Preoperative Fasting: Knowledge and Perceptions


Optimal surgical, anesthesia, andnursing outcomes depend onadequate patient preparation. Preoperative fasting is an essential ele- ment of the patient preparation pro- cess. The goal of fasting is to empty the stomach, thereby reducing the risk of aspiration of stomach contents during the anesthetic period.

Before 1999, the traditional, general guideline for preoperative fasting was that patients should be NPO after mid- night on the day of surgery. In 1999, after examining rele’ant research find- iiigs, the American Society of Anesthesi- ologists (ASA) released new, more lenient preoperative fasting guidelines for healthy, nonpregnant patients. The new guidelines called for preoperative fasting from clear fluids for two hours before any procedure that requires seda- tion or anesthesia as well as fasting from solid foods for at least six hours before anesthesia or sedation is administered. The ASA recommends that these guide- lines be modified for any patient with a condition that affects gastric emptying as well as for patients with potential air- way management issues.’

At a community hospital near Boston, Massachusetts, one staff RN in the Pread- mission Testing area became aware that surgical patients at the facility seemed to be fasting for excessive lengths of time, a perception that was echoed by other perioperative nurses on staff. The hospital was beginning its journey toward Magnet status, and hospital administrators were implementing a nursing research and clinical inx’estigation program. At the urging of the director of nursing staff development and nursing research, the staff RN who had originally identified the problem and a clinical nurse special-

ist in the Surgical Services Department decided to conduct a clinical investiga- tion of preoperahve fasting at this facility. The pLirpose of fhis clinical project was to determine whether patients were fasting excessively and, if so, to explore the atti- tudes and beliefs of surgical patients and their care providers to determine why patients still fast excessively despite re- search findings advocating shorter pre- operative fasting periods and updated fasting guidelines from the ASA.


Many anesthesiologists have changed their practice and no longer require the traditional eight-hour fast before elective surgery. In a national survey of 1,337 ASA members, 94% of the respondents were aware of new literature recom- mending shorter fasting periods before elective surgery, and 68% of those had changed their practice.-

ABSTRAQ PREOPERATIVE PATIENT EASTING is an essential element of the patient preparation process, but pa- tients may be fasting for excessive lengths of time.

INVESTIGATORS AT ONE FACILITY used semi- structured interviews to explore the knowledge and beliefs of patients, nurses, and anesthesia care providers regarding the practice of preoperative patient fasting.

FINDINGS INDICATE that some patients had excessive fasting times, and practitioners had erro- neous perceptions about patient knowledge regard- ing the rationale for fasting and compliance with instructions. Clinicians expressed concern about the effects of excessive fasting but were reluctant to relax the policy. AORN} 86 (October 2007) 609- 617. © AORN, Inc, 2007.

. lnc.2f)07 OCTOBER 2007, VOl 85, NO 4 • AUIÍN lOUkN.-M • 6 0 9

OCTOBER 2007, VOL 86, NO Baril — Portman

One reason for excessive preoperative

patient fasting could be related to a

general mistrust on the part of

practitioners that patients will

understand and comply with their

fasting instructions.

Pandit et aP studied the practices of anesthesi- ologists in the United States and found that 627(1 of participating anesthesiologists had an institu- tional policy in place that allowed patients to ingest clear liquids two to three hours before elective surgery. Thirty-five percent of partici- pants allowed patients to ingest a light breakfast six hovirs before surgery. The researchers deter- mined that the key factors affecting how long patients fast include hospital policy, nurse and anesthesia care provider kiiowledge of current research findings, and patient education regard- ing the length of and rationale for fasting.

Lengthy preoperative fasts have been com- mon. Crenshaw and Winslow^ found that pa- tients fasted for an average of 12 to 14 hours, with some fasting for more than 20 hours. Tra- ditional preoperative fasting instructions (ie, NPO after midnight) were common practice at the time their study was undertaken. Pearse and Rajakulendran’̂ also found excessive fast- ing times in their study. The average fasting time was 12 to 14 hours with an overall range of 4.5 to 20 hours. It appeared that patients were beginning the preoperative fast long before the instructed time.

