Overview
This study aims to investigate whether reduced heart function is associated with differences in stomach contents before elective coronary artery bypass graft (CABG) surgery. Patients undergoing elective cardiac surgery will be divided into two groups based on their left ventricular ejection fraction (LVEF), a measure of how well the heart pumps blood: patients with an LVEF below 40% and patients with an LVEF of 40% or higher. Before surgery, the researchers will use ultrasound to examine the stomach. They will assess the presence and amount of stomach contents using the Perlas grading system and ultrasound measurements of the gastric antrum. The main objective is to compare gastric ultrasound findings between the two groups. The researchers will also evaluate estimated gastric volume and the frequency of stomach findings associated with a higher risk of aspiration during anesthesia.
Description
This prospective, single-center, observational cohort study will investigate the association between left ventricular systolic function and preoperative gastric ultrasonography findings in adult patients undergoing elective coronary artery bypass grafting (CABG) surgery.
A total of 50 patients will be enrolled consecutively and categorized into two groups according to preoperative left ventricular ejection fraction (LVEF): patients with LVEF \<40% (n=25) and those with LVEF ≥40% (n=25). Group allocation will be based on pre-existing cardiac function without any study-related intervention. Demographic characteristics, relevant comorbidities, preoperative medication use, gastrointestinal symptoms, fasting duration, and echocardiographic findings will be documented to evaluate potential factors associated with gastric ultrasound findings.
Preoperative gastric ultrasonography will be performed before induction of general anesthesia by an anesthesiologist experienced in point-of-care gastric ultrasound. The examiner will be blinded to the patients' clinical and echocardiographic findings, including LVEF values. A 2-5 MHz convex transducer will be used to examine the gastric antrum in the epigastric region, using standard anatomical landmarks. Gastric assessment will be performed in both the supine and right lateral decubitus (RLD) positions.
Gastric contents will be assessed qualitatively using the Perlas grading system. Grade 0 indicates an empty antrum in both positions; Grade 1 indicates clear fluid visible only in the RLD position; and Grade 2 indicates clear fluid visible in both positions or the presence of solid or particulate gastric contents.
The gastric antral cross-sectional area (CSA) will be calculated in the RLD position using the anteroposterior and craniocaudal diameters according to the formula:
CSA (cm²) = (AP diameter × CC diameter × π) / 4.
For patients with clear gastric fluid, gastric volume will be estimated using the Perlas mathematical model:
Estimated gastric volume (mL) = 27.0 + (14.6 × CSA) - (1.28 × age). Estimated gastric volume will also be expressed in mL/kg. The volume estimation model will not be applied to patients with solid or thick particulate gastric contents.
A high-risk stomach will be defined as an estimated gastric volume greater than 1.5 mL/kg or the presence of solid or thick particulate gastric contents.
The study will evaluate the association between left ventricular systolic function and preoperative gastric ultrasound findings, with particular emphasis on gastric content characteristics, antral dimensions, and indicators of increased gastric aspiration risk.
Eligibility
Inclusion Criteria:
- Age ≥18 years.
- Scheduled for elective coronary artery bypass grafting (CABG) surgery with cardiopulmonary bypass.
- Willingness to participate in the study and provision of written informed consent.
Exclusion Criteria:
- Emergency surgery.
- History of upper gastrointestinal surgery.
- Known gastroparesis or severe gastrointestinal motility disorders.
- Active nausea or vomiting.
- Body mass index (BMI) \>40 kg/m².
- History of gastroesophageal reflux disease (GERD).
- Inability to cooperate with gastric ultrasonography assessment.
- Refusal to participate in the study.
