Comparison of fasting gastric volume using ultrasound in diabetic and non-diabetic patients in elective surgery: An observational study

Preoperative ultrasound assessment of gastric content in patients with diabetes: A meta-analysis based on a systematic review of the current literature

STUDY OBJECTIVE

To conduct a systematic literature review of the current evidence on the effect of diabetes mellitus on gastric volume observed during a preoperative ultrasound examination. Using the results of this systematic literature review, a meta-analysis was performed to investigate whether there was an association between diabetes mellitus and an increased risk of presenting with a high-risk stomach (gastric volume associated with an increased risk of pulmonary aspiration).

DESIGN

Review article and meta-analysis.

SETTING

Review of published literature.

PATIENTS

A total of 3366 patients underwent surgery.

INTERVENTION

Gastric ultrasound examination.

MEASUREMENTS

Data for the meta-analysis and literature review were collected from the PubMed/Medline, Embase, Web of Science, and Google Scholar databases of the National Library of Medicine from the date of inception to January 2023. All included studies measured the gastric antral cross-sectional area and/or gastric residual volume in patients with diabetes and those without diabetes. The data utilized in the meta-analysis included all studies that evaluated the incidence of high-risk stomachs based on ultrasonographic measurements of the gastric antral cross-sectional area or gastric residual volume.

MAIN RESULTS

Most collated studies revealed that diabetes mellitus was associated with increased antral cross-sectional area and gastric residual volume. A meta-analysis of published reports indicated that patients with diabetes have an increased rate of high-risk stomachs.

CONCLUSIONS

Diabetes mellitus is associated with an increased rate of high-risk stomachs. The authors recommend large prospective trials to ascertain the safety of the current fasting guidelines for patients with diabetes undergoing surgery.

Baseline Gastric Volume in Fasting Diabetic Patients Is Not Higher than That in Nondiabetic Patients: A Cross-sectional Noninferiority Study

BACKGROUND

The physiology of diabetes mellitus can increase the risk of perioperative aspiration, but there is limited and contradictory evidence on the incidence of "full stomach" in fasting diabetic patients. The aim of this study is to assess the baseline gastric content (using gastric ultrasound) in diabetic and nondiabetic patients scheduled for elective surgery who have followed standard preoperative fasting instructions.

METHODS

This was a prospective, noninferiority study of 180 patients (84 diabetic and 96 nondiabetic patients). Bedside ultrasound was used for qualitative and quantitative assessment of the gastric antrum in the supine and right lateral decubitus positions. Fasting gastric volume was estimated based on the cross-sectional area of the gastric antrum and a validated model. The hypothesis was that diabetic patients would not have a higher baseline fasting gastric volume compared to nondiabetic patients, with a noninferiority margin of 0.4 ml/kg. Secondary aims included the comparison of the incidence of full stomach (solid content or more than 1.5 mL/kg of clear fluid), estimation of the 95th percentile of the gastric volume distribution in both groups, and examination of the association between gastric volume, glycemic control, and diabetic comorbidities.

RESULTS

The baseline gastric volume was not higher in diabetic patients (0.81 ± 0.61 ml/kg) compared to nondiabetic patients (0.87 ± 0.53 ml/kg) with a mean difference of -0.07 ml/kg (95% CI, -0.24 to 0.10 ml/kg). A total of 13 (15.5%) diabetic and 11 (11.5%) nondiabetic patients presented more than 1.5 ml/kg of gastric volume (95% CI for difference, -7.1 to 15.2%). There was little correlation between the gastric volume and either the time since diagnosis or HbA1C.

CONCLUSIONS

The data suggest that the baseline gastric volume in diabetic patients who have followed standard fasting instructions is not higher than that in nondiabetic patients.

EDITOR’S PERSPECTIVE

Development and validation of a novel nomogram model to assess the risk of gastric contents in outpatients undergoing elective sedative gastrointestinal endoscopy procedures

BACKGROUND

Gastric contents may contribute to patients' aspiration during anesthesia. Ultrasound can accurately assess the risk of gastric contents in patients undergoing sedative gastrointestinal endoscopy (GIE) procedures, but its efficiency is limited. Therefore, developing an accurate and efficient model to predict gastric contents in outpatients undergoing elective sedative GIE procedures is greatly desirable.

