Ultrasound Assessment of Gastric Residual Volume in Children Scheduled for Elective Surgery After Clear Fluids Fasting for One Versus Two Hours: a Comparative Study

Overview

Ultrasound guided comparison of gastric residual volume after clear fluid fasting for one versus two hours in pediatrics scheduled for elective surgery.

Full Title of Study: “Ultrasound Assessment of Gastric Residual Volume in Children Scheduled for Elective Surgery After Clear Fluids Fasting for One Versus Two Hours; a Comparative Study”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Diagnostic
    • Masking: Triple (Participant, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: July 2020

Detailed Description

Introduction:

The general purpose of preoperative fasting is to allow enough time for the stomach to empty, hence reducing the incidence of regurgitation of gastric contents into the trachea which is a dangerous complication despite its rare incidence in pediatrics.(1) Most modern fasting guidelines consider the balance between the risk of pulmonary aspiration and the harmful effects of prolonged preoperative fasting (thirst, dehydration, hypoglycemia and hypotension).(2) The American Society of Anesthesiology (ASA), the European Society of Anesthesiology (ESA) and the Scandinavian guidelines recommend children to be fasted 2h for clear fluids.(3,4,5) However, those guidelines are usually exceeded leading to prolonged fasting.(6) Data from volunteer studies indicate that the gastric emptying half-life after clear fluid intake is short, with gastric volumes returning to baseline within 1 h after drinking.(7) Recent clinical studies indicate that fluid fasting shorter than the recommended minimum of 2 h might be feasible.(8,9).however, in both studies gastric aspiration was used to assess the residual volume which might underestimate the gastric residual volume. Moreover, the studies used to estimate the gastric residual volume with nasogastric tube aspiration are largely heterogenous with a very wide range of agreement compared to standard gastroscope.(10,11,12) Ultrasound is an emerging tool for assessment of the gastric residual volume through measurement of antral cross sectional area which have proved effective with fair ability to discriminate an empty antrum in pediatric patients.(13) Many studies have used ultrasound for assessment of gastric contents in pediatric following normal fasting hours (14,15) but none has compared one versus two hours clear fluids fasting in pediatrics scheduled for elective surgery.

Objectives:

- To assess gastric residual volume in pediatrics having clear fluids fasting for one hour before elective surgery

- To compare gastric residual volume in pediatrics having clear fluids fasting for one versus two hours before elective surgery using ultrasound.

- To assess the risk of aspiration of gastric contents in both groups.

Hypothesis:

We hypothesized that clear fluids fasting for one hour dos not result in larger gastric residual volumes compared to two hours fasting for children scheduled for elective surgery under general anesthesia.

2. Study Protocol Following approval from ethics and research committee of anesthesia department, Faculty of Medicine, Cairo University, an informed consent will be obtained from parent/care giver prior to commencement of the study.

In the preparation room (or holding area), eligible children weight will be measured prior to the examination by a scale in the holding area. children fasting for 6 to 8 hours will be allowed to drink 3 mL/kg of apple juice to a maximum of 250 ml one hour before surgery in group 1 (G)1 and two hours before surgery in group 2 (G2). Parent/ care giver will be allowed to accompany her/his child during the examination period to alleviate anxiety and ensure compliance of parents. Child weight will be measured prior to the examination by a scale in the holding area. Volume of given "apple juice" will be calculated by a 50 mL scaled clean syringe.

Ultrasound examination will be performed using a high frequency (5-10 MHz) ultrasound probe (S-NerveTM; SonoSite Inc., Bothell, WA, USA). Children in both groups will be scanned in two positions: supine position and right lateral position (RLP) one and two hours following the clear fluid intake and before admission to the operation room in groups 1 and 2 respectively. Gastric antrum will be located in the sagittal plane with simultaneous identification of left lobe of the liver and the descending abdominal aorta or inferior vena cava.

According to its shape and contents, the antrum will be considered to be either empty (if it was flat with juxtaposed anterior and posterior walls), fluid-containing (if it was distended, with thin walls and hypoechoic content), or solid-containing (if it was distended with a content of mixed echogenicity).

