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PRACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open forum commentary, and clinical feasibility data.This update includes data published since the Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration were adopted by the ASA in 1998 and published in 1999.*For these Guidelines, preoperative fasting is defined as a prescribed period of time before a procedure when patients are not allowed the oral intake of liquids or solids. Perioperative pulmonary aspiration is defined as aspiration of gastric contents occurring after induction of anesthesia, during a procedure, or in the immediate period after surgery.The purposes of these Guidelines are to (1) enhance the quality and efficiency of anesthesia care, (2) stimulate evaluation of clinical practices, and (3) reduce the severity of complications related to perioperative pulmonary aspiration of gastric contents.Enhancements in the quality and efficiency of anesthesia care include, but are not limited to, the cost-effective use of perioperative preventive medication, increased patient satisfaction, avoidance of delays and cancellations, decreased risk of dehydration or hypoglycemia from prolonged fasting, and the minimization of perioperative morbidity.Clinical practices include, but are not limited to, withholding solids and liquids for specified time periods before surgery, and prescribing pharmacologic agents to reduce gastric volume and acidity.Complications of aspiration include, but are not limited to, aspiration pneumonia, respiratory disabilities, and related morbidities.These Guidelines focus on preoperative fasting recommendations, as well as recommendations regarding the administration of pharmacologic agents to modify the volume and acidity of gastric contents during procedures in which upper airway protective reflexes may be impaired. Prevention of perioperative pulmonary aspiration is part of the larger process of preoperative evaluation and preparation of the patient.Airway management techniques that are intended to reduce the occurrence of pulmonary aspiration are not the focus of these Guidelines. For example, a rapid-sequence induction/tracheal intubation technique or an awake tracheal intubation technique may be useful to prevent this problem during the delivery of anesthesia care. In addition, these Guidelines do not address the selection of anesthetic technique.The intended patient population for these Guidelines is limited to healthy patients of all ages undergoing elective procedures. These Guidelines do not apply to patients who undergo procedures with no anesthesia or only local anesthesia when upper airway protective reflexes are not impaired, and when no risk factors for pulmonary aspiration are apparent. These Guidelines are also not intended for women in labor.These Guidelines may not apply to, or may need to be modified for (1) patients with coexisting diseases or conditions that can affect gastric emptying or fluid volume (e.g. , pregnancy, obesity, diabetes, hiatal hernia, gastroesophageal reflux disease, ileus or bowel obstruction, emergency care, enteral tube feeding) and (2) patients in whom airway management might be difficult. Anesthesiologists and other anesthesia providers should recognize that these conditions can increase the likelihood of regurgitation and pulmonary aspiration. Additional or alternative preventive strategies may be appropriate for such patients.These Guidelines are intended for use by anesthesiologists and other anesthesia providers. They also may serve as a resource for other health care professionals who advise or care for patients who receive anesthesia care during procedures. Anesthesia care during procedures refers to general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia care). Throughout these Guidelines, preoperative should be considered synonymous with preprocedural, as the latter term is often used to describe procedures that are not considered operations.The original Guidelines were developed by a Task Force of 10 members, including anesthesiologists in both private and academic practice from various geographic areas of North America, and a consulting methodologist from the ASA Committee on Standards and Practice Parameters.The Task Force developed the original Guidelines by means of a six-step process. First, they reached consensus on the criteria for evidence. Second, original published research studies from peer-reviewed journals relevant to preoperative fasting were reviewed and evaluated. Third, expert consultants were asked (1) to participate in opinion surveys on the effectiveness of various preoperative fasting management recommendations and (2) to review and comment on a draft of the Guidelines. Fourth, the Task Force held open forums at a national meeting†to solicit input on the draft recommendations. Fifth, expert consultants were surveyed to assess their opinions on the feasibility of implementing the Guidelines. Sixth, all available information was used to build consensus within the Task Force to finalize the Guideline recommendations (appendix 1).In 2009, the ASA Committee on Standards and Practice Parameters requested that scientific evidence for these Guidelines be updated. This update consists of an evaluation of literature that includes new studies obtained after publication of the original Guidelines, new surveys of expert consultants, and a survey of a randomly selected sample of active ASA members.Preparation of this update used the same methodologic process as was used in the original Guidelines to obtain new evidence from two principal sources: scientific evidence and opinion-based evidence (appendix 2). The protocol for reporting each source of evidence is described below.Study findings from published scientific literature were aggregated and are reported in summary form by evidence category, as described below. All literature (e.g. , randomized controlled trials, observational studies, case reports) relevant to each topic was considered when evaluating the findings. However, for reporting purposes in this document, only the highest level of evidence (i.e. , level 1, 2, or 3 within category A, B, or C) is included in the summary.Randomized controlled trials report statistically significant (P < 0.01) differences between clinical interventions for a specified clinical outcome.Level 1. The literature contains multiple randomized controlled trials. Aggregated findings are supported by meta-analysis.