The literature also revealed several possible reasons for excessive preoperative fasting. One reason is that there seems to be a general mis- trust on the part of practitioners that patients will understand and comply with a fasting policy. One study found that anesthesiologists and surgeons believed that if patients were told that they could ingest clear liquids, they

might also consume solid foods.* Patients’ lack of knowledge regarding the

rationale for preoperative fasting is another factor that may contribute to excessive fasting. Chapman’ found that 85″^ of surgical patients received no explanation for fasting, SI”/» were unaware of the reason for preoperative fasting, and 50% thought the reason for fasting was to reduce vomiting. Only 187« of patients associ- ated vomiting with possible aspiration of gas- tric contents. In addition, Hung’̂ found that surgical patients not only did not know the reason for preoperative fasting, but they also were not comfortable asking their health care providers about it because they did not want to be perceived as demanding.

Another possible reason for lengthy fasting times is concern about rapidly changing surgi- cal schedules. In a study by Green et al,*” anes- thesiologists cited the economic impact of delays and cancellations on the surgical sched- ule as a reason for their reluctance to relax fast- ing guidelines.

An additional factor that contributes to ex- cessive fasting times may be related to health care facilities’ policies on fasting. The absence of a formal fastüig policy or staff members’ inade- quate knowledge of the policy has been found to affect fasting times.”‘” Chapman” interviewed anesthetists, surgical nurses, and patients scheduled for elective surgery regarding their knowledge of recommended preoperative fast- ing guidelines. In the study facility, there was no formal policy for preoperative fasting, and the average fasting time was 11 hours. Half of the anesthetists were aware of current research findings and recommended two- to three-hour liquid fasts; however, participating nurses were unaware of these findings. Chapman attributes the nurses’ knowledge deficit to the fact that at the time her study was performed, most of the published research regarding preoperative fast- ing appeared in medical journals rather than nursing journals.”

Seymour” conducted a study of nurses and anesthetists to assess their knowledge of hospital policy. She reported that less-experienced physi- ciaiis and nurses did not realize that the hospital had a preoperative fasting policy, but 50% of sen- ior nurses and all anesthesia attending physicians


Bari! — Portman OCTOBER 2007. VOL 86, NO 4

were aware of the policy. Patients at this facility still fasted excessively, however, with fasting times ranging from 3.5 to 17.75 hours.

Excessive fasting can lead to patient dis- comfort and may even increase morbidity of surgical patients.” Some researchers suggest that the ritualistic approach to preoperative fasting be reevaluated through collaboration between nurses and anesthesia care providers to allow for more flexible fasting instructions based on current research findings.”‘”


A clinical investigation was conducted at a 200-bed community hospital in a suburb north of Boston. The project participants included anesthesiologists, certified registered nurse anesthetists (CRNAs), registered nurses, and surgical patients. All anesthesia care providers im the permanent staff as well as RNs working in the Preadmission Testing Department, Day Surgery Department, and OR were eligible for inclusion in the project. The patient population included men and women with no history of cognitive deficits who were scheduled for elec- tive surgery and had an ASA Physical Status Classification score of 1 or 2. An ASA score of 1 indicates a normal, healthy patient whose only medical problem is the condition for which surgery is being per- formed. An ASA score of 2 indicates a patient who has at least one medical condition that is under control and does not pose a significant threat to his or her health.”


The investigators developed a series of open-ended inter- view questions that they asked oí eligible patients (n = 34), nurses (n – 15), and anesthesia care providers (n = 12). The content of these interview questions was based on empir- ical data found during the liter- ature review. All participants signed a consent form inform-

ing them of the investigators’ intent to tape- record the interviews, and they were given assurances of confidentiality. Patients were interviewed on the day of surgery either preop- erativeiy or postoperatively. Nurses and anes- thesia care providers were interviewed at a time that was con’enient for them.

All interviews were tape-recorded and tran- scribed word for word. The investigators then analyzed the transcripts to identify themes and major ideas. Tlie tapes and transcripts were kept in a locked area at all times and were destroyed after the data were analyzed.


