, Oakley E, Hennessy M. Reduction of paediatric in-patient cardiac arrest and death with a medical emergency team: preliminary results. Arch Dis Child. 2005;90:1148–52. doi: 10.1136/adc.2004.069401.
    1. Parshuram CS, Hutchison J, Middaugh K. Development and initial validation of the Bedside Paediatric Early Warning System score. Crit Care. 2009;13:R135. doi: 10.1186/cc7998.
    1. Tucker KM, Brewer TL, Baker RB, Demeritt B, Vossmeyer MT. Prospective evaluation of a pediatric inpatient early warning scoring system. J Spec Pediatr Nurs. 2009;14:79–85. doi: 10.1111/j.1744-6155.2008.00178.x.
    1. Edwards ED, Mason BW, Oliver A, Powell CV. Cohort study to test the predictability of the Melbourne criteria for activation of the medical emergency team. Arch Dis Child. 2011;96:174–9. doi: 10.1136/adc.2010.187617.
    1. Parshuram CS, Duncan HP, Joffe AR, Farrell CA, Lacroix JR, Middaugh KL, et al. Multicentre validation of the bedside paediatric early warning system score: a severity of illness score to detect evolving critical illness in hospitalised children. Crit Care. 2011;15:R184. doi: 10.1186/cc10337.
    1. Parshuram CS, Bayliss A, Reimer J, Middaugh K, Blanchard N. Implementing the Bedside Paediatric Early Warning System in a community hospital: a prospective observational study. Paediatr Child Health. 2011;16:e18–22.
    1. Brennan TA, Leape LL. Adverse events, negligence in hospitalized patients: results from the Harvard Medical Practice Study. Perspect Healthc Risk Manage. 1991;11:2–8. doi: 10.1002/jhrm.5600110202.
    1. Thomas EJ, Studdert DM, Burstin HR, Orav EJ, Zeena T, Williams EJ, et al. Incidence and types of adverse events and negligent care in Utah and Colorado. Med Care. 2000;38:261–71. doi: 10.1097/00005650-200003000-00003.
    1. Baker GR, Norton PG, Flintoft V, Blais R, Brown A, Cox J, et al. The Canadian Adverse Events Study: the incidence of adverse events among hospital patients in Canada. CMAJ. 2004;170:1678–86. doi: 10.1503/cmaj.1040498.
    1. Wilson RM, Runciman WB, Gibberd RW, Harrison BT, Newby L, Hamilton JD. The Quality in Australian Health Care Study. Med J Aust. 1995;163:458–71.
    1. Davis P, Lay-Yee R, Briant R, Ali W, Scott A, Schug S. Adverse events in New Zealand public hospitals I: occurrence and impact. N Z Med J. 2002;115:U271.
    1. Slater A, Shann F, Pearson G. PIM2: a revised version of the Paediatric Index of Mortality. Intensive Care Med. 2003;29:278–85.
    1. Slater A. Monitoring outcome in paediatric intensive care. Paediatr Anaesth. 2004;14:113–6. doi: 10.1111/j.1460-9592.2004.01148.x.
    1. Leteurtre S, Duhamel A, Grandbastien B, Lacroix J, Leclerc F. Paediatric logistic organ dysfunction (PELOD) score. Lancet. 2006;367:897. doi: 10.1016/S0140-6736(06)68371-2.
    1. Hayes RJ, Bennett S. Simple sample size calculation for cluster-randomized trials. Int J Epidemiol. 1999;28:319–26. doi: 10.1093/ije/28.2.319.
    1. Campbell MK, Elbourne DR, Altman DG. CONSORT statement: extension to cluster randomised trials. BMJ. 2004;328:702–8. doi: 10.1136/bmj.328.7441.702.
    1. Ruttimann UE, Patel KM, Pollack MM. Length of stay and efficiency in pediatric intensive care units. J Pediatr. 1998;133:79–85. doi: 10.1016/S0022-3476(98)70182-9.
    1. 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;131:575–81. doi: 10.1016/S0022-3476(97)70065-9.
    1. Slater A, Shann F. The suitability of the Pediatric Index of Mortality (PIM), PIM2, the Pediatric Risk of Mortality (PRISM), and PRISM III for monitoring the quality of pediatric intensive care in Australia and New Zealand. Pediatr Crit Care Med. 2004;5:447–54. doi: 10.1097/01.PCC.0000138557.31831.65.
    1. Pearson GA, Stickley J, Shann F. Calibration of the paediatric index of mortality in UK paediatric intensive care units. Arch Dis Child. 2001;84:125–8. doi: 10.1136/adc.84.2.125.
    1. Aylin P, Bottle A, Elliott P, Jarman B. Surgical mortality: Hospital episode statistics v central cardiac audit database. BMJ. 2007;335:839. doi: 10.1136/.
