Effect of a carbohydrate lollipop on the gastric volume of fasted pediatric patients

Abstract Background Preoperative fasting is part of routine practice. Children subjected to prolonged preoperative fasting often suffer adverse effects. Consuming a preoperative lollipop may lessen their anxiety and have clinical benefits. Aims To assess the effect of consuming a lollipop on gastric volume and the feasibility of administering a lollipop to a child preoperatively. Methods In this prospective, repeated measures interventional study, we measured gastric antrum volume using ultrasound in children aged 2–18 years. We measured antrum volumes after participants had fasted for a minimum of 6 h for solids and 2 h for clear fluids. They then consumed a standard carbohydrate lollipop, and we repeated the antrum volume measurements after 1 h. Results Of the 38 patients enrolled, 32 completed the study; four had ingested additional food or liquid, and two were diagnosed with systemic disease the day after data collection. The gastric volume data were normally distributed. The mean volume change was 0.01 ml kg−1 (95% CI −0.02 to 0.05; p = .460). The mean postlollipop volume was 0.51 ml kg−1 (95% CI 0.43 to 0.58). Conclusions Consuming a standard lollipop did not affect the gastric volume of fasted pediatric patients.

the guidelines classified only two recommendations as level A: (1) Shortened preoperative fasting times and (2) Clear fluid consumption allowed down to 2 h preoperatively. 9 In 2020, after mounting evidence emerged regarding the low incidence of aspiration, and efficacious introduction of a 1 h preoperative fast for clear fluids, an international consensus statement endorsed unrestricted clear fluid 1 h preoperatively in pediatric and adult patients. 10 Guidelines by the European Society of Anaesthesiology (ESA) in 2011 recommended continuing surgery if boiled sweets were sucked beforehand. 8 Current guidelines omit this recommendation, as it was extrapolated from chewing gum findings. 1,2 The effect of preoperative boiled sweets on gastric volume has not yet been investigated.
Point-of-Care Ultrasonography (POCUS) of gastric content is a valuable tool for anesthesiologists when a patient's fasting status is unknown. 2,11,12 The cross-sectional area (CSA) of the gastric antrum in pediatric patients is readily identified and correlates well with total gastric residual volume (GRV). 2,13 Mathematical equations for estimating GRV from the antral CSA in pediatric patients 14,15 have been utilized to investigate the effect of carbohydrate fluids on GRV and gastric emptying times. 16,17 We hypothesized that consumption of a standard carbohydrate lollipop would not increase the gastric volume of fasted pediatric patients after 1 h. Our aims were to assess the effect of a lollipop on gastric volume and the feasibility of giving a lollipop to a child preoperatively.

| MATERIAL S AND ME THODS
The Stellenbosch University Health Research Ethics Committee approved the study (10 October 2020, Reference No. S20/05/117).
We registered the study with the South African National Health Research Database (https://nhrd.health.gov.za; Reference no. WC_202010_042). It was a single center prospective cohort study, conducted at Tygerberg Hospital, Western Cape, South Africa. We performed the study according to the ethics of the Declaration of Helsinki. Methodology followed recommendations of the TREND statement for reporting nonrandomized studies. 18 Our primary outcome was to establish whether in fasted children, there is a difference in gastric residual volume per kilogram bodyweight (ml kg −1 ) 1 h after consuming a lollipop. The secondary outcome was to determine whether there was a change in qualitative sonographic gastric antrum grading.
The legal guardians of children aged 2-18 years, scheduled for elective surgical procedures, provided written, informed consent.
Children older than 7 years provided additional assent. They consented a day before data collection, to ensure overnight fasting compliance. We collected our data on the morning of the day prior to surgery, while ensuring that participants' daily feeding schedules were not interrupted. Exclusion criteria were any known medical condition, BMI > 35 kg m −2 , drugs that altered gastric motility, an Each examination was performed with the child placed first in the supine and then in the right lateral decubitus position (RLD). The transducer was placed inferior to the xiphisternum in a sagittal or parasagittal plane, with the probe pointer directed cephalad. The transducer was tilted or rotated to optimize the image of the gastric antrum. The correct plane was identified when the antrum was visualized adjacent to the pancreas or left liver lobe, with the aorta or inferior vena cava visualized in a longitudinal axis. 14,15 Qualitative grading of the gastric antrum was assessed using the 3-point grading system described by Perlas et al. 11 The antrum was described as empty if it appeared flat, with the anterior and posterior walls juxtaposed during a dynamic scan. The antrum was deemed to contain fluid if it appeared to have an endo cavitary lumen with hypoechoic or anechoic content and distended walls. Solid matter was described if echoic content was seen, such as the described "frosted glass" appearance. A grading score of 0, 1, or 2 was applied as fol-