The average length of the preoperative fast in this clinical project was similar to those noted in the studies performed by Crenshaw and Winsiow^ and Pearse and Raja ku lend ran,’ both of which found an average patient fasting time of 12 to 14 hours, with some patients fast- ing as long as 20 hours. Patients in the current clinical investigation reported fasting for five to 23 hours before surgery, with a mean fasting time of 11.70 hours. Sixty-seven percent of patients fasted for at least 12 hours, and 50% fasted for more than 14 hours (Figure 1).

Time spent fasting

Figure 1 • Length of preoperative fasting times for patient participants.


OCTOBER 2007, VOL 86, NO 4 Baril — Portman

The participants voiced many recurring ideas related to preoperative fasting during the interviews. These included • practitioner concerns about patient compli-

ance with instructions, • confusion among practitioners regarding

who is responsible for instructing patients about the preoperative fast,

• knowledge deficits among patients regard- ing the rationale tor fasting,

• knowledge deficits among practitioners regarding hospital policy on preoperative fasting, and

• practitioner concerns that patients would be confused if allowed to consume clear liq- uids before surgery. 11

From the many different ideas , i that emerged from the inter- ‘ views, the investigators iden- tified three overarching themes: perceptions, safety concerns, and knowledge.


One overarching theme the investigators identified was practitioners’ perceptions re- garding patients’ knowledge about why they need to fast, the extent to which patient noncompliance with fasting affects the surgical schedule, and the effectiveness of the current hospital fasting policy. The interviews revealed that anesthesia care providers’ and nurses’ perceptions were simi- i [ lar on some topics but differed on others.

PATIENTS’ KNOWLEDGE ABOUT FASTING. Anesthesia care providers’ perceptions demonstrated a belief that patients lacked sufficient knowledge about the preoperaHve fasting process. One anesthesia care provider commented, “I think most patients have no clue why they have to fast.” Another stated, “I don’t think they understand NPO.”

The nurses believed that patients either do not understand the instructions given to them or are not given proper instructions to begin

Both nurses and

anesthesia care

providers expressed a

belief that patients

da not know or da not

understand why

they need ta fast


with. One nurse said, “T don’t think anyone explaiiis to them why they have to be NPO after midnight. I think they tell them not to eat anything, but don’t tell them the importance of not eating.” Another nurse commented,

Ma/be they don’t understand what is told to them because they don’t understand their preoperative instructions. They just don’t believe that they have to fast and why they have to fast.

ALTERATIONS TO THE SURGICAL SCHEDULE. Another perception practitioners voiced was a belief that the surgical schedule is altered markedly by patients’ noncompliance with preoperative

fasting instructions. One anesthesia care provider said, “I think we have about 10% who don’t comply with in- structions.” Another noted, “Patients are more comfort- able when they don’t have to be totally NPO, but at the same time, it affects us; some- times the surgery can get cancelled.”

Nurses also believed that lack of compliance with fast- ing instructions can alter the surgical schedule. One nurse noted, “If they’re not instruct- ed properly, it’s not going to work well because they’re going to drink at the wrong time and then foul up the time schedule here.” Another participant said, “It’s for the hospital OR’s benefit to keep

things moving. It’s better for them to have everybody NPO overnight.”

Some anesthesia care providers expressed a preference for having flexibility in the surgical schedule to accommodate last minute changes, which may only work if patients have been fast- ing. One participant stated, “It would be nice if they could have clear liquids, but if the case gets changed, and they get called sooner, then it would interfere.” This sentiment was echoed by another anesthesia care provider, who said.


0CT08ER 2007, VOL 86, NO 4 Bari] — Portman

There is a trend toward giving people a light breakfast in the morning. The problem with that is if your case gets moved up earlier in the day, the patient is denied that spot; and in this institution, when we zoork at such a high pace, that can happen frequently, and it ends up tying it up. So we made a conscious decision not to do that here.

