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CompletedNCT04544371Updated Feb 2, 2021

Ultrasound Assessment of Gastric Residual Volume in Obese Patients

An observational study in Aspiration Pneumonia, sponsored by Fayoum University Hospital. Completed at 1 site in Egypt. Open to participants aged 20 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-02-02.

Sponsored by Fayoum University Hospital · Observational

Study type
Observational
Model
Case-control
Time perspective
Prospective
Enrollment
100
Ages
20 Years to 60 Years
Sex
All
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Study summary

Gastric emptying is a major risk factor for aspiration of gastric contents.Aspiration into the lungs represents a fatal complication that can occur during anesthesia.

Not only gastric emptying importance to anesthetists is related to aspiration but also it is important to determine the systemic availability of substances given through the mouth. Delayed gastric emptying represents a major danger as it causes nausea and vomiting and prevents a return to oral feeding. Lastly it may cause morbidity and mortality.

Both humoral and neural influences have their impact on emptying. Volume and composition of gastric food act as major determinants for the rate of gastric emptying. The effect of body weight on gastric emptying are inconsistent.

ASA fasting guidelines application represents the primary method to avoid aspiration as it ensures that stomach is empty before induction of anesthesia.

These guidelines cannot be applied on all cases as in urgent or emergent situations or in morbidities associated with delayed gastric emptying.

Ultrasound can be used perioperatively to asses gastric content and volume at bedside.

Read the detailed description

The objective of the current study is to evaluate gastric residual volume in obese patients versus healthy controls scheduled for elective surgery, using gastric ultrasound.

This prospective observational study was performed on 100 patients undergoing elective surgery from July 2019 to June 2020 at Fayoum University hospital after approval of the local institutional ethical committee (M420). A detailed informed consent was signed by the eligible participants before enrollment.

Our study adheres to the CONSORT guidelines. The study was conducted on 100 Patients were assigned to one of two groups of (50) patients in each group. Group obese ASA II from( 30-40) BMI, ASA III above 40 BMI without other comorbidities and group non obese ASA I control.Obese patients whose BMI >30 and healthy patients whose BMI = 18-24.9 who was scheduled for an elective surgery were included in this trial. All patients were enrolled in the study aged above >20 y. This study included patients scheduled for elective surgery after 8-hour overnight fast after a light meal.

Ultrasound scanning:

Focused gastric ultrasound by was performed by a trained physician in semi-sitting position then right lateral position using low frequency (2-5MHz) mindray curved transducer and mindray DP-20 ultrasound system. The antrum of the stomach was located in the epigastrium after a sweep of the probe from left to right subcostal margins. This could be done using left lobe of liver as an anterior landmark and descending abdominal aorta as a posterior landmark.

The antrum was considered to be empty if flat with juxtaposed anterior and posterior walls, fluid-containing if distended with thin walls and hypoechoic contents, solid -containing if distended with a content with mixed echogenicity according to antral shape and contents .

The antral cross sectional area (CSA) was measured using the two antral dimensions, craniocaudal (D1) and anteroposterior (D2) dimensions, according to the following equation: π [D1×D2]/4 provided that π = 22/7.

The gastric residual volume was calculated according to patient position as follows:

Bouvet and colleagues equation for semi-sitting position: gastric residual volume (ml) =215 + 57 log CSA (mm2) - 0.78 age (year) - 0.16 height (cm) - 0.25 weight (kg) - 0.80 ASA.

Perlas and colleagues equation for right lateral position: gastric residual volume (ml) = 27.0 + 14.6 × right-lateral CSA - 1.28 × age.

Using the classification of Ven de Putte and perlas, the study could asses the risk of aspiration as follows: (a) low risk of aspiration: patients with empty antrum and patients with gastric residual volume less than 1.5 ml/kg.(b) high risk of aspiration: patients with solid contents and patients with gastric residual volume more than 1.5 ml/kg.

Nasogastric tube (18-french) was inserted after induction of anaesthesia and endotracheal intubation. Aspiration of gastric contents was performed through gentle suction using 50 ml syringe with synchronous epigastric massage and gentle movement of nasogastric tube in and out for 10 minutes after confirmation of nasogastric tube position.

Statistical Analysis The collected data were organized, tabulated and statistically analyzed using SPSS software statistical computer package version 22 (SPSS Inc, USA). Numerical variables were not normally distributed and were presented as median and interquartile range (IQR); Mann-Whitney U test was used as a test of significant. Qualitative data were presented as numbers and percentages, and the chi-squared test was used to determine significance. A two-sided P-value of \<0.05 was considered statistically significant.

Sample size Sample size calculated using G-Power© software version 3.1.7 results with effect size (0.57), two sided (two tails) type I error 0.05 and power of 80%, each group should include at least (50) Subjects. the authors expected no dropout rates or missing data.

02

Conditions studied

  • Aspiration Pneumonia

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Keywords

  • Gastric residual volume
  • Obese
  • Ultrasound
  • Aspiration
03

In context

Pneumonia, Aspiration

64 studies on the registry are indexed under Pneumonia, Aspiration; 12 are open to participants now.

This study's enrollment of 100 is close to the median of 91 across 22 observational studies indexed under Pneumonia, Aspiration.

Browse Pneumonia, Aspiration studies →

Lead sponsor

Fayoum University Hospital is the lead sponsor of 73 studies on the registry; 12 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
20 Years to 60 Years
Sexes eligible
All
Accepts healthy volunteers
Yes
Sampling method
Probability sample

Study population

This prospective observational study will be performed on 100 patients undergoing elective surgery in fayoum university

Inclusion criteria

  • Adult patients aged from 20 years to 60 years
  • Patients scheduled for elective surgery after an 8-hour overnight fast after a light meal (200 ml milk, 50 g white cheese, and 120 g bread).
  • American society of anesthesiologists physical status I-III.

