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Table of Contents  
Year : 2016  |  Volume : 10  |  Issue : 3  |  Page : 607-612  

The risk of shorter fasting time for pediatric deep sedation

1 Division of Critical Care Medicine, St. Louis University, St. Louis, MO, USA
2 Department of Statistics, University of Missouri, Columbia, MO, USA
3 Women's and Children's Hospital Campus, University of Missouri Health Care, Columbia, MO, USA
4 Department of Child Health, Division of Critical Care Medicine, University of Missouri School of Medicine, Columbia, MO, USA

Date of Web Publication27-Sep-2016

Correspondence Address:
Abdallah Dalabih
Department of Child Health, Division of Critical Care Medicine, University of Missouri School of Medicine, 400 Keene Street, Suite 016C, Columbia, MO 65201
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0259-1162.186598

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Background: Current guidelines adopted by the American Academy of Pediatrics calls for prolonged fasting times before performing pediatric procedural sedation and analgesia (PSA). PSA is increasingly provided to children outside of the operating theater by sedation trained pediatric providers and does not require airway manipulation. We investigated the safety of a shorter fasting time compared to a longer and guideline compliant fasting time. We tried to identify the association between fasting time and sedation-related complications.
Methods: This is a prospective observational study that included children 2 months to 18 years of age and had an American Society of Anesthesiologists physical status classification of I or II, who underwent deep sedation for elective procedures, performed by pediatric critical care providers. Procedures included radiologic imaging studies, electroencephalograms, auditory brainstem response, echocardiograms, Botox injections, and other minor surgical procedures. Subjects were divided into two groups depending on the length of their fasting time (4–6 h and >6 h). Complication rates were calculated and compared between the three groups.
Results: In the studied group of 2487 subjects, 1007 (40.5%) had fasting time of 4–6 h and the remaining 1480 (59.5%) subjects had fasted for >6 h. There were no statistically significant differences in any of the studied complications between the two groups.
Conclusions: This study found no difference in complication rate in regard to the fasting time among our subjects cohort, which included only healthy children receiving elective procedures performed by sedation trained pediatric critical care providers. This suggests that using shorter fasting time may be safe for procedures performed outside of the operating theater that does not involve high-risk patients or airway manipulation.

Keywords: Fasting time, pediatric, sedation

How to cite this article:
Clark M, Birisci E, Anderson JE, Anliker CM, Bryant MA, Downs C, Dalabih A. The risk of shorter fasting time for pediatric deep sedation. Anesth Essays Res 2016;10:607-12

How to cite this URL:
Clark M, Birisci E, Anderson JE, Anliker CM, Bryant MA, Downs C, Dalabih A. The risk of shorter fasting time for pediatric deep sedation. Anesth Essays Res [serial online] 2016 [cited 2021 Oct 28];10:607-12. Available from:

   Introduction Top

The goal of effective procedural sedation and analgesia (PSA) is to provide effective sedation to obtain high-quality images and assure the proper conduction of medical procedures, at the same time minimize medication risks and minimize periprocedural pain. PSA is associated with multiple possible complications: airway complications (pulmonary aspiration, oxygen desaturation, apnea, laryngospasm, and need for suctioning), hypotension, arrhythmias and nausea and vomiting.[1],[2],[3],[4],[5],[6],[7] Pulmonary aspiration, although infrequent,[2],[3],[4] is one of the more-feared complications and is therefore, a primary reason for fasting before PSA. However, the relationship between fasting times and PSA complications may not be simple,[5],[8],[9],[10] and gastric content volume may not correlate with the fasting time.[11]

The American Academy of Pediatrics (AAP) has adopted the fasting time before sedation guidelines set forth by the American Society of Anesthesiologists (ASA).[12],[13],[14] According to those guidelines, it is recommended that pediatric patients undergo fasting times of 2 h for clear liquids, 4 h for breast milk, 6 h for infant formula or light meals, and a fasting time of 8 h for intake of fried or fatty foods.[13] These guidelines are different than those set forth by the American College of Emergency Physicians (ACEP) for PSA in the emergency department (ED).[15],[16] In their most recent clinical policy recommendation, the ACEP removed any specific requirement for fasting before PSA in the ED, citing lack of evidence for decreased risk with fasting. The ACEP advised not to consider the fasting time alone when evaluating the need for PSA, but rather evaluating the whole picture stating “Do not delay procedural sedation in adults or pediatrics in the ED based on fasting time.”[16] In their argument, the authors of the clinical policy citied the lack of evidence in the literature for the relationship between fasting time, gastric volume, gastric acidity, and the risk of emesis/reflux or pulmonary aspiration in humans as one of their reasons for adapting these new sedation policies in the ED.

