Preoperative fasting guidelines in pediatric anesthesia: are we ready for a change?

Retrospective comparison between MRI examinations during radiographer-administered intranasal sedation or general anesthesia

INTRODUCTION

In order for young children to be able to undergo a Magnetic Resonance Imaging (MRI) examination, general anesthesia is often required. The aim of this study was to compare the image quality, times, and costs of the examinations of infant brains performed with MRI either during sedation with dexmedetomidine administered by radiographers or anesthesia with propofol administered by anesthesia staff.

METHODS

This study was a quantitative retrospective study of 27 consecutive standard brain examinations performed under sedation or anesthesia, involving 15 children under sedation and 12 under anesthesia. The age of the children was from 0.5 to five years old. The image quality was evaluated by three radiologists experienced in pediatric MRI examinations. Information such as examination time and the expense of the examination was also collected.

RESULTS

There was no statistically significant difference in the general image quality, but one image series was assessed to have significantly better image quality under sedation than under anesthesia, but all images had very high quality. However, it emerged that children under anesthesia were at the hospital on average 55 min longer and the scanner room was occupied 20 min longer on average. The anesthesia examinations were three times more expensive.

CONCLUSION

This study demonstrated equivalent image quality between sedation and anesthesia. In addition, sedation was less time-consuming and had a lower price, partly because no extra anesthetic staff were required. The use of intranasal sedation offers a possibility to expand the competence area for radiographers.

IMPLICATIONS FOR PRACTICE

If radiographers learn to perform intranasal sedation, examinations can be performed in less time, at a third of the staff costs while maintaining image quality.

Rapid Evaluation of Gastric Content With Ultrasound: An Educational Tool

Pulmonary aspiration is a severe complication in patients receiving anesthesia for surgical procedures. The risk and severity of aspiration are significantly higher in the presence of substantial gastric contents. Bedside ultrasound imaging of the gastric antrum is emerging as a rapid and valuable method to evaluate gastric contents before surgery. Rapid gastric ultrasound using a three-category grading system promotes timely decision-making to help in emergent or urgent surgeries by identifying patients with potentially high gastric volumes or solid food contents. In emergent cases with limited time, a single ultrasound view of the gastric antrum is still likely to yield helpful information. In this report, we argue that bedside ultrasound offers a more reliable assessment of gastric contents than assumptions based on time-based fasting guidelines.

Reducing Preoperative Fasting Through Technology and Education in an Acute General Surgical Adult Cohort

BACKGROUND

Despite widespread support for reduced fasting protocols prior to anesthesia, the traditional "fast from midnight" (FFMN) remains widely employed. This study implemented a pilot preoperative fasting reduction program for patients booked for acute surgery in the Department of General Surgery at a busy metropolitan tertiary hospital, including use of an electronic health record (EHR)-based solution, aiming to measure effect on fasting times and use of intravenous fluid (IVF).

METHODS

A pilot program was implemented in August 2021 in the Emergency General Surgery (EGS) unit at the Royal Melbourne Hospital, Australia. This included a new smart phrase within the EHR (EU2WU6: Eat until 2, drink water until 6) and an education campaign. Adult patients who underwent preoperative fasting between September 1 and December 31, 2021, were screened. Uptake of the protocol was recorded. Further, total fasting times (TFT) and IVF use were recorded. Potential impact with varying levels of protocol uptake was modeled.

RESULTS

Uptake of EU2WU6 increased from 0% to 80%. TFT and total time on IVF (TT-IVF) were lower using EU2WU6 (TFT 7 hours vs. 13 hours, p < 0.001; TT-IVF 3 hours vs. 8 hours, p < 0.001). Proportion of patients requiring fluid overnight when using EU2WU6 was lower (18/45 vs. 34/50, p = 0.0062). Hospitalwide yearly savings, with 100% application of EU2WU6, were projected at 2,050 bags of IVF (at a cost savings of A$2,296), 10,251 minutes for physicians, and 20,502 minutes for nurses.

CONCLUSION

The pilot preoperative fasting reduction program successfully reduced disparity between evidence and clinical practice.

