Preoperative Gastric Residual Volumes in Fasted Patients Measured by Bedside Ultrasound: A Prospective Observational Study

Abstract

The purpose of this prospective observational study was to measure gastric volumes in fasted patients using bedside gastric ultrasound. Patients presenting for non-emergency surgery underwent a gastric antrum assessment, using the two-diameter and free-trace methods to determine antral cross-sectional area. Gastric residual volume (GRV) was calculated using a validated formula. Univariate and multivariable analyses were performed to examine any potential relationships between 'at risk' GRVs (>100 ml) and patient factors. Two hundred and twenty-two successful scans were performed; of these 110 patients (49.5%) had an empty stomach, nine patients (4.1%) had a GRV >100 ml, and a further six patients (2.7%) had a GRV >1.5 ml/kg. There was no significant relationship between 'at risk' GRV and obesity, diabetes mellitus, gastro-oesophageal reflux disease or opioid use, although our study had insufficient power to exclude an influence of one or more of these factors. Our results indicate that despite compliance with fasting guidelines, a small percentage of patients still have GRVs that pose a pulmonary aspiration risk. Anaesthetists should consider this background incidence when choosing anaesthesia techniques for their patients. While future observational studies are required to determine the role of preoperative bedside gastric ultrasound, it is possible that this technique may assist anaesthetists in identifying patients with 'at risk' GRVs.

Ultrasound assessment of gastric content in fasted patients before elective laparoscopic cholecystectomy: a prospective observational single-cohort study

“…9,10 Indeed, according to some studies that used gastric ultrasonography, 2.7-6.2% of fasted patients had a full stomach before elective surgery. 9,10 Cholecystectomy is one of the most common elective abdominal surgeries. 11 Patients undergo cholecystectomy mainly because of symptomatic gallbladder diseases such as cholecystitis; further, compared with normal control subjects, patients with symptomatic gallbladder diseases have been reported to exhibit delayed gastric emptying.…”

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

“…Several studies have described the use of USG for GRV assessment, with advantages such as performance at the bedside, lack of radiation exposure and availability of real-time data. [ 3 4 5 6 7 8 9 10 11 12 13 14 ] The GRV in these studies, even after following uniform fasting guidelines, has been variable. Sharma studied 100 patients presenting for elective surgery who had fasted for at least 6 h; 42 patients had GRV between 40 and 80 mL.…”

“…In other studies, this proportion has ranged between 2.7% to 28%, with higher values seen in studies that included patients with risk factors for delayed gastric emptying. [ 8 11 12 14 15 ] The clinical implication of this finding is unknown as none of these studies were powered to look at the incidence of aspiration under anaesthesia, which is a very rare event.…”

Ultrasonographic Assessment of Metoclopramide Administration Effectiveness in Accelerating Gastric Emptying Before Urgent Surgery in Patients with Insufficient NPO Time

“…As mentioned, most still recommend proper fasting time before induction of general anesthesia as usual practice (2-4). However, the effectiveness of standard fasting guidelines has been assessed by gastric ultrasonography, and no correlation was found between hours of fasting and residual gastric volume, and despite compliance with fasting guidelines, some patients are still at risk of aspiration (17,18). Therefore, it seems that interventions may be needed to facilitate gastric emptying before the induction of general anesthesia or anesthesiologists should consider another technique for their patients, particularly in emergency cases.…”