In this study, our goal was to examine the relationship between various fasting times and PSA complications when performed by pediatric critical care providers outside of the operating theater. We focused on evaluating airway-related complications and pulmonary aspiration as they are the most commonly cited reasons for prolonged fasting time before PSA. We hypothesized that the shorter fasting time is not associated with higher sedation complication rates, especially airway-related complications.

   Methods Top

This is a prospective observational study. Our primary objective was to identify the association between fasting time and sedation-related complications. All subjects were contacted the day before the procedure and were asked to fast for at least 4 h before PSA; the nature of the oral intake was not specified as so not to cause any confusion about the duration of fasting. The subjects were divided into two groups according to the length of fasting time before the procedure (4–6 h and >6 h). The actual fasting times were verified and recorded before the administration of sedation medications. We did not change our clinic practice for the purpose of this study, but rather evaluated our current sedation policy and procedure safety.

Our primary outcome measure was the difference in airway-related complication rates between the two studied groups (4–6 h and >6 h fasting time). Our secondary outcome measure was the difference in all other complications between the two groups.

Subjects presented to our pediatric procedure suite at a tertiary care university hospital the same day of their scheduled procedure. At that time, they were evaluated by a sedation nurse. Vital signs and weight were obtained, and subjects were escorted to their designated sedation rooms. All subjects were informed that unidentified patient information is being collected and stored in a database to research PSA efficacy and complications. Patients and families were given the option to opt out of this study, in which case no data were recorded for that specific encounter.

Presedation assessment was performed by a board certified pediatric critical care provider. The providers evaluated and recorded relevant medical history, ASA scores, and performed a focused medical exam. If a subject was deemed appropriate for sedation, the sedation nurse obtained intravenous (IV) access if needed, and started recording patient information on a data collection sheet. After the administration of the first sedation medication dose, sedation nurses began documenting vital signs, level of sedation, and procedure progress every 3–5 min while the procedure was in progress, then every 5–10 min until the subject's level of consciousness was back to baseline. Nurses also documented all medications administered during the procedure. At the end of the procedure, all subjects were observed for at least 1 h after the administration of the last sedation medication and until their level of consciousness was back to baseline, before assessing readiness for discharge. All complications were documented on the data collection sheet, which later was retrieved by data entry personnel and stored in a secure electronic database.

Inclusion criteria for this study were as follows: all electively performed deep sedation procedures in our pediatric procedure suite, procedures performed by pediatric critical care providers, for patients 2 months to 18 years of age. Subjects with an ASA physical status classification of I and II.[9] Deep sedation was defined as an achieved sedation level of 3 or 4 on the University of Michigan Sedation Scale (UMSS) anytime during the procedure.[17] We documented only achieved level of sedation regardless of the targeted level; this was determined by the sedation nurse and documented every 3–5 min. As sedation level is a continuum, subjects achieving even brief durations of deep sedation during the procedure were included in the analysis.

We excluded patients stratified as ASA III or higher, moderate sedation (<3 on UMSS), subjects undergoing esophagogastroduodenoscopy, and procedures performed urgently or in an inpatient setting. We also excluded subjects who had any oral intake (including clear fluid) earlier than the required 4 h of fasting time.

While the database did not include patient identifiers, it captured relevant demographics such as age, gender, weight, diagnosis, and procedure performed. It also captured medications used during PSA, achieved level of sedation, fasting times, procedural time, recovery time, any relevant complications, and subject disposition.

