A 38-year-old woman is scheduled for elective laparoscopic cholecystectomy under general anesthesia. During pre-anesthetic evaluation, she reports consuming a light breakfast 3 hours before arrival at the hospital. She is otherwise healthy with no comorbidities. Which investigation is most appropriate to assess her gastric emptying status before proceeding with anesthesia?

Explanation

## Gastric Emptying Assessment in Pre-anesthetic Evaluation ### Clinical Context The patient consumed food 3 hours before arrival, which falls within the fasting guideline window (2 hours for clear liquids, 6 hours for solid food). However, the question asks for the **investigation of choice** to assess actual gastric emptying status — not just adherence to guidelines. ### Gastric Ultrasound: Gold Standard **Key Point:** Gastric ultrasound (measuring antral cross-sectional area and gastric volume) is the non-invasive, real-time investigation of choice to assess gastric emptying and aspiration risk in the pre-operative period. **High-Yield:** - **Antral cross-sectional area (CSA)** measured in the sagittal plane at the level of the aorta and superior mesenteric vein - CSA ≤ 1.0 cm² = empty stomach (safe for anesthesia) - CSA 1.0–2.0 cm² = intermediate risk - CSA > 2.0 cm² = full stomach (high aspiration risk) **Clinical Pearl:** Gastric ultrasound is increasingly used in modern anesthesia practice because it: - Provides real-time assessment of gastric contents - Guides decisions on anesthesia induction technique (rapid sequence intubation vs. standard) - Reduces unnecessary delays in emergency surgery - Is non-invasive and radiation-free ### Why Gastric Ultrasound Over Other Tests | Investigation | Utility in Fasting Assessment | Limitation | |---|---|---| | **Gastric ultrasound** | Direct visualization of gastric volume; real-time; guides RSI decision | Operator-dependent; requires training | | Serum amylase/lipase | Assess pancreatic injury, not gastric emptying | Irrelevant to fasting status | | Upper GI endoscopy | Visualizes gastric mucosa; invasive; not practical pre-operatively | Invasive; delays surgery; not indicated for fasting assessment | | Abdominal X-ray | Poor sensitivity for gastric contents; radiation exposure | Insensitive; not recommended | **Mnemonic:** **FAST** (Focused Assessment with Sonography for Trauma) principles adapted for gastric assessment — **G-FAST** (Gastric-FAST) is increasingly recognized in pre-operative evaluation. **Tip:** In the NEET PG exam, when a stem asks for "investigation of choice" for gastric emptying or aspiration risk in the pre-operative period, **gastric ultrasound** is the modern, evidence-based answer.