Anesthesia FAQs

Why can't I eat or drink before my surgery/procedure?

Answer:
The purpose of fasting guidelines is to minimize the volume of stomach contents. Depression of our protective reflexes occurs during anesthesia. One of the most basic protective reflexes is to keep stomach contents from entering the airway. When stomach contents enter the airway, aspiration occurs. Aspiration is less likely to happen when the stomach is empty.

Why is aspiration so bad?

Answer:
Solid or semi-solid stomach contents may make exchange of gases in the lungs impossible. Liquid stomach contents that are acidic may burn the lungs and make gas exchange impossible. Both types of aspiration may cause brain damage or death. It is possible to treat aspiration once it occurs and most people survive aspiration, but treatment in an intensive care unit is often necessary. Aspiration may prolong your hospital stay by days to weeks.

Who came up with these guidelines?

Answer:
The durations for fasting are based on analysis of the current medical literature and expert opinion. The American Society of Anesthesiologists and the European Society of Anesthesiologists appointed separate task forces to develop guidelines. Faculty in the Department of Anesthesia at the University of Iowa adapted these guidelines for the University of Iowa Hospitals and Clinics.

When the MRI for my 6 month old was scheduled I was told not to allow clear fluids for 3 hours instead of 2 hour prior to the scheduled procedure start time. Why is the timing different from the guidelines?

Answer:
It may be possible to start your child’s MRI sooner than the scheduled time, so the fasting period is adjusted for both safety and efficiency.

Should I wake my child up two hours before the scheduled time for the procedure or surgery to give him or her clear liquids?

Answer:
Yes, avoiding dehydration is very important. For example, if your 5 year old child’s procedure or surgery is schedule to start at 10:00 o’clock in the morning, you could give up to 4 ounces of a clear fluid up to 6:00 o’clock in the morning. For any particular procedure calculated differences between the actual and scheduled start time may suggest that the start time may be earlier so you may have been told to wake your child and give the fluid at 5:00 am.

I was in an automobile accident and need emergency surgery. I ate just before the accident and it has only been four hours. My doctor says I need the operation now. Why don't I have to wait 8 hours before I can have my surgery?

Answer:
Guidelines assist doctors and patients in making decisions about health care. Fasting guidelines are not intended as standards or absolute requirements. The risk of aspiration must be weighed against the risk of not having surgery in a timely manner. Your anesthesiologist may modify the type of anesthesia to mitigate your risk.

Can I chew gum or suck on hard candy while waiting for my procedure or surgery?

Answer:
Gum and hard candy fall into the category of a “light meal” so a minimum duration of fasting should be 8 hours.

When should I stop chewing tobacco or putting snuff in my mouth before my procedure/surgery?

Answer:
Oral use of chewing tobacco or snuff fall into the category of a “light meal” so a minimum duration of fasting should be 8 hours.

If I take food in through a nasogastric tube (e.g., stomach tube) or a tube directly into my stomach-a "feeding tube" or enteral tube feeding-should I observe the same fasting intervals?

Answer:
Feeding should be stopped at the first sign of increasing stomach residual volumes. Two to four hours fasting following the last feeding is safe if residual volumes are not increasing. Continuous duodenal feedings poses a lesser risk of aspiration than stomach feeding. The urgency of the procedure and the need for continuous nutritional support versus the increased risk of aspiration need to be considered by patients and all the medical specialists involved in patient care.

What about Jello?

Answer:
Jello® is a trade name for one company which produces many forms of gelatins. Gelatins are created when a powder is mixed with water and forms a semi-solid when cooled. Some forms of gelatins may also contain milk products and fat, such as puddings. Scientific studies have found that the gelatin can be found in patients’ stomachs several hours following ingestion. This residual stomach contents poses as an aspiration risk. Anesthesia and sedation following ingestion of gelatin increases the risk of aspiration. Therefore, all gelatins are treated as “food” and the fasting period following ingestion must be 8 hours. Risk and benefit for patient safety regarding the urgency of the procedure following gelatin consumption verses the risk of aspiration must be discussed among the patient and medical specialists involved in the patient’s care.

What about oral contrast?

Answer:
Oral contrast is a mixture of Gastrografin® 50 cc, Black Cherry Drink Mix, and water to form a solution which looks and tastes like Kool-aid®, containing a Ph of about 6.0 to 7.6. When patients are not going to have anesthesia, an adult is required to drink between 800 cc and a liter of oral contrast. Children are asked to drink a certain volume of oral contrast based on age and the type of anesthesia for the procedure (general anesthesia or sedation). Risk and benefit for patient safety regarding the urgency of the procedure following oral contrast consumption verses the risk of aspiration must be discussed among the patient and medical specialists involved in the patient’s care.

Fasting guidelines are specifically designed for elective procedures; what is an "elective procedure"?

Answer:
The University of Iowa Hospitals and Clinics operate using a Triage Schema. Triage priority is based upon patient’s condition. The triage priorities are defined as follows:* Class A – Life, limb, and/or sight threatening condition requiring immediate surgery, and takes precedence over any other case.* Class B – Life, limb, and/or sight threatening requiring immediate surgery within four hours.* Class C – A non-life threatening condition that may lead to severe complications if surgery is not performed within 8 hours of classification.* Class D – A non-life threatening condition but requiring surgery within 24 hours or severe complications will occur.* Class U – Urgent – inpatient referrals or patients admitted who require surgical intervention within 48 to 72 hours; these cases may be worked into the existing schedule.* Elective add-on – a patient/case that does not meet the urgency/emergency criteria of the triage emergency prioritization system.