Determining residual gastric volume in healthy children using ultrasound

PURPOSE

Fasting guidelines for children recommend restricting clear fluids for one or two hours before a procedure to reduce pulmonary aspiration. Gastric volumes < 1.5 mL·kg-1 do not seem to present an increased risk of pulmonary aspiration. Our aim was to quantify the time to achieve a gastric volume < 1.5 mL·kg-1 after clear fluid ingestion in children.

METHODS

We conducted a prospective observational study in healthy volunteers aged 1-14 yr. Participants followed American Society of Anesthesiologists fasting guidelines prior to data collection. Gastric ultrasound (US) was performed in the right lateral decubitus (RLD) position to determine the antral cross-sectional area (CSA). Following baseline measurements, participants consumed 250 mL of a clear fluid. We then performed gastric US at four time intervals: 30, 60, 90, and 120 min. Data were collected following a predictive model for gastric volume estimation using the formula: volume (mL) = -7.8 + (3.5 × RLD CSA) + (0.127) × age (months).

RESULTS

We recruited 33 healthy children aged 2-14 yr. The mean gastric volume per weight (mL·kg-1) at baseline was 0.51 mL·kg-1 (95% confidence interval [CI], 0.46 to 0.57). The mean gastric volume was 1.55 mL·kg-1 (95% CI, 1.36 to 1.75) at 30 min, 1.17 mL·kg-1 (95% CI, 1.01 to 1.33) at 60 min, 0.76 mL·kg-1 (95% CI, 0.67 to 0.85) at 90 min, and 0.58 mL·kg-1 (95% CI, 0.52 to 0.65) at 120 min.

CONCLUSION

Our results show that total gastric fluid volume was < 1.5 mL·kg-1 after 60 min, suggesting that current fasting guidelines for children could be liberalized.

Reducing the use of nil per os past midnight for inpatient diagnostic and therapeutic procedures: A quality improvement initiative

BACKGROUND

Pre-procedural fasting (nil per os [NPO]) is a commonly implemented protocol to prevent aspiration during certain diagnostic and therapeutic procedures. However, evidence suggests aspiration risk is quite low. Current guidelines support a reduced fasting duration before procedures necessitating anesthesia or sedation, but many health systems persist in the use of NPO past midnight.

OBJECTIVE

We aimed to reduce the use of NPO p MN before inpatient diagnostic and therapeutic procedures necessitating anesthesia or sedation by 50% within 6 months.

DESIGN, SETTING AND PARTICIPANTS

We performed a quality improvement initiative at a single academic health system in Southeast Texas. We include the experience of patients of all ages across 4 affiliated hospitals (one main academic hospital and three community satellite hospitals).

INTERVENTION

An interprofessional team was convened to review best practices and oversee this quality improvement initiative. Diagnostic imaging protocols previously requiring NPO were amended to reflect evidence-based fasting requirements. A pre-procedure clear liquid diet was also implemented.

MAIN OUTCOME AND MEASURES

We describe the steps to implementation, feasibility of implementation as described through key process measures, and the safety of implementation (balancing measures).

RESULTS

NPO requirements were removed from 70% of existing diagnostic imaging and therapeutic orders. After these amended protocols and the implementation of a pre-procedure clear liquid diet, we displayed an immediate 50% reduction in NPO past midnight usage. Further stakeholder engagement/education and targeted interventions reduced NPO past midnight usage to only 33% of pre-procedural diet orders. Surgery remains the most common indication for continued use of NPO. Aspiration events and procedural delays were rare.

Perioperative Acetaminophen Dosing in Obese Children

Acetaminophen is a commonly used perioperative analgesic drug in children. The use of a preoperative loading dose achieves a target concentration of 10 mg/L associated with a target analgesic effect that is 2.6 pain units (visual analogue scale 1–10). Postoperative maintenance dosing is used to keep this effect at a steady-state concentration. The loading dose in children is commonly prescribed per kilogram. That dose is consistent with the linear relationship between the volume of distribution and total body weight. Total body weight is made up of both fat and fat-free mass. The fat mass has little influence on the volume of distribution of acetaminophen but fat mass should be considered for maintenance dosing that is determined by clearance. The relationship between the pharmacokinetic parameter, clearance, and size is not linear. A number of size metrics (e.g., fat-free and normal fat mass, ideal body weight and lean body weight) have been proposed to scale clearance and all consequent dosing schedules recognize curvilinear relationships between clearance and size. This relationship can be described using allometric theory. Fat mass also has an indirect influence on clearance that is independent of its effects due to increased body mass. Normal fat mass, used in conjunction with allometry, has proven a useful size metric for acetaminophen; it is calculated using fat-free mass and a fraction (Ffat) of the additional mass contributing to total body weight. However, the Ffat for acetaminophen is large (Ffat = 0.82), pharmacokinetic and pharmacodynamic parameter variability high, and the concentration–response slope gentle at the target concentration. Consequently, total body weight with allometry is acceptable for the calculation of maintenance dose. The dose of acetaminophen is tempered by concerns about adverse effects, notably hepatotoxicity associated with use after 2–3 days at doses greater than 90 mg/kg/day.

