CEPEF1
The foundations
The first large-scale confidential enquiry established a new international benchmark for equine anaesthetic outcomes.
CEPEF5ContactConfidential Enquiry into Perioperative Equine Fatalities
The next phase in equine anaesthesia safety
CEPEF5 is a new international collaborative research project, building on more than three decades of evidence and worldwide cooperation.
Expected study launch
January 2027Centre recruitment will open soonPreparing for CEPEF5
A new chapter for a global research community
The CEPEF team is currently developing the fifth phase of this international research programme.
CEPEF5 will continue the programme's commitment to confidential, collaborative investigation of perioperative outcomes in horses. Details of the study protocol, eligibility requirements and participation process will be published before recruitment opens.
01Study design
In development
02Centre recruitment
Opening soon
03Study launch
January 2027
Built on CEPEF4
International evidence, translated into safer practice
The definitive CEPEF4 study documented a reduction in perioperative mortality compared with CEPEF2, while identifying factors that can inform clinical decisions and improve patient safety.
Read the 2025 open-access paper47,396general anaesthetics
93participating centres
28countries represented
1.2%overall mortality
Figures reported in the definitive CEPEF4 publication, 2025.
The CEPEF programme
Five phases of shared learning
CEPEF2
A global reference
The landmark multicentre study quantified perioperative mortality and shaped clinical discussion for more than two decades.
CEPEF3
Comparing practice
A multicentre randomised study examined outcomes associated with commonly used inhalational anaesthetic agents.
CEPEF4
Evidence for today
Modern web-based data collection brought together 93 centres in 28 countries and 47,396 general anaesthetics.
CEPEF5
The next chapter
A new international phase is now in development, with the study expected to begin in January 2027.
The people behind CEPEF
An international scientific collaboration
The CEPEF CIC is the five-person core of the programme. Three collaborators support CEPEF5 across study leadership, statistics and the digital platform.
CEPEF CIC · Core team
Miguel Gozalo-Marcilla
CEPEF CIC Principal Investigator
The University of EdinburghJosé I. Redondo
Veterinary Anaesthetist and Statistical advisor
Universidad CEU Cardenal HerreraRegula Bettschart-Wolfensberger
Senior Equine Veterinary Anaesthetist
University of ZürichG. Mark Johnston
CEPEF founder · Clinical information
VetstreamPolly M. Taylor
CEPEF founder · Equine anaesthesia
Taylor MonroeCollaborators
Álvaro Gutiérrez-Bautista
CEPEF5 leader
University of HannoverLuis Domenech
IT team & statistical advisor
Universidad CEU Cardenal HerreraJavier Domenech
IT team & CEPEF5 webmaster
FreelanceParticipation
Recruitment is not yet open
Invitations to participating centres will be announced before the study begins. The protocol, eligibility criteria and onboarding information will be available here when recruitment opens.
CEPEF Publications
The complete research collection
Three decades of research, from the original CEPEF studies to the worldwide CEPEF4 programme and the next phase, CEPEF5.
The foundations: CEPEF1–3
The original studies established the evidence base for the CEPEF programme.
1995↗2002↗2004↗
CEPEF1 · Preliminary results
Confidential enquiry of perioperative equine fatalities (CEPEF-1): preliminary results
Johnston GM, Taylor PM, Holmes MA, Wood JLN.
Equine Veterinary Journal. 1995;27(3):193–200.
DOI: 10.1111/j.2042-3306.1995.tb03062.x
CEPEF1 & CEPEF2 · Mortality results
The confidential enquiry into perioperative equine fatalities (CEPEF): mortality results of Phases 1 and 2
Johnston GM, Eastment JK, Wood JLN, Taylor PM.
Veterinary Anaesthesia and Analgesia. 2002;29(4):159–170.
DOI: 10.1046/j.1467-2995.2002.00106.x
CEPEF3 · Randomised controlled trial
Is isoflurane safer than halothane in equine anaesthesia? Results from a prospective multicentre randomised controlled trial
Johnston GM, Eastment JK, Taylor PM, Wood JLN.