Exclusion criteria

Exclusion Criteria:

  • Pregnancy
  • Renal failure
  • Liver cell failure
  • History of upper GIT morbidity (hiatus hernia and gastric cancer)
  • History of upper abdominal surgery.
05

Study design

Observational model
Case-control
Time perspective
Prospective
Enrollment
100 participants (actual)
Patient registry
No

Groups and cohorts

  • normal weight patients

    patients with body mass index =18-24.9 kg/m2 will be examined by abdominal ultrasound to assess gastric antrum cross sectional area in semi-sitting and right lateral positions

    Device: gastric ultrasound · Procedure: nasogastric tube insertion

  • obese patients

    patients with body mass index \>30 kg/m2 will be examined by abdominal ultrasound to assess gastric antrum cross sectional area semi-sitting and right lateral positions

    Device: gastric ultrasound · Procedure: nasogastric tube insertion

Interventions

  • Devicegastric ultrasound

    Focused gastric ultrasound was performed in semi-sitting position then right lateral position mindray curved transducer for examination of abdomen with low frequency (2-5 MHz) by a trained physician. The antrum of the stomach was located in the epigastrium after a sweep of the probe from left to right subcostal margins. This could be done using left lobe of liver as an anterior landmark and descending abdominal aorta as a posterior landmark

  • Procedurenasogastric tube insertion

    Nasogastric tube (18-french) was inserted after induction of anaesthesia and endotracheal intubation. Aspiration of gastric contents was performed through gentle suction using 50 ml syringe with synchronous epigastric massage and gentle movement of nasogastric tube in and out for 10 minutes after confirmation of nasogastric tube position.

    Also known as: Ryle tube

06

What researchers measure

Primary outcomes

  1. measurement of gastric residual volume in semi-sitting position

    in cubic centimetre

    Time frame: 5 minutes preoperatively

Secondary outcomes

  1. measurement of gastric residual volume in right lateral position.

    in cubic centimetre

    Time frame: 5 minutes preoperatively

  2. Antral cross sectional area in semi-sitting position

    in millimetre square

    Time frame: 5 minutes preoperatively

  3. Antral cross sectional area in right lateral position

    in millimetre square

    Time frame: 5 minutes preoperatively

  4. volume of fluid aspirated from nasogastric tube

    in cubic centimetre

    Time frame: 1 minute after induction of anesthesia

  5. grade of aspiration risk

    less (low risk) or more (high risk) 1.5 millilitre/kilogram

    Time frame: 5 minutes preoperatively

  6. Grading for assessment of antrum of the stomach

    : 3 points as follows: grade 0: empty antrum, grade 1: minimal fluid in right lateral position only, grade 2: distention of antrum in both right lateral and semi-sitting position

    Time frame: 5 minutes preoperatively

Other outcomes

  1. Age

    in years

    Time frame: 1 hour preoperatively

  2. Weight

    in kilograms

    Time frame: 1 hour preoperatively

  3. Body mass index

    in kilograms/ square metre

    Time frame: 1 hour preoperatively

  4. Height

    in centimetre

    Time frame: 1 hour preoperatively

07

Study locations

1 site
  • Fayoum University hospital
    Madīnat Al Fayyūm, Faiyum Governorate Egypt 63514, Egypt
08

References and documents

Publications

  • Sun H, Wu CW, Zhang D, Makay O, Zhao Y, Carcofaro P, Kim HY, Dionigi G, Pino A, Caruso E, Pontin A, Pappalardo V. New Paradigms for Neural Monitoring in Thyroid Surgery. Surg Technol Int. 2019 May 15;34:79-86. PubMed 30664223 ↗
  • Bakalinis E, Makris I, Demesticha T, Tsakotos G, Skandalakis P, Filippou D. Non-Recurrent Laryngeal Nerve and Concurrent Vascular Variants: A Review. Acta Med Acad. 2018 Nov;47(2):186-192. doi: 10.5644/ama2006-124.230. PubMed 30585070 ↗
  • Neelakanta G, Chikyarappa A. A review of patients with pulmonary aspiration of gastric contents during anesthesia reported to the Departmental Quality Assurance Committee. J Clin Anesth. 2006 Mar;18(2):102-7. doi: 10.1016/j.jclinane.2005.07.002. PubMed 16563326 ↗
  • Bouvet L, Mazoit JX, Chassard D, Allaouchiche B, Boselli E, Benhamou D. Clinical assessment of the ultrasonographic measurement of antral area for estimating preoperative gastric content and volume. Anesthesiology. 2011 May;114(5):1086-92. doi: 10.1097/ALN.0b013e31820dee48. PubMed 21364462 ↗
  • Zaremba S, Shin CH, Hutter MM, Malviya SA, Grabitz SD, MacDonald T, Diaz-Gil D, Ramachandran SK, Hess D, Malhotra A, Eikermann M. Continuous Positive Airway Pressure Mitigates Opioid-induced Worsening of Sleep-disordered Breathing Early after Bariatric Surgery. Anesthesiology. 2016 Jul;125(1):92-104. doi: 10.1097/ALN.0000000000001160. PubMed 27171827 ↗

Individual participant data

Plan to share: Undecided

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Feb 2, 2021, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT04544371
Lead sponsor
Fayoum University Hospital
Responsible party
Atef Mohamed Sayed mahmoud (Principal investigator, Fayoum University Hospital) — Principal investigator
First posted
Sep 10, 2020
Start date
Oct 15, 2019
Primary completion
Dec 20, 2020
Completion
Dec 30, 2020
Last update
Feb 2, 2021

Study contacts

Atef M sayed, MD
principal investigator · Fayoum University
maged L Bolis, MD
study chair · Fayoum University

Oversight

FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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