Aspiration, Perioperative

Risk of aspiration: Approximately 3 per 10,000 anesthetics, 11 per 10,000 emergency and/or after-hours cases, and 29 per 10,000 emergency cases in ASA IV and V pts

Loss of protective reflexes and sphincter function

Obstructed or abnormal GI motility

Increased gastric fluid volume; decreased pH

Inadequate anesthesia leading to coughing and straining during airway manipulation or induction

Trauma, emergency/night surgery, pregnancy, difficult airway, advanced age, long-standing diabetes mellitus, pain, analgesics, and ASA status >2

Obesity: not an independent risk factor

Mortality after aspiration: 5%; higher if ASA >2 or if mechanical ventilation required for >24 h after the aspiration event

Of pts who aspirated, 20% had no risk factor: of these, 66% had difficult intubation

Rapid-sequence induction may have deleterious effects on heart rate and blood pressure

Clinical worsening may be delayed up to 24 h after the inciting aspiration event

Prevention of aspiration best because there is no definitive treatment.

Vast majority of pts with risk factor(s) do not aspirate.

Consider aspiration in differential diagnosis of bronchospasm with hypoxemia.

Loss of protective reflexes: Sedation, neuromuscular disorders/relaxants, and altered mental status

Obstructed or abnormal motility: Achalasia, gastroparesis, pain, and opioids

Increased GI contents: Bleeding, obstruction, and feeds