METHODS

This study retrospectively analyzed 1501 patients undergoing sedative GIE procedures. Gastric contents were observed under direct gastroscopic vision and suctioned through the endoscope. High-risk gastric contents were defined as having solid content or liquid volume > 25 ml and pH < 2.5; otherwise, they were considered low-risk gastric contents. Univariate analysis and multivariate analysis were used to select the independent risk factors to predict high-risk gastric contents. Based on the selected independent risk factors, we assigned values to each independent risk factor and established a novel nomogram. The performance of the nomogram was verified in the testing cohort by the metrics of discrimination, calibration, and clinical usefulness. In addition, an online accessible web calculator was constructed.

RESULTS

We found BMI, cerebral infarction, cirrhosis, male, age, diabetes, and gastroesophageal reflux disease were risk factors for gastric contents. The AUROCs were 0.911 and 0.864 in the development and testing cohort, respectively. Moreover, the nomogram showed good calibration ability. Decision curve analysis and Clinical impact curve demonstrated that the predictive nomogram was clinically useful. The website of the nomogram was https://medication.shinyapps.io/dynnomapp/.

CONCLUSIONS

This study demonstrates that clinical variables can be combined with algorithmic techniques to predict gastric contents in outpatients. Nomogram was constructed from routine variables, and the web calculator had excellent clinical applicability to assess the risk of gastric contents accurately and efficiently in outpatients, assist anesthesiologists in assessment and identify the most appropriate patients for ultrasound.

Feasibility and Utility of Routine Point-of-Care Gastric Ultrasonography in Patients Undergoing Upper Gastrointestinal Endoscopy Procedures: A Prospective Cohort Study

OBJECTIVES

Previous studies have indicated that point-of-care ultrasonography (POCUS) of the gastric antrum can predict the adequacy of fasting before surgery and anesthesia. The aim of this study was to evaluate the utility of gastric POCUS in patients undergoing upper gastrointestinal (GI) endoscopy procedures.

METHODS

We performed a single-center cohort study in patients undergoing upper GI endoscopy. Consenting patient's gastric antrum was scanned before anesthetic care for endoscopy to determine the cross-sectional area (CSA) and qualitatively determine safe and unsafe contents. Further, an estimate of residual gastric volume was determined using the formula and the nomogram methods. Subsequently, gastric secretions aspirated during endoscopy were quantified and further correlated with nomogram and formula-based assessments. No patient required a change in the primary anesthetic plan except for using rapid sequence induction in those with unsafe contents on POCUS scans.

RESULTS

Qualitative ultrasound measurements consistently determined safe and unsafe gastric residual contents in 83 patients enrolled in the study. Unsafe contents were determined by qualitative scans in 4 out of 83 cases (5%) despite adequate fasting status. Quantitatively, only a moderate correlation was demonstrated between measured gastric volumes and nomogram (r = .40, 95% CI: 0.20, 0.57; P = .0002) or formula-based (r = .38, 95% CI: 0.17, 0.55; P = .0004) determinations of residual gastric volumes.

CONCLUSION

In daily clinical practice, qualitative POCUS determination of residual gastric content is a feasible and useful technique to identify patients at risk of aspiration before upper GI endoscopy procedures.

Randomized Controlled Trial Comparing the Effects of Preoperative Carbohydrate and Non-carbohydrate Loading on Gastric Emptying in Diabetic and Non-diabetic Patients Posted for Elective Surgery

Background Preoperative fasting for six hours and accepting clear fluids till two hours of surgery is followed as a regular practice. Carbohydrate-rich fluids antagonize catabolism and are claimed to be tolerated better. This study aims to compare the effect of carbohydrate-rich drinks on gastric volume and blood sugar control in diabetic and non-diabetic patients undergoing elective surgery with plain water. Methods Two hundred forty patients aged 40 to 65 undergoing elective surgery under regional anesthesia were randomized into diabetic control, diabetic study, non-diabetic control, and non-diabetic study. Control groups were given 400 ml of plain water, while the study group received 50 grams of dextrose dissolved in 400 ml of water two hours prior to surgery. Gastric volume was evaluated using USG, and thirst and discomfort were assessed using the Likert scale. Perioperatively, blood sugar values were monitored and kept under control using insulin. Results Mean gastric volume (ml) in diabetic control (35.3±12.95 ml), diabetic study (31.2±11.75 ml), non-diabetic control (29±11.42 ml), and non-diabetic study (30.4±9.12 ml) showed no statistically significant difference (p>0.05). Capillary blood glucose (CBG) values two hours post fluid intake showed a significant increase in CBG levels in the diabetic study (183.2±28.67 mg/dl) compared to the diabetic control group (138.66±15.81 mg/dl). The values returned to baseline within six hours. Thirst and discomfort were significantly lower in the study group of diabetic and non-diabetic populations. Conclusion We conclude that carbohydrate loading does not affect gastric volume in diabetics and non-diabetics. However, the sugar values do increase which may warrant hourly checking and administration of insulin in diabetics.

