Out-of-hospital cardiac arrest in Finland

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DISSERTATIONS | PAMELA HILTUNEN | OUT-OF-HOSPITAL CARDIAC ARREST IN FINLAND | No 343

uef.fi

PUBLICATIONS OF

THE UNIVERSITY OF EASTERN FINLAND Dissertations in Health Sciences

ISBN 978-952-61-2078-2 ISSN 1798-5706

Dissertations in Health Sciences

PUBLICATIONS OF

THE UNIVERSITY OF EASTERN FINLAND

PAMELA HILTUNEN

OUT-OF-HOSPITAL CARDIAC ARREST IN FINLAND

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Out-of-hospital Cardiac Arrest in Finland

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PAMELA HILTUNEN

Out-of-hospital Cardiac Arrest in Finland

To be presented by permission of Health Sciences, University of Eastern Finland for public examination in Kuopio University Hospital, Kuopio, on Friday, April 29^th 2016, at 12 noon

Publications of the University of Eastern Finland Dissertations in Health Sciences

Number 343

Centre for Prehospital Care, Institute of Clinical Medicine, Faculty of Health Sciences, Kuopio University Hospital,

Kuopio, 2016

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Grano Oy Jyväskylä, 2016

Series Editors:

Professor Veli Matti Kosma, M.D., Ph.D.

Institute of Clinical Medicine, Pathology Faculty of Health Sciences Professor Hannele Turunen, Ph.D.

Department of Nursing Science Faculty of Health Sciences Associate Professor Tarja Malm, Ph.D.

A.I. Virtanen Institute for Molecular Sciences Faculty of Health Sciences

Professor Kai Kaarniranta, M.D., Ph.D.

Institute of Clinical Medicine, Ophtalmology Faculty of Health Sciences

Lecturer Veli-Pekka Ranta, Ph.D.

School of Pharmacy Faculty of Health Sciences

Distributor:

University of Eastern Finland Kuopio Campus Library

P.O.Box 1627 FI-70211 Kuopio, Finland http://www.uef.fi/kirjasto ISBN (print): 978-952-61-2078-2

ISBN (pdf): 978-952-61-2079-9 ISSN (print): 1798-5706

ISSN (pdf): 1798-5714 ISSN-L: 1798-5706

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Author’s address: Centre for Prehospital Care, Institute of Clinical Medicine Kuopio University Hospital

P.O.Box 100 FIN-70029 KYS FINLAND

Supervisors: Docent Jouni Kurola, M.D., Ph.D.

Kuopio University Hospital KUOPIO

FINLAND

Helena Jäntti, M.D., Ph.D.

Kuopio University Hospital KUOPIO

FINLAND

Docent Tom Silfvast, M.D., Ph.D Helsinki University Hospital HELSINKI

FINLAND

Reviewers: Docent Jouni Nurmi, M.D., Ph.D.

Helsinki University Hospital HELSINKI

FINLAND

Docent Olli Anttonen, M.D., Ph.D.

Päijät-Häme Central Hospital LAHTI

FINLAND

Opponent: Professor Klaus Olkkola, M.D., Ph.D.

University of Helsinki HELSINKI

FINLAND

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Hiltunen, Pamela

Out-of-hospital Cardiac Arrest in Finland

University of Eastern Finland, Faculty of Health Sciences

Publications of the University of Eastern Finland. Dissertations in Health Sciences Number 343.

2016. 160 p.

ISBN (print):978-952-61-2078-2 ISBN (pdf): 978-952-61-2079-9 ISSN (print): 1798-5706 ISSN (pdf): 1798-5714 ISSN-L: 1798-5706 ABSTRACT

Out-of-hospital cardiac arrest (OHCA) remains a major health challenge worldwide.

Despite the development of medicine and prehospital care during the last decades, only a modest increase in survival has been reported, and overall survival has remained low.

After cardiac arrest, there are only a few minutes for effective resuscitation. Optimisation of survival is ideally achieved by strengthening all links in the “chain of survival”: 1) early recognition of cardiac arrest, 2) early cardiopulmonary resuscitation, 3) early defibrillation and 4) post-resuscitation care.

The aim of this prospective cohort study was to describe the epidemiology and outcomes of OHCA and study the elements of the “chain of survival” in Finland. The study area included southern and eastern Finland. For six months, data from all cases dispatched as cardiac arrests in the Emergency Medical Dispatch Centre inside the study area were collected to a combined database. Additionally, Emergency Medical Services (EMS) personnel documented all cardiac arrests according the Utstein template, and this information was linked to the database. Moreover, data for patients successfully resuscitated prehospitally and admitted to the intensive care unit (ICU) were collected for 12 months. This information also included the use of therapeutic hypothermia (TH) and involved nearly every ICU in Finland.

This study found an incidence of EMS-attempted resuscitation of 51/100,000 inhabitants/year. The emergency medical dispatchers recognised 80.3% of cardiac arrests as the reason for the emergency call. One-third had a primary shockable rhythm, and more than half of the patients had a cardiac arrest of presumed cardiac origin. Nearly half of the patients received bystander cardiopulmonary resuscitation (CPR) before EMS arrival. Overall survival at one year was 13.4%, with 32.7% survival for patients resuscitated from shockable rhythms and 4.6% for patients resuscitated from non- shockable rhythms. A primary shockable rhythm, short delays from collapse to initiation of CPR and to EMS arrival on scene, the presence of an EMS physician during OHCA treatment and the use of TH for patients resuscitated from shockable rhythms were associated with improved survival. EMS personnel most commonly used endotracheal

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intubation as an airway technique. Endotracheal intubation was usually performed by an advanced life support (ALS) provider. Overall success rates of airway management for both basic level and ALS personnel were within acceptable levels. TH was widely implemented in intensive care units, and was also in use for patients with a non-shockable primary rhythm. Survival to hospital discharge among ICU-treated unconscious OHCA patients was 51.6% and was improved if TH was used for patients resuscitated from a shockable primary rhythm. TH was not associated with survival among patients with a non-shockable rhythm.

Overall survival from OHCA was similar to that reported earlier from Finland. Survival was improved, however, among patients resuscitated from bystander-witnessed cardiac arrest with a primary shockable rhythm of presumed cardiac origin. These survival rates are also commendable when compared to studies from other countries. The ability of Finnish dispatchers to recognise cardiac arrest was high. Bystander CPR should be increased. Current national recommendations concerning airway management in OHCA seem practical and lead to desirable results. TH was used widely in Finland and was also used for patients resuscitated from non-shockable primary rhythms.

National Library of Medicine Classification: WG 214, WG 205, WA 292, WF 145, WX 215, WA 900, W 84.7

Medical Subject Headings: Out-of-Hospital Cardiac Arrest; Airway Management; Cardiopulmonary Resuscitation; Emergency Medical Services; Intensive Care Units; Hypothermia, Induced; Incidence ; Survival Rate; Time-to-Treatment; Treatment Outcome ; Patient Outcome Assessment; Critical Pathways; Cohort Studies; Prospective Studies

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Hiltunen, Pamela

Out-of-hospital Cardiac Arrest in Finland Itä-Suomen yliopisto, terveystieteiden tiedekunta

Publications of the University of Eastern Finland. Dissertations in Health Sciences Nro.343. 160 s.

TIIVISTELMÄ

Sairaalan ulkopuolinen sydänpysähdys on merkittävä kansanterveydellinen ongelma.

