Pulmonary acid aspiration syndrome: should prophylaxis be routine?

Area of Science:

• Anesthesiology
• Gastroenterology
• Pharmacology

Background:

• Aspiration of gastric contents during anesthesia can lead to acid aspiration syndrome.
• Preoperative fasting and antacids are used to reduce gastric volume and acidity.
• The efficacy of sodium citrate as a preoperative antacid was investigated.

Purpose of the Study:

• To assess the risk of acid aspiration syndrome in prepared and emergency patients.
• To evaluate the effectiveness of sodium citrate in reducing gastric acidity and volume.
• To recommend alternative antacid strategies for preoperative patients.

Main Methods:

• Gastric contents were aspirated from three patient groups: prepared, untreated emergency, and prepared with sodium citrate.
• Gastric pH and volume were measured at the beginning and end of anesthesia.
• Patients undergoing upper abdominal surgery were specifically analyzed for increased risk.

Main Results:

• Approximately 50% of patients in both emergency and prepared groups were at initial risk for acid aspiration.
• Untreated patients had 13% and 31% gastric volumes at induction and extubation, respectively.
• Sodium citrate (15 ml of 0.3 M) proved ineffective as an antacid in this study.

Conclusions:

• A significant proportion of patients remain at risk of acid aspiration syndrome, particularly those undergoing upper abdominal surgery.
• Sodium citrate is not an effective preoperative antacid for reducing gastric acidity.
• Mist. magnesium trisilicate B.P. is strongly recommended as a preoperative antacid to mitigate aspiration risks.