Prospective audit on fasting status of elective ambulatory surgery patients, correlated to gastric ultrasound

INTRODUCTION

Recent guidelines advocate a preoperative fasting interval of 6 h for solid food, 4 h for breast milk and 2 h for clear fluids. Long nil per mouth intervals give rise to complications and discomfort in the perioperative period. Gastric ultrasound is easily accessible and generates reliable information about gastric content.

PATIENTS AND METHODS

One hundred patients were offered a questionnaire regarding preoperative fasting. Important outcome measures were hour of last meal, last clear fluids intake, the source of preoperative information. Gastric ultrasound was performed in prone position and lateral decubitus.

RESULTS

The mean duration of fasting for solid food was 13h29 and 9h51 for clear fluids. 48% of patients were well aware of the correct fasting guidelines. The most frequent source of information was the preoperative phone call. Gastric ultrasound only found insignificant amounts of gastric content.

DISCUSSION

Too few patients are aware of the correct guidelines or fear complications and therefore adhere to the nil per mouth from midnight as most conservative measure. A phone call informing patients about the hour of surgery and allowing clear fluid intake until 2 h before surgery, is still not convincing enough. Some health care providers advise their patients the nil per mouth from midnight rule, due to risk of interfering with the operating room schedule.

CONCLUSION

It is still difficult to implement liberal intake of clear fluids according to current guidelines. Ambulatory surgery patients have long fasting intervals with decrease of subjective well-being and increased incidence of hunger and thirst.

2023 American Society of Anesthesiologists Practice Guidelines for Preoperative Fasting: Carbohydrate-containing Clear Liquids with or without Protein, Chewing Gum, and Pediatric Fasting Duration-A Modular Update of the 2017 American Society of Anesthesiologists Practice Guidelines for Preoperative Fasting

These practice guidelines are a modular update of the "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." The guidance focuses on topics not addressed in the previous guideline: ingestion of carbohydrate-containing clear liquids with or without protein, chewing gum, and pediatric fasting duration.

Gastrointestinal Fluid Volumes in Pediatrics: A Retrospective MRI Study

The volume and distribution of fluids available in the gastrointestinal (GI) tract may substantially affect oral drug absorption. Magnetic resonance imaging (MRI) has been used in the past to quantify these fluid volumes in adults and its use is now being extended to the pediatric population. The present research pursued a retrospective, explorative analysis of existing clinical MRI data generated for pediatric patients. Images of 140 children from all pediatric subpopulations were analyzed for their resting GI fluid volumes in fasting conditions. In general, an increase in fluid volume as a function of age was observed for the stomach, duodenum, jejunum, and small intestine (SI) as a whole. No specific pattern was observed for the ileum and colon. Body mass index (BMI), body weight, body height, and SI length were evaluated as easy-to-measure clinical estimators of the gastric and SI fluid volumes. Although weight and height were identified as the best estimators, none performed ideally based on the coefficient of determination (R2). Data generated in this study can be used as physiologically relevant input for biorelevant in vitro tests and in silico models tailored to the pediatric population, thereby contributing to the efficient development of successful oral drug products for children.