Huolimatta lääketieteen ja ensihoidon kehittymisestä, kokonaisselviytyminen on matala, joskin pientä parantumista on vuosikymmenien saatossa havaittu. Kun sydänpysähdys tapahtuu, on aikaa vain muutama minuutti tehokkaille elvytystoimille. Niin sanottu

”chain of survival” – ketjun vahvistaminen optimoi potilaan selviytymisen. Nämä ketjun osat ovat: 1) sydänpysähdyksen varhainen tunnistaminen, 2) varhain aloitettu painelu- tai/ja painelu-puhalluselvytys, 3) varhainen defibrillaatio ja 4) elvytyksenjälkeinen hoito.

Tämän prospektiivisen kohorttitutkimuksen tarkoituksena oli kuvata sairaalan ulkopuolisen sydänpysähdyspotilaan epidemiologiaa ja hoitotuloksia sekä tarkastella

”chain of survival” ketjua ja sen osasten vaikutusta selviämiseen. Tutkimusalueena oli itäinen ja eteläinen Suomi. Tiedonkeruu kesti kuusi kuukautta, minkä aikana tutkimusalueen hätäkeskuksista kerättiin tietokantaan tiedot kaikista tehtävistä jotka koskivat sydänpysähdystä. Ensihoitohenkilöstö dokumentoi omalta osaltaan hoitamansa sydänpysähdyspotilaat ja nämä tiedot syötettiin yhteiseen tietokantaan. Niistä potilaista, jotka otettiin tehohoitoon, järjestettiin erillinen tiedonkeruu jota jatkettiin 12 kuukauden ajan, ja tässä keräyksessä olivat mukana lähes kaikki Suomen teho-osastot.

Tässä tutkimuksessa todettiin ensihoitajien hoitamien elvytystapahtuminen ilmaantuvuudeksi 51/100,000 asukasta/vuosi. Hätäkeskuspäivystäjät tunnistivat 80.3%

elottomuudesta hätäpuhelun soittohetkellä. Yhdellä kolmasosalla potilaista oli defibrilloitava rytmi tavattaessa, ja yli puolella potilaista arvioitiin olevan sydänperäinen taustasyy. Vajaa puolet potilaista sai maallikkoelvytystä ennen ensihoidon paikalle tuloa.

Kokonaisselviytyminen vuoden kohdalla oli 13.4%, ja 32.7% niiden potilaiden osalta jotka oli elvytetty defibrilloitavasta alkurytmistä. Vastaava selviytymisluku ei-defibrilloitavista rytmeistä elvytetyillä oli 4.6%. Defibrilloitava alkurytmi, lyhyet viiveet sydänpysähdyksestä paineluelvytyksen aloittamiseen ja ensihoidon paikalle tuloon, ensihoitolääkärin osallistuminen hoitoon sekä hypotermiahoito teho-osastolla niille potilaille, jotka oli elvytetty defibrilloitavasta rytmistä, olivat yhteydessä potilaan selviytymiseen sekä elossa sairaalasta että 1 vuoden kohdalla. Ensihoitajat yleisimmin varmistivat ilmatien intubaatiolla ja suorittajana oli yleisimmin hoitotaso.

Onnistumisprosentit olivat hyväksyttävällä tasolla sekä perus- että hoitotason ensihoitajilla. Terapeuttinen hypotermiahoito oli laajasti käytössä Suomen teho-osastoilla, ja myös potilaita, jotka oli elvytetty ei-defibrilloitavista rytmeistä, viilennettiin.

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Kokonaisselviytyminen niillä tajuttomilla potilailla, jotka otettiin sairaalaan tehohoitoon, oli 51.6%, ja hypotermiahoito vaikutti positiivisesti defibrilloitavista rytmeistä elvytettyjen ennusteeseen. Hypotermiahoidolla ei ollut vaikutusta ei-defibrilloitavista rytmeistä elvytettyjen potilaiden selviytymiseen.

Kokonaisselviytyminen sairaalan ulkopuolisesta sydänpysähdyksestä oli samaa luokkaa kuin mitä aiemmin on Suomesta raportoitu. Selviytyminen oli kuitenkin parantunut niillä potilailla, joiden elottomuus oli nähty, joiden alkurytmi oli defibrilloitava sekä sydänpysähdyksen taustasyy oletetusti sydänperäinen. Näiden potilaiden selviytymisluvut olivat kansainvälisestikin tarkasteltuna hyviä. Hätäkeskuspäivystäjän kyky tunnistaa sydänpysähdys oli korkea. Maallikkoelvyttäjien antamaa elvytystä sydänpysähdystilanteessa tulisi lisätä. Nykyiset kansalliset suositukset hengitystien varmistamisesta sydänpysähdyksen yhteydessä ovat mielekkäät ja käytännölliset ja johtavat hyviin onnistumislukuihin. Terapeuttinen hypotermia oli laajassa käytössä Suomessa ja sitä käytettiin myös potilaille, joilla alkurytmi oli ei-defibrilloitava rytmi.

Luokitus: WG 214, WG 205, WA 292, WF 145, WX 215, WA 900, W 84.7

Yleinen suomalainen asiasanasto: sydämenpysähdys; epidemiologia; akuuttihoito; ensihoito; elvytys; hypotermia; selviytyminen;

hoitoketjut; kohorttitutkimus; seurantatutkimus

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To my mother Vaula

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Acknowledgements

It feels somewhat surreal to write this page for my thesis as it took six years to finish this study. During this time, I have been blessed for crossing paths with so many people; those who have gave me their love, friendship and support during this journey. Some of them live literally on the other side of the world. I hope, although not mentioned, these people know in their hearts how grateful I am for them for entering and being in my life, sometimes just at the right moment when I was diving through the deepest oceans and storms with this thesis.

My warmest appreciation and respect goes to Professor Esko Ruokonen. Many years ago I got a phone call from you asking whether I was interested in doing some research (with pigs first, of course). I thought about it thoroughly for couple of days, but finally said yes.

Later on you guided me to the FINNRESUSCI project. You have inspired me with your passionate attitude towards science. I have always enjoyed listening to your lectures, making scientific research sound like a fascinating world that every doctor could (and should) easily join into.

My supervisors Docent Jouni Kurola, Docent Tom Silfvast and Helena Jäntti, PhD. I somehow managed to have these amazing supervisors who helped me finalise this study.

Jouni. You make my head spin around and around nearly every time we meet – your endless energy towards anything is unstoppable! I have strongly felt your support and presence close to me over these years. You have taught me so much, in research and clinically. Thank you; Tom, your sharp comments and simple suggestions for solutions have been most valuable. Sharing your extensive experience from prehospital work has helped me to look at things from the right perspective; Helena, my supervisor, my colleague, my friend. Your fantastic ability to simplify even difficult issues has led me out of many deadlocks. The word “resilience” gets its meaning from you! YOU are the heart of HEMS. Your steady, unwavering support and friendship have carried me along in science and also in my civilian life.

Docent Markku Kuisma, co-author. You have provided me with prompt information when needed, with quick responses to any questions I have had, even the silly ones… It now feels crazy to remember but we two sat down 1,5 years ago in Toowoomba, Australia for two hours. You, while travelling, gave me your time to help me with this study. I never forget that day. It has also been a great pleasure to get to know you personally as well.

