SNAP2 (EpiCCS)

SNAP2 (EpiCCS) aimed to provide a 'snapshot' of clinical activity in hospitals throughout the UK over a one week period in 2017.

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.

SNAP2 (EpiCCS) explored 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 explored the areas of quality and accuracy of risk stratification, critical care bed capacity, and clinical uncertainty that critical care admission would be of benefit.

EpiCCS was a prospective observational cohort study with two principle components:

• Main EpiCCS patient study
  All patients undergoing inpatient surgery (elective or emergency) during the study week were enrolled onto the main EpiCCS study.
• Clinicians sub-study
  All anaesthetists and surgeons who undertook perioperative care for inpatient surgery during the study period were invited to participate. If they declined, they were asked to provide the reason why. If they agreed and completed the questionnaire, this was taken as evidence of implied consent.

Additionally, an organisational questionnaire for each hospital was 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.

The two part nature of SNAP2 (EpiCCS) study required two types of participant, with differing approaches to consent for each type:

• Main EpiCCS patient study: Section 251 exemption 
  To be able to collect patient data without consent, we were granted a Section 251 exemption. The reason for a non-consenting approach was an attempt to avoid sampling bias. It is likely that patients who are of higher perioperative risk would be unable or unwilling to provide consent - we have data from SNAP1 to support this assertion.
• Clinicians' perceptions sub-study: implied consent approach
  We proposed an implied consent approach, with completion of the questionnaire as evidence of consent. Every perioperative anaesthetist and surgeon during the study week was asked to complete a questionnaire which explored their approach to risk stratification and postoperative care. Given that there are national guidelines regarding these questions, we were keen to provide reassurance to perioperative anaesthetists and surgeons that their responses would be used in confidence, without risk of litigation or reprisal. If anaesthetists or surgeons chose not to answer the questionnaire, then they were asked to provide a reason why, for the purposes of analysis.

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

Patients who indicated they did 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.

• 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.

Please click here for SNAP2 Study Documents, including the protocol, ethics information, and help sheets.