Korean J Anesthesiol.  2004 Aug;47(2):228-232. 10.4097/kjae.2004.47.2.228.

No Difference in the pH of Gastric Contents between Moderate Obese and Lean Gynecological Patients

• Kim SS
• Choi TS
• Kim DS
• Ryu SJ
• Kim SH

• KMID: 2237533
• DOI: http://doi.org/10.4097/kjae.2004.47.2.228

Abstract

BACKGROUND: Two results have been conflict regarding the pH of gastric contents in obese and lean surgical patients. Obese patients have been considered to have lower pH of gastric contents than lean surgical patients since the study by Vaughan, whereas Harter reported no significant difference in the pH's of obese and lean surgical patients. The author wanted to investigate whether gastric content pH differs or not between obese and lean surgical patients aged from 20 to 60 years.
METHODS
Forty patients scheduled for elective abdominal hysterectomy under general endotracheal anesthesia were studied. Group I (n = 20) was composed of lean patients whose body mass indices (BMIs) were between 20 and 25, whereas Group II (n = 20) was composed of obese patients whose BMIs were above 30. Every patient was fasted between 8 and 14 hours preoperatively. Within 10 minutes of endotracheal intubation, gastric contents were withdrawn with a 20 cc syringe connected to a 16F nasogastric tube placed in the stomach. pH and the incidences of pH <2.5, and pH <1.8 were compared.
RESULTS
No significant difference in pH (P = 0.199) or in the incidences of pH less than 2.5 (P = 0.23) or 1.8 (P = 0.52) were observed between obese and lean patients.
CONCLUSIONS
Obese and lean patients have similar fasting gastric pH's, as long as the obesity is not too severe (BMI under 40).

Keyword

obesity; pH of gastric content; preoperative fasting

MeSH Terms

Anesthesia
Fasting
Humans
Hydrogen-Ion Concentration*
Hysterectomy
Incidence
Intubation, Intratracheal
Obesity
Stomach
Syringes