Critical IllnessCIRCANCT04219384
Critical Illness Related Cardiac Arrest (CIRCA)
An observational study of Critical Illness, run by Intensive Care National Audit & Research Centre at 1 site in United Kingdom.
Trial summary
CIRCA aims to determine the incidence and outcomes of in-hospital cardiac arrest (IHCA) in UK intensive care units (ICUs) and explore associated risk factors with ICU and hospital survival and quality of survival following hospital discharge. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Critical Illness
- How many people
- 1,320 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 27 Jan 2020to 1 Oct 2022
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Adult, Older adult
Study population: Adults having cardiac arrest (defined as receipt of chest compressions and/or defibrillation) after admission to an Intensive Care Unit (ICU) participating in the Case Mix Programme in a hospital participating in the National Cardiac Arrest Audit
Who may be able to join
- Age 18 years old or more; and either
- Cardiac arrest (defined as receipt of chest compressions or defibrillation) occurring while in-hospital and within intensive care (defined as either ICU, HDU or combined ICU/HDU); or
- Family member of a patient surviving to discharge from intensive care after a cardiac arrest within ICU
Who cannot join
- There are no exclusion criteria
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Intensive Care National Audit & Research Centre
London, WC1V 6AZ
About this study
Official title: Critical Illness Related Cardiac Arrest (CIRCA): an Investigation of the Incidence and Outcome of Cardiac Arrest Within Intensive Care Units in the United Kingdom
CIRCA aims to determine the incidence and outcomes of in-hospital cardiac arrest (IHCA) in UK intensive care units (ICUs) and explore associated risk factors with ICU and hospital survival and quality of survival following hospital discharge.
Read the detailed description
Cardiac arrest is often categorised by location, out-of-hospital or in-hospital (IHCA), as there are important differences in population characteristics and aetiology. The National Cardiac Arrest Audit (NCAA) was established to audit resuscitation teams in response to IHCA, and collects information about patient characteristics, resuscitation processes, and patient outcomes. However, it does not audit IHCAs that are not attended by the resuscitation team.
Critically ill patients managed in ICUs are experiencing failure of one or more organs and therefore more intensive and invasive therapies are needed to support these failing organs. As a result, ICUs have higher nursing and medical staffing ratios, and monitoring is usually continuous. Moreover, the skill mix of the multidisciplinary team is geared to advanced life support. Thus, the risk of cardiac arrest occurring, the involvement (or not) of the resuscitation team, and the probability of return of spontaneous circulation are all likely to be different to other IHCAs.
Accurate data on cardiac arrests in ICU are lacking and the investigators do not know how many IHCA occur in ICU in the UK, nor is the impact of an IHCA in ICU on outcome known. In addition, it is not known if these IHCAs in ICUs represent an unavoidable consequence of critical illness or, more importantly, whether they can be predicted and/or prevented.
CIRCA is a prospective, multi-centre observational cohort study nested in the Case Mix Programme (CMP) and NCAA national clinical audits. The investigators aim to determine the incidence and outcomes of IHCA in UK ICUs and explore associated risk factors with ICU and hospital survival and quality of survival following hospital discharge.
- Conditions
- Critical Illness
- Keywords
- Critical Illness Related Cardiac Arrest
- Medical subject headings
- Critical Illness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Critical-illness related cardiac arrest (CIRCA) | Those experiencing a critical illness-related cardiac arrest in a participating adult, general ICU |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence
Incidence of critical illness related cardiac arrest
Measured: Up to 12 months
Secondary outcomes (12)
Subsequent incidence of in-hospital cardiac arrest
Subsequent incidence of in-hospital cardiac arrest obtained through data linkage to the National Cardiac Arrest Audit
Measured: Up to 12 months
Survival status at hospital discharge
Survival status at hospital discharge obtained from data linkage to the Case Mix Programme
Measured: Up to 12 months
Survival status at 12 months
Survival status at 12 months obtained from data linkage to NHS Digital
Measured: 12 months
Patient quality of life measured through EQ-5D-5L questionnaire completion at 3 months
Patient quality of life measured through completion of EuroQol 5 Dimension (5 level) questionnaire at 3 months following critical illness related cardiac arrest
Measured: 3 months
Patient quality of life measured through EQ-5D-5L questionnaire completion at 6 months
Patient quality of life measured through completion of EuroQol 5 Dimension (5 level) questionnaire at 6 months following critical illness related cardiac arrest
