Preoperative assessment of gastric contents and volume using bedside ultrasound in adult patients: A prospective, observational, correlation study

Ultrasound evaluation of gastric residual volume in fasting end-stage renal failure patients

STUDY OBJECTIVE

To evaluate the gastric contents and gastric residual volume in patient with end-stage renal failure by gastric ultrasound.

DESIGN

Prospective observational study.

SETTING

Tertiary care teaching hospital.

PATIENTS

Adults of either gender with BMI < 40 kg/m2 with end-stage renal failure scheduled to undergo arteriovenous graft or fistula.

INTERVENTIONS & MEASUREMENTS

The cross-sectional area of the gastric antrum was measured by gastric ultrasound with patient in both supine and right lateral decubitus positions. The volume of the gastric contents were calculated using suitable validated formula. In addition, the nature of the gastric contents was also determined by gastric ultrasound.

MAIN RESULTS

The incidence of delayed gastric emptying was found to be 57.7% in the population studied despite following the prescribed preoperative standard fasting guidelines.

CONCLUSIONS

There is a high incidence of delayed gastric emptying in patients with end-stage renal failure presenting for surgery which may predispose them to risk of pulmonary aspiration perioperatively.

Glucagon-Like Peptide Receptor-1 Agonists Used for Medically-Supervised Weight Loss in Patients With Hip and Knee Osteoarthritis: Critical Considerations for the Arthroplasty Surgeon

Patients with morbid obesity and concomitant hip or knee osteoarthritis represent a challenging patient demographic to treat as these patients often present earlier in life, have more severe symptoms, and have worse surgical outcomes following total hip and total knee arthroplasty. Previously, bariatric and metabolic surgeries represented one of the few weight loss interventions that morbidly obese patients could undergo prior to total joint arthroplasty. However, data regarding the reduction in complications with preoperative bariatric surgery remain mixed. Glucagon-like peptide receptor-1 (GLP-1) agonists have emerged as an effective treatment option for obesity in patients with and without diabetes mellitus. Furthermore, recent data suggest these medications may serve as potential anti-inflammatory and disease-modifying agents for numerous chronic conditions, including osteoarthritis. This review will discuss the GLP-1 agonists and GLP-1/glucose-dependent insulinotropic polypeptide dual agonists currently available, along with GLP-1/glucose-dependent insulinotropic polypeptide/glucagon triple agonists presently being developed to address the obesity epidemic. Furthermore, this review will address the potential problem of GLP-1-related delayed gastric emptying and its impact on the timing of elective total joint arthroplasty. The review aims to provide arthroplasty surgeons with a primer for implementing this class of medication in their current and future practice, including perioperative instructions and perioperative safety considerations when treating patients taking these medications.

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

Comparison of ultrasonographic measurement of gastric antral volume and pH with or without pharmacological acid aspiration prophylaxis in low-risk surgical patients - A randomized clinical trial

Background and Aims

The role of preoperative pharmacological prophylaxis in preventing aspiration pneumonitis under general anesthesia (GA) in patients at low risk of aspiration pneumonitis is still under debate. We addressed the need for routine pharmacological aspiration prophylaxis in at-risk population by assessing the change in gastric volume using ultrasound with and without pharmacological acid aspiration prophylaxis.

Material and Methods

A single-center, randomized double-blinded trial, with 200 adult patients scheduled for elective surgical procedures under GA, were randomized into a prophylaxis group, in which the patients received oral famotidine and metoclopramide, and a no prophylaxis group, in which the patients did not receive any prophylaxis. Gastric volume derived from preinduction measurement of gastric antral volume by ultrasound, postinduction gastric pH, and incidences of aspiration pneumonitis were compared. Bland-Altman plot was used to determine the level of agreement between measured gastric volume and ultrasonography based on calculated gastric volume.

Results

The gastric antral cross-sectional area (CSA) and volume in the no prophylaxis group (3.12 cm2 and 20.11 ml, respectively) were comparable to the prophylaxis group (2.56 cm2 and 19.67 ml, respectively) (P-values 0.97 and 0.63, respectively). Although there was a statistically significant decrease in gastric pH in the no prophylaxis group (P-value 0.01), it was not clinically significant to increase the risk of aspiration pneumonitis based on Roberts and Shirley criteria (P-value 0.39).

