Probing the future - Can gastric ultrasound herald a change in perioperative fasting guidelines?

Emulsion acid colloidal stability and droplet crystallinity modulate postprandial gastric emptying and short-term satiety: a randomized, double-blinded, crossover, controlled trial in healthy adult males

BACKGROUND

Emulsion droplet triacylglycerol (TAG) crystallinity and colloidal stability can alter the postprandial metabolism, although evidence of their interactive effects is limited.

OBJECTIVES

This acute meal crossover study investigated the influences of droplet TAG crystallinity at 37°C and colloidal gastric stability on gastric emptying (GE), acute lipemia, and satiety.

METHODS

We gave 15 healthy adult males (mean ± SD age, 24.9 y ± 4.5 y; BMI, 26.0 kg/m2 ± 2.0 kg/m2; fasting TAG, 0.9 mmol/L  ± 0.3 mmol/L) 250 mL of four 20% palm stearin or palm olein emulsions with similar particle size distributions and containing partially crystalline droplets that remained stable (SS) or destabilized (SU) or containing liquid droplets that remained stable (LS) or destabilized (LU) when exposed to simulated gastric conditions. Baseline and 6-h postprandial ultrasound gastric antrum measurements, satiety visual analogue scales (VAS), and blood samples for analyses of plasma TAG, peptide YY (PYY), glucagon-like peptide-1 (GLP-1), ghrelin, leptin, glucose-dependent insulinotropic polypeptide, insulin, and glucose were collected. Changes from baseline and incremental area under the curve (iAUC) values were analyzed by repeated-measures ANOVA.

RESULTS

TAG responses did not differ significantly. The gastric antrum area decreased faster (P ≤ 0.01) after treatment with the acid-unstable emulsions (SU and LU), and satiety VAS ratings and plasma endpoints differed between treatments. After LS treatment, participants had 65% and 59% lower 3-h iAUC values for hunger (P = 0.021) and desire to eat (P = 0.031), respectively, compared to after SU treatment. LS treatment resulted in higher 6-h iAUC values for ghrelin (141%; P = 0.023) and PYY (150%; P = 0.043) compared to SU treatment, and LS treatment also resulted in higher GLP-1 values compared to SU (38%; P = 0.016) and LU (76%; P = 0.001) treatment.

CONCLUSION

Emulsion acid colloidal stability, independent of TAG physical state, delayed GE, and satiety was enhanced after consuming acid stable emulsions containing TAG in the liquid state. The study was registered at clinicaltrials.gov as NCT03990246.

Ultrasound-guided assessment of gastric residual volume in patients receiving three types of clear fluids: A randomised blinded study

Background and Aims:

Ultrasonography (USG) is used to evaluate gastric residual volume (GRV); however, this technique may have inter-assessor variability. This study aimed to measure GRV in three groups of fasted patients 2 h after they received 200 mL of water, clear apple juice or apple-flavoured oral rehydration solution (ORS) and to determine inter-assessor reliability of USG-guided GRV measurement.

Methods:

We randomised 90 adult patients planned for elective cancer surgery, with no risk factors for delayed gastric emptying, to receive 200 mL of water, clear apple juice or apple-flavoured ORS after overnight fasting. Two hours later, two blinded assessors (a trained anaesthesiologist and a radiologist) independently determined USG-guided GRV. The primary outcome was GRV measured by the radiologist. The secondary outcome was inter-assessor correlation and agreement in GRV measurements.

Results:

There was no statistically significant difference in median GRV between groups (apple-flavoured ORS 74.8 mL, apple juice 63.7 mL, and water 62.1 mL, P = 0.11). We found poor correlation between measurements of radiologist and anaesthesiologist (Intra-class correlation coefficient 0.3, 95% confidence intervals 0.09 to 0.48, P value 0.002). The average (mean) bias was 5.4 mL (standard deviation 42.3 mL) and the 95% limits of agreement were -79.2 ml to +90 ml.

Conclusion:

Patients receiving 200 mL of water, clear apple juice or apple-flavoured ORS had comparable GRV after 2 h. There was poor correlation and agreement between GRV measurements of different assessors, indicating that more training may be required for anaesthesiologists to attain proficiency in the quantitative assessment of GRV.