Jukka Vaahersalo, MD, FINNRESUSCI researcher and co-author. Together we made it!

With your kind permission as main author I have been able to use study IV as part of my thesis. Co-authors Juha Rutanen, PhD, Tuomas Oksanen, MD, Kirsi-Maija Kaukonen, PhD, Docent Jyrki Tenhunen, Professor Tero Ala-Kokko, Vesa Lund, PhD,

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Matti Reinikainen, PhD, Outi Kiviniemi, MD, Tero Varpula, PhD, Professor Ville Pettilä.

Juha, your help especially in the very start of the study but also later, has been irreplaceable. Matti, with your guidance I overcame the “blank paper syndrome” and moved forward from page 1 in this thesis. Marjaana Tiainen, PhD, neurologist evaluating FINNRESUSCI patients’ neurological outcomes. Though extremely busy, you gave your time and help for this study.

Docent Ari Uusaro. I can only imagine what has it been like to guide me when I was starting my research (with those pigs). I was totally unfamiliar with research nuances, and I was in the middle of it, like ground zero… I thank you for your patience and encouraging comments as a co-author, especially concerning my first published article.

Your advice have helped me enormously with this study as well.

Docent Olli Anttonen and Jouni Nurmi, my official reviewers. I read very carefully your insightful comments and thoughts. With them, I managed to improve my dissertation, which I was writing alone through the darkest and rainiest days at the end of last year, wondering to myself whether any of it would be even close to publishable.

Docent David Laaksonen, thank you for editing the English. Marja-Leena Lamidi, your quick and prompt replies concerning my statistical problems over these years have been in great value.

FH60 crew, all the doctors, flight paramedics and pilots. Whatever seems to happen to me, you stand beside me like rock to lean on. You encouraged me to write and finish this thesis, and never got tired listening to my endless talk about this project (or did you?). I feel privileged to fly and work with you. Thank you for being such an important part of my life.

EMS doctors and paramedics inside the study area. Without your assistance with data collection this dissertation would never exist. I deeply thank each and every one of you for helping me to create this dissertation and hence, showing the status quo of management of out-of-hospital cardiac arrest patients in Finland. We share the same out-of-hospital world, which sometimes extends far beyond. It must have been a challenge to cope with this critical patient group, remember all the treatment given and write things down for FINNRESUSCI research purposes. Nina Nakari, research nurse. I am grateful for your help with prehospital data collection and handling in the HUS area.

My sincerest thanks go to all the nurses and doctors participating in FINNRESUSCI data collection in 21 ICUs. This is very impressive and makes me very proud of the massive ICU network we have in Finnish ICUs. Research nurses Elina Halonen, Sari Rahikainen, Saija Rissanen. Thank you for your contribution.

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In 2014, I worked overseas in Australia for one year. The journey was unforgettable.

Australia will always have a special place in my heart. I send my warmest greetings to all the people I was able to meet and work with. This research project has walked with me even there, down under. It sure has seen it all!

I have desired many things and have craved to experience life as much as I can. By living so, it undoubtedly has leaded to limited time to spend with my friends. I have humbly noticed how those I need still seem to stay near. Petteri. With you the world has shown its humorous side, and the friendship we have has lasted since medical school. Thank you also for bringing Sari into my life. Sari. With you I double my joys and half the sorrows I’ve felt. Heli and Jari, Henna and Teemu, Teea. I thank you all for letting me leave medicine behind time to time.

Anne, my sister-in-law, Eila and Jorma, my parents-in-laws. I am very fortunate to have you near my family and me. Thank you for your never-failing help and support for everything and also for looking after our children and never counting hours or kilometres.

My sister Seidi and brother Ali. We all live apart, but it is always easy to call you whatever the issue would be. My father Matti. Your support for anything I have strived for in my life is invaluable. You never stop thinking positive, and I admire that attitude of yours.

With your love I would and actually have moved mountains.

My husband Jani. I assume neither of us knew how much work and time this dissertation would actually take. I often wished I had a magic wand to wipe away the sadness from your look when I was too focused to see anything else but this. Research work can be all- embracing and can make loved ones feel second best, which is untrue. I promise to give the best of me to our life that we still have ahead of us. I will never stop admiring your patience waiting for this dissertation to be finished.

Our children Luka and Neela. Luka you once said: “Einstein has said that if you cannot explain difficult things with simple words, you have not understood it…” thank you for this advice, I have tried to keep it in mind when writing this thesis! Neela, you may be a small girl still, but inside you lives a soul beyond your years that I never stop admiring.

Whatever I might yet achieve, you two will always be the best and most beautiful creations that I have brought into this world.

My late mother Vaula. To my sorrow, we ran out of time for you to see me finish this dissertation. I still feel your presence and love around me, though. I know you would be proud of me. Luckily, for some reason, just before Christmas I printed out a version of this thesis to be sent to reviewers, and you and I sat down and briefly read through it together.

I promise to continue to reflect on all those good things you showed and taught me. I dedicate this thesis to you; thank you for being the best äiti ever.

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I am thankful for all the financial support received from EVO funding from Kuopio University Hospital, the Foundation of Emergency Medicine, the Finska Läkaresällskapet Foundation, the Päivikki and Sakari Sohlberg Foundation and the Finnish Society of Anesthesiologists.

Kuopio, April 2016 Pamela Hiltunen

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List of original publications and studies

This Dissertation is based on the following original publications and studies:

I Hiltunen P, Kuisma M, Silfvast T, Rutanen J, Vaahersalo J, Kurola J. Regional variation and outcome of out-of-hospital cardiac arrest (ohca) in Finland – the Finnresusci study.

Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine 20:80, 2012.

II Hiltunen P, Silfvast T, Jäntti H, Kuisma M, Kurola J and for the FINNRESUSCI Prehospital Study Group. Emergency dispatch process and patient outcome in bystander- witnessed out-of-hospital cardiac arrest with a shockable rhythm. European Journal of Emergency Medicine 22(4):266-72, 2015.

IIII Hiltunen P, Jäntti H, Silfvast T, Kuisma M, Kurola J. Airway management in out-of- hospital cardiac arrest: current practises and outcomes. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine 2016. In press.

IV Vaahersalo J, Hiltunen P, Tiainen M, Oksanen T, Kaukonen Kirsi-Maija, Kurola J, Ruokonen E, Tenhunen J, Ala-Kokko T, Lund V, Reinikainen M, Kiviniemi O, Silfvast T, Kuisma M, Varpula T, Pettilä V. Therapeutic hypothermia after out-of-hospital cardiac arrest in Finnish intensive care units: the FINNRESUSCI study. Intensive Care Medicine 39:836-837, 2013.

The publications were adapted with the kind permission of the copyright owners.

