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© 2000 International Anesthesia Research Society
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Abstract |
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A more tolerant approach to preoperative fasting guidelines for healthy adults undergoing elective surgery was recently recommended by a task force appointed by the American Society of Anesthesiologists. This recommendation liberalizes the intake of clear liquids and specifically allows a light breakfast (e.g., toast and tea or coffee) up to 6 h before elective surgery. We conducted a national survey to determine whether anesthesiologists giving anesthesia in an outpatient setting in the United States were currently following these recommendations, and whether institutional policy reflects these new guidelines. The population consisted of the entire active membership of the Society for Ambulatory Anesthesia, providing an initial sample size of 623 subjects. Most conservatively calculated, we had a response rate of 59.6%. A total of 62% of the respondents said they have an institutional policy in place to allow clear liquids orally 2–3 h before the induction of anesthesia. However, only 35% of the respondents said their institutions had a policy in place allowing a light breakfast 6 h before elective surgery. Nevertheless, only 3% of the responders said they would cancel the operation if a patient actually arrived at the facility after consuming a light breakfast, such as toast and tea 6 h before elective surgery, 32% would delay surgery to later that day, and 65% would proceed without delay. We concluded that most anesthesiologists practicing outpatient anesthesia in the United States have already changed their practice pattern to conform to the recent recommendations of the American Society of Anesthesiologists task force on preoperative fasting time.
Implications: Findings of this national survey conducted among active members of the Society for Ambulatory Anesthesia may encourage anesthesiologists throughout the world to take a more liberal attitude toward allowing clear liquids 2–3 h and a light breakfast 6 h before an elective surgery in healthy patients.
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Introduction |
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In 1883, Baron Joseph Lister, an English surgeon wrote, "While it is desirable that there should be no solid matter in the stomach when chloroform is administered, it will be found very salutary to give a cup of tea or beef-tea two hours previously" (1). Most anesthesiologists and surgeons throughout the world followed the essence of that advice for many decades. Then, in 1946, the well known paper by Mendelson (2) revealed an alarmingly high incidence of pulmonary aspiration during general anesthesia (GA) in obstetrics. At approximately that time, the traditional practice of nothing by mouth after midnight was firmly established in clinical practice. In complying with this universal practice, physicians were ignoring the already recognized differences in the exit times of solid foods and clear liquids from the stomach (3,4).
As outpatient surgery gained popularity throughout the 1980s, investigators recommended liberalization of preoperative fasting guidelines, specifically regarding clear liquids (5). A number of studies showed that clear liquids ingested 2–3 h before an elective surgery did not increase residual gastric volume nor the risk of pulmonary aspiration (6–7). In 1996, a national survey on practice patterns (8) showed that 68% of practicing anesthesiologists allowed clear liquids 2–4 h before an elective surgery in children, and approximately 41% would allow the same in adults. However, only 28% of the facilities surveyed had actually updated their institutional policies to include this new recommendation.
More recently, in 1996, the American Society of Anesthesiologists (ASA) appointed a task force to recommend a practice guideline for fasting before elective surgery. The recommendations of this task force were accepted by the ASA in October 1998. The resulting report was published in the journal, Anesthesiology, and in a well known textbook (9,10). These recommendations state that a healthy patient may be allowed clear liquids (e.g., water, clear fruit juice etc.) up to 2 h before an elective surgery; human breast milk 4 h before surgery; nonhuman milk 6 h before surgery; a light breakfast (e.g., toast and tea) 6 h before surgery; and solid food 8 h before surgery. Are anesthesiologists in the United States following these recent guidelines, especially about the recommendation to allow a light breakfast 6 h before an elective operation? To answer that question, we conducted a national survey among the active members of the Society for Ambulatory Anesthesia (SAMBA). We hypothesized that anesthesiologists currently practicing elective outpatient anesthesia in the United States would not allow a light breakfast 6 h before surgery.
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Methods |
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A questionnaire with 17 simple questions was prepared and sent to a randomly selected sample of all active SAMBA members who currently practice in the United States. A total of 1869 eligible members were stratified by geographical location of practice by state and a random sample drawn of every three consecutive names toward systematic selection, which yielded 623 potential respondents. We determined that, at a 60% response rate, the margin of error (twice the standard error of an estimated proportion or mean) would be <5% for an estimated proportion near 0.5. As responses were received, they were entered into a database to be later tabulated and analyzed. The survey was conducted between June and December 1999.