The tracked complications included (1) Desaturation to <90% SpO2 for more than 10 s, with or without the need for airway interventions including repositioning, suctioning, supplemental oxygen, oral or nasal airway placement, application of positive airway pressure through bag mask ventilation, and tracheal intubation, (2) Apnea: cessation or pause of ventilation for more than 20 s, with or without the need to use one or more interventions to assist ventilation (e.g., application of positive airway pressure through bag mask ventilation and tracheal intubation).[18] We also tracked other complications that included, (3) Prolonged recovery time, i.e., more than 1 h sleeping after the end of the procedure, (4) crying for more than 30 min after awakening, (5) hypotension with blood pressure <5th percentile for age or 20% below baseline, (6) IV fluid administration, (7) nausea or emesis, (8) arrhythmia including bradycardia defined as heart rate below the 5th percentile for age, (9) allergic reaction, and (10) pulmonary aspiration. Those complications were tracked and recorded by the sedation nurses; the criteria were agreed on by all the nurses and physicians who interacted with the study subjects before the initiation of the study.

Although those complications are comprehensive, our team decided to deviate from the consensus-based recommendations for standardizing terminology and reporting adverse events for sedation in children.[18] This deviation was in an attempt to cluster complications in a clinically practical and relevant way. For example, we felt that it is more appropriate to report desaturation that needed positive pressure ventilation separate from desaturation that only needed stimulation or repositioning to be resolved. For that reason, we divided the airway complications into two categories: (1) Minor airway complications: desaturation with or without the need for airway repositioning, suctioning, oxygen delivery (other than prophylaxis), (2) major airway complications: desaturation with: apnea of more than 20 s, need for positive pressure ventilation, pulmonary aspiration, and airway instrumentation.

In this study, airway-related complications were reported for each subject depending on the highest level of complication. If a subject had one or more of the minor airway complications but had at least one major airway complication that subject would have been reported as major airway complication and would not be reported in the minor airway complication category. This approach was adopted to decrease the confusion with minor airway complications, as all subjects with major airway complication, had at least one minor airway complication or intervention. In addition, if a subject had multiple minor or major airway complications, those were reported in their relevant category as one complication.

For statistical analysis, Pearson Chi-square and binary logistic regression tests were used via IBM SPSS Statistics for Windows (Version 22.0. Armonk, NY: IBM Corp). A two-sided P < 0.05 was considered statistically significant. The study design was approved by our Institutional Review Board.

   Results Top

During the study period January 2013 to September 2015, a total of 3134 PSA's were performed. Only 2487 PSA encounters met inclusion criteria and were included in the analysis [Figure 1]. Because of the study design, we did not track the number of subjects who opted out of the database. Demographic features of the study population are shown in [Table 1]. Propofol was the primary sedation medication used in our study; it was used in 77% of the cases. The list of all other medications used is included in [Table 2].
Figure 1: Subject selection flow chart

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Table 1: Subjects' demographics

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Table 2: List of sedation medications used

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We were not able to identify a significant association between any of the studied complications and fasting time [Table 3]. We found the overall rate of complications to be 15%, the rate of major airway complications was only 4% while the rate of minor airway complications was 13%. Forty-one subjects (4%) of the 4–6 h and 63 (4%) of the >6 h fasting time groups, respectively had suffered a major complication. Neither overall nor major complication rates were related to the fasting time before sedation. There were no cases of pulmonary aspiration nor need for endotracheal intubation in our study, so those two complications were not added to [Table 3]. The list of performed procedures is included in [Table 4].
Table 3: Deep sedation complications in regard to fasting time

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Table 4: The list of all procedures performed during this study

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   Discussion Top

Prolonged fasting times before sedation for outpatient procedures in children are often problematic. The long hours of fasting are not always well-tolerated, especially by younger children. Current guidelines recommended by ASA and AAP [3],[12],[13] are intended to increase the safety of sedation provided in the operating theater. It has been demonstrated, however, that longer fasting times may be associated with increased complications, such as vomiting, hypoglycemia, and decreased the efficacy of medications.[5],[19],[20],[21] In addition, Pimenta and de Aguilar-Nascimentoreported that shortened fasting times may shorten postoperative length of stay.[22] Other studies performed in emergency settings have also found no differences in outcome with shorter fasting times.[8],[10],[23]

Currently, the ASA and ACEP PSA guidelines differ on fasting time recommendations because of the variation of personnel, urgency of procedures, location, procedures performed, level of sedation, and medications used.[9],[13],[15],[24] The latest AAP guidelines indicate that tracheal intubation may place the patient at increased risk for pulmonary aspiration separate from the risk of PSA.[24] This is not the typical practice for PSA provided outside of the operating theater by pediatric critical care or ED providers. Both guidelines suggest that further studies were needed in specific patient care settings to truly address the risk of PSA.