‡Level 2. The literature contains multiple randomized controlled trials, but there is an insufficient number of studies to conduct a viable meta-analysis for the purpose of these Guidelines.Level 3. The literature contains a single randomized controlled trial.Information from observational studies permits inference of beneficial or harmful relationships among clinical interventions and clinical outcomes.Level 1. The literature contains observational comparisons (e.g. , cohort, case-control research designs) of clinical interventions or conditions and indicates statistically significant differences between clinical interventions for a specified clinical outcome.Level 2. The literature contains noncomparative observational studies with associative (e.g. , relative risk, correlation) or descriptive statistics.Level 3. The literature contains case reports.The literature cannot determine whether there are beneficial or harmful relationships among clinical interventions and clinical outcomes.Level 1. Meta-analysis did not find significant differences among groups or conditions.Level 2. The number of studies is insufficient to conduct meta-analysis, and (1) randomized controlled trials have not found significant differences among groups or conditions, or (2) randomized controlled trials report inconsistent findings.Level 3. Observational studies report inconsistent findings or do not permit inference of beneficial or harmful relationships.The lack of scientific evidence in the literature is described using the terms defined below.Silent. No identified studies address the specified relationships among interventions and outcomes.Inadequate. The available literature cannot be used to assess relationships among clinical interventions and clinical outcomes. The literature either does not meet the criteria for content as defined in the “Focus” of the Guidelines or does not permit a clear interpretation of findings due to methodological concerns (e.g. , confounding in study design or implementation).All opinion-based evidence relevant to each topic (e.g. , survey data, open-forum testimony, Internet-based comments, letters, editorials) was considered in the development of the original Guidelines. New opinion surveys were developed to address each clinical intervention identified in the document, and identical surveys were distributed to both expert consultants and a random sample of active ASA members.Survey responses from Task Force–appointed expert consultants are reported in summary form in the text. A complete listing of consultant survey responses reported in a table in appendix 2.Survey responses from active ASA members are reported in summary form in the text. A complete listing of ASA member survey responses reported in appendix 2.Survey responses are recorded using a 5-point scale and summarized based on median values.§Strongly Agree. Median score of 5 (at least 50% of responses are 5).Agree. Median score of 4 (at least 50% of responses are 4 [or 4 and 5]).Equivocal. Median score of 3 (at least 50% of responses are 3—or no other response category or combination of similar categories contain at least 50% of responses).Disagree. Median score of 2 (at least 50% of responses are 2 [or 1 and 2]).Strongly Disagree. Median score of 1 (at least 50% of responses are 1).Open-forum testimony, Internet-based comments, letters, and editorials were all informally evaluated and discussed during the development of the original Guideline recommendations.No controlled trials were found that address the impact of conducting a preoperative assessment (e.g. , history, physical examination, survey/interview) on the frequency or severity of pulmonary aspiration of gastric contents during the perioperative period (Category D evidence ). Studies with observational findings suggest that certain predisposing conditions (e.g. , age, comorbid disease) may be associated with the risk of perioperative aspiration (Category B2 evidence ).1,2The consultants and ASA members strongly agree that a review of pertinent medical records, a physical examination, and patient survey or interview should be performed as part of preoperative evaluation. They also strongly agree that patients should be informed of fasting requirements, and the reasons for them, sufficiently in advance of their procedures. In addition, both the consultants and ASA members strongly agree that verification of patient compliance with fasting requirements should be assessed at the time of the procedure.A review of pertinent medical records, a physical examination, and patient survey or interview should be performed as part of preoperative evaluation. The history, examination, and interview should include pertinent assessment of gastroesophageal reflux disease, dysphagia symptoms, or other gastrointestinal motility disorders, potential for difficult airway management, and metabolic disorders (e.g. , diabetes mellitus) that may increase the risk of regurgitation and pulmonary aspiration. Patients should be informed of fasting requirements, and the reasons for them, sufficiently in advance of their procedures. Verification of patient compliance with fasting requirements should be assessed at the time of the procedures. When the fasting recommendations in these Guidelines are not followed, the practitioner should compare the risks and benefits of proceeding, with consideration given to the amount and type of liquids or solids ingested.Meta-analysis of randomized controlled trials3–10comparing fasting times of 2–4 4 report gastric and gastric in patients given clear liquids 2–4 before a procedure (Category evidence findings for gastric are (Category evidence of randomized controlled gastric (Category evidence and findings regarding differences in gastric volume for given clear liquids 2–4 before a procedure fasting for 4 before a procedure (Category evidence of clear liquids in the studies from to for and 2 to for clinical evidence is insufficient to address the between fasting times