The effect of oral hydration on the risk or aspiration and hemodynamic stability before the induction of anesthesia: A systematic review and meta-analysis

Ultrasound evaluation of gastric emptying time of standardized high-calorie liquid meals in healthy adults: A double-blind cross-over randomized study

BACKGROUND AND AIMS

Commercially available high-calorie drinks containing fat and protein can be used as dietary supplements in surgical patients. According to preoperative fasting guidelines, high-calorie drinks are non-clear fluids and should not be consumed 6 h before elective procedures. The aim of this study was to evaluate the gastric emptying time of commercially available high-calorie drink formulations in healthy adults using gastric ultrasound.

METHODS

25 healthy adult volunteers were included in this double-blind, cross-over prospective study. On three study sessions, fasted volunteers ingested one of the three study products: a solution of 75 g of glucose in 200 ml of water, a fat-free liquid meal, and a nutritionally complete liquid meal with equal volume and energy content. Gastric ultrasound examinations were performed to evaluate the gastric contents qualitatively and the volume of the gastric contents was calculated from the cross-sectional area of the gastric antrum measured in right lateral position by using a validated model. Repeated gastric ultrasounds were performed at baseline and half-hourly after ingesting the products in supine and right lateral position until the criteria for an empty stomach were met.

RESULTS

The glucose solution and the standard fat-free high-calorie drink with the same caloric content had a median gastric emptying time of 150 min. The nutritionally complete liquid meal had a median gastric emptying time of 180 min. Gastric emptying was complete in all participants before 6 h had elapsed since ingesting the study products.

CONCLUSIONS

High calorie liquid meals have a gastric emptying time longer than the recommended fasting time for clear fluids, but shorter than the recommended fasting time for solids in healthy adults.

Effects of Preoperative Oral Carbohydrate Electrolyte Drinks on Preoperative Hypokalemia Incidence in Patients Scheduled for Laparoscopic Colorectal Resection: A Three-arm Randomized Clinical Trial

PURPOSE

In our previous study, hypokalemia incidence was high in patients scheduled for laparoscopic colorectal resection. This trial was conducted to verify the effects of preoperative carbohydrate drinks containing potassium in these patients.

DESIGN

A three-arm randomized controlled design was used.

METHODS

Patients were randomly assigned to control, placebo, and treatment groups. In the control group, patients fasted from midnight. In the placebo group, patients fasted from midnight and received carbohydrate drinks 2 to 3 hours before surgery. In the treatment group, patients fasted from midnight and received carbohydrate drinks containing potassium supplementation 2 to 3 hours before surgery. The primary outcome was the incidence and severity of preoperative hypokalemia. Other outcomes included postoperative gastrointestinal function, including the time to postoperative first flatus (FFL) and first feces (FFE), and other complications.

FINDINGS

The final analysis included 122 participants. The incidence of preoperative hypokalemia in the treatment group was significantly lower than that in the control and placebo groups (50% vs 88.1% vs 77.5%, P < .001). The severity of hypokalemia in the control and placebo groups was greater than that in the treatment group. No regurgitation or aspiration occurred in the three groups. No significant differences were observed among the three groups regarding time to FFL and FFE.

CONCLUSIONS

Preoperative carbohydrate drinks containing potassium significantly reduced the incidence of preoperative hypokalemia and improved preoperative thirst and hunger, but did not reduce the postoperative time to FFL and FFE or length of hospital stay. However, as part of the enhanced recovery after surgery protocol, preoperative carbohydrate drinks containing potassium should be considered, as early as first admittance to hospital.