None listed
Conditions
Brief summary
Fasting of solids and fluids before general anaesthesia is essential to patient safety in order to reduce the risk of the pulmonary aspiration. The high acidity of stomach contents upon aspiration can cause significant damage to lung tissue. The estimated incidence of pulmonary aspiration is low, ranging between 1/2000 to 1/14000 with morbidity relating to aspiration even lower ranging between 1/4000 to 1/99000. Current fasting guidelines according to American Society of Anesthesiologists recommend a 2-hour fast for clear fluids before general anaesthesia. However, clear scientific evidence supporting this recommendation is lacking and the ideal fasting time and maximal permissible volume for water have yet to be determined. New evidence suggests that water up to 450mls can be safely consumed up to 90 minutes before induction of anaesthesia and that stomach volumes are lower in those who had consumed preoperative water than those who had a fast of 6 hours. Others have demonstrated that preoperative water consumption can also decrease patient thirst and anxiety without adverse effects. The proposed project aims to investigate the effect on stomach contents as measured by level of acidity and volume, following consumption of 200 ml of water up to 45 minutes before general anaesthesia. For this pilot study, approximately 90 elective adult patients scheduled for gastroscopy will be recruited. Patients will be randomly allocated into 2 groups. Both groups will be fasted for solids and clear fluids as per standard guidelines (6 hours for solids and 2 hours for clear fluid) but they will then be randomized to drink 200 ml (standard drinking cup) at 90-150 minutes or 45-60 minutes prior to their procedure respectively. Immediately post induction, gastric content is suctioned and emptied under direct vision via the gastroscope to assess for its volume and pH. This will strengthen the body of evidence that water consumption before general anesthesia up to 45 minutes before anaesthesia has minimal effect on gastric contents and may be potentially beneficial to patients.
Interventions
Comparison of pH and volume of gastric content following two fasting protocols for water before anaesthesia
Arm 1: Standard fasting protocol (fasting for solids for 6 hours, fasting for clear fluids for 2 hours), 200ml water consumption at 45-60 mins prior to anaesthesia
Arm 2: Standard fasting protocol (fasting for solids for 6 hours, fasting for clear fluids for 2 hours), 200 ml water consumption at 90-150 mins prior to anaesthesia
Test water volume: 200ml (standard volume of drinking cup
Comparison of pH and volume of gastric content following two fasting protocols for water before anaesthesia Arm 1: Standard fasting protocol (fasting for solids for 6 hours, fasting for clear fluids for 2 hours), 200ml water consumption at 45-60 mins prior to anaesthesia Arm 2: Standard fasting protocol (fasting for solids for 6 hours, fasting for clear fluids for 2 hours), 200 ml water consumption at 90-150 mins prior to anaesthesia Test water volume: 200ml (standard volume of drinking cup in hospital setting)
Sponsors
Monash Medical Centre
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Blinded (masking used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Adult patients scheduled for elective gastrocopy
Exclusion criteria
Patients who i) are under 18 years of age ii) are not competent in English iii) are pregnant iv) have active upper gastrointestinal haemorrhage v) have achalasia or gastric outlet obstruction vi) have Insulin requiring Diabetes Mellitus vii) has had previous gastric surgery
Outcome results
None listed