Re: why can't patients scheduled for surgery consume beverages or food?

Your question raises a critical point regarding patients safety. 
Basically, the risk induced by anesthesia is the risk of asphyxia, leading 
to poor oxygen delivery to the brain, and therefore permanent post 
operative damage (e.g. chronic coma).
This mishap is due to two leading causes:
- the first one is "cannot intubate (i.e. cannot put a tube in the trachea) 
and cannot ventilate (i.e. cannot make oxygen go deep enough in the lungs). 
This is a real nightmare for anesthesiologists (and for patients as 
well..). Doctors put a special emphasis on highlighting high risk patients 
during the preoperative visit
- the second one is inhalation of gastric content. When you are put asleep, 
you loose your gag and cough refelexes (think to what happens when you 
swallow in the wrong way, and that a drop of water or coffee goes into your 
trachea. You cough, and cough, until all the liquid has been expelled). The 
danger is therefore that your gastric content is regurgitated and returns 
into your trachea and lungs. THer consequence is both pulmonary burns (your 
gastric content is acid, very acid: pH close to 2!) and secondary infection 
due to food.
Starving rules are nowadays well established:
- adults should remain NPO (nothing per os) for at least 6 hours before 
anesthesia
- breast fed newborns and infants for 4 hours
- non particular fluids (apple juice, plain water) are in some 
circumstances allowed until 2 hours before anesthesia

In summary, NPO rules are designed for patients' safety, in order to 
prevent aspiration of gastric content leading to real tragedies. If you are 
planned for anesthesia in the weeks to come, I suggest you closely follow 
the NPO instructions given to you. Feel free to ask your anesthesiologist 
any extra explanation if needed.

A "smiling" personal observation: a few months ago, a young girl, 2 years 
old, was scheduled for "minor" (I hate that word, regarding anesthesia) 
ophtalmologic surgery. Her elder sister was 7 years old. The little girl 
had no breakfeast that morning. Parents and the two children drove for 30 
minutes from home to the hospital. While parking the car in front of the 
pediatric ward, the mom became aware that the little girl was chewing 
something. It was a donut. "How did you get that?". The elder sister 
explained: "Mom, you forgot to give Anne something to eat, this morning. So 
I took a donut in the kitchen, and gave her during the trip. She was very 
hungry, you know..........." Surgery was posponed for 24 hours, and all 
went well.

Luc

Luc A Ronchi, MD
Ped Anaesth
Hopital de St Nazaire