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Results |
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Of 623 questionnaires sent, 378 members responded. The US Post Office returned another 30 envelopes because of unknown addresses. Of the 378 responders, 17 stated that they were retired and chose not to answer any questions. The least conservative approach to calculation would yield a response rate of 62.7% (378 minus 17 of 623 minus 47). By considering the 17 retirees as nonresponders, the response rate is 61% or (378 minus 17 of 623 minus 30). Most conservatively calculated, the response rate would be 59.6%, (378 minus 17 of 623 minus 17). Sixty-four percent of responders were primarily hospital based, 34% were surgery center based, and 2% were office based. Although 15 yr of practice was the mode with a median of 17 yr, responder-years-in-practice ranged from 3 to 50 yr.
In regard to whether their institutional policy allowed clear liquids 2–3 h before elective surgery, 62% of the institutions did, 37% did not, and 1% provided no response. However, 79% would not allow coffee or tea with milk or cream 2–3 h before anesthesia and 21% would or might. However, 68% would allow human breast milk 4 h before surgery.
Only 35% of responders had an institutional policy allowing a light breakfast, such as tea and toast, 6 h before an elective surgery under GA; 64% did not allow a light breakfast. Affirmative responses were higher (46% vs 35%) if the patient were to have only monitored anesthesia care or regional anesthesia. However, responses changed when the question was asked differently. That is, when asked, if they discovered that a patient had consumed a light breakfast, such as toast and tea 6 h before the scheduled time of the induction of GA for an elective outpatient surgery, only 3% would cancel, 65% would proceed as planned, and 32% would delay the procedure to later the same day. Of those who said their practice policy about a light breakfast had changed, 84% said they had no reason to regret their decision to allow the patient a light breakfast 6 h before anesthesia. Only 7% said yes to this question and 9% had no response. Of the 7% with regrets, several volunteered that the problems they encountered were related to schedule changes. None reported pulmonary aspiration.
Toast and tea or coffee was by far the most often allowed breakfast. Other acceptable foods included were bread, sugar cookies, soup, crackers, Jell-O, cereal, low-fat milk, and fruit. Many responders noted that the toast should not be buttered or lightly buttered. Foods not allowable were fatty foods, greasy food, any solid meat (sausage, bacon, steak, chicken), whole milk, eggs, cheese, fried foods, or a heavy breakfast.
If the patient had consumed solid food (rather than a light breakfast) 8 h before the scheduled elective surgery, 9% of responders would cancel the surgery, 10% would delay the start time, and 81% would proceed as planned.
Practice patterns did not vary by state for preoperative fasting times. Additionally, there were no consistent common characteristics among nonresponders to explain their reluctance to participate in the survey (e.g., the state of practice, years in practice, or site of primary practice, such as hospital, surgery center or office setting).
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Discussion |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Active SAMBA members represent a cross section of anesthesiologists who practice outpatient anesthesia in the United States. A response rate of 60% to 63% is an adequate return for a self-administered mail survey. It is not surprising that most active SAMBA members (62%) now have an institutional policy in place to allow clear liquids to be consumed by patients (adults and children) two to three hours before an elective surgery. This percentage is significantly more than what a previous national survey (8) showed (28%) approximately six years ago. Although tea and coffee are included as clear liquids, the majority of the anesthesiologists (79%) would not allow milk or cream in the coffee or tea. Lack of data on this issue may be the reason for this cautious approach.
As the results of a similar national survey (8) conducted in 1993 show, institutional policy change always lags behind the practice patterns of physicians. On the question of light breakfast, we find the same lag in our survey. Whereas only 35% of the respondents said an institutional policy about light breakfast before elective operation was already in place at their respective facilities, 97% would not cancel the case if their patient had actually consumed a light breakfast six hours before the scheduled elective surgery. This is a major shift from the known practice patterns of 10 to 15 years ago. At that time, any patient discovered to have deviated from the strict traditional "nothing by mouth after midnight" rule would have been automatically canceled.
It was assumed for years that the incidence of regurgitation of stomach content and pulmonary aspiration are related directly to the residual gastric volume. However, a close scrutiny of the existing data by the ASA task force could not establish that link (9). Ranging from a study by Beaumont (3) as early as 1834, to a more recent one by Minami and McCallum (4) in 1984, investigators have demonstrated that liquids and solids behave differently after being ingested. Thus, there should be little controversy regarding consumption of clear liquids two to three hours before an operation. However, the variability of gastric emptying is more pronounced after solid food. Factors that influence the gastric emptying time for solid food include type of food (i.e., proportion of carbohydrate, protein, and fat), body posture after food intake, exercise, meal weight, caloric density, size of the food particles swallowed, and total amount of food (11,11a).