Conclusion

In an adequately fasted low-risk population, the amount of residual gastric volume was similar and below the aspiration threshold, regardless of the aspiration prophylaxis status.

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.

Gastric Ultrasound for Gastric Content Evaluation

Gastric content aspiration occurs once every 2000-3000 general anaesthetics. It is associated with a 20% incidence of in-hospital mortality. The incidence of pulmonary aspiration in patients undergoing surgery is at least three times more, up to 1 in 895 general anaesthetics. Pulmonary aspiration indeed is associated with half of our airway-related mortality linked with anaesthesia. The pulmonary aspiration causes significant morbidity including respiratory failure, acute lung injury, and multi-organ failure in adults. This review study aims to compare the stomach volume and contents in patients following standard fasting guidelines by Point of care gastric ultrasound measurements. Perioperative gastric ultrasound is a developing diagnostic modality that is modest, easy, non-invasive and efficient. It is very helpful to determine gastric contents in adult, obese, paediatric, and obstetric patients. It is a dependable and replicable tool that can be used for effective anaesthetic management. Gastric ultrasound is an irreplaceable procedure to complement the use of fasting guidelines, particularly when these guidelines have not been followed, or may not be relevant. Further series of research with metanalysis is required to understand the influence of point-of-care gastric ultrasound assessment on perioperative outcomes.

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.

Gastric insufflation and surgical view according to mask ventilation method for laparoscopic cholecystectomy: a randomized controlled study

BACKGROUND

Proper mask ventilation is important to prevent air inflow into the stomach during induction of general anesthesia, and it is difficult to send airflow only through the trachea without gastric inflation. Changes in gastric insufflation according to mask ventilation during anesthesia induction were compared.

METHODS

In this prospective, randomized, single-blind study, 230 patients were analyzed to a facemask-ventilated group (Ventilation group) or no-ventilation group (Apnea group) during anesthesia induction. After loss of consciousness, pressure-controlled ventilation at an inspiratory pressure of 15 cmH2O was performed for two minutes with a two-handed mask-hold technique for Ventilation group. For Apnea group, only the facemask was fitted to the face for one minute with no ventilation. Next, endotracheal intubation was performed. The gastric cross-sectional area (CSA, cm2) was measured using ultrasound before and after induction. After pneumoperitoneum with carbon dioxide, gastric insufflation of the surgical view was graded by the surgeon for each group.

RESULTS

Increase of postinduction antral CSA on ultrasound were not significantly different between Ventilation group and Apnea group (0.04 ± 0.3 and 0.02 ± 0.28, p-value = 0.225). Additionally, there were no significant differences between the two groups in surgical grade according to surgeon's judgement.

CONCLUSIONS

Pressure-controlled ventilation at an inspiratory pressure of 15 cmH2O for two minutes did not increase gastric antral CSA and insufflation of stomach by laparoscopic view.

TRIAL REGISTRATION

http://cris.nih.go.kr (KCT0003620) on 13/3/2019.

Ultrasound assessment of gastric residual volume in patients over 60 years of age undergoing gastroscopy under sedation: a prospective cohort study

BACKGROUND

We aimed to assess the accuracy of ultrasonographic measurement of the antral cross-sectional area (CSA) in the preprocedural evaluation of gastric contents and volume in fasted patients > 60 yr of age scheduled for gastroscopy under sedation.

