Effects of fasting intervals on gastric volume and pH

Objective: to evaluate effect of different intervals of fasting on gastric ph and volume before surgery. methods:-in this observational study 65 patients of asa p1 ≥11 status and age 15 to 50 years of both sex undergoing general anesthesia for elective surgery were studied and time of last fluid/solid intake was noted. after induction of ga a multiorifice orogastric tube (18f) was passed in the stomach and after confirmation gastric fluid was aspirated by 50cc syringe,volume and ph was measured. results: patients who had fasted upto 8 hours had gastric fluid volume of 27.857±3.058cc and ph 3.929±0.997 and patients who had fasted from 8 to 12 hours had gastric fluid volume of 27.400±2.980cc and gastric ph 2.914±0.355. patients who had fasted from 12 hours and above had gastric fluid volume 27.470±15.550cc and ph 2.848±0.284. conclusion: fasting interval more than 8 hours neither reduce gastric fluid volume nor increase its ph more than 2.5 and prolong fasting interval doesn't guarantee empty stomach and there is no relationship between a prolonged fast and safe gastric environment.