European Preoperative Fasting Audit (EUROFAST)

A multicentre audit of the incidence of pulmonary aspiration with different fasting regimens.

Principal Investigator: Peter Frykholm, Department of Surgical Sciences, Uppsala
University

Backgroud

The purpose of preoperative fasting is to achieve an empty stomach at the time of anaesthesia induction. Several international associations have accordingly issued guidelines for preoperative fasting. The American Society of Anesthesiology (ASA) recommend fasting intervals of 6 hours for solids, 4 hours for breast milk and 2 hours for clear fluids, respectively.(1) The European Society of Anaesthesiology (ESA) and the Scandinavian guidelines follow the ASA recommendations but differ regarding infant formula where they recommend fasting for 4 – 6 h prior to surgery.(2,3) These current fasting guidelines all take into account the balance between the risk of pulmonary aspiration and the harmful effects of prolonged preoperative fasting. However, there is increased awareness among pediatric as well as general anaesthesiologists that many patients suffer from prolonged duration of fasting in spite of the reasonable nominal respective limits of 6-4-2 hours. Prolonged fasting may be harmful, especially in small children, but also in adults with a poor nutritional status. The latter has been emphasized within the Enhanced Recovery After Surgery (ERAS) concept. (4)(5) The research leading to the recommendation of a minimum of 2-hours fasting for clear fluids mainly focused on proving non-inferiority of this regimen compared to the traditional ‘NPO after midnight’. What we now know about gastric emptying suggests that even shorter fasting intervals may be safe.(5) In accordance with the latter insight, several centres have adopted more liberal fasting regimens for clear liquids and/or a light breakfast of semi-solids. In Sweden and Australia, some paediatric hospitals allow children clear fluids until called to surgery, the 6-4-0 regimens (6,7) and in the UK, several centres are allowing clear fluids until 1 hour prior to anaesthesia induction (the 6-4-1 regimen) in line with a recent publication.(8) Importantly, the incidence of fasting more than six hours was significantly reduced.(9) Accordingly, the European Society for Paediatric Anaesthesia, together with the French and the British national paediatric anaesthesia societies, issued a joint consensus statement, stating that: “based on the current convincing evidence base, unless there is a clear contra-indication, it is safe and recommended for all children able to take clear fluids to be allowed and encouraged to have them up to one hour before general anaesthesia.”(10) The The European Society of Anaesthesia and Intensive Care (ESAIC) recently published a guideline, recommending 6 hours of fasting for solids, 4 for infant formula, 3 hours for breast milk and 1 hour for clear fluids.(11) However, there is still a need for a large multicentre trial to confirm a low incidence of pulmonary aspiration when the new fasting regimen is implemented, to provide more solid evidence of safety and feasibility.

Aim

The primary aim is to determine the safety of reducing the required fasting time for clear fluids to at least one hour in children fasting before elective procedures requiring general anaesthesia (as recommended in the the ESAIC guideline).

Hypothesis: neither the 6-4-0 nor the 6-4-1 fasting regimen increases the risk of pulmonary aspiration compared to the 6-4-2 fasting regimen in children.

Secondary aims are to investigate risk factors for aspiration and real fasting times associated with registered events.

Material and methods

The study has an open prospective non-randomised multi-centre observational cohort design. Hospitals that provide anaesthetic services for children with a volume of at least 1000 cases per year are recruited to participate. Each hospital appoints a local study co-ordinator (LSC) that records the number of procedures with general anaesthesia, if possible the fasting times, and any events of regurgitation or vomiting or suspected aspiration events (SAE) occurring. The LSC supplies monthly reports to the central study co-ordinator (CSC). These reports contain two different sets of information:

1. Denominator data – the number of anaesthetics
2. Numerator data - for each suspected aspiration event, the following information is sought:

• Age, sex, weight and ASA score of the patient.
• Date and time for start of the procedure.
• Type of anaesthesia (General anaesthesia, regional anaesthesia, procedural sedation without planned airway intervention)
• Type of airway (none, face mask, laryngeal mask, intubation, patient already intubated or with tracheostomy)
• Type of induction (mask or i.v.)
• Type of surgery (gastro-intestinal, thoracic, cardiac, genitourinary, neurosurgery, ophthalmologic, ENT/plastic surgery, orthopaedic, dermatologic, non-surgical procedure)
• Was the procedure elective, urgent (within 24 h) or emergency?
• At which stage of the anaesthesia procedure did the SAE occur: induction, maintenance, emergence or recovery?
• Did the SAE lead to chest x-ray examination?
• If so, what was the result (radiologist´s report)
• Did the SAE lead to a higher level of postoperative care than planned?
• If so: increased PACU stay, unplanned over-night admission, observation in HDU or ICU, ventilator therapy, brain damage, death?
• Was the SAE limited to vomiting without desaturation?
• Was the SAE limited to vomiting, coughing and desaturation lasting < 30 minutes
• Was liquid gastric content observed/suctioned from the trachea?
• Was solid gastric content observed/suctioned from the trachea?
• When did the child drink before induction? How much, and which fluid?
• When did the child eat solid food before induction? How much?
• When did the child eat/drink milk-based food or breast milk? How much?
• Which fasting regimen was implemented?
• Had the parents understood the fasting regimen? Had they breached it, willingly or unwittingly?

The CSC collects the monthly reports from each participating centre, sends reminders to the LSCs if needed and compiles the data base. Feedback regarding the progress of the trial will be published on the study website.

Definitions

Vomiting: gastric contents found in the pharynx or mouth; no desaturation < 90%.

Regurgitation: gastric contents found in the pharynx or mouth without any active movement from the patient; no desaturation < 90%.

Suspected Aspiration Event (SAE): coughing or bucking in conjunction with vomiting or regurgitation during or immediately after general anaesthesia. Desaturation < 90%.

Confirmed pulmonary aspiration (CPA): SAE leading to respiratory symptoms that require HDU/ICU admission AND gastric content observed in the trachea OR radiologic findings typical for aspiration pneumonia.

Outcome measures

The primary endpoint is the incidence of confirmed pulmonary aspiration.

Secondary endpoints are the incidences of vomiting or regurgitation without aspiration, suspected aspiration events, the real fasting times and risk factors associated with aspiration and regurgitation events.

Statistical methods

Power analysis: to prove non-inferiority, 60000 children in each group are needed, based on the previously observed incidence of 2 per 10000.(11) Ideally, we would therefore recruit 60000 patients from hospitals implementing the 6-4-2, the 6-4-1 and the 6-4-0 regimens, amounting to 180000 patients. However, since the primary aim is to investigate the safety of the new 6-4-1 regimen, in the amended plan we aim to recruit at least 60 000 elective procedures from centres using the 6-4-1 regimen, and in total up to 200 000 anaesthetic procedures. If this goal has been reached by December 31st 2023 the study will be terminated.

For the primary outcome, the difference between fasting regimens will be analysed by chi-square. If needed, studies with a similar design such as the Walker R et al (2013) will be used for comparison of fasting regimens.(12) For secondary outcomes, ANOVA and logistic regression will be used.

Ethics

EUROFAST is an audit of current paediatric anaesthesia practice using only anonymized data. Ethics permission has been granted from the Swedish Ethics Review Authority, with a waiver concerning informed consent from individual subjects. In some countries, informed consent will be required for the numerator data even if obtained and reported anonymously. Consent for obtaining data will be then be asked for in retrospect by the attending anaesthetist. If informed consent is not obtained, the SAE is classified as suspected aspiration with missing data.

End of study

Recruitment ends on December 31st 2023 if at least 60000 anaesthetics from centres implementing the 6-4-1 regimen have been audited.