We greatly appreciate Dr. Sosis’s interest in our paper (1). This also gives us an opportunity to clarify the prevalent ambiguity about types of “clear” liquid that are allowed 2–3 h before elective surgery. Dr. Sosis has asked a very relevant question: is coffee (or tea) a clear liquid? According to the Webster’s dictionary, the word “clear” (adjective) has many meanings. Some of these are, bright, luminous, obvious, plain, cloudless, free from blemishes, free from impurity, transparent, and free from doubt.
Dr. Sosis has interpreted “clear” as “transparent” or colorless, something that we can see through, e.g., water, transparent glass, a noncola drink (such as 7-Up). According to this interpretation, black coffee, plain tea, pulp-free orange juice, some types of apple juice, and cola drinks may not be accepted as “clear” liquid. However, if one takes the other meaning of “clear,” that is, free from blemishes or particulates, then all of the above liquids are actually “clear.” Milk, however, is not a clear liquid, because it forms curd (solid particulate material) as soon as it reaches the stomach. So, adding milk or cream to coffee makes it “unclear.”
We have taken an informal poll among the members of our department, and almost everyone agreed that black coffee and black tea are examples of clear liquid.
Reviewing the published literature, we find that several authors have studied the implications of ingestion of black coffee before elective surgery. Hutchinson et al. (2) and Maltby et al. (3) found that neither the residual gastric volume nor the gastric acidity is increased after ingestion of black coffee (150 mL) or pulp-free orange juice (150 mL) 2–3 h before surgery, with or without ranitidine. Both concluded black coffee and pulp-free orange juice may be safely allowed 2–3 h before the induction of general anesthesia. Shevde and Trivedi (4) gave 240 mL of water, pulp-free orange juice, or black coffee to volunteers and found all volunteers had a gastric volume less than 25 mL with a slight decrease in pH within 2 h of orally taking one of the three 240-mL liquids. They concluded that ingestion of (any of the three) clear liquids (water, pulp-free orange juice, or black coffee) 2 h before general anesthesia is safe.
In summary, it is clear to us, as it is to a majority of practicing anesthesiologists in North America, that black coffee, black tea, apple juice, pulp-free orange juice, cola drinks, and of course, water are examples of clear liquid that could be allowed 2–3 h before elective surgery.
Finally, we would strongly suggest that the title of this correspondence that Dr. Sosis has supplied, “Coffee is Not a Clear Liquid,” is inappropriate, because it sounds like a conclusion. It is not; at best, it is controversial. By looking at the title, a casual reader will get a wrong impression about the controversy. So, we would suggest a title: “Is Coffee a Clear Liquid?”
Sujit K. Pandit MD
Katherine W. Loberg BS
Uma A. Pandit MD
1. Pandit SK, Loberg KW, Pandit UA. Toast and tea before elective surgery? A National survey on current practice. Anesth Analg 2000; 90: 1348–51.
2. Hutchinson A, Maltby JR, Reid CR. Gastric volume and pH in elective inpatients. Part I. Coffee or orange juice versus overnight fast. Can J Anaesth 1988; 35: 12–5.
3. Maltby JR, Reid CR. Gastric volume and pH in elective inpatients. Part II. Coffee or orange juice with ranitidine. Can J Anaesth 1988; 35: 16–9.
4. Shevde K, Trivedi N. Effects of clear liquids on gastric volume and pH in healthy volunteers. Anesth Analg 1991; 72: 528–31.