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6 DISCUSSION……….37 6.1 Main findings……….37 6.1.1 Epidemiology and outcome………37 6.1.2 Factors related to survival………...37 6.1.3 Elements of chain of survival……….37 6.2. Incidence and outcomes in relation to previous studies……….38 6.2.1 Incidence of OHCA………..38 6.2.2 Withholding resuscitation………...39 6.2.3 Aetiology………40 6.2.4 Increased survival rates and survival from shockable rhythms………41 6.2.5 Survival from non-shockable rhythms………..42 6.2.6 Different EMS systems……….42 6.3. Factors related to survival……….43 6.3.1 Early provision of CPR……….43 6.3.2 EMS arrival……….43 6.3.3 EMS physician………44 6.4 Different elements in OHCA..………...………45 6.4.1 Dispatch process……….45 6.4.2 Airway management………..45 6.4.3 Therapeutic hypothermia………..46 6.4.4 Cardiac arrest in special circumstances………...47 7 LIMITATIONS OF THE STUDY……….49 8 CONCLUSIONS………..51 9 FUTURE IMPLICATIONS………53 10 REFERENCES……….55 11 APPENDIX:

Original publications I, II and IV Study III

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Abbreviations

AED Automated external defibrillator

ALS Advanced life support

APACHE II Acute Physiology and Chronic Health Evaluation II Score

BLS Basic life support

BVM Bag-valve-mask

CPC Cerebral Performance Category

CRF Case Report Form

CPR Cardiopulmonary resuscitation

DNAR Do not attempt resuscitation

EMD Emergency Medical Dispatch

EMS Emergency Medical Services

EMT Emergency Medical Technician

ERC European Resuscitation Council

ETI Endotracheal intubation

ICU Intensive care unit

PEA Pulseless electrical activity

PCI Percutaneous Coronary Intervention ROSC Return of spontaneous circulation

RCT Randomised controlled trial

T-CPR Telephone-guided cardiopulmonary resuscitation

TH Therapeutic hypothermia

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OHCA Out-of-hospital cardiac arrest

SAD Supraglottic airway device

VF Ventricular fibrillation

VT Ventricular tachycardia

Definitions

Considered for resuscitation Patient without of signs of circulation. Does not include patients:

- in whom resuscitation was not attempted (see below), or it was immediately discontinued after initial assessment (i.e. unwitnessed cardiac arrest with asystole, or pre-existing DNAR)

- patients with clear secondary signs of death - patients with lethal trauma (e.g. decapitated body) - patients alive upon EMS arrival despite suspected OHCA at dispatch

Attempted resuscitation resuscitation continued with cardiopulmonary resuscitation (CPR), early defibrillation and/or airway management

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1 INTRODUCTION

In Europe, the annual incidence of Emergency Medical Services (EMS) -treated out-of- hospital cardiac arrest (OHCA) is approximately 38/100,000/year (Atwood et al. 2005).

Without any resuscitation efforts, patients with a stopped heart will die. Some of these patients will undergo cardiopulmonary resuscitation (CPR) by bystanders before the EMS arrive and continue resuscitation efforts to restore life. International guidelines for CPR are published every five years, most recently in 2015 (Monsieurs et al. 2015). Nevertheless, despite these efforts, survival is poor, roughly 10% of all OHCAs (Berdowski et al. 2010, Ong et al. 2015).

To optimise the “chain of survival”, the recognition of cardiac arrest, early activation of EMS, early CPR efforts provided by a caller or bystander, possibly with telephone-guided CPR (T-CPR), and early defibrillation are the key acts that need to be performed effectively and as rapidly as possible. Successful return of spontaneous circulation (ROSC) represents the first step of recovery from OHCA. Many complex pathophysiological changes commence after ROSC is achieved (Nolan et al. 2008). Post-resuscitation care plays an important role in patient outcome by providing support and treatment for multiple organs affected by cardiac arrest (Kirves et al. 2007, Sunde et al. 2007).

The aim of this nationwide study was to prospectively study the epidemiology and outcomes of OHCA in Finland. Of all OHCA patients, patients with a witnessed cardiac arrest and a primary shockable rhythm (ventricular fibrillation or ventricular tachycardia) have the best prognosis. It is vital to recognise OHCA when the emergency call is processed. Additionally, the practice of EMS prehospital management of the airway in patients with OHCA is not known. We also studied the use and outcome of therapeutic hypothermia for resuscitated OHCA patients in Finnish intensive care units.

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2 REVIEW OF THE LITERATURE

2.1 PREHOSPITAL EMERGENCY CARE

2.1.1 History and development

In previous times, people who were injured or sick were transported to hospital by any vehicle available – by horses, farm machinery, taxicabs or simply by carrying them. No treatment was given during transport, and people capable of patient care were unavailable. It was not until in the late 1700s, when Napoleon’s chief military physician, surgeon Baron Larrey, recognised the need for better prehospital care and constructed horse-drawn “flying ambulances” for soldiers injured on the battlefield (Remba et al. 2010) (in fact, the word “ambulance” originates from Latin meaning to “walk, move or wander”

about). He stressed that not only that these ambulances should transport patients rapidly, but they should also include medically trained personnel capable of care en route to the nearby hospital. Larrey established the theory of prehospital care, and he can be considered as the father of EMS in the modern era.

Despite the efforts of Larrey, prehospital care for civilians remained practically undeveloped until wars in Korea, Vietnam and the Middle East. Many injured soldiers were rescued by medics who initiated ventilation support, performed external bleeding control and transfused fluids intravenously before arrival to hospital. These interventions saved many of the military personnel who normally would have died on the field. As a result, these experiences triggered prehospital systems established worldwide in civilian era. This development was more than welcome. In fact, for example in the 1950s in United States, the only requirements for an ambulance were that the patient was able to lie down during transportation. Moreover, over half of the ambulances were operated by morticians (McSwain 2005). Experienced physicians returning home from Korea and Vietnam claimed that soldiers were more likely to survive in a combat zone than a normal citizen on the street.

An impressive report were published in United States in 1966 by researchers from the National Academy of Sciences (Howard 2000). It concluded that “…both the public and government were insensitive to the magnitude of the problem of accidental death and injury…” and that “most ambulances used in this country are unsuitable, have incomplete equipment, carry inadequate supplies, and are manned by untrained attendants”. Several guidelines were developed and recommendations were given. These publications lead departments in different areas worldwide to initiate training personnel to treat patients prehospitally, including those suffering from cardiac arrest. For example, in the late 1960s, a group of Seattle Fire Department personnel began a training course for firemen designed by dedicated physicians, many of them with wartime medical experience. These first trained paramedics started their work in the prehospital environment on March 7, 1970 and were instructed by law to have a physician with them on every emergency task.

However, the governor of California Ronald Reagan signed the Wedworth Townsend Act of 1970 to become law. It had many important consequences in the future development of

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the EMS system in the US (Pozner et al. 2004). Importantly, it led paramedics to work without the presence of physicians, but still providing more advanced patient care than previously had been possible.

Along with progress in “EMS infrastructure”, significant inventions and treatments have been developed. Major advances in the care of lifeless patients were brought into practice in the 1950s. The defibrillator was introduced as a tool for life-saving treatment of lethal ventricular arrhythmia (ZOLL et al. 1956) along with modern ventilation strategies (SAFAR, ESCARRAGA & CHANG 1959). In addition, William Kouwenhoven introduced external chest compressions in order to maintain even minor cardiac output during cardiac arrest (KOUWENHOVEN, JUDE & KNICKERBOCKER 1960). In the 1960s, the city of Belfast introduced the first mobile intensive care unit that was physician staffed and carried a defibrillator. This unit treated patients suffering chest pain or sudden cardiac arrest only (Pantridge, Geddes 1967).

In the 1970s and 1980s, multiple EMS systems were founded internationally in a variety of ways. Mostly they were organised with at least two tiers, where emergency medical technicians (EMTs) represented the first tier (BLS) and paramedics the second tier (ALS).