Pro-Con Debate: 1- vs 2-Hour Fast for Clear Liquids Before Anesthesia in Children

Perioperative fasting guidelines are designed to minimize the risk of pulmonary aspiration of gastrointestinal contents. The current recommendations from the American Society of Anesthesiologists (ASA) and the European Society of Anaesthesiology and Intensive Care (ESAIC) are for a minimum 2-hour fast after ingestion of clear liquids before general anesthesia, regional anesthesia, or procedural sedation and analgesia. Nonetheless, in children, fasting guidelines also have consequences as regards to child and parent satisfaction, hemodynamic stability, the ability to achieve vascular access, and perioperative energy balance. Despite the fact that current guidelines recommend a relatively short fasting time for clear fluids of 2 hours, the actual duration of fasting time can be significantly longer. This may be the result of deficiencies in communication regarding the duration of the ongoing fasting interval as the schedule changes in a busy operating room as well as to poor parent and patient adherence to the 2-hour guidelines. Prolonged fasting can result in children arriving in the operating room for an elective procedure being thirsty, hungry, and generally in an uncomfortable state. Furthermore, prolonged fasting may adversely affect hemodynamic stability and can result in parental dissatisfaction with the perioperative experience. In this PRO and CON presentation, the authors debate the premise that reducing the nominal minimum fasting time from 2 hours to 1 hour can reduce the incidence of prolonged fasting and provide significant benefits to children, with no increased risks.

Identification of the risk factors in perioperative respiratory adverse events in children under general anesthesia and the development of a predictive model

BACKGROUND

This study explored the risk factors of perioperative respiratory adverse events in children under 12 years old undergoing general anesthesia surgery. A prediction model was constructed according to the related risk factors to provide a basis for timely clinical intervention and decision-making.

METHODS

Children under 12 years old who underwent general anesthesia in our hospital between January 2016 and December 2020 were included in this study. The clinical data, including age, gender, weight, American Society of Anesthesiologists (ASA) grade classification, operation season, preoperative hospital stay, anesthesia time, and postoperative pain score, were collated. Continuous variables were converted to categorical variables. Logistic regression analysis was used to screen independent risk factors and a nomogram was constructed to predict the probability of adverse events. Fitting curves and receiver operating characteristic (ROC) curves were utilized to verify the model.

RESULTS

Logistic regression analyses demonstrated that age [odds ratio (OR) =1.32, 95% confidence interval (CI): 1.08 to 1.49], body weight (OR =1.49, 95% CI: 1.21 to 1.84), anesthesia time (OR =1.61, 95% CI: 1.32 to 1.78), and surgery season (OR =1.12, 95% CI: 1.07 to 1.39) were independent risk factors for respiratory adverse events in children undergoing general anesthesia (P<0.05). The risk of respiratory-related adverse events increased in children with grade II ASA classification compared to children with grade I ASA classification (P<0.05). Similarly, the risk of respiratory adverse events increased in children with level III pain scores compared to children with level I pain scores (P<0.05). The calibration curve showed that the predicted curve was consistent with the actual curve. The area under the ROC curve (AUC) was 0.707, indicating that model showed great predictive ability.

CONCLUSIONS

Age, weight, anesthesia time, operation season, ASA grade, and pain score were identified as independent risk factors for respiratory adverse events in children undergoing general anesthesia. Using the above risk factors, a nomogram was established to predict the risk of respiratory system-related adverse events. The predicted results were highly consistent with the actual risk, and the false positive rate was within a reasonable range.

Integrating anthropometric and cardiometabolic health methods in stress, early experiences, and development (SEED) science

Within Stress, Early Experiences, and Development (SEED) science, there is a growing body of research demonstrating complex associations not only between stress, development, and psychopathology, but also with chronic disease risk factors. We argue that it is important for SEED researchers to consider including child anthropometric and physical health measures to more comprehensively capture processes of risk and resilience. Broader adoption of harmonized anthropometry and health measures in SEED research will facilitate collaborations, yielding larger datasets for research in high-risk populations, and greater opportunity to replicate existing findings. In this review, we identify optimal anthropometric and cardiometabolic health measurement methods used from infancy through adolescence, including those that are low-burden and inexpensive. Methods covered include: waist, hip, and head circumference, height, length, weight, pubertal development, body composition, blood pressure, arterial stiffness, carotid intima media thickness, and serum measures of cardiometabolic risk and inflammation. We provide resources for SEED researchers to integrate these methods into projects or to better understand these methods when reading the literature as well as where to find collaborators for more in-depth studies incorporating these measures. With broader integration of psychological and physical health measures in SEED research, we can better inform theory and interventions to promote health and resilience in individuals who have experienced early stress.