Compared with the large number of studies addressing the implications of allowing clear liquids two to three hours before surgery, only a few address the question of allowing solid food before surgery. The absence of an easy and readily available method of assessing gastric contents after solid food in the perioperative period may be the reason for this paucity of interest. Miller et al. (12) gave patients a light breakfast consisting of a slice of buttered toast, and a cup of tea or coffee with milk two to four hours before surgery and measured gastric contents after the induction of anesthesia by inserting a gastric tube. They concluded there was no significant difference in gastric volume or pH between the control group (fasting) and the study group. Soreide et al. (13) gave healthy female volunteers a standard hospital breakfast consisting of one slice of white bread with butter and jam, one cup (150 mL) of coffee without milk or sugar, and one glass (150 mL) of pulp-free orange juice. Gastric contents were measured by repeated ultrasonography and paracetamol absorption techniques. No solid food could be detected in the stomach in any subject 240 minutes after ingestion of breakfast. They concluded that at least four hours is needed for solid food to empty from the stomach before an operation. In light of these known facts about the physiology of gastric emptying, duration of fasting and types of food for light breakfast allowed by the respondents in this survey appear sensible.
Although we surveyed only members of SAMBA, our conclusions should apply to all elective surgeries. Almost 80% of all elective surgeries today are either ambulatory or same-day admittance. A total of 64% of survey responders are primarily hospital based. Policies and practices regarding the preanesthetic preparation, such as fasting guidelines, for all elective surgery including ambulatory surgery are the same.
We conclude that the majority of the active members of the SAMBA are already following the practice guidelines proposed by the ASA task force on preoperative fasting. 
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Acknowledgments |
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We would like to thank James M. Lepkowski MPH, PhD, University of Michigan, Ann Arbor, Michigan, for his advice on the survey methodology. We are particularly thankful to all Society for Ambulatory Anesthesia members who promptly responded to our questionnaire.
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Footnotes |
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Presented, in part, at the 74th Congress of the International Anesthesia Research Society (IARS) at Honolulu, HI, March 10–14, 2000.
Address correspondence and reprint requests to Sujit K. Pandit, MD, Department of Anesthesiology, University of Michigan Health System, 1G323 University Hospital, Box 0048, 1500 E. Medical Center Dr., Ann Arbor, MI 48109-0048. Address e-mail to psujit@umich.edu.
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References |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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Strunin L. How long should patients fast before surgery? time for new guidelines. Brit J Anaesth 1993;70:1–3.
[Free Full Text] - Mendelson CL. The aspiration of stomach contents into the lungs during anesthesia. Am J Obstet Gynecol 1946;52:191–205.[Web of Science]
- Beaumont W. Experiments and observations on the gastric juice and physiology of digestion. Boston:Lily, Wait, 1834:159–60.
- Minami H, McCallum RW. The physiology and pathology of gastric emptying in humans. Gastroenterology 1984;86:1592–610.[Web of Science][Medline]
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Maltby JR, Sutherland AD, Sale JP, Shaffer EA. Preoperative oral fluids: is a five hour fasting justified? Anesth Analg 1986;65:1112–6.
[Abstract/Free Full Text] - Schreiner MS, Triebwasser A, Keon TP. Ingestion of liquids compared with preoperative fasting in pediatric outpatients. Anesthesiology 1990;72:593–97.[Web of Science][Medline]
- Maltby JR, Lewis P, Martin A, Sutherland LR. Gastric fluid volume and pH in elective patients following unrestricted oral fluid until 3 hours before surgery. Can J Anaesth 1991;38:425–9.
- Green CR, Pandit SK, Schork MA. Preoperative fasting time: is the traditional policy changing? A national survey. Anesth Analg 1996;83:123–8.[Abstract]
- Warner MA, Epstein BS, Gibbs CP, et al. Practice guidelines for preoperative fasting and the use of pharmacologic drugs to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures. Anesthesiology 1999;90:896–905.[Web of Science][Medline]
- Miller RD, ed. Anesthesia. 5th ed. New York, NY: Churchill Livingston, 2000:2852–61.
- Moore JG, Christian PE, Coleman RE. Gastric emptying of varying meal weight and composition in man: evaluation by dual liquid and solid-phase isotopic method. Dig Dis Sci 1981;26:16–22.[Web of Science][Medline]
- Moukarzel AA, Sabri MT. Gastric physiology and function: effects of fruit juices. J Am Coll Nutr 1996;15:18S–25S.[Abstract]
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Miller M, Wishart HY, Nimmo W. Gastric contents at induction of anesthesia. is a 4-hour fast necessary? Br J Anaesth 1983;55:1185–8.
[Abstract/Free Full Text] - Soreide E, Hausken J, Soreide JA, Steen PA. Gastric emptying of a standard hospital breakfast: a study using real time ultrasonography. Acta Anaesth Scand 1996;40:549–33.[Web of Science][Medline]
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