Additionally, some systems had physicians involved as a third tier. Eisenberg et al.

reported encouraging results in 1980 showing that survival from cardiac arrest was improved if patient care was provided by ALS-level personnel (Eisenberg, Bergner &

Hallstrom 1980, Eisenberg et al. 1980), which provided support for a two-tiered system at least in the prehospital setting. In Europe, prehospital care is typically physician led (Langhelle et al. 2004), whereas in the USA it is paramedic led (Pozner et al. 2004).

Nowadays, EMS exists to fulfill the basic principles of first aid: Preserve Life, Prevent Further Injury, and Promote Recovery. This theme in medicine is illustrated by a “star of life”, and it includes six points that are used to describe high-quality prehospital care: (1) early detection, (2) early reporting, (3) early response, (4) good on-scene care, (5) care in transit and (6) transfer to definitive care. Many ways of coordinating EMS exist, and there is variability in this process of care (Roudsari et al. 2007).

2.1.2 Prehospital system in Finland

2.1.2.1 Short history of the development of prehospital care

In 1877, the Finnish subsection of the Red Cross sent a unit to the Russo-Turkish War. This unit can be considered the first prehospital provider in Finland. Furthermore, the military developed prehospital care in the wars that Finland was involved in (the Finnish Civil War in 1918, World War II) similarly as in other countries worldwide. Especially after World War II, the Finnish Red Cross recognised the need for ambulance services and transportation for civilian emergencies. In 1953, the Chairman of the Finnish Red Cross, medical councilor Leo Kaprio, sent an enquiry for communities about how they organised prehospital transportation for patients. Of 486 communities, 411 did not have any transportation system. Thirty-three communities left the enquiry unanswered. When organised (75/486), the provider of the ambulance service was usually the rescue

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department. In a minority of communities, hospitals, private drivers (taxis), the Red Cross, or industries were the providers of this service. Nevertheless, these “ambulances” were also used to transport deceased people and served as taxis, with basically no medical equipment. The driver had no assisting personnel. In 1956, the Ministry of Health defined the minimum equipment for the ambulances. Gradually, improvements in education and equipment enabled ambulance personnel to better provide first aid (Järvinen 1998).

Helsinki, the capital city of Finland, and its rescue department, initiated ambulance service in 1904. Moreover, the first physician-staffed ambulance, the Mobile Intensive Care Unit (MICU), was established in Helsinki in 1972 and has been in operation ever since. It was dispatched for high risk emergencies, and at first it also transported patients. At the end of 1980s this physician-staffed unit stopped transporting patients, improving availability for other emergency situations (Nyström 2005).

In other parts of Finland, inspired by the experiences of the Helsinki MICU, other physician-staffed ambulances were founded (e.g. in Kuopio) but were soon stopped due to lack of support of local authorities. Finland did not have legislative guidance for EMS until in 1994 when the municipalities became responsible for organising the EMS in their area. The first helicopter EMS (HEMS) began in 1992 in the southern part of Finland (“Medi-Heli”) and was initially a strongly charity-based unit. In 2011, the legislation was revised. Instead of municipalities organising EMS, hospital districts became responsible for coordinating EMS, including dispatch criteria and administrative EMS medical director. New legislation also determined the minimum educational standards of basic- level and advanced-level ambulance personnel (Finlex 2011).

2.1.2.2 Emergency Medical Services (EMS)

Nowadays EMS services are organised by 20 hospital districts. They can provide this service themselves or buy it from municipal services or private companies. The EMS system is three-tiered. By law, in every ambulance unit there must be at least one educated, professional health care provider. First responders and EMTs serve as the first tier, i.e. basic life support (BLS). First responders are usually voluntary personnel from the local fire brigade and have completed a short course for first responders. BLS personnel may also be practical nurses or registered nurses in prehospital emergency care. Advanced life support (ALS) units have at least one of the personnel who is a registered nurse (bachelor) in emergency care or a registered nurse with one year of additional education for prehospital care.

The first tier is capable of defibrillating and, in case of a cardiac arrest, to use bag-valve- mask ventilation (BVM) and a supraglottic airway device (SAD). In southern part of Finland, the first tier is also allowed to use endotracheal intubation (ETI) in cardiac arrest patients, if trained and experienced in the ETI procedure. Additionally, the first tier is allowed to start intravenous fluid administration and give medication by natural routes (orally, inhaled, intranasally, rectally) and, if registered nurses, also intravenously either independently or after consulting an EMS or other physician. Adrenalin can be administered intravenously in OHCA without consultation.

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The second tier (ALS level) works more independently than the first tier. Instructions are given locally by the EMS medical coordinator and vary. The ALS level can use ETI as a first-line choice in case of a cardiac arrest. Moreover, ALS level is trained for intubating also in non-arrest situations, but nationwide recommendations follow Scandinavian guidelines in which performing ETI for an unconscious patient is a procedure that a prehospital physician performs (Berlac et al. 2008).

Physician-staffed units represent the third tier and are available 24/7. One ground unit exists in the capital city, Helsinki, with an additional five HEMS units nationwide. There are also two helicopter unit staffed with nurses only, one of which is funded by local charity. Two cities, Pori and Lahti, provide physician-staffed ground unit EMS for limited hours of the day.

HEMS is coordinated by FinnHEMS, which is the national administrative unit for HEMS and is owned by the five university hospital districts. Funding comes from the state via the Ministry of Social Affairs and Health.

Physician staffed units are dispatched simultaneously in areas where they are available, for high-risk trauma and non-trauma cases. They are involved in treatment for critically injured or sick patients and, additionally, give instructions and advice via telephone if needed. Physicians are consultants in anaesthesiology and intensive care or in their final stage of specialisation. In 2015, HEMS covered 60% of the Finnish population within a 30- minute response time (personal communication, Jukka Pappinen, FinnHEMS). The aforementioned physician-staffed ground unit operating in Helsinki also reaches all cardiac arrest patients in Helsinki within a 30-minute response time.

2.1.2.3 Emergency Medical Dispatch (EMD)

Emergency dispatch centres in Finland were first established in the late 1950s and were community-based and operating as part of rescue department services. Police, the rescue department and the ambulance service all had separate dispatch numbers. By 1954, Helsinki had installed 600 emergency phones inside the city area, and these calls were answered by Helsinki dispatch centre provided by Helsinki telephone company.

Legislation in 1976 required municipalities to be responsible for the organisation of

emergency calls. As a result, Finland initially had 58 dispatch centres based on the existing telephone network. No uniform number to call for help existed, and people answering the calls were untrained dispatchers, often former firemen or police personnel. At first, there was a variety of ways to alert ambulances. One could call to a dispatch centre, who only transmitted the request for an ambulance to the provider and did not do any assessment of need for transportation overall nor gave any instructions to the caller.

The emergency number in Finland is “112”, the official emergency number inside the European Union, and was adopted for use in the early 1990s. The system of dispatch centres was established in 2001 due to new legislation. Prior to this, in 1996 authorities combined four dispatch centers for a four-year period to test the liaison of rescue and police dispatch centres. The aim was to optimise the dispatching organisation. The results

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were encouraging. The goal was to reduce the large amount of dispatch centres Finland had at that time. Between 2001-2005 a nationwide reorganisation was established, and nowadays only six dispatch centres exists. These are combined centres for EMS, police and fire and rescue services. Little by little, dispatchers were trained for their role, first through different courses 2-4 weeks in duration and organised by rescue departments. Modern Emergency Medical Dispatcher (EMD) training contains 1,5 years of formal education in emergency-telephone-call processing and dispatching, and was started in 1997. Since then, medical call processing and dispatching have been based on the patient’s chief complaint and the patient’s current condition according to uniform national emergency medical dispatch guidelines given by Ministry of Social Affairs and Health. These criteria-based dispatch guidelines are based on those developed in 1990 by the King County Emergency Medical Services Division (King County Government Health Services 2015).