    1. Jarman B, Gault S, Alves B, Hider A, Dolan S, Cook A, et al. Explaining differences in English hospital death rates using routinely collected data. BMJ. 1999;318:1515–20. doi: 10.1136/bmj.318.7197.1515.
    1. Canadian Institute for Health Information . HSMR: a New approach for measuring hospital mortality trends in Canada. Ottawa: Canadian Institute for Health Information; 2007.
    1. Postovsky S, Levenzon A, Ofir R, Ben Arush MW. “Do not resuscitate” orders among children with solid tumors at the end of life. Pediatr Hematol Oncol. 2004;21:661–8. doi: 10.1080/08880010490501088.
    1. Yun YH, Lim MK, Choi KS, Rhee YS. Predictors associated with the place of death in a country with increasing hospital deaths. Palliat Med. 2006;20:455–61. doi: 10.1191/0269216306pm1129oa.
    1. Higginson IJ, Thompson M. Children and young people who die from cancer: epidemiology and place of death in England (1995-9) BMJ. 2003;327:478–9. doi: 10.1136/bmj.327.7413.478.
    1. Feudtner C, Hexem KR, Shabbout M, Feinstein JA, Sochalski J, Silber JH. Prediction of pediatric death in the year after hospitalization: a population-level retrospective cohort study. J Palliat Med. 2009;12:160–9. doi: 10.1089/jpm.2008.0206.
    1. Hays RM, Valentine J, Haynes G, Geyer JR, Villareale N, McKinstry B, et al. The Seattle Pediatric Palliative Care Project: effects on family satisfaction and health-related quality of life. J Palliat Med. 2006;9:716–28. doi: 10.1089/jpm.2006.9.716.
    1. Feudtner C, Feinstein JA, Satchell M, Zhao H, Kang TI. Shifting place of death among children with complex chronic conditions in the United States, 1989-2003. JAMA. 2007;297:2725–32. doi: 10.1001/jama.297.24.2725.
    1. Vickers J, Thompson A, Collins GS, Childs M, Hain R. Place and provision of palliative care for children with progressive cancer: a study by the Paediatric Oncology Nurses’ Forum/United Kingdom Children’s Cancer Study Group Palliative Care Working Group. J Clin Oncol. 2007;25:4472–6. doi: 10.1200/JCO.2007.12.0493.
    1. Gries CJ, Curtis JR, Wall RJ, Engelberg RA. Family member satisfaction with end-of-life decision making in the ICU. Chest. 2008;133:704–12. doi: 10.1378/chest.07-1773.
    1. Jarman B, Bottle A, Aylin P, Browne M. Monitoring changes in hospital standardised mortality ratios. BMJ. 2005;330:329. doi: 10.1136/bmj.330.7487.329.
    1. Aylin P, Bottle A, Jarman B, Elliott P. Paediatric cardiac surgical mortality in England after Bristol: descriptive analysis of hospital episode statistics 1991-2002. BMJ. 2004;329:825. doi: 10.1136/bmj.329.7470.825.
    1. Jarman B, Aylin P, Bottle A. Trends in admissions and deaths in English NHS hospitals. BMJ. 2004;328:855. doi: 10.1136/bmj.328.7444.855.
    1. Chen J, Flabouris A, Bellomo R, Hillman K, Finfer S. The Medical Emergency Team System and not-for-resuscitation orders: results from the MERIT study. Resuscitation. 2008;79:391–7. doi: 10.1016/j.resuscitation.2008.07.021.
    1. Berg MD, Nadkarni VM, Zuercher M, Berg RA. In-hospital pediatric cardiac arrest. Pediatr Clin North Am. 2008;55:589–604. doi: 10.1016/j.pcl.2008.02.005.
    1. Garros D, Rosychuk RJ, Cox PN. Circumstances surrounding end of life in a pediatric intensive care unit. Pediatrics. 2003;112 doi: 10.1542/peds.112.5.e371.
    1. Pierucci RL, Kirby RS, Leuthner SR. End-of-life care for neonates and infants: the experience and effects of a palliative care consultation service. Pediatrics. 2001;108:653–60. doi: 10.1542/peds.108.3.653.
    1. Devictor D, Latour JM, Tissieres P. Forgoing life-sustaining or death-prolonging therapy in the pediatric ICU. Pediatr Clin North Am. 2008;55:791–804. doi: 10.1016/j.pcl.2008.02.008.
    1. Truog RD. Is it always wrong to perform futile CPR? N Engl J Med. 2010;362:477–9. doi: 10.1056/NEJMp0908464.
    1. Your Guide to the International Liaison Committee on Resuscitation (ILCOR). 2009. (Accessed March 28 2015, at ).
    1. Soar J, Deakin CD, Nolan JP, Abbas G, Alfonzo A, Handley AJ, et al. European Resuscitation Council guidelines for resuscitation 2005. Section 7. Cardiac arrest in special circumstances. Resuscitation. 2005;67 Suppl 1:S135–70. doi: 10.1016/j.resuscitation.2005.10.004.

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