Ultrasound Assessment of Gastric Residual Volume in Obese Patients

Evaluation of Gastric Residual Volume in Fasting Obese Patients Using Gastric Ultrasound: a Comparative Study

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.

Study Overview

• Status: Completed
• Conditions: Aspiration Pneumonia
• Intervention / Treatment: Device: gastric ultrasound; Procedure: nasogastric tube insertion

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.

• Study Type: Observational
• Enrollment (Actual): 100

Contacts and Locations

Study Locations

• Egypt
  • Faiyum Governorate Egypt
    • Madīnat Al Fayyūm, Faiyum Governorate Egypt, Egypt, 63514
      • Fayoum University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

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

Description

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:

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

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
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; 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; Procedure: nasogastric 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.; Other Names: Ryle tube
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; 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; Procedure: nasogastric 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.; Other Names: Ryle tube

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
measurement of gastric residual volume in semi-sitting position	in cubic centimetre	5 minutes preoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
measurement of gastric residual volume in right lateral position.	in cubic centimetre	5 minutes preoperatively
Antral cross sectional area in semi-sitting position	in millimetre square	5 minutes preoperatively
Antral cross sectional area in right lateral position	in millimetre square	5 minutes preoperatively
volume of fluid aspirated from nasogastric tube	in cubic centimetre	1 minute after induction of anesthesia
grade of aspiration risk	less (low risk) or more (high risk) 1.5 millilitre/kilogram	5 minutes preoperatively
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	5 minutes preoperatively

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Age	in years	1 hour preoperatively
Weight	in kilograms	1 hour preoperatively
Body mass index	in kilograms/ square metre	1 hour preoperatively
Height	in centimetre	1 hour preoperatively

Collaborators and Investigators

• Sponsor: Fayoum University Hospital
• Investigators: Principal Investigator: Atef M Sayed, MD, Fayoum university; Study Chair: maged L Bolis, MD, Fayoum university

Publications and helpful links

General 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.
• 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.
• 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.
• 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.
• 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.

Study record dates

Study Major Dates

• Study Start (Actual): October 15, 2019
• Primary Completion (Actual): December 20, 2020
• Study Completion (Actual): December 30, 2020

Study Registration Dates

• First Submitted: September 3, 2020
• First Submitted That Met QC Criteria: September 3, 2020
• First Posted (Actual): September 10, 2020

Study Record Updates

• Last Update Posted (Actual): February 2, 2021
• Last Update Submitted That Met QC Criteria: February 1, 2021
• Last Verified: February 1, 2021

More Information

Terms related to this study

• Keywords: Ultrasound; Gastric residual volume; Obese; Aspiration
• Additional Relevant MeSH Terms: Infections; Respiratory Tract Infections; Respiratory Tract Diseases; Pneumonia; Lung Diseases; Pneumonia, Aspiration
• Other Study ID Numbers: M420

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No