Observance of preoperative clear fluid fasting in pediatric anesthesia: oral and written information versus text message information. A before-and-after study

INTRODUCTION

Prolonged fasting before surgery is common in pediatrics. In the literature, it is responsible for hypotension, irritability and postoperative nausea and vomiting. Despite clear instructions given during the preanesthetic consultation, fasting rules are respected in only 30%-40% of cases. We aimed to evaluate the benefit of sending a text message the day before surgery to improve the parents' observance of fasting rules.

METHODS

We conducted a before-and-after study at the University Hospital of Poitiers. From August to October 2018, 172 parents of children under 15 years of age scheduled for all types of surgery were enrolled into two groups according to the period: the control group with parents receiving information on preoperative fasting rules during the preanesthetic consultation several days before surgery, and the text message group, receiving the same information during consultation plus a text message the day before the surgery.

RESULTS

There was a difference in observance of clear fluid fasting instructions (between 2 and 3 h before the admission at hospital) in favor of the text message group 33% versus 92% OR 29.2 (10.9-95.2) p < 0.001, and in average fasting time for clear fluids 8.7 h ± 4.8 h vs. 4.3 h ± 2.4 h (p < 0.001).

CONCLUSION

Sending of a reminder text message to the parents the day before the surgery resulted in a significant increase in observance of fasting rules in children undergoing scheduled surgery.

Nulla Per Os (NPO) guidelines: time to revisit?

PURPOSE OF REVIEW

Preoperative fasting guidelines are generalized to elective procedures and usually do not distinguish between the ambulatory and inpatient setting. Prevalence of aspiration is low while prolonged preoperative fasting is common clinical reality. Recently, changes in preoperative fasting guidelines have been widely discussed.

RECENT FINDINGS

Rates of prolonged clear fluid fasting (>4 h) prior to surgery are reported in up to 80% of patients with mean fasting duration of up to 16 h and beyond. Prolonged fasting may result in adverse effects such as intraoperative hemodynamic instability, postoperative delirium, patient discomfort, and extended hospital length of stay. Liberal approaches allowing clear fluids up to 1 h prior to anesthesia or until premedication/call to the operating room have shown no increase in adverse events among children. Various anesthesia societies now encourage clear fluid intake up to 1 h prior to pediatric elective anesthesia. Similar reports in the adult cohort are scarce.

SUMMARY

Allowing sips of water until call to the operating room may help reducing prolonged preoperative fasting and improving patient comfort while keeping a flexibility in operating room schedule. The feasibility and safety of a liberal clear fluid fasting regimen among adults undergoing elective anesthesia needs to be evaluated in future studies.

Elaboration, validation and reliability of the safety protocol for pediatric thirst management

Objective:

to elaborate, validate and evaluate the reliability of the Safety Protocol for Pediatric Thirst Management in the immediate postoperative period.

Method:

methodological quantitative research, based on the assumptions on measurement instrument development. The protocol was elaborated after literature review, interview with specialists and observation of the child’s anesthetic recovery. The judges performed theoretical validation through apparent, semantic and content analysis. Content Validity Index was calculated for content validation, whose minimum established concordance was 0.80. Protocol’s reliability was evaluated in children between three and 12 years old in the Post Anesthesia Care Unit.

Results:

in its final version, the protocol consisted of five evaluation criteria: level of consciousness, movement, airway protection, breathing pattern and nausea and vomiting. It presented easy comprehension and relevant content, and all indexes exceeded the minimum agreement of 0.80. Pairs of nurses applied the protocol 116 times to 58 children, resulting in a high reliability index (kappa general = 0.98)

Conclusion:

the unprecedented protocol developed is valid and is a useful tool for use in anesthetic recovery, aiming to assess safety for reducing the thirst of infant patients.

Metabolic and Inflammatory Benefits of Reducing Preoperative Fasting Time in Pediatric Surgery

OBJECTIVE

To investigate the metabolic/inflammatory impact of reducing the preoperative fasting time in preschool children.

METHODS

Forty children were randomly assigned to a fasting group (absolute fasting after 00:00) and a carbohydrate (CHO) group (allowed to ingest, two hours before surgery, a carbohydrate-rich beverage). Blood samples were collected right before and after surgery to quantify the levels of albumin, interleukin-6, glucose, insulin, C-reactive protein and to calculate insulin resistance by the HOMA-IR index.

