Full stomach

Learning objectives

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

Factors delaying gastric emptying