It is important to differentiate between PSA provided by pediatric critical care providers outside of the operating theater and that by general anesthesia providers in the operating theater. One of the more distinctive factors is the degree of airway manipulation. Sedations administered by pediatric critical care providers are typically limited to relatively healthy children, usually with an ASA score of I–II and III in some cases. The agents used are also limited to few well-studied medications, such as propofol, dexmedetomidine, midazolam, ketamine, pentobarbital, and opioids. Thus, shorter fasting times should be studied to truly evaluate safety in such different settings.

de Aguilar-Nascimento et al. has shown that patients given an oral supplement of carbohydrate plus whey, 150–210 min before a sedated elective gastroscopy had gastric emptying that was similar to overnight fasting.[25] The use of oral contrast solution for computed tomography is often also in violation of the ASA guidelines for fasting before sedated procedures. Kharazmi et al. demonstrated the safety of this practice when compared to the ASA guideline's recommended fasting time.[26] Although those studies are limited by a low number of participants, they highlighted the need for further evaluation of the current ASA fasting guidelines for patients undergoing sedation for minor procedures and imaging studies.

Summary of key findings

This study found a low complication rate among our patient cohort, whether fasting times were 4–6 or >6 h, which is comparable to complication rates reported in the previous studies.[1],[2],[3],[4],[5],[23],[27]

Study limitations

Limitations of this study are as follows: performed at a single institution did not include the sedation medication doses and did not control for the quantity or characteristics of prior oral intake. In addition, our subjects were not randomized to the length of preprocedural fasting time and were not controlled to sedation medication administered or procedure performed. It is important to note that although our study did include a large number of subjects, complications such as pulmonary aspiration are rare events and the risk may not be adequately evaluated by our study population. Finally, nausea may have been underreported as it is subjective and dependent upon self-reporting. This is especially true in younger subjects.

Controversies raised by the study

The complications we documented and studied in this study are practical in our groups' opinion; this does not mean that it will be agreed on by all sedation providers. We think that the presence of an intervention performed in response to a clinical event should be documented as a clinical complication as it reflects the providers' clinical judgment about the significance of the event in the clinical context. In this study, we included the number and type of interventions performed and attempted to further stratify them according to their relative clinical significance as major or minor airway complications.

This study was designed to address a specific question in a very specific setting. The sedation was provided for relatively healthy children, did not include any airway procedures or intended airway manipulation and was performed electively by highly trained providers. All this should be considered when evaluating the generalizability of those results.

Future research directions

Further studies should control for the quantity, quality, and timing of oral intake, and be specific for medications and procedures. In today's evidence-based driven medical practice, preprocedural sedation fasting time should be addressed, and recommendations should be readjusted according to the accumulated evidence through larger multicenter comprehensive studies.

   Conclusions Top

This study demonstrated that in this specific setting, children with shorter fasting times who received deep sedation for elective procedures outside of the operating theater appear to have similar rates of complications to those who have longer fasting times.

This study attempted to continue the debate and encourage further discussions on this very controversial topic.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

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Schmitz A, Kellenberger CJ, Neuhaus D, Schroeter E, Deanovic D, Prüfer F, et al. Fasting times and gastric contents volume in children undergoing deep propofol sedation – An assessment using magnetic resonance imaging. Paediatr Anaesth 2011;21:685-90.  Back to cited text no. 11
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American Society of Anesthesiologists Committee. Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: Application to healthy patients undergoing elective procedures: An updated report by the American Society of Anesthesiologists Committee on Standards and Practice Parameters. Anesthesiology 2011;114:495-511.  Back to cited text no. 13
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Malviya S, Voepel-Lewis T, Tait AR, Merkel S, Tremper K, Naughton N. Depth of sedation in children undergoing computed tomography: Validity and reliability of the University of Michigan Sedation Scale (UMSS). Br J Anaesth 2002;88:241-5.  Back to cited text no. 17
Bhatt M, Kennedy RM, Osmond MH, Krauss B, McAllister JD, Ansermino JM, et al. Consensus-based recommendations for standardizing terminology and reporting adverse events for emergency department procedural sedation and analgesia in children. Ann Emerg Med 2009;53:426-35.e4.  Back to cited text no. 18
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  [Figure 1]

  [Table 1], [Table 2], [Table 3], [Table 4]

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