Equine Veterinary Journal. 2004;36(1):64–71.
DOI: 10.2746/0425164044864723
The path to CEPEF4
The 2012 and 2013 editorials highlighted the need for a new multicentre study. The 2020 letters then marked the launch of the current CEPEF4 programme.
2012↗2013↗2020↗2020↗
The call for CEPEF4 · Editorial
Confidential enquiry into perioperative equine fatalities: CEPEF 4 – a chance to gain new evidence about the risks of equine general anaesthesia
Bettschart R, Johnston M.
Equine Veterinary Journal. 2012;44(1):7.
DOI: 10.1111/j.2042-3306.2011.00483.x
The call for CEPEF4 · Editorial
Peri-anaesthetic mortality in horses – the need for CEPEF-4
Gent TC, Bettschart-Wolfensberger R.
Veterinary Anaesthesia and Analgesia. 2013;40(6):e1–e2.
DOI: 10.1111/vaa.12070
CEPEF4 launch · Letter
A new equine anaesthetic mortality study two decades after CEPEF2: CEPEF4 is going live!
Gozalo-Marcilla M, Redondo JI, Johnston M, Taylor P, Bettschart-Wolfensberger R.
Equine Veterinary Journal. 2020;52(6):891–892.
DOI: 10.1111/evj.13327
CEPEF4 launch · Letter
CEPEF4: update and plan
Gozalo-Marcilla M, Redondo JI, Johnston M, Taylor P, Bettschart-Wolfensberger R.
Veterinary Anaesthesia and Analgesia. 2020;47(5):724–725.
DOI: 10.1016/j.vaa.2020.08.004
CEPEF4 and the path to CEPEF5
2021↗2025↗2025↗2025↗2025↗2025↗2026↗2026↗2026↗
Research article · Animals
Data Collection for the Fourth Multicentre CEPEF4 Study: New Technology and Preliminary Results
Systematic review · Equine Veterinary Journal
A systematic review of the prevalence of post-operative complications after general anaesthesia in adult horses (2000–2023)
Research article · Animals
Donkey and Hybrid Anaesthetic Mortality in an Observational, Prospective, Multicentre Cohort Study
Research article · Veterinary Anaesthesia and Analgesia
The Confidential Enquiry into Perioperative Equine Fatalities: phase 4 (CEPEF4) – a worldwide observational, prospective, multicentre cohort study in 2025
Methods paper · Veterinary Anaesthesia and Analgesia
Error management in large data sets: A critical component of data collection in veterinary medicine
Review article · Veterinary Anaesthesia and Analgesia
Sixty years of equine anaesthesia – are we getting better at it?
Research article · Equine Veterinary Journal
Intraoperative monitoring and anaesthetic complications in horses: A secondary analysis of the CEPEF4 multicentre cohort
Editorial · Equine Veterinary Journal
Interpreting the CEPEF4 data: Handling small data subsets without losing confidentiality
Research article · Equine Veterinary Journal
Fatalities within seven days after equine standing sedation: A prospective, multicentre study
Congresses & conferences
CEPEF4 around the world
Scientific communications, invited lectures and discussions presented from the launch of CEPEF4 through its latest satellite studies.