Measured: 6 months
Patient quality of life measured through EQ-5D-5L questionnaire completion at 12 months
Patient quality of life measured through completion of EuroQol 5 Dimension (5 level) questionnaire at 12 months following critical illness related cardiac arrest
Measured: 12 months
Patient quality of life measured through IQCODE questionnaire completion at 3 months
Patient quality of life measured through completion of Informant Questionnaire on Cognitive Decline in the Elderly questionnaire at 3 months following critical illness related cardiac arrest
Measured: 3 months
Patient quality of life measured through IQCODE questionnaire completion at 6 months
Patient quality of life measured through completion of Informant Questionnaire on Cognitive Decline in the Elderly questionnaire at 6 months following critical illness related cardiac arrest
Measured: 6 months
Patient quality of life measured through IQCODE questionnaire completion at 12 months
Patient quality of life measured through completion of Informant Questionnaire on Cognitive Decline in the Elderly questionnaire at 12 months following critical illness related cardiac arrest
Measured: 12 months
Family member quality of life measured through FROM-16 questionnaire completion at 3 months
Quality of life of family member of patients surviving critical illness related cardiac arrest measured through completion of Family Reported Outcome Measures 16 questionnaire at 3 months following patient arrest
Measured: 3 months
Family member quality of life measured through FROM-16 questionnaire completion at 6 months
Quality of life of family member of patients surviving critical illness related cardiac arrest measured through completion of Family Reported Outcome Measures 16 questionnaire at 6 months following patient arrest
Measured: 6 months
Family member quality of life measured through FROM-16 questionnaire completion at 12 months
Quality of life of family member of patients surviving critical illness related cardiac arrest measured through completion of Family Reported Outcome Measures 16 questionnaire at 12 months following patient arrest
Measured: 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Jan 2020
- Study start27 Jan 2020
- Primary completion1 Oct 2021
- Study completion1 Oct 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Critical IllnessStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 1,320 participants (actual)
Sponsor and investigators
- Lead sponsor
- Intensive Care National Audit & Research Centre
- Sponsor type
- University, hospital or other
- Collaborators
- North Bristol NHS Trust
- Responsible party
- Sponsor
- Investigators
- Matt Thomas, MD, Principal investigator, North Bristol NHS Trust
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04219384
- Sponsor's protocol ID
- ICNARC/02/11/2019
- Acronym
- CIRCA
- Status last verified
- Nov 2026
- First submitted
- 21 Nov 2019
- Last updated
- 5 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: An anonymised study dataset will be available from ICNARC on request to the Chief Investigator, subject to any necessary approvals
Publications
Darnell R, Broomhall J, Newell C, Gendall E, Harrison D, Rowan K, Doidge J, Mouncey P, Gould D, Thomas M. Critical Illness Related Cardiac Arrest (CIRCA): a prospective investigation of the incidence and outcome of cardiac arrest within intensive care units in the United Kingdom. Resuscitation. 2026 Feb;219:110933. doi: 10.1016/j.resuscitation.2025.110933. Epub 2025 Dec 22.
PubMed 41443583Darnell R, Newell C, Edwards J, Gendall E, Harrison D, Sprinckmoller S, Mouncey P, Gould D, Thomas M. Critical illness-related cardiac arrest: Protocol for an investigation of the incidence and outcome of cardiac arrest within intensive care units in the United Kingdom. J Intensive Care Soc. 2022 Nov;23(4):493-497. doi: 10.1177/17511437211055899. Epub 2022 Mar 13.
PubMed 36751345
Study at a glance
From the registry record, last updated by the sponsor on 5 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Critical Illness Related Cardiac Arrest (CIRCA): an Investigation of the Incidence and Outcome of Cardiac Arrest Within Intensive Care Units in the United Kingdom
- ClinicalTrials.gov ID
- NCT04219384
- Acronym / sponsor ID
- CIRCA / ICNARC/02/11/2019
- Conditions
- Critical Illness
- Keywords
- Critical Illness Related Cardiac Arrest
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 1,320 participants (actual)
- Lead sponsor
- Intensive Care National Audit & Research CentreUniversity, hospital or other
- Collaborators
- North Bristol NHS Trust
- Study start
- 27 Jan 2020 (actual)
- Primary completion
- 1 Oct 2021 (actual)
- Study completion
- 1 Oct 2022 (actual)
- First posted
- 7 Jan 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
CIRCA aims to determine the incidence and outcomes of in-hospital cardiac arrest (IHCA) in UK intensive care units (ICUs) and explore associated risk factors with ICU and hospital survival and quality of survival following hospital discharge.
