Effect of saliva on PH and volume of gastric contents while sampling from stomach with two different techniques of orogastric intubation

Abstract

Objectives: To explore the effect of saliva on pH and volume of gastric aspirate by using two different techniques of blind gastric aspiration of gastric contents. Materials and Methods: This prospective and randomized clinical trial was conducted in the Department of Anaesthesia at King Khalid University Hospital, Al-Riyadh, Saudi Arabia from August to December, 2006 on 140 adult inpatients of either sex, aged 15-70 years and American Society of Anesthesiologists physical status I-II. An orogastric tube was passed by conventional method in Group A and through an endotracheal tube placed in esophagus in Group B. Gastric contents were aspirated with a large bore, multi-orifices gastric tube after tracheal intubation and analyzed for the presence of bile salts, pH and volume. Results: Thirty nine (28.57 %) samples were contaminated with duodenal contents and one with blood. Six patients have no gastric contents in Group A due to failed orogastric intubation and none in Group B (p 0.0280). Saliva, by conventional method of orogastric intubation, significantly affected both the pH (A-2 versus B-2: p <0.0001) and volume (A-2 versus B-2: p 0.0045) of gastric contents. Duodenogastric refluxate significantly affected both the pH (A-1 versus A-2: p0.0236), B-1 versus B-2: p 0.0019) and volume (A-1 versus A-2: p .0343), B-1 versus B-2: p 0.0005) of gastric contents. Conclusion: Saliva significantly affected both the pH and volume of gastric contents when sampled by conventional method of orogastric intubation. Duodenogastric refluxate significantly affected both the pH and volume of gastric contents.