One anesthesia care provider voiced a per- ception that procedures needed to be can- celled or rescheduled 10″/) to 15’X. of the time. In fact, during the six-month data collection period, the actual rate of cancellations due to insufficient preoperative fasting was 0.11% according to the cancellation log. This log, however, only captures cancellations, not patients delayed until later in the day to ac- commodate a short fasting time, and therefore may not adequately reflect the impact on the surgical schedule of patients who are noncom- pliant with fasting instructions.

HOSPITAL FASTING POLICY. At the time this project was undertaken, the hospital fasting policy called for patients to be NPO after midnight with clear liquids allowed in healthy, nonpreg- nant patients up to six hours before surgery. Perceptions differed among practitioners re- garding how well the current hospital policy was working. One nurse voiced the comment, “It’s not working well because each anesthesiol- ogist decides what they’re going to do.” Anoth- er said, “It’s one policy, and it’s supposed to be followed by everyone, but then there are varia- tions depending on the anesthesia person.”

One CRNA noted, “It fluctuates to the point that the surgeon went from one anesthesiolo- gist to another to try to find someone to relax [the policy].” An anesthesiologist stated,

/ think our policy is a little bit flexible so that patients can be moved up, which is important; so that is one way our policy works well. Con- sistency is important because if the nurses have lo give out different policies for different patients, there’s always confusion.

Nurses and anesthesia care providers also were asked their opinion on what the ideal hos- pital policy should be. Nurses expressed the

need for more individualized instructions ac- cording to the time of surgery. One nurse said.

If the patient is having surgery at 5 o’clock in the afternoon and they are fasting since mid- night, IthatJ is way too long. If the surgery is at 7 AM, they can have food at midnight; if thei/ are having surgeiy at 5 PM, ivhy can’t thei/ have food six hours prior to their surgery? Wliat dijference does it make if they are sleeping or not? It just doesn’t make sense to me.

Another nurse stated.

It depends on the time of the patient’s surgery; it should not be “after midnight.” Some patients’ surgery is at 4 o’clock; it should be like eight hours before the surgery. It’s hard; it’s easier just to say, ‘nothing after midnight’ to everybody.

Anesthesia care providers’ responses re- garding the ideal hospital fasting policy varied widely. Among aiiesthesia care providers, • 50% wanted no change to the current hospi-

tal policy; • 25% wanted the policy to become more rigid,

changing to flat NPO for eight hours before surgery with no difference regarding guide- lines for ingesting liquids or solids; and

• 25% wanted to make the policy more liberal in some way.

One anesthesia care provider wanted to fully comply with ASA recommendations, allowing patients to ingest clear liquids up to two hours before surgery and light solids four to six hours before surgery. The other anesthesia care providers who thought the policy should be more liberal wanted to change it for specific populations, with one citing pédiatrie patients and the other citing “minor surgery” patients as the patients who should be allowed more liberal fasting guidelines.

SAFETY CONCERNS Anesthesia care providers and nurses were

asked what they thought patients cared about as well as what they, as practitioners, were concerned with in regard to preoperative fast- ing. The practitioners seemed to believe that

6 1 4 • AORISI JOURNALwhen the report includes participant comments it indicate qualitative

Baril — Portman OCTOBER 2007, VOL B6, NO 4

patients were not concerned about the conse- quences of not following the instructions for tasting. One anesthesia care provider stated, “I don’t think NPO is very important to them. . . . 1 think comfort is more important to them.” Acciirding to another participant, “They all want to eat. They don’t care about anything. They don’t know the risks.” One nurse stated, “In some instances, 1 think they just disregard [the instructions!; they’re get- ting their kid ready for school, anci they just grab something [to eat].”

Although the patients could not

articulate a concrete rationale for

preoperative fasting, most knew on

some level that surgery, anesthesia,

and a full stomach do not mix.

When asked about their main concerns re- garding preoperahve fasting, nurses responded that they were concerned about the potential for adverse effects of prolonged fasting, such as dehydration, nausea and vomiting, and caffeine withdrawal headaches. One nurse said, “I think the longer a patient fasts, the more problems they would encounter, dehydration during the summer, and nausea and vomiting for long NPO status.” According to another nurse,

/ think that where surgeries are getting shorter, I think that the patients are in the OR for a shorter period of time and that they are hi/drated less. I think ive see a lot more dclu/drution; along with that we see some headaches. I think we see nausea front lack of solid food more frequenthf.

