Full stomach - NYSORA | NYSORA

Full stomach

Learning objectives

  • Outline the risks of having a full stomach in combination with anesthesia
  • Describe the factors that delay gastric emptying
  • Anesthetic management of a patient with a full stomach

Definition and mechanisms

  • In anesthesia, the term “full stomach” applies to patients that have recently ingested foods and/or have pharmacologic, metabolic, anatomic, or hormonal conditions, which impair gastric emptying
  • A full stomach and any reduction in the functional integrity of the lower esophageal sphincter (LES) predispose a patient to regurgitation
  • The active process of vomiting and the passive process of regurgitation of gastric contents are more hazardous in a patient with a full stomach
  • No patient can ever be assumed to have a completely empty stomach

General anesthesia suppresses the upper airway reflexes that prevent pulmonary aspiration of active or passively regurgitated gastric contents

  • Aspiration of solid material can cause a mechanical obstruction with subsequent lung collapse, pneumonia, or abscess formation
  • Aspiration of liquid (>25 mL, pH <2.5) can cause bronchospasm, pneumonitis, bronchopneumonia, and acute respiratory distress syndrome

Strategies to reduce the risk of pulmonary aspiration

  • Minimize residual gastric volumes → fasting (stomach is considered “empty” within 6 hours after food and milky drinks, 4 hours after breast milk, and 2 hours after water)
  • Rapidly secure the anesthetized airway

Emergency patients are more likely to have a full stomach as

  • Presenting pathology causes a mechanical obstruction (e.g., laparotomy for small bowel obstruction)
  • Surgery is urgent and cannot wait for the full fasting time
  • The surgical pathology results in pain and anxiety

Risk factors

Factors delaying gastric emptying

  • Mechanical obstruction of the gastrointestinal tract 
  • Ileus
  • Following surgical manipulation of the bowel (postoperative)
  • Recent trauma
  • Electrolyte imbalance
  • Peritonitis
  • Pain
  • Fear and anxiety
  • Third trimester of pregnancy
  • Drugs


full stomach, management, preoperative, intraoperative, postoperative, lower esophageal sphincter, reflux, heartburn, hiatus hernia, meoclopramide, nasogastric tube, sodium citrate, H2-blocking drugs, proton pump inhibitor, opioids, anticholinergics, cuffed endotracheal tube, rapid sequence induction, preoxygenation, cricoid pressure, head-up position, lateral position, tilted head-down

Suggested reading

  • Pollard BJ, Kitchen G. Handbook of Clinical Anaesthesia. 4th ed. Taylor & Francis group; 2018. Chapter 4 Gastrointestinal tract, Jackson MJ.

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