What is already known about the topic?
Routine preoperative fasting is often prolonged in elective pediatric surgery, despite pulmonary aspiration being rare.
The influence of a lollipop on gastric volume has not been accurately investigated.

What new information this study adds?
Children's gastric volumes do not increase 1 h after consuming a pure carbohydrate lollipop.
volume. 14 The cross-sectional area (CSA) of the antrum, expressed in cm 2 , was measured using the ultrasound machine's internal caliper free-tracing tool, by tracing the outer layer of the antrum corresponding to the gastric serosa. The mean of the three values obtained from each image was used for gastric volume calculation. We used an equation previously derived by Spencer and colleagues, 14

| Data analysis
We planned a prospective, repeated measures, interventional study, testing for equivalence. We employed the method of Jones et al. 19 to calculate the required sample size. For calculation of the expected effect size, we accepted an increase in gastric volume of ≤1.0 ml kg −1 (standard deviation 0.84 ml kg −1 ) as constituting low risk for aspiration of gastric contents. We based our 1.0 ml kg −1 value firstly on the findings of two studies of fasted children 14,20 that employed the Spencer et al. equation, 14 in which mean volume changes were 0.28 and 0.63 ml kg −1 , and secondly on a gastric volume threshold of 1.5 ml kg −1 that is accepted as constituting an increased risk for aspiration. 11,14 . We derived the standard deviation of 0.84 ml kg −1 from a study by Song et al., 16 who measured antrum volumes in 79 children after ingestion of carbohydrate drinks. For 90% power and two-sided alpha 0.05, the required sample size is 30 subjects. We intended to recruit 40 participants to allow for dropouts and protocol violations.
We conducted statistical analyses using computer software  Table A1 in the Appendix S1 displays the tests employed. We regarded an alpha value of <.05 as indicating statistical significance. We specified a priori that the preand postlollipop antrum volume measurements would be regarded as equivalent if the 95% confidence interval (95% CI) of the mean volume change was <1.0 ml kg −1 . Thus, the null hypothesis was that the 95% CI of the mean volume change would be ≥1.0 ml kg −1 . We also compared pre-and postlollipop antrum volumes by conducting a paired t-test, for which the null hypothesis was that there would be no statistically significant difference. We regarded a high risk of aspiration to be present if the postlollipop antrum volume was ≥1.5 ml kg −1 .

| RE SULTS
We recruited 38 participants. The CONSORT flow diagram is shown in Figure 1. Of the six excluded recruits, four opted to eat or drink before the second measurement and two were diagnosed with infectious diseases on the day of their data collection.
A total of 32 ASA physical grading 1 participants were included in the final analysis of whom 23 (72%) were male and 9 (28%) were female. Participant demographics are summarized in Table 1.
Procedures the participants underwent are depicted in the Appendix S1 (Table A2).
All 32 participants consumed their lollipops within 1 h, and all gastric antra were visualized successfully. No episodes of vomiting, regurgitation, or discomfort occurred during the study. Volume measurements are shown in Table 2. The gastric volume data were normally