for clear liquids and the risk of or pulmonary aspiration (Category D evidence the consultants and ASA members strongly agree that for healthy 2 and fasting from the intake of clear liquids at least 2 before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be is appropriate to from intake of clear liquids at least 2 before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia care). of clear liquids include, but are not limited to, clear and These liquids should not include The volume of is the type of with observational findings are regarding the impact of 4 before a procedure on the risk of or of gastric contents during a procedure (Category evidence literature is insufficient to the of the of of and the perioperative of or pulmonary aspiration (Category D evidence consultants agree and the ASA members strongly agree that for healthy and fasting from the intake of at least 4 before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be is appropriate to from intake of at least 4 before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia study with observational findings is regarding the impact of 4 before a procedure on the risk of or of gastric contents during a procedure (Category evidence literature is insufficient to the of the of of and the perioperative of or pulmonary aspiration (Category D evidence the consultants and ASA members agree that for and fasting from the intake of at least before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be The consultants agree and the ASA members strongly agree that for fasting from the intake of at least before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be is appropriate to from intake of at least before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia randomized controlled a an of 4 before a procedure with fasting findings regarding gastric volume and for (Category evidence with findings for given 4 or before a procedure who for 4 report gastric (Category B2 evidence and gastric (Category evidence study with observational findings that fasting for may be associated with hypoglycemia in (Category B2 evidence literature is insufficient to the of the of of solids and and the perioperative of or pulmonary aspiration (Category D evidence consultants agree and the ASA members strongly agree that fasting from the intake of a (e.g. , and a clear or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be the consultants and ASA members strongly agree that fasting from the intake of a that includes or or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be the consultants and ASA members agree that for fasting from the intake of or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be The consultants agree and the ASA members strongly agree that for and fasting from the intake of or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be is appropriate to from intake of a or or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia care). The Task Force that intake of or or may gastric emptying Additional fasting time (e.g. , or may be in these the amount and type of be considered when an appropriate fasting is similar to solids in gastric emptying the amount be considered when an appropriate fasting of randomized the of to reduce gastric volume (Category evidence is regarding the of on gastric acidity (Category evidence the perioperative The literature is insufficient to the of gastrointestinal on the perioperative of or pulmonary aspiration (Category D evidence the consultants and ASA members that gastrointestinal should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary preoperative use of gastrointestinal to the risk of pulmonary aspiration in patients who have no increased risk for pulmonary aspiration is not Meta-analysis of randomized trials the of to reduce gastric the perioperative period (Category evidence ). Meta-analysis of randomized the of to reduce gastric volume and acidity during the perioperative period (Category evidence ). trials that is in gastric volume and acidity (Category evidence controlled trials the of in gastric volume and acidity (Category evidence similar findings reported for (Category evidence literature is insufficient to the of either or on the perioperative of or pulmonary aspiration (Category D evidence the consultants and ASA members that should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary aspiration. The ASA members and the consultants strongly that should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary preoperative use of that gastric to the risks of pulmonary aspiration in patients who have no increased risk for pulmonary aspiration is not controlled trials that preoperative (e.g. , increase gastric during the perioperative period (Category evidence findings regarding gastric volume (Category evidence ). The literature does not sufficiently the between gastric acidity and the frequency of pulmonary aspiration or in does the literature sufficiently whether gastric acidity or volume is associated with decreased or in patients given preoperative who have gastric contents (Category D evidence consultants and ASA members both that preoperative should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary aspiration. The consultants and ASA members both strongly agree that only should be used when are for selected preoperative use of to the risks of pulmonary aspiration in patients who have no increased risk for pulmonary aspiration is not should be used when are for selected patients for purposes other the risk of pulmonary controlled trials that the preoperative administration of in and during the period after (Category evidence ). The literature does not sufficiently the between the preoperative use of and the frequency of pulmonary aspiration (Category D evidence consultants and ASA members both that preoperative should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary preoperative use of to reduce the risks of pulmonary aspiration in patients who have no increased risk for pulmonary aspiration is not trials are regarding the of reduce gastric volume or acidity (Category evidence ASA members and the consultants strongly that preoperative should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia to the risk of pulmonary