RESULTS

Preoperative fasting time in the CHO group were shorter than in the fasting group (2.49h vs. 11.24h, p <0.001). Pre- and post-surgical CRP levels were significantly lower in the CHO group (p = 0.05 and p = 0.02, respectively). The preoperative CRP/albumin ratios in the CHO group were lower than in the fasting group (p = 0.03). Four patients (21%) in the fasting group but none in the CHO group were hyperglycemic before surgery (p = 0.04). The two groups had similar levels of albumin, interleukin-6, insulin and HOMA index. There were no adverse events.

CONCLUSION

Reducing the preoperative fasting time with carbohydrate-rich beverages improves the perioperative metabolic and inflammatory responses of preschool children undergoing inguinal hernia surgery.

Duration of preoperative clear fluid fasting and peripheral intravenous catheterization in children: A single-center observational cohort study of 9693 patients

BACKGROUND

Children routinely undergo inhalational induction of general anesthesia. Intravenous line placement typically occurs after induction of anesthesia and can be challenging, particularly in infants and young children.

AIMS

We conducted a retrospective observational study to determine whether there was an association between clear liquid fasting time and the number of peripheral intravenous catheter insertion attempts in anesthetized children. The secondary aim was to identify factors associated with multiple attempts to insert intravenous lines.

METHODS

After institutional research board approval, we retrieved a data set of all children between 0 months and 18 years who received general anesthesia at our hospital between January 1, 2016, and September 30, 2017. Data included age, gender, weight, race, ASA status, gestational age, number of peripheral intravenous catheter insertion attempts, any assistive device for insertion, and insertion site. Inclusion criteria were mask induction, ASA status 1 or 2, nonemergency, ambulatory surgical procedures, and placement of a single intravenous line during the anesthetic.

RESULTS

A total of 9693 patients were included in the study. Of which 8869 patients required one insertion attempt and 824 underwent multiple insertion attempts. 50% of patients in the single insertion attempt group had clear liquid fasting time <6.9 hours compared to 51.8% of patients requiring multiple attempts. Logistic regression model adjusted for age, ASA status, gender, and BMI did not find an association between duration of clear liquid fasting time and rate of multiple insertion attempts for intravenous catheters (OR: 0.99, 95% CI: 0.98-1.01, P = .47).

CONCLUSION

Clear liquid fasting time was not associated with multiple insertion attempts for intravenous line insertion in children receiving general anesthesia. Factors such as patient age, ethnicity, time of day of induction of anesthesia, and American Society of Anesthesiologists Physical Status classification show a greater association with the risk of multiple intravenous line insertion attempts.

Preoperative Fasting Practices Across Three Anesthesia Societies: Survey of Practitioners

Background

Pulmonary aspiration of gastric contents is recognized as a complication of anesthesia. To minimize that risk, anesthesiologists advised fasting for solid foods and liquids for an often prolonged period of time. However, 30 years ago, evidence was promulgated that fasting for clear liquids was unnecessary to ensure an empty stomach. Despite a strong evidence base and the knowledge that fasting may be physiologically harmful and unpleasant for patients, the adoption of society guidelines recommending short fasting periods for clear fluids into clinical practice is uncertain.

Objective

This study aimed to determine the current practices of anesthetists with respect to fasting guidelines.

Methods

An electronic internet survey was distributed to anesthetists in Canada (CAN), Australia and New Zealand (ANZ), and Europe (EUR) during April 2014 to February 2015. The anesthetists were asked about fasting guidelines, their recommendations to patients for the consumption of clear fluids and solid foods, and the reasons and consequences if these guidelines were not followed.

Results

A total of 971 anesthetists completed the survey (CAN, n=679; ANZ, n=185; and EUR, n=107). Although 85.0% (818/962) of these participants claimed that their advice to patients followed current society guidelines, approximately 50.4% (476/945) enforced strict fasting and did not allow clear fluids after midnight. The primary reasons given were with regard to problems with a variable operating room schedule (255/476, 53.6%) and safety issues surrounding the implementation of clear fluid drinking guidelines (182/476, 38.2%).

Conclusions

Many anesthetists continue to follow outdated practices. The current interest in further liberalizing preoperative fluid intake will require more change in anesthesia culture.