| DISCUSS ION
We assessed participants' gastric volumes after an overnight fast, and 1 h after being offered a lollipop. To our knowledge, this is the first investigation regarding the effect of a carbohydrate lollipop on gastric volume in children, using ultrasound. We did not detect a significant change in gastric volumes. The volume changes met our a priori specification for gastric volume equivalence.
Gastric physiology is complex and differs between fasted and fed states. 21 Saliva and gastric secretions, respectively, contribute up to 1 and 0.6 ml kg −1 h −1 of baseline volume. A GRV <1.5 ml kg −1 corresponds to baseline secretions and is regarded as low risk for aspiration. 11,14 A GRV >1.5 ml kg −1 corresponds to volumes exceeding fasted gastric volume and indicates high risk for aspiration.
According to the qualitative grading system, the two Grade-2 participants should indicate high aspiration risks. However, not one participant experienced a postlollipop volume considered a risk for aspiration (increase >1 ml kg −1 or postlollipop volume >1.5 ml·kg −1 ). 11,14 Prior studies indicate that qualitative grading of gastric content is a useful preoperative screening tool, and that increases in qualitative antrum grading are accompanied by increased gastric volumes. 13,14,20 ESA guidelines recommend qualitative grading for airway management decisions in patients with an unsure fasting status (weak recommendation, low-quality evidence). 2 However, measured volumes in Grade-2 antra are often smaller than 1.5 ml kg −1 , and prior studies  recommend quantitative measurement should complement qualitative assessment in children. 13,20 Figure A1 in the Appendix S1 depicts our subjects' considerable overlap regarding volume measurements in the three grades. The two Grade-2 participants were classified as Grade-2 before and after consuming lollipops. Their volumes were small (Table 3 legend). Our few Grade-2 numbers preclude statistical comparison with previous studies; however, those studies reveal considerable variation regarding Grade-2 volumes (Table A3 in the Appendix S1). 13,14,20 Our study supports the use of quantitative methods in addition to qualitative grading. 13,20 A randomized controlled trial compared control, placebo, and fentanyl lollipop effects on GRV and pH, using nasogastric tube aspiration. 22 There was no significant increase in GRV between the fasted control and placebo carbohydrate lollipop groups. A statistically significant increased GRV was detected in the fentanyl lollipop group, that was clinically unimportant. There was no difference in gastric pH between the groups. Mean times to consume the lollipops were <20 min. Our study corroborates the negligible volume change after consumption of carbohydrate lollipops and the feasibility of children to completely consume them within an hour.
Providing preoperative carbohydrates to children, such as chewing gum and fluids, have been investigated. A meta-analysis of 287 patients concluded that chewing gum increases GRV with statistical significance, but the increase is clinically unimportant.
Gastric pH remains unchanged. 23 Oral fluids have been investigated using ultrasound. Song and colleagues found a mean decrease of 0.24 cm 2 in antral CSA (95% CI 0.06 to 0.43; p = .01) 2 h after an oral carbohydrate fluid regimen. 16 Taye and colleagues found that after ingestion of fluid volumes between 3 and 5 ml kg −1 , weight adjusted GRV returned to baseline after 50 min. 17 Our lollipop volume was 3.5 ml, less than the volumes used in previous studies. Boiled sweets may increase saliva and gastric secretions during digestion. 21 Our findings of no significant increase in gastric volume between prelollipop and postlollipop measurements, support other studies' findings of this increase in secretions not being clinically relevant, possibly due to gastric emptying promotion from carbohydrates. 16,24 Gastric antral ultrasound enables qualitative and quantitative assessment of gastric contents. It is reliable, reproducible, and noninvasive. 25 It is used for preoperative assessment in both adults and children. 11 We observed no significant change in gastric volume when using the CSA in the RLD position. Our mean gastric volumes prelollipop and postlollipop are similar to fasted means in studies that used magnetic resonance imaging 24 and ultrasound. 13,20 Increased GRV is a contributing factor to aspiration risk, but it is

TA B L E 3
Comparison of gastric volumes measured in Grade-0, Grade-1 and Grade-2 gastric antra compounds such as fats, proteins, or gelatin that delay stomach emptying.

| CON CLUS ION
We conclude that children's gastric volumes do not increase after

Tygerberg Hospital Department of Clinical Technology and
Tygerberg Hospital nursing staff.

CO N FLI C T O F I NTE R E S T
None to declare.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are openly available