simethicone and Pneumonia--Aspiration

One hundred twenty-six parturients for elective cesarean section under general anesthesia were allocated to either a cimetidine or an antacid group in a randomized, double-blind, multicenter trial. The cimetidine-treated group received 300 mg cimetidine orally the evening before the operation and 300 mg intramuscularly between 1 and 3 h preoperatively. The antacid-treated group received 30 ml of Mylanta-II orally on both occasions. Gastric volume, 30 min after induction of anesthesia and 30 min before response to oral commands, was less in the cimetidine-treated group. Gastric pH 30 min after induction was greater in the cimetidine-treated group. The maternal serum level of cimetidine at birth was 1.31 +/- 0.12 micrograms/ml and the umbilical venous level was 0.78 +/- 0.05 micrograms/ml. The neonatal gastric acidity, Apgar scores, and Early Neonatal Neurobehavioral Scale (ENNS) scores were similar in both groups. No maternal or neonatal complication was attributed to treatment.

Topics: Adolescent; Adult; Aluminum Hydroxide; Anesthesia, General; Anesthesia, Obstetrical; Antacids; Cesarean Section; Cimetidine; Double-Blind Method; Drug Combinations; Drug Evaluation; Female; Gastric Acid; Guanidines; Humans; Magnesium; Magnesium Hydroxide; Pneumonia, Aspiration; Postoperative Complications; Pregnancy; Premedication; Silicones; Simethicone

Sucralfate is an effective agent in reducing the incidence of upper GI tract (UGIT) stress bleeding and nosocomial pneumonia in critically ill patients. Many of these patients are not intubated and are at increased risk for aspiration of large volumes of UGIT contents containing sucralfate. The effects of aspirated sucralfate are unknown. To investigate this, large-volume aspiration (2 ml/kg) was simulated in freshly tracheostomized rats (n = 6, all experimental groups) using normal saline, particulate antacid, and sucralfate adjusted to pH 3.6 and 5.0. Four hours after aspiration, the rats were killed and their lungs were formalin-fixed. Significant increases in lung inflammation were seen by light microscopy in all experimental groups at pH 3.6. Antacid aspirated at pH 5.0 induced significant increases in airway as well as parenchymal inflammation. At pH 3.6, the antacid aspiration led to significant increases in lung edema and hemorrhage. Sucralfate aspiration produced significant increases in pulmonary hemorrhage at pH 5.0. Our microscopic findings are consistent with the acute pulmonary histopathologic changes known to occur after large-volume aspiration of particulate materials, including antacids. Additionally, we show that large-volume aspiration of sucralfate produced significant acute pneumonitis, including pulmonary hemorrhage. In view of the proven usefulness of sucralfate, further investigations are indicated to evaluate these experimental findings before extrapolating to critically ill patients.

Topics: Aluminum Hydroxide; Animals; Antacids; Drug Combinations; Hemorrhage; Hydrogen-Ion Concentration; Lung Diseases; Magnesium Hydroxide; Pneumonia, Aspiration; Pulmonary Atelectasis; Pulmonary Edema; Rats; Rats, Inbred Strains; Simethicone; Sucralfate

The effects of aspiration of (a) 2 ml of Mylanta (a particulate antacid) mixed with 2 ml of hydrochloric acid (pH 1.5), (b) 2 ml of half-strength Bicitra (a soluble antacid) mixed with 2 ml of hydrochloric acid (pH 1.5), (c) 4 ml of hydrochloric acid (pH 1.5), and (d) 4 ml of normal saline (pH 6.5) on arterial blood gas tensions and lung pathology were compared in anesthetized rabbits. PaO2 decreased similarly in all animals 15 minutes after aspiration, but recovered to normal levels 4 hours after aspiration of saline and 48 hours after aspiration of Bicitra. PaO2 remained depressed after aspiration of Mylanta and HCl. Gross and microscopic evidence of lung injury was most severe in animals that aspirated Mylanta. One animal died 8 hours after aspiration of Mylanta.

Topics: Aluminum Hydroxide; Animals; Antacids; Citrates; Citric Acid; Drug Combinations; Magnesium; Magnesium Hydroxide; Male; Oxygen; Partial Pressure; Pneumonia, Aspiration; Postoperative Complications; Preoperative Care; Rabbits; Silicones; Simethicone