MRI-Based Quantification of Pan-Alimentary Function and Motility in Subjects with Diabetes and Gastrointestinal Symptoms

Background: Diabetes-induced gastrointestinal (GI) symptoms are common but difficult to correctly diagnose and manage. We used multi-segmental magnetic resonance imaging (MRI) to evaluate structural and functional GI parameters in diabetic patients and to study the association with their symptomatic presentation. Methods: Eighty-six participants (46 with diabetes and GI symptoms, 40 healthy controls) underwent baseline and post-meal MRI scans at multiple timepoints. Questionnaires were collected at inclusion and following the scans. Data were collected from the stomach, small bowel, and colon. Associations between symptoms and collected data were explored. Utilizing machine learning, we determined which features differentiated the two groups the most. Key Results: The patient group reported more symptoms at inclusion and during MRI scans. They showed 34% higher stomach volume at baseline, 40% larger small bowel volume, 30% smaller colon volume, and less small bowel motility postprandially. They also showed positive associations between gastric volume and satiety scores, gastric emptying time and reflux scores, and small bowel motility and constipation scores. No differences in gastric emptying were observed. Small bowel volume and motility were used as inputs to a classification tool that separated patients and controls with 76% accuracy. Conclusions: In this work, we studied structural and functional differences between patients with diabetes and GI symptoms and healthy controls and observed differences in stomach, small bowel, and colon volumes, as well as an adynamic small bowel in patients with diabetes and GI symptoms. Associations between recorded parameters and perceived symptoms were also explored and discussed.

A Comparative Study of Fasting Gastric Volume in Diabetic and Non-diabetic Patients Undergoing Elective Surgeries Using Ultrasonography: A Prospective Observational Study

BACKGROUND

Gastric ultrasound can be used to evaluate the residual gastric volume (GV) and contents before anesthetizing a patient. Autonomic gastropathy in patients with diabetes increases the risk of pulmonary aspiration of gastric contents. Therefore, the present study was conducted to assess the fasting GV among diabetics and healthy individuals using point-of-care (POC) ultrasonography.

MATERIALS AND METHODS

This prospective observational study was conducted in a tertiary care hospital between January 2021 and February 2022. A total of 122 patients included in the study were divided into two groups: group D (n = 61) patients had a history of diabetes mellitus and group C (n = 61) patients were non-diabetics (control). Gastric ultrasound was performed in supine and right lateral decubitus (RLD) positions. The following parameters were measured: duration of fasting, craniocaudal (CC) diameter, anteroposterior (AP) diameter, cross-sectional area (CSA), and GV using CC and AP diameters.

RESULTS

The mean age of the participants was found to be 46.60 ± 13.77 years with 51.6% female patients and 48.4% male patients. Among the patients, there was a significantly higher mean level of CC diameter, AP diameter, and CSA in the supine position in diabetics compared to controls (p < 0.05). Similarly, there was a significantly higher mean level of CC diameter, AP diameter, and CSA in the RLD position in diabetics compared to healthy individuals (p < 0.05). The GV was significantly higher in diabetics (9.96 ± 14.520) compared to healthy individuals (-8.991 ± 20.95; p < 0.05).

CONCLUSION

Fasting GV assessed using POC ultrasonography in diabetic individuals was higher when compared to non-diabetics after similar periods of fasting.

Ultrasound assessment of gastric volume in older adults after drinking carbohydrate-containing fluids: a prospective, nonrandomized, and noninferiority comparative study

PURPOSE

The aim of this study was to evaluate the safety of drinking carbohydrate-containing fluids two hours prior to surgery in older adults using ultrasonography.

METHODS

We conducted a nonrandomized and noninferiority comparative study in 60 patients aged over 65 yr who were scheduled for total knee arthroplasty. Patients who were fasted from midnight (fasting group) or who drank 400 mL of a carbohydrate-containing fluid (carbohydrate ingestion group) two hours prior to surgery were matched for age, sex, and body mass index. We measured the cross-sectional area (CSA) of gastric antrum using ultrasound and estimated the gastric fluid volume as the study's primary outcome measure. The noninferiority margin (δ) for the mean difference was predefined as 50 mL. The secondary outcome measures included CSA of the antrum and qualitative gastric volume.