Detailed description
Cardiac arrest is often categorised by location, out-of-hospital or in-hospital (IHCA), as there are important differences in population characteristics and aetiology. The National Cardiac Arrest Audit (NCAA) was established to audit resuscitation teams in response to IHCA, and collects information about patient characteristics, resuscitation processes, and patient outcomes. However, it does not audit IHCAs that are not attended by the resuscitation team.
Critically ill patients managed in ICUs are experiencing failure of one or more organs and therefore more intensive and invasive therapies are needed to support these failing organs. As a result, ICUs have higher nursing and medical staffing ratios, and monitoring is usually continuous. Moreover, the skill mix of the multidisciplinary team is geared to advanced life support. Thus, the risk of cardiac arrest occurring, the involvement (or not) of the resuscitation team, and the probability of return of spontaneous circulation are all likely to be different to other IHCAs.
Accurate data on cardiac arrests in ICU are lacking and the investigators do not know how many IHCA occur in ICU in the UK, nor is the impact of an IHCA in ICU on outcome known. In addition, it is not known if these IHCAs in ICUs represent an unavoidable consequence of critical illness or, more importantly, whether they can be predicted and/or prevented.
CIRCA is a prospective, multi-centre observational cohort study nested in the Case Mix Programme (CMP) and NCAA national clinical audits. The investigators aim to determine the incidence and outcomes of IHCA in UK ICUs and explore associated risk factors with ICU and hospital survival and quality of survival following hospital discharge.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Critical-illness related cardiac arrest (CIRCA) | – | –Those experiencing a critical illness-related cardiac arrest in a participating adult, general ICU |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- Adults having cardiac arrest (defined as receipt of chest compressions and/or defibrillation) after admission to an Intensive Care Unit (ICU) participating in the Case Mix Programme in a hospital participating in the National Cardiac Arrest Audit
Key inclusion criteria (3 listed)
- Age 18 years old or more; and either
- Cardiac arrest (defined as receipt of chest compressions or defibrillation) occurring while in-hospital and within intensive care (defined as either ICU, HDU or combined ICU/HDU); or
- Family member of a patient surviving to discharge from intensive care after a cardiac arrest within ICU
Key exclusion criteria (1 listed)
- There are no exclusion criteria
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Incidence
Time frame: Up to 12 months
Incidence of critical illness related cardiac arrest
12 secondary outcomes
Subsequent incidence of in-hospital cardiac arrest
Time frame: Up to 12 months
Survival status at hospital discharge
Time frame: Up to 12 months
Survival status at 12 months
Time frame: 12 months
Patient quality of life measured through EQ-5D-5L questionnaire completion at 3 months
Time frame: 3 months
Patient quality of life measured through EQ-5D-5L questionnaire completion at 6 months
Time frame: 6 months
Patient quality of life measured through EQ-5D-5L questionnaire completion at 12 months
Time frame: 12 months
Patient quality of life measured through IQCODE questionnaire completion at 3 months
Time frame: 3 months
Patient quality of life measured through IQCODE questionnaire completion at 6 months
Time frame: 6 months
Patient quality of life measured through IQCODE questionnaire completion at 12 months
Time frame: 12 months
Family member quality of life measured through FROM-16 questionnaire completion at 3 months
Time frame: 3 months
Family member quality of life measured through FROM-16 questionnaire completion at 6 months
Time frame: 6 months
Family member quality of life measured through FROM-16 questionnaire completion at 12 months
Time frame: 12 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Nov 2026.
- Derived from this study: PubMed 41443583Darnell R, Broomhall J, Newell C, Gendall E, Harrison D, Rowan K, Doidge J, Mouncey P, Gould D, Thomas M. Critical Illness Related Cardiac Arrest (CIRCA): a prospective investigation of the incidence and outcome of cardiac arrest within intensive care units in the United Kingdom. Resuscitation. 2026 Feb;219:110933. doi: 10.1016/j.resuscitation.2025.110933. Epub 2025 Dec 22.
- Derived from this study: PubMed 36751345Darnell R, Newell C, Edwards J, Gendall E, Harrison D, Sprinckmoller S, Mouncey P, Gould D, Thomas M. Critical illness-related cardiac arrest: Protocol for an investigation of the incidence and outcome of cardiac arrest within intensive care units in the United Kingdom. J Intensive Care Soc. 2022 Nov;23(4):493-497. doi: 10.1177/17511437211055899. Epub 2022 Mar 13.
- Individual participant dataSharing planned: Yes. An anonymised study dataset will be available from ICNARC on request to the Chief Investigator, subject to any necessary approvals
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Matt Thomas, MD principal investigator
North Bristol NHS Trust
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Critical Illness, run by Intensive Care National Audit & Research Centre at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence (time frame: Up to 12 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04219384, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Nov 2026.