Gastric Ultrasound Assessing Gastric Emptying of Preoperative Carbohydrate Drinks: A Randomized Controlled Noninferiority Study

Abstract

BACKGROUND: Tools for the evaluation of gastric emptying have evolved over time. The purpose of this study was to show that the risk of pulmonary aspiration is not increased with carbohydrate drink, by demonstrating that the gastric antral cross-sectional area (CSA) of the NO-NPO group is either equivalent to or less than that of the NPO (nil per os) group. METHODS: Sixty-four patients scheduled for elective laparoscopic benign gynecologic surgery were enrolled and randomly assigned to the NPO group (n = 32) or the NO-NPO group (n = 32). After having a regular meal until midnight before surgery, the NPO group fasted until surgery, while the NO-NPO group ingested 400 mL of a carbohydrate drink at midnight and freely up to 2 hours before anesthesia. The primary outcome was the gastric antral CSA by gastric ultrasound in right lateral decubitus position (RLDP). Noninferiority was defined as a mean difference of CSA <2.8 cm2. Secondary outcomes included CSA in supine position, gastric volume (GV), GV per weight (GV/kg), GV/kg >1.5 mL/kg, and Perlas grade. RESULTS: CSA in RLDP was not different between the NPO group (6.25 ± 3.79 cm2) and the NO-NPO group (6.21 ± 2.48 cm2; P = .959). The mean difference of CSA in RLDP (NO-NPO group − NPO group) was 0.04 (95% confidence interval [CI], −1.56 to 1.64), which was within the noninferiority margin of 2.8 cm2. CSA was not different between the 2 groups (4.17 ± 2.34 cm2 in NPO group versus 4.28 ± 1.23 cm2 in NO-NPO group; P = .828). GV in NPO group (70 ± 56 mL) was not different from NO-NPO group (66 ± 36 mL; mean difference, 3.66; 95% CI, −20 to 27; P = .756). GV/kg in the NPO group (1.25 ± 1.00 mL/kg) was not different from the NO-NPO group (1.17 ± 0.67 mL/kg; P = .694). The incidence of GV/kg > 1.5 mL/kg was not different between NPO (31.3%) and NO-NPO group (21.9%; P = .768). The median (interquartile range) of the Perlas grade was 1 (0–1) in NPO group and 0.5 (0–1) in NO-NPO group (P = .871). CONCLUSIONS: Preoperative carbohydrates ingested up to 2 hours before anesthesia do not delay gastric emptying compared to midnight fasting, as evaluated with gastric ultrasound.

Differences in Preoperative Gastric Ultrasound Findings Between Old and Young Surgical Patients: A Retrospective Case-Control Study

“…The ASA class was higher in the elderly group (2 (1-2)] than in the young group (1 (1-1), <0.001). Fasting time for solids in the young group was 12 (10)(11)(12)(13)(14)(15) hours and that in the elderly group was 15 (14-19) hours (P < 0.001). Fasting time for uids did not differ between the groups (P > 0.05). ]…”

“…[4,5] Although the mathematical models for calculating GVs are known to be reliable, [2,3] they sometimes lack reproducibility after adjusting for different patient populations. [12] In addition, the assessment of the risk of pulmonary aspiration with mathematical models may be somewhat cumbersome compared with that with the grading system or the CSA. This is because mathematical models involve calculation by combining speci c constants.…”

“…The antrum was scanned in the epigastrium, located between the left lobe of the liver and pancreas, as previously described. [12] First, the gastric antrum was assessed for emptiness. A gastric antrum without any gastric contents was de ned as "empty."…”

“…The antral CSA was calculated using the following formula: CSA = 𝜋 × LD × SD/4. [12] Estimated GV was calculated using the formula reported by Perlas et al: [9] GV = 27.0 + 14.6 × CSA RDLP − 1.28 × age.…”

The Effects of Intravenous Vitamin C on Stress Response Severity in Abdominal Hysterectomy Following Prolonged Fasting Time

“…However, according to the American Society of Anesthesiologists (ASA) classification, the incidence of pulmonary aspiration during anesthesia is 1 in 7000-8000 cases in ASA classes I and II, and 1 in 400 cases in ASA classes III and IV ( 2 ). Contrary to popular perception, prolonged fasting time does not provide a safer condition for the patient and may increase the risk of pulmonary aspiration ( 3 ). In the clinical setting, the routine preoperative fasting time is recommended for both solids and liquids without attention to the different times of gastric emptying, which is 3-6 hours for solids and 2 hours for clear liquids ( 4 - 6 ).…”