RESULTS

The mean (standard deviation) gastric volume was not significantly different between the fasting group and the carbohydrate ingestion group (30.2 [25.4] mL vs 28.4 [35.8] mL; each group, n = 30; P = 0.81). The mean difference in gastric volume was -1.9 mL (95% confidence interval [CI], -17.9 to 14.2), and the upper limit of the 95% CI was lower than the prespecified noninferiority limit (δ = 50 mL). Secondary outcomes were not significantly different between the two groups.

CONCLUSION

Drinking of carbohydrate-containing fluid two hours prior to surgery was noninferior to overnight fasting with respect to residual gastric volume at induction of anesthesia in healthy older adults who undergoing total knee arthroplasty.

STUDY REGISTRATION

ClinicalTrials.gov (NCT04514380); registered 14 August 2020.

Anesthesia and Enhanced Recovery After Surgery in Bariatric Surgery

The Enhanced Recovery After Surgery Society published guidelines for bariatric surgery reviewing the evidence and providing specific care recommendations. These guidelines emphasize preoperative nutrition, multimodal analgesia, postoperative nausea and vomiting prophylaxis, anesthetic technique, nutrition, and mobilization. Several studies have since evaluated these pathways, showing them to be safe and effective at decreasing hospital length of stay and postoperative nausea and vomiting. This article emphasizes anesthetic management in the perioperative period and outlines future directions, including the application of Enhanced Recovery After Surgery principles in patients with extreme obesity, diabetes, and metabolic disease and standardization of the pathways to decrease heterogeneity.

Abstract No.: ABS1363: A comparative evaluation of gastric residual volume using ultrasound in fasting diabetic and non-diabetic adults undergoing elective surgery under general anaesthesia

Background & Aims:

Diabetic patients despite standard preoperative fasting may be at an increased risk of aspiration due to gastroparesis. This study aimed to evaluate the gastric residual volume using ultrasound in fasting diabetic and non-diabetic adults undergoing elective surgery under general anaesthesia.

Methods:

This study was conducted in 30 non-diabetic and 30 diabetics, aged 40 to 80 years, of either gender, BMI <35kg/m2, belonging to American Society of Anesthesiologists physical status I-III. Pregnant patients, those with history of upper gastrointestinal morbidity or upper abdominal surgery and patients with liver and kidney disease were excluded. Preoperatively, using gastric sonography, antrum was assessed in semi-setting and right lateral decubitus positions. The type of gastric contents (empty, fluid, solid) was noted, and gastric residual volume (GRV) was estimated by measuring antral cross-sectional area (CSA) and using mathematical models. After induction of anaesthesia, orogastric tube was inserted and gastric contents aspirated.

Results:

Diabetic patients had significantly higher mean antral CSA and calculated mean GRV in both right lateral and semi-sitting position (p <0.0001). Gastric antrum appeared empty in significantly greater number of non-diabetic patients as compared to diabetic patients in both right lateral (p <0.0001) and semi-sitting positions (p =0.0002). A higher mean volume of gastric aspirate was also found in the diabetics as compared to the non-diabetics (p <0.0001).

Conclusion:

The current fasting guidelines for elective surgery are not conclusive in patients with long-standing diabetes. Hence, we recommend the use of point-of-care ultrasound as an effective screening tool to assess the aspiration risk and to tailor anaesthetic management.

Gastric content and perioperative pulmonary aspiration in patients with diabetes mellitus: a scoping review

BACKGROUND

Gastric emptying may be delayed in patients with diabetes mellitus (DM). However, the incidence of full stomach in fasting patients with DM and their risk of pulmonary aspiration under anaesthesia is not well understood.

METHODS

A scoping review was undertaken to map the literature on aspiration risk in DM. A search was conducted in seven bibliographic databases, including MEDLINE and Embase, for original articles that studied aspiration risk, gastric emptying, or gastric content and volume. Selection and characterisation were performed by two independent reviewers using a predefined protocol registered externally.

RESULTS

The search identified 5063 unique records, and 16 studies (totalling 775 patients with DM) were selected: nine studied gastric emptying and seven studied gastric content or volume. There were no studies reporting the incidence of aspiration in subjects with DM. All nine studies reported delayed emptying in patients with DM compared with healthy controls. Amongst the seven studies that compared gastric residual content/volume (GRV) in the perioperative period, five reported clinically negligible GRV in both patients with DM and controls, whereas two observed a higher incidence of 'full' stomach in patients with DM.

CONCLUSIONS

The evidence concerning the aspiration risk for surgical patients with DM is based on a limited number of studies, mostly unblinded, reporting physiological data on gastric emptying and gastric volume as surrogate markers of aspiration risk. Data on fasting gastric content and volume in patients with DM are limited and contradictory; hence, the true risk of aspiration in fasting patients with DM is unknown.