Dispatchers play an important role in patient care in the prehospital setting. They gather information on the patient’s condition and location, decide what kind of response is needed and communicate with the dispatched units. In case of a cardiac arrest, they also give T-CPR instructions. By law, only the emergency dispatch centre can take and process emergency calls in Finland.

2.2 EPIDEMIOLOGY AND OUTCOME OF OUT-OF-HOSPITAL CARDIAC ARREST (OHCA)

In 1991, a statement was issued to establish uniform terms and definitions for OHCA and resuscitation. Reports from different countries and different systems were infrequently compatible. To improve comparability, an “Utstein-style template” was developed (Cummins et al. 1991). The first meeting was held at Utstein Abbey, in Norway in 1990 by the European Resuscitation Council, which was founded one year earlier. The goal was to be able to compare cardiac arrest reports more reliably and share information internationally. Since then, the Utstein template has been updated (Jacobs et al. 2004, Perkins et al. 2015), and it has been used widely in published outcome studies of cardiac arrest.

According to Utstein definitions, cardiac arrest is a lack of cardiac mechanical activity that is confirmed by the absence of signs of circulation and, in case of OHCA, occurring in an out-of-hospital environment. The patient is unresponsive, not breathing or with agonal respirations and has no pulse. Convulsions may occur. Death will follow if arrest is untreated. The World Health Organisation (WHO) defines cardiac death as sudden if it is manifested within 1 hour of the onset of symptoms (WHO Scientific Group 1985).

Additionally, especially in scientific studies other definitions are also in use (Zipes et al.

2006) in which cardiac arrest is sudden if it results within minutes after the onset of symptoms and is unexpected.

2.2.1 Incidence and aetiology of OHCA

The overall incidence of OHCA globally has been reported to be between 37 and 121 alle nelinkertainen per 100,000 habitants/year (Berdowski et al. 2010). In Finland, earlier

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studies reported the incidence of OHCA in the cities of Helsinki and Tampere to be between 80-113 per 100,000 habitants/year (Silfvast 1990, Kuisma, Määttä 1996, Kämäräinen et al. 2007). The situation across the country has been unknown.

Table 1.Incidence and demography of out-of-hospital cardiac arrest (OHCA) in earlier studies from Finland in the cities of Helsinki and Tampere in 1987, 1994 and 2004, respectively.

Incidence is reported per 100,000 inhabitants/year. *EMS-witnessed OHCAs included.

Community Populati on served

OHCA considered for resuscitati on

OHCA incidence considered for resuscitati on

EMS-treated OHCA incidenc e

Primary shockabl e rhythm (%)

Bystand er CPR (%)

Overall survival to hospital discharg e (%)

Survival from witnessed primary shockable rhythm (%) Helsinki

1987

(Silfvast) 500 000 563 113 53 62 Not

reported not

reported 27*

Helsinki 1994

(Kuisma) 516 000 412 80 67 37 22 13 32

Tampere 2004

(Kämäräinen) 203 000 191 94 46 30 31 13 28

Variation in incidence exist between countries and communities (Atwood et al. 2005, Fredriksson, Herlitz & Nichol 2003). There may be many reasons for this, including inclusion and exclusion criteria of studies and data collection (Fredriksson, Herlitz &

Nichol 2003, Nishiyama et al. 2014). To overcome this variation, a common dataset has been established (Wnent et al. 2015), European Registry of Cardiac arrest, “EuReCa”. It may help to find explanations for reported differences in epidemiology, treatment and outcome in OHCA.

The majority of OHCAs are of cardiac origin, and this patient group is also associated with a more favourable outcome (Ong et al. 2015, Kuisma, Määttä 1996, Pell et al. 2003, Franek, Pokorna & Sukupova 2010). There has been a debate on the difficulty and, on the other hand, the importance of defining the term “cardiac origin” and its use in practice (Eisenberg, Bergner & Hearne 1980). A report from Finland showed significant differences in causes of death from unsuccessful prehospital resuscitation followed by autopsy or no autopsy (Virkkunen et al. 2008). Nevertheless, most often the assessment of the origin of the cardiac arrest in OHCA studies relies only on EMS personnel treating the patient before hospital phase. Understandably, this may vary because of individual judgement or personal opinion.

Besides intracardial causes, Kuisma and Alaspää reported in 1997 that 34.1% of OHCA patients had a cardiac arrest of non-cardiac origin. The most common causes were trauma, non-traumatic bleeding and intoxication (Kuisma, Alaspää 1997). This patient group may receive resuscitation efforts that differ from standard protocol (Monsieurs et al. 2015).

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Verifying the cause of cardiac arrest by autopsy for outcome reports is challenging and costly. The overall number of autopsies has been decreasing over the last decades (Marwick 1995), also in Finland (Tilastokeskus 2014a). In an earlier report from Finland in 1991, an autopsy was performed in 39% of the patients who died after unsuccessful resuscitation efforts in a prehospital setting (Silfvast 1991). Moreover, many factors may play a role in causing lethal arrhythmias. Therefore, it has been agreed that cardiac arrest should be considered of cardiac origin unless it is known or likely to have been caused by trauma, submersion, drug overdose, asphyxia, exsanguination, or any other non-cardiac cause as best determined by rescuers (Cummins et al. 1991, Jacobs et al. 2004).

Ischaemic heart disease represents the leading cause of death in the world (Murray, Lopez 1997, Newton et al. 2015). On initial evaluation, about 25-30% of OHCA patients have ventricular fibrillation (VF), but the incidence of VF has been declining over the past decades (Cobb et al. 2002, Väyrynen et al. 2011). There may be multiple reasons for this decline, but probably most importantly it is due to enhanced treatment of coronary artery disease and its risk factors (hypercholesterolemia, hypertension, etc.). One interesting potential cause could be urbanisation and an increasing number of single-person households. Most cardiac arrests occur at home, and if unwitnessed, prognosis is understandably poor (Väyrynen et al. 2011). In general, patients with VF have a better outcome than patients with non-shockable rhythms (Nichol et al. 2008, Holmgren et al.

2010). Even so, survival is still highly dependent on a short time from collapse to defibrillation (Weaver et al. 1986). On average, each non-treated minute means 7% to 10%

reduction in likelihood of survival for an OHCA patient in VF (Cummins et al. 1991).

2.2.2 Indications for out-of-hospital resuscitation efforts

There are two main questions that challenge health care providers especially in the EMS world: when to start and when to stop cardiopulmonary resuscitation? Cardiac arrest is a life-threatening condition that will lead to death within minutes without interventions.

