SNAP-2 Outline


SNAP-2: EpiCCS will be the second Sprint National Anaesthesia Project, managed by the National Institute of Academic Anaesthesia - Health Services Research Centre (NIAA-HSRC) in conjunction with the UCL/UCLH Surgical Outcomes Research Centre (SOuRCe).

SNAP-2: EpiCCS will describe the epidemiology of perioperative risk and outcome, and critical care referral and admission after inpatient surgery in the UK. A secondary aim is to estimate the clinical effectiveness of planned postoperative critical care admission as an intervention to reduce postoperative morbidity.

Background and Rationale

SNAP-2: EpiCCS aims to provide a 'snapshot' of clinical activity in hospitals throughout the UK over a one week period in March 2017. The exact dates will be publicised in due course.

Surgical morbidity and mortality is a well-described public health issue. An estimated 313 million operations take place world-wide each year. Morbidity or complications after surgery occur up to ten times more frequently than short-term mortality and are associated with reduced long-term survival, even after accounting for known preoperative patient-related risk factors. Planned postoperative critical care admission is recommended for the "high risk surgical patient"; cohort studies reveal that despite this, the majority of patients undergoing non-cardiac, non-neurological surgery who die before hospital discharge do not have planned critical care admission after surgery.

SNAP-2: EpiCCS will explore the referral patterns and resource limitations which may be responsible for patients not being admitted to critical care, despite being high risk according to national guidelines. In particular, we will explore the areas of Quality and accuracy of risk stratification, Critical Care bed capacity, and Clinical uncertainty that critical care admission would be of benefit.

Study Design

EpiCCS will be a prospective observational cohort study with three principle components:

  • Main EPICCS patient study
    All patients undergoing inpatient surgery (elective or emergency) during the study week will be enrolled onto the main EPICCS study.
  • Quality of Recovery sub-study
    Patients undergoing surgery on a single day in each Trust will be given a participant information sheet on admission to hospital. They will then be approached to complete a preoperative QoR questionnaire - if they agree to do so, this will be taken as evidence of implied consent. By random allocation, hospitals will be asked to collect QoR sub-study data on patients undergoing surgery on either Monday, Tuesday, or Friday.
  • Clinicians sub-study
    All anaesthetists and surgeons who undertake perioperative care for inpatient surgery during the study period will be invited to participate. If they decline, they will be asked to provide the reason why. If they agree and complete the questionnaire, this will be taken as evidence of implied consent.
    Additionally, an organisational questionnaire for each hospital will be completed to describe structure and process in those institutions, and critical care unit occupancy at regular time-intervals throughout the one-week data collection period.

Ethical considerations

The three part nature of SNAP-2: EpiCCS study will require three types of participant, with differing approaches to consent for each type:

  • Main EpiCCS patient study: Section 251 exemption to be sought
    To be able to collect patient data without consent, we will apply for Section 251 exemption. The reason for a non-consenting approach is an attempt to avoid sampling bias. It is likely that patients who are of higher perioperative risk will be unable or unwilling to provide consent - we have data from SNAP-1 to support this assertion.
  • QoR patient sub-study: implied consent approach
    We will use an implied consent approach for this study. All patients will be given a participant information sheet (PIS) as early as possible on the day of surgery. Patients will be asked to complete the first questionnaire before their surgery; on the form we will ask patients to provide contact details (telephone number) for postoperative follow-up. If a patient declines consent, or is unable to complete the follow-up questionnaire, this will be recorded in a local screening log. The implied consent approach was used for collection of similar data in the SNAP-1 study.
  • Clinicians' perceptions sub-study: implied consent approach
    We propose an implied consent approach, with completion of the questionnaire as evidence of consent. Every perioperative anaesthetist and surgeon during the study week will be asked to complete a questionnaire which explores their approach to risk stratification and postoperative care. Given that there are national guidelines regarding these questions, we are keen to provide reassurance to perioperative anaesthetists and surgeons that their responses will be used in confidence, without risk of litigation or reprisal. If anaesthetists or surgeons choose not to answer the questionnaire, then they will be asked to provide a reason why, for the purposes of analysis.

Inclusion Criteria

Adult ( >=18 years ) patients undergoing surgery or other interventions who are expected to require overnight stay in hospital which require the support of an anaesthetist. These would include all procedures taking place in an operating theatre, radiology suite, endoscopy suite or catheter laboratory for which inpatient (overnight) stay is planned, including both planned and emergency/urgent surgery of all types, Caesarean section, surgery for complications of childbirth, endoscopy and interventional radiology.

Exclusion Criteria

Patients who indicate they do not want to participate in the study; Ambulatory surgery; children (<18 years); non-surgical obstetrics; ASA-PS grade VI; non-interventional diagnostic imaging (e.g. CT or MRI scanning without interventions); emergency department or critical care interventions requiring anaesthesia or sedation but no interventional procedure.

How will SNAP-2: EpiCCS work in my hospital?

The intention is that data collection at each site will be managed predominantly by anaesthetic trainees, with support from consultants and research nurses, under the supervision of a Local Principal Investigator who may be the Quality Audit and Research Coordinator (QuARC), the departmental audit lead, the clinical director, or another nominated representative. We are applying for adoption onto the NIHR portfolio; as the main study will not be a consenting study, this will not count towards your local target recruitment to NIHR studies; however, both the clinician perception and Quality of Recovery sub-studies will be consenting studies and therefore should count towards NIHR accruals. This should mean that you can access support for recruiting to the study from NIHR funded Clinical Research Network nurses. Your local NIHR Clinical Research Network lead, or your local R&D office should be able to provide you with support and information. As soon as we have more details about our portfolio status, we will post it here and tweet via our Twitter handle @SNAP2EPICCS.

How do I get involved?

At the moment we are still in set-up for SNAP-2. Over the next few months, we will contact SNAP-1 local lead investigators to ask them to register their Trust's interest in the study. If you are a trainee or consultant who would like to be involved, please stay in touch via our Twitter feed @SNAP2EPICCS.


  • To collect data on all patients undergoing inpatient surgery for one week in UK NHS hospitals.
  • To measure and analyse patient-level estimates of perioperative risk using previously validated risk prediction tools to determine their accuracy (discrimination and calibration) in a comprehensive national sample.
  • To use three different analytic techniques (regression, instrumental variable and propensity score matched analyses) to measure the relationship between patient risk factors, postoperative critical care admission and patient outcomes (morbidity mortality and quality of recovery).
  • To survey anaesthetists and surgeons on their attitudes and behaviours regarding risk prediction and postoperative critical care admission.