use of to the risks of pulmonary aspiration is not controlled trials when (i.e. , are with gastrointestinal (i.e. , the of the two is in both gastric volume and acidity (Category evidence when with gastrointestinal are to in gastric acidity are when the are to gastrointestinal as the findings for gastric volume are controlled trials other single report inconsistent findings regarding gastric volume and (Category evidence ASA members and the consultants strongly that preoperative multiple agents should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no risk for pulmonary preoperative use of multiple agents in patients who have no increased risk for pulmonary aspiration is not Fasting liquids 2 4 recommendations apply to healthy patients who are undergoing elective procedures. They are not intended for women in the Guidelines does not guarantee complete gastric The fasting periods apply to patients of all of clear liquids include clear and is similar to solids in gastric emptying the amount be considered when an appropriate fasting consists of and clear that include or or may gastric emptying Additional fasting time (e.g. , or may be in these the amount and type of be considered when an appropriate fasting recommendations are by type with In addition, of the are not for No No No No No No No No No No No No No No these Guidelines, a literature review is used in combination with opinions obtained from expert consultants and other (e.g. , American Society of Anesthesiologists members, open the literature review and opinion data are based on evidence or regarding potential relationships between clinical interventions and outcomes. The interventions were to assess their impact on pulmonary aspiration and other outcomes. for the interventions include, but are not limited to, pulmonary volume and acidity of gastric (e.g. , (e.g. , and other (e.g. , of in the literature relevant clinical studies were identified and of the For the original Guidelines, and a period from The literature for this update the period from and included review of that related to the evidence review of the studies did not provide evidence and were A of findings related to at least of the evidence No evidence literature with and information to conduct an analysis of aggregated studies (i.e. , A complete used to these Guidelines, by is available as 2, literature is according to the or of the to the an a study should either a or methodological (e.g. , for For these Guidelines, the of are pulmonary aspiration and these Guidelines focus on the between a preoperative intervention and the frequency of pulmonary and the between a preoperative intervention and the frequency or severity of an associated with aspiration (e.g. , However, the literature is insufficient to such The literature of relationships between preoperative interventions and of These of relationships are to as or a either between an intervention (e.g. , and a clinical or between two (e.g. , gastric volume and In the studies reviewed with the between of the identified interventions in the Guidelines and the of pulmonary aspiration was not a between an intervention of and pulmonary aspiration cannot be (e.g. , gastric were considered by the to be of a risk of pulmonary of such comparisons are not to provide 2 4 comparisons that for an outcome. For example, to the effectiveness of a on pulmonary the of the on gastric content as well as the occurrence of be content and are between the intervention and pulmonary aspiration. This be considered a 2 a in which or between the intervention and the of However, level 2 relationships do not the between an intervention of and the occurrence of pulmonary 3 contains of to the Guidelines (i.e. , 4 contains the other of to the Guidelines (i.e. , between an intervention and clinical from pulmonary that related to preoperative fasting and the administration of pharmacologic agents were insufficient to relationships that the interventions of in these Guidelines with the occurrence of pulmonary aspiration or the clinical from pulmonary the literature was not for assessment related to pulmonary findings for each intervention of regarding is each pertinent reported in a study is as an evidence a or These are summarized to obtain a assessment for each evidence before conducting a The literature to evidence studies with and information to conduct These evidence (1) preoperative fasting of liquids between 2 and 4 for (2) preoperative fasting of liquids between 2 and 4 for (3) preoperative preoperative and preoperative Meta-analysis was limited to gastric volume and acidity or are obtained for are obtained for are used as (1) the based on of the reported from the studies, and (2) the of the studies by each of the by the of the procedure based on the for study using 2 2 is used with frequency level is at a of for of the studies are to among study are obtained when significant is found (P < for potential a is No for studies was no for research were be as significant agree with both of data are In the of findings from the and agree with each other to be considered statistically the original Guidelines, among Task Force members and two was by using a for are as (1) type of study (2) type of (3) evidence and literature for (1) (2) (3) literature These to of was obtained from multiple (1) survey opinion from consultants who were selected based on their or in preoperative fasting and of pulmonary (2) survey opinions from active members of the American Society of (3) from of a held open forum for the original Guidelines held at a national anesthesia commentary, and Task Force opinion and The survey of was of for the consultants responses were from active American Society of Anesthesiologists members the original Guidelines, an survey was to the consultants to of the evidence their clinical practices the Guidelines were The of consultants no associated with each were as preoperative preoperative fasting of preoperative fasting of preoperative fasting of gastrointestinal pharmacologic of gastric and multiple of that the Guidelines have no on the amount of time on a For all the increase in the amount of time on a case was reported that the Guidelines increase the amount of time The time increase for these two was 5 and