Understandably, it is impossible to gain 100% survival for these patients. Patients should have a reversible, treatable cause for cardiac arrest and the capability to recover from resuscitation in the post-resuscitation phase. In other words, not all patients benefit nor are entitled for resuscitation efforts. Resuscitation is considered to be inappropriate if it is clear that it will be futile or is against the wishes of the patient. However, current practices and legislation vary internationally. For example, in South Korea it is not possible for EMS crews to withhold prehospital resuscitation, and they cannot stop resuscitation without declaration of death by a physician, requiring mandatory transportation to hospital for patients with ongoing resuscitation (Ahn et al. 2010). Similar practices exist in many East Asian countries (Kajino et al. 2008), giving the possibility not to initiate resuscitation only in obvious cases of death, e.g. asystole and the presence of decapitation, decomposition, dependent lividity, presence of brain matter from a head wound and rigor mortis.

Interventions must be performed rapidly and efficiently. Otherwise a good neurological outcome is unachievable. However, the decision to start or discontinue resuscitation efforts in prehospital setting is challenging due to lack of information about the overall

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health status of the patient, including what actually was the situation just prior to the cardiac arrest. Nevertheless, if the cardiac arrest was not seen or heard, and the patient is found without a palpable pulse and having asystole as the primary rhythm, he can be considered to be dead and resuscitation attempts can be withheld, which is the practice in the Finnish EMS system. Functional and sensitive prediction rules for termination of resuscitation efforts for EMS personnel have been published (Morrison et al. 2006). The ERC Guidelines include a chapter concerning the ethics of resuscitation and end-of-life decisions and when withholding or withdrawing CPR should be considered (Bossaert et al. 2015).

In unclear situations, which OCHA mainly is at the initial phase, it is reasonable to start resuscitation efforts, and when further information of patient’s previous medical history or underlying cause (e.g., primary rhythm, time intervals from emergency call to EMS arrival, witnessed vs. found, end-stage cancer) is gathered, termination of resuscitation can be established shortly after arrival on the scene. Nevertheless, in the end this decision is based on the judgment of unresponsiveness of individuals to advanced cardiac life support (Monsieurs et al. 2015). It has been said that critical care is a method to remove a temporary threat to life, and in many ways this same definition also applies to resuscitation.

2.2.3 Factors related to outcome in OHCA

Even for a young, previously healthy patient, after cardiac arrest there are only minutes to spend for effective resuscitation before irreversible cerebral and cardiac changes occur, resulting in either patient death or making recovery to or near his previous functional capacity impossible. Unfortunately, survival is achieved only for a small minority of people. Studying factors that may influence the positive outcome among these patients is vital. On the other hand, knowledge and recognition of these factors will help health care personnel to make a decision to withhold or not to even initiate resuscitation efforts in obviously futile situations.

Before modern cardiopulmonary resuscitation was adopted in 1960s, very few patients survived cardiac arrest (Cooper, Cooper & Cooper 2006). Furthermore, factors that may have had influence on outcome were not properly identified or documented. However, in 1976 Mickey Eisenberg and his colleagues initiated the Project Restart study to determine factors associated with successful resuscitation in prehospital setting (Eisenberg, Bergner

& Hallstrom 1979). They concluded that four factors had a significant association with better survival rates: paramedic (not EMT) service, time from collapse to initiation of CPR, rapid transport time to definitive care and bystander-initiated CPR. Interestingly, initial rhythm alone was not associated with better outcome. On the other hand, only 50% of the cardiac arrests were overall even monitored, and of these patients, 64% had ventricular fibrillation (VF) as first documented rhythm. Time from the collapse to defibrillation, when performed, was also not documented. Eisenberg reported that CPR initiated within four minutes and rapid transportation to definitive care, the latter performed more rapidly by paramedics than emergency medical technicians (EMTs), were associated with survival. The study group suggested citizen training for providing CPR for a patient, thus

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buying time until definitive care reaches the patient, and indeed both Seattle and King County took CPR into their programme for citizen education. Eisenberg at his colleagues indeed led the EMS world towards meaningful things in OHCA care.

According to Sasson (Sasson et al. 2010), the associations between key predictors and survival have been stable for over a decade. These key predictors are: initial cardiac rhythm, provision of CPR, arrest witnessed by a bystander or EMS, or the return of spontaneous circulation. The most important factor affecting survival is time from collapse to initiation of resuscitation efforts (Eisenberg, Bergner & Hallström 1979). Early chest compressions from the beginning of collapse have been shown to have a positive effect on outcome in other studies as well (Holmberg et al. 2001, Nordberg et al. 2009).

Additionally, patient survival has been linked to the quality of CPR; suboptimal chest compression reduces survival to discharge after OHCA up to 30% (Stiell et al. 2012).

Another study including patients with in-hospital cardiac arrests showed that higher chest compression rates correlated with higher rates of ROSC (Abella et al. 2005).

Shockable rhythms - ventricular fibrillation (VF) and ventricular tachycardia (VT), have been associated with a more favourable outcome than other rhythms (Cummins et al.

1991, Herlitz et al. 2005). As a result, the best prognosis is among those people whose cardiac arrest has been witnessed, whose cause of arrest is of cardiac origin and in whom VF/VT is the primary rhythm (Pell et al. 2003). Actually, the best results have been achieved from casinos where non-medical personnel, security officers, were trained to use defibrillator and succeeded in defibrillating VF patients within approximately four minutes of collapse. Overall survival from hospital discharge was 38%, and 59% among patients having VF as an initial rhythm (Valenzuela et al. 2000).

2.2.4 Outcomes of OHCA worldwide and in Finland

Reported outcomes for OHCA have been poor – 10.7% for all initial rhythms. For VF, survival improved up to 21.2% (Atwood et al. 2005). Nevertheless, a small improvement in overall OHCA survival rates has been seen over the last few decades. A meta-analysis published in 2010 showed survival rates to be between 6.7% and 8.4% (Sasson et al. 2010) despite of many advances in treatment and practices over time. In this meta-analysis, bystander CPR and shockable rhythms were positive predictors of survival, well-known factors affecting patient outcome. A recent ROC report concluded that OHCA patients survival had increased (Daya et al. 2015) slightly, from 8.2% to 10.4% between 2006 and 2010 in US and Canadian sites. One explanation for this modest improvement may be the simultaneous decrease of three known predictors of survival: shockable initial rhythm, cardiac arrest of cardiac origin and public location. In a review, Savastano et al. reported a significant decrease in mortality over three different time periods, with a survival rate at hospital discharge of 9.2% after the year 2005.

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Figure 1. Rate of survival to hospital discharge after OHCA in the three periods. OHCA, out-of- hospital cardiac arrest. According to Savastano et al. 2014.

In Finland, overall OHCA survival to hospital discharge has been reported to be 13%

(Table 1). These studies included only single EMS providers covering the city areas of Helsinki and Tampere. However, it seems that when comparing patients whose cardiac arrest was witnessed, of presumed cardiac origin, and with an initial shockable rhythm, the prognosis of this patient group has improved in Finland (Silfvast 1990, Kuisma, Määttä 1996, Kämäräinen et al. 2007, Kuisma, Alaspää 1997). This improvement has also been noted in other countries (Iwami et al. 2009).

