It is one of the cardinal rules of surgical preparation; NOTHING by mouth after midnight, or NPO after MN. That is one of the easiest and most clear cut ways for an anesthesiologist to cancel a case. The surgeon will rarely argue with an anesthesiologist on this point. Some anesthesiologists adhere to this rule so strictly that they will cancel a procedure if the patient is even found chewing gum before surgery.
The reason we discourage patients from eating or drinking anything before receiving anesthesia is that we don't want any contents in the stomach during the procedure. If the stomach is full of food or liquids, there is a risk that the patient will vomit the half digested gastric bolus while under sedation and aspirate it into the lungs. This could lead to severe aspiration pneumonia and possibly death. The doctors and the hospital frown upon unexpected operating room deaths.
But now NPO after MN maybe getting a closer scrutiny. The American Society of Anesthesiologists has for years recommended that cases can proceed if the patient has only clear liquids up to two hours before surgery. Clears means anything that one can see through. Water is obviously considered clears. So is apple juice, grape juice, and, surprisingly, black coffee. Milk, orange juice, and coffee with cream are not clear liquids.
Now a study has been released that may actually encourage doctors to recommend patients have a drink before an operation. As Anesthesiology News reported, researchers at Texas Tech University Health Sciences Center had one group of patients drink a carbohydrate rich clear drink two hours before surgery and another group remain fasting after midnight. Not surprisingly, the group who got to drink before surgery felt less thirsty before their operation. But they also felt significantly less anxiety and greater comfort overall. The researchers concluded that perhaps patients should be allowed to drink clear liquids before they have their surgeries.
First of all I think that is a fine idea that should be further explored. While I would hesitate to let a patient drink as much as these study patients did, 360 mL of fluid which is a little more than one can of soda, I think a couple of gulps wouldn't hurt. We frequently ask our patients to take their medications with small sips of water before coming to the hospital and I don't know of anybody who has aspirated because of that.
Let's face it, NPO after MN is rather barbaric. No elective surgery starts at 2:00 AM. It is especially cruel if the patient's operation isn't scheduled until the early afternoon like 1:00 PM. Is the patient supposed to go without food or water for that long? They can do it but it is not comfortable. Plus by the time the patients comes to preop, they are so dehydrated that it makes starting an IV more difficult. The only reason we tell patients not to eat or drink anything after midnight, even for late starting procedures, is that just in case an early procedure gets cancelled, we can move another patient up without worrying about whether he had just drank something. The last thing the hospital wants is for an expensive operating room to sit empty while we wait for the two hour window to pass.
So let's do patients a favor and consider letting them drink a refreshment up to two hours before surgery. They will feel better when they come to preop. If they are happy, they will make your life better too.