The antral cross sectional area will be calculated after measuring the two dimensions of the antrum (D1 and D2) according to the following equation: π [D1 × D2] /4, where D1 and D2 are the anteroposterior and craniocaudal diameters, respectively. Measurements will always be made from the outer layer of the gastric wall, and all images will be obtained between peristaltic contractions. Three measurements will be collected and average values will be used.

The gastric residual volume will be calculated using a mathematical model previously validated in the pediatric population as follows :(16) Gastric residual volume (ml/kg) = [-7.8 + (0.035 ×RLP CSA (mm2) + 0.127 × age (months)]/ body weight (kg)

For assessment of the risk of aspiration, we will use the classification previously settled by( Ven de Putte and Perlas 2014) (17) as follows:

1. Low risk of aspiration: children with empty antrum and or children with gastric residual volume less than 1.5 mL/Kg.

2. High risk of aspiration: children with solid contents and or children with gastric residual volume more than 1.5 mL/Kg.

If the child has high risk of aspiration, the surgery will be postponed for one hour and we will reassess the antrum and gastric residual volume.

Interventions

  • Device: gastric ultrasound
    • Children in both groups will be scanned in two positions: supine position and right lateral position (RLP) one and two hours following the clear fluid intake and before admission to the operation room in groups 1 and 2 respectively. Gastric antrum will be located in the sagittal plane with simultaneous identification of left lobe of the liver and the descending abdominal aorta or inferior vena cava.
  • Other: the clear fluid intake
    • the clear fluid intake

Arms, Groups and Cohorts

  • Active Comparator: clear fluids fasting for one hour
    • children fasting for 6 to 8 hours will be allowed to drink 3 mL/kg of apple juice to a maximum of 250 ml one hour before surgery
  • Placebo Comparator: clear fluids fasting for two hours
    • children fasting for 6 to 8 hours will be allowed to drink 3 mL/kg of apple juice to a maximum of 250 ml two hours before surgery

Clinical Trial Outcome Measures

Primary Measures

  • Antral cross-sectional area in supine position after one-hour of clear fluid intake
    • Time Frame: one-hour of clear fluid intake

Secondary Measures

  • Antral cross-sectional area in right lateral position after one-hour clear fluid intake
    • Time Frame: one-hour clear fluid intake
  • Antral cross-sectional area in right lateral and supine positions after two hours clear fluid intake
    • Time Frame: two hours clear fluid intake
  • Gastric residual volume in supine position in both groups
    • Time Frame: one hour after clear fluid intake
  • Gastric residual volume in right lateral position in both groups
    • Time Frame: one and two hours after clear fluid intake
  • Grade of aspiration risk (frequency of high risk and low risk)
    • Time Frame: one and two hours after clear fluid intake
  • Qualitative grading for assessment of gastric antrum: three-point grading will be evaluated
    • Time Frame: one and two hours after clear fluid intake

Participating in This Clinical Trial

Inclusion Criteria

  • • ASA physical state I or II
  • Age 3 to 10 years.
  • Gender: both sexes.
  • Scheduled for non-GIT elective day-case surgery under general anesthesia with endotracheal intubation.

Exclusion Criteria

  • • Parent/ care giver refusal
  • Ages < 3 or > 10 years old
  • Children with gastro-esophageal reflux disease (GORD): either on treatment or under investigation
  • Renal failure, Diabetes mellitus and cerebral palsy patients
  • Esophageal strictures, achalasia or any intestinal disease that may impair the gastric emptying.
  • GIT surgery and neurosurgical patients
  • Emergency surgery

Gender Eligibility: All

Minimum Age: 3 Years

Maximum Age: 10 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Kasr El Aini Hospital
  • Provider of Information About this Clinical Study
    • Principal Investigator: Khaled Abdelfattah Abdallah Sarhan, lecturer of anesthesia – Kasr El Aini Hospital
  • Overall Official(s)
    • Khaled A Sarhan, MD, Principal Investigator, Lecturer of anesthesia, Cairo university
  • Overall Contact(s)
    • Khaled A Sarhan, MD, +201020067816, khaled.sarhan@kasralainy.edu.eg

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