Anesthesia care providers stated that their concern is the safety and comfort of their

patients. The primary concern for one was “Safety—you want to know that the stomach is empty so that the patient doesn’t aspirate.” Another noted, “Their safety is of prime im- portance, and their comfort.” According to a third participant.

There’s a movement going on in our societi/ to try and he as relaxed as possible on NPO because it is uncomfortable and inconvenient for the patients, but you have to draw the line on patient safety. A lot of times the patients, nurses, or surgeons don’t understand that we’re really dohig this for the patient’s safety and not just because of some guideline.


Another main theme the investigators identi- fied from the interviews involved patients’ and practitioners’ knowledge in relation to preopera- tive lasting. This included patients’ and practi- tioners’ knowledge regarding the rationale for Fasting as well as practitioners’ knowledge of the guidelines for preoperative fasting.

KNOWLEDGE OF RATIONALE FOR FAsnNG. Contrary to the beliefs of nurses and anesthesia care pro- viders, patients consistently identified a ration- ale for fasting that was not entirely erroneous. Of the patient participants, 82’/o had some idea of the rationale for preoperative fasting.

Wiien patients were asked why they needed to be NPO, they were not able to articulate a con- crete rationale; most patients, howe’er, knew on some level that surgery, anesthesia, and a full stomach do not mix. One patient said, “You can exasperate [sic] if you have stuff in your stom- ach.” Another stated, “1 don’t know the reason. I would assume it has something to do with the anesthesia.” According to a third patient, “You could throw up and choke on your own vomit.” Another patient said,

/ understand that you have no food in your stomach so you could possibly, I don’t know, have a reaction to anesthesia, or it could somehoiv cloud ivliatever they need to look at.

Anesthesia care providers and nurses also were asked what they believed to be the ration- ale for prooperative fasting. The anesthesia care


OCTOBER 2007, VOL 86, NO Baril — Portman

providers all were able to identify the potential for aspiration with increased risk of pneumonia as the rationale for patients’ fasting before sur- gery. Of the nurses surveyed, 7y% cited aspira- tion and its potential complications as the rationale for preoperative fasting.

GUIDELINES FOR FASTING. Nurses and anesthesia care providers were asked about their knowl- edge of the current hospital policy on preoper- ative fasting as well as the guidelines used by the ASA. Of the participants, 66% of nurses and 8′)o of anesthesia care providers could articulate the hospital policy. The exact ASA guidelines were known by y% of nurses and 16% of anesthesia care providers who were surveyed (Figure 2). ^


This clinical investigation was limited in that it was a survey of participants at a single site and included a relatively small sample size. The findings of this project reflect only

Knowledge of hospital policy

Knowledge of American Society of Anesthesiologists guidelines

Staff members

Figure 2 • Percentage of nurses and anesthesia care providers

who know the hospital policy and the American Society of

Anesthesiologists guidelines on preoperative fasting.

the thoughts and opinions of clinicians and patients from this sample and cannot be gener- alized as representative of the opinions of anesthesia care providers, perioperative nurs- es, or patients at other facilities.

A formal, qualitative research sti.idy on this topic may reveal more generalizable trends as well as factors to be researched in the future. The nature of qualitative research is defined by the in-depth study of a phenomenon. This type of research is not intended to prove anything, but to explore an issue in a thorough fashion.

Potential areas for future research may in- clude how individualizing the fasting policy to the patient affects compliance with the policy as well as what effect a policy change may have on the flow of the surgical schedule. Another possi- ble area for research is a correlation between the amount of time surgical patients fasted and their postoperative symptoms, such as headache, nau- sea, vomiting, and dehydration.