2.3 CHAIN OF SURVIVAL

The “chain of survival” remains a model of resuscitation throughout the world. This concept was established in 1991, and it means all actions linked with survival in patients with cardiac arrest (Cummins et al. 1991). Initially this chain involved 1) recognition of early warning signs, 2) activation of the emergency medical system, 3) basic cardiopulmonary resuscitation, 4) defibrillation, 5) intubation, and 6) intravenous administration of medications. Research on different factors affecting survival has modified this chain over the years. In 2010 this sequence had four links: 1) early recognition of those at risk of cardiac arrest, 2) early provision of CPR, 3) early defibrillation, and 4) post-resuscitation care (Nolan et al. 2010). Updated resuscitation guidelines in 2015 stress the importance of interactions between the emergency medical dispatcher, the bystander who provides CPR and the early use of automated external defibrillators in patient survival from OHCA (Nolan et al. 2015).

In 1992, an International Liaison Committee on Resuscitation (ILCOR) was formed to have liaison between resuscitation organisations worldwide (ILCOR 2015). The European Resuscitation Council represents one of the member organisations. ILCOR offers a forum for discussion of different aspects of resuscitation worldwide, provides a mechanism for collecting and sharing data on different topics and points to areas where further research is needed. It also provides statements on different issues in regard to resuscitation. A massive review on resuscitation and closely related issues is performed regularly by the

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ILCOR and is followed by ERC guidelines every five years, based on evidence whenever possible, and if sufficiently strong evidence is lacking, on consensus of available scientific evidence and experts’ opinion and best practice.

2.3.1 Role of the bystander – importance of the emergency call and CPR

In cardiac arrest, it is essential that a bystander who witnesses the arrest identifies this life- threatening situation and makes the emergency call. More ideal would be the citizen’s capability, with training, to recognise people at risk of cardiac arrest and call for help before the cardiac arrest even occurs. ERC recommends that citizens should be trained to give standard CPR that includes compressions and ventilation, or alternatively, to learn compression-only CPR (Monsieurs et al. 2015). Delays may occur if the bystander calls to a relative or friend first instead of making an immediate call to an emergency dispatch centre. Training increases the actions of a bystander to initiate and perform CPR (Cave et al. 2011). It has been shown in studies that bystander CPR (Sasson et al. 2010) improves outcome. Unfortunately, many people having a cardiac arrest will not receive any bystander resuscitation efforts. According to studies lack of bystander CPR is approximately one fourth of all OHCA events (Nichol et al. 2008), ranging from 1% (Ong et al. 2011) to 40% (Ong et al. 2015). Efforts made to increase these rates are crucial for OHCA patient management.

2.3.2 Role of the dispatcher – recognition of OHCA

The effectiveness of many interventions in OHCA relies on the rapid response of EMS activation. Dispatchers play a major role in this entity when taking emergency calls.

Cardiac arrest represents only a minority of medical emergencies. In addition, dispatch centres in Finland are combined centres for EMS, police and fire and rescue services. In other words, dispatchers also receive many non-medical or non-urgent medical calls.

Nonetheless, they should rapidly and correctly identify this critical patient group, activate an adequate EMS response, and simultaneously initiate telephone-guided cardiopulmonary resuscitation orders (T-CPR). Thus, early recognition of cardiac arrest is the first link in the chain of survival (Monsieurs et al. 2015, Bobrow, Panczyk & Subido 2012) and has been shown to improve patient survival (Berdowski et al. 2009, Rea et al.

2001).

To recognise OHCA by telephone assessment is a challenging task. A recent review by Vaillancourt et al showed that the sensitivity of telephone assessment of the patient as unconscious and with no or abnormal breathing varied (38-97%), but were reliable in OHCA (Vaillancourt et al. 2011). Dispatchers confront many barriers during the emergency call, affecting their recognition of OHCA, ie. caller’s physical and emotional proximity (Alfsen et al. 2015). If the caller describes the patient as breathing normally, dispatchers rarely give T-CPR. It seems important that the protocol includes the question

“is patient breathing normally?” If the answer is no, and the patient is not conscious, the dispatcher should treat the situation as cardiac arrest (Berdowski et al. 2009). Agonal breathing has been shown to mislead dispatchers to believe patient is alive, leaving true cardiac arrest patients unrecognised (Bang, Herlitz & Martinell 2003). Additionally, recognition takes 1-4 minutes (Culley et al. 1991, Heward, Donohoe & Whitbread 2004).

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Despite these difficulties and challenges, the correct recognition of an OHCA has been reported to be as high as 70-83% (Garza et al. 2003, Kuisma et al. 2005, Nurmi et al. 2006).

After recognising a cardiac arrest, T-CPR instructions are given for those willing to perform chest compressions. In Finland, T-CPR instructions are given unless CPR is already ongoing or the caller says he or she knows how to perform cardiopulmonary resuscitation. Rather than asking whether the caller would like to try CPR, the dispatcher should encourage the caller by saying: “We need to start CPR. I will help you.” It has been shown that CPR before EMS arrival improves survival, and therefore the guidance of dispatcher for bystander to provide CPR for a lifeless patient of great importance (Lerner et al. 2012). Unfortunately, rates of T-CPR offered has been shown to be low (Rea et al.

2001, Kuisma et al. 2005). In a study from South Korea, only 5.2% of OHCA patients received CPR before EMS arrival. T-CPR-instructions were given in 24.2% of the cases (Song et al. 2013). On the other hand, Bohm et al reported that sometimes dispatchers may not offer T-CPR instructions for suitable cases (Bohm et al. 2007). The same study reported also that bystanders seem to be motivated and willing to give CPR to a lifeless patient.

In summary, dispatchers should always start the call by excluding cardiac arrest as a cause for the call and provide prearrival CPR instructions in case of cardiac arrest. This strengthens the Chain of Survival and helps save lives from OHCA (Lerner et al. 2012).

2.3.3 Role of EMS – following resuscitation protocol

The cardiac arrest patient needs immediate treatment after collapse. Treatment can be partly provided by bystanders (CPR, even early defibrillation), but it is mainly in the hands of EMS personnel. Their role is to resuscitate according to a set protocol in concordance with guidelines. Major interventions include continuing and assuring good quality CPR, early monitoring of the initial rhythm and defibrillation of a shockable rhythm, airway management, opening intravenous access and administration of vasoactive drugs.

When arriving to a patient side, EMS personnel assess the patient’s status by responsiveness of the patient (shaking, pain stimuli) and opening the airway. If the patient is not awake and is not breathing normally, patient is considered to be in cardiac arrest, and chest compressions are initiated unless the bystander CPR is already ongoing. Rapid assessment of carotid pulse by ALS personnel is allowed, but should not exceed 10 seconds. Continuous CPR is important throughout the resuscitation. Ideally, this is initiated by a bystander immediately after the collapse. CPR enables limited, but critical blood circulation to the heart and brain. By increasing the intrathoracic pressure and directly compressing the heart (KOUWENHOVEN, JUDE & KNICKERBOCKER 1960), CPR aims to offer sufficient oxygen delivery to vital organs during the resuscitation period.

The American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care pointed out five critical components of high-quality CPR:

minimal interruptions in chest compressions, compressions of adequate rate and depth,

Out-of-hospital cardiac arrest in Finland

uef.fi

Dissertations in Health Sciences

PAMELA HILTUNEN

OUT-OF-HOSPITAL CARDIAC ARREST IN FINLAND

Out-of-hospital Cardiac Arrest in Finland

Out-of-hospital Cardiac Arrest in Finland

Acknowledgements

List of original publications and studies

Contents

Abbreviations

Definitions

1 INTRODUCTION

2 REVIEW OF THE LITERATURE