2025↗2025↗2025↗2025↗2025↗2025↗2024↗2023↗2022↗2022↗2022— 2022↗2022↗2022↗2022↗2020↗
Intraoperative complications in anaesthetised horses: A comprehensive prospective study
WCVAA • Paris, France • 17–18 September 2025
Prospective monitoring of post-anaesthetic morbidities in horses: Preliminary results from a CEPEF-4 satellite study
WCVAA • Paris, France • 17–18 September 2025
Standing sedation in horses and ponies: perioperative fatalities in a worldwide observational, prospective, multicentre cohort study
WCVAA • Paris, France • 17–18 September 2025
Interobserver agreement in the classification of anaesthetic deaths in horses: A tie-breaker approach
WCVAA • Paris, France • 17–18 September 2025
Equine anaesthesia, what can go wrong? Lessons from CEPEF4
35th ECVS Annual Scientific Meeting • 4 July 2025
Peri-operative morbidity discussion panel: CEPEF4 results and post-operative complications
BEVA Congress • Birmingham, United Kingdom • September 2025
CEPEF – what we knew then and what we know now
AVA 60th Anniversary Autumn Meeting • London, United Kingdom • September 2024
Lessons from Confidential Enquiry into Perioperative Equine Fatalities 4 (CEPEF4)
WCVAA • Sydney, Australia • 27–30 March 2023
A step forward in CEPEF4: data collection over 14 months using an internet-based method
AVA Spring Meeting • Nafplio, Greece • 19–20 May 2022
Mortality risks in horses undergoing standing sedation for surgery and advanced diagnostic imaging
AVA Spring Meeting • Nafplio, Greece • 19–20 May 2022
Mortalidad anestésica equina en España: contribución de nuestro país al CEPEF4
XVI SEAAV Congress • Torremolinos, Spain • 26–28 May 2022 • Public abstract not available online
CEPEF4 Australia: Preliminary data from Scone Equine Hospital
Science Week • Gold Coast, Australia • 23–25 June 2022
CEPEF-4: an update
BEVA Congress • Liverpool, United Kingdom • 8–10 September 2022
Quoi de neuf du côté du risque anesthésique : étude de Morbi-Mortalité CEPEF 4, résultats préliminaires (dont résultats français)
AVEF Annual Conference • Reims, France • 8–10 November 2022
CEPEF-4: Resultados do mais recente estudo sobre morbidade e mortalidade associada a anestesia em equinos
XV Brazilian Congress of Veterinary Anaesthesiology • Águas de Lindóia, Brazil • 2 December 2022
CEPEF4 going live
AVA Spring Meeting • Dublin, Ireland • 11–13 March 2020
CEPEF4 on video
Sharing the project
Interviews, project introductions and scientific presentations that brought CEPEF4 to an international audience.
Universidad CEU Cardenal Herrera · 2:57
CEPEF4, the largest world’s study on anaesthesia in horses, meets at CEU UCH
Watch on YouTubeUniversidad CEU Cardenal Herrera · 2:33
Contributing to a safer anaesthesia in horses: CEU UCH, at CEPEF-4
Watch on YouTubeUniversidad CEU Cardenal Herrera · 17:00
CEPEF: the world's largest international study on equine anaesthesia
Watch on YouTubeCEPEF4 project archive · Scientific presentation
CEPEF4 going live – AVA Spring Meeting 2020
Watch on YouTubeFrequently asked questions
What we know so far
This information reflects the current development phase and will be expanded when the study protocol and recruitment call are ready.
01What is CEPEF5?+
CEPEF5 is the next phase of the international Confidential Enquiry into Perioperative Equine Fatalities. It will build on the evidence, methods and worldwide collaboration developed across the previous CEPEF studies.
02When will the study begin?+
The study is expected to begin in January 2027. The definitive timetable will be confirmed before centre recruitment opens.
03Is centre recruitment open?+
Not yet. The international call for centres, eligibility criteria and participation process are currently being prepared.
04Which centres will be able to participate?+
CEPEF5 is intended as an international multicentre study. Detailed eligibility requirements for equine hospitals, clinics and practices will be published with the study protocol.
05What will participation involve?+
Participating centres will receive a study protocol, onboarding information and clear guidance on confidential perioperative data collection. The exact requirements will be announced before recruitment.
06How will confidentiality be protected?+
Confidentiality is central to the CEPEF programme. The CEPEF5 protocol will define data governance, centre identification and reporting procedures before case collection begins.
Contact the project
Questions about CEPEF5?
Contact the CEPEF team about project development, research collaboration or future centre participation.
Current CEPEF contactcontact@cepef.net ↗
Recruitment enquiries will be answered when the international call opens.
What comes next
CEPEF5 begins in January 2027
The CEPEF5 scientific objectives, research team and participation information will be announced as development progresses.
Centre recruitment opening soon