Preoperative fasting remains a confusing concept for patients and a source of frustration for practitioners. Hospitals and ambulatory surgery centers need sensible preoperative fasting policies that reflect current research findings. Anesthesia care providers, surgeons, and nurses must collaborate to create and enforce policies that are safe for patients undergoing surgery and accepted by all practi- tioners. Personnel providing instruction to patients must have a clear knowledge of the facility’s fasting policy. In some instances, staff members at a surgeon’s office, who may not be aware of the rationale for fasting or the impli- cations of excessive fasting, provide the preop- erative instructions. To protect the patients’ well-being, hospital nursing staff members must be aware of what patients are being told and who is telling it to them. Patients must be given clear preoperative instructions that explain the rationale for and importance of preoperative fasting.

This project demonstrated that patients are more likely to fast for an excessive rather than insufficient amount time before surgery. The investigators presented their findings from this project, the current ASA recommendations, and


Baril — Portman OCTOBER 2007. VOL 86, NO

findings from other research studies at surgeon and anesthesia committee meetings at their facility. Tliis led to a change in the hospital fast- ing policy. Although patients still are required to fast from solid foods after midnight on the day of surgery, they now are allowed to ingest clear liquids up until four hours before their scheduled surgery. The new fasting policy does not fully reflect the ASA recommendations because there still is a high level of concern among anesthesia care providers about keeping the surgical schedule flexible.

Fasting excessively has been shown to in- crease the discomfort and possibly the morbid- ity of surgical patients.” To minimize risks associated with insufficient or excessive fast- ing, patients must have a clear understanding i>f the rationale for fasting and the potential ad’erse effects of excessive fasting. Optimal surgical, anesthesia, and nursing outcomes depend on it. –

Acknozi’ledgement: Tlie ant¡iors thank tlieir men- tor, Kathleen Bei/erman, EdD, RN, CNA, director of nursing research atui nursing staff development, Winchester Hospital, Winchester, MA, for her expertise and guidance.

REFERENCES 1. Practice guidelines for preoperative fasting ¿ind the use of pharmacologie agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedLires: a report by the American Society of Anesthesiologists Task Force on Preoperati’e Fasting. Anesthesiology.

2. McKinley AC, james RL, Mims GR 3rd. NPO after midnight before elective surgery is no longer common practice for the majority of anesthesiolo-

gists. Am / Aucsthciiiol. 1’í95;22(2):88-92. 3. Pandit SK, Loberg KW, Pandit UA. Toast and tea before elective surgery? A national survey on cur- rent practice. Am-sth Ámüg. 2000;90(6):l348-1351. 4. Crenshaw JT, Winslow EH. Preoperative fasting: old habits die hard. Am ¡ Nurs. 2n02;102(5):36-44. 5. Pearse R, Rajakiilendran Y. Pre-opcrative fasting and administration of regular medications in adult patients presenting for elective surgery. Has the now evidence changed practice? Eur } Anaesthesiol. 1999;]6(8):%5-568. 6. Murphy GS, Ault ML, Wong HY, Szokol JW. The effect of a new NPO policy on operating room uti- lization. / Clin AncstlL 200b;12(l):48-51. 7. Chapman A. Current theory and practice: a study of pre-operative tasting. Nurs’stmui. 1996;10(18):33-36. 8. Hung P. Preoperative fasting. Niirfi Times. 1992;88 (48}:57-6Ü. 9. Green CR, Pandit SK, Schork MA. IVeoperative fasting time: is the traditional policy changing? Results of a national survey. Anestti Anal^. 1996;83 (1):123-128. 10. Seymour S. Preoperative fluid restrictions: hos- pital policy and clinical practice. Br } Nurs. 2000; 9(14):925-930. 11. Napoli M. Preoperative fasting: rules changed. HfoltliFact^. June 2Ü02. http://www.medicalconsu Accessed July 11,2007. 12. ASA Physical Status Classification System. American Society of Anesthesiologists, http:// Ac- cessed July 11, 2007.

Patrice Baril, MS, RN, CNOR, is the nurse manager of the OR at Winchester Hospital, Winchester, MA.

Harriet Portman, BSN, RN, CAPA, is a staff RN, Preadmission Testing, at Winches- ter Hospital, Winchester, MA.

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