METHODS

We included n = 81 patients > 60 yr of age and n = 79 younger controls scheduled to undergo elective gastroscopy in a prospective cohort study. A gastric ultrasound examination was performed to measure the antral CSA in both semisitting and right lateral decubitus (RLD) positions. Afterward, patients were graded using the Perlas qualitative grading scale. The actual gastric volume was endoscopically suctioned. Full stomach was defined as gastric volume > 1.5 mL·kg-1 and/or the presence of solid particles. We constructed receiver operating characteristic curves to determine the accuracy of ultrasonographic measurement of RLD CSA to detect a gastric volume > 1.5 mL·kg-1 and calculated the diagnostic test attributes of RLD CSA for the identification of a gastric volume > 1.5 mL·kg-1 RESULTS: The incidence of full stomach was 8/81 (9.8%) in patients > 60 yr of age and 1/79 (1.2%) in young patients (risk difference, 8.6%; 95% CI, 1.3 to 15.8; P = 0.03). The cut-off value of RLD CSA was 10.4 cm2 for the detection of gastric volume > 1.5 mL·kg-1 in patients > 60 yr of age, with a sensitivity of 75%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 98.6%.

CONCLUSION

Patients > 60 yr of age scheduled for gastroscopy under sedation had a higher incidence of a full stomach detected with ultrasound compared with a younger cohort, which is potentially associated with a higher aspiration risk. We calculated a cut-off value of RLD CSA for detecting gastric volume in patients > 60 yr of age of approximately 10 cm2, which may help to quickly assess patients at risk of aspiration.

TRIAL REGISTRATION

www.chictr.org.cn (ChiCTR2100048994); registered 19 July 2021.

Carbohydrate Loading and Aspiration Risk in Bariatric Patients: Safety in Preoperative Enhanced Recovery Protocols

BACKGROUND

Enhanced recovery protocols have been developed to improve perioperative outcomes; however, there is ongoing concern for aspiration with recent oral intake in patients with obesity, who may be predisposed to impaired gastrointestinal motility and greater gastric volumes. We aim to study the safety of a 300-mL preoperative carbohydrate-loading drink preceding bariatric surgery.

STUDY DESIGN

Data were collected prospectively from patients undergoing primary bariatric surgery. All bariatric patients at our institution are prescribed a proton pump inhibitor for 4 weeks before surgery and undergo a screening preoperative esophagogastroduodenoscopy (EGD) before surgery with a traditional 8-hour fast (NOCARB), followed by an intraoperative day-of-operation EGD with carbohydrate loading (CARB) 2 to 4 hours before incision. Gastric volumes and pH are measured after being endoscopically suctioned via direct visualization during both settings.

RESULTS

We identified 203 patients: 94 patients (46.3%) in the CARB group and 109 patients (53.7%) in the NOCARB group. The patients were 82.3% female with a mean age of 42.8 years and average BMI of 41.7 kg/m 2 . There was no difference in gastric volume between NOCARB and CARB (17.0 vs 16.1 mL, p = 0.59). The NOCARB group had lower pH values than the CARB group (2.8 vs 3.8, p = 0.001). Subset analysis of 23 patients who had measurements on both screening and intraoperative EGD revealed lower gastric volumes in CARB patients (13.3 vs 18.3, p < 0.0001).

CONCLUSIONS

When included in an enhanced recovery protocol, proton pump inhibitor use and preoperative carbohydrate loading 2 to 4 hours before bariatric surgery does not increase aspiration risk based on gastric volumes and pH and should be strongly considered in all eligible bariatric patients.

Comparative preoperative sonological assessment of gastric contents in patients with chronic kidney disease versus those with normal renal function - A prospective observational study

Background and Aims

Though the role of fasting preoperative gastric ultrasound has been validated in different patient populations, namely, obese, pregnant and diabetics, it has not been explored in patients with chronic kidney disease (CKD). This prospective, observational study compared the fasting sonological assessment of gastric contents in patients with CKD versus those with normal renal function scheduled for elective surgery.

Methods

After ethical approval and trial registration were obtained, preoperative gastric ultrasound was done in 115 CKD patients and 115 with normal renal function. Qualitative and quantitative assessment of residual gastric volume was done. Also, the patients were administered the Porto Alegre Dyspeptic Symptoms Questionnaire (PADYQ) to evaluate gastroparesis objectively. The researcher was not blinded to the patient groups. Data analyses were done using the Statistical Package for Social Sciences (SPSS) for Windows software (version 22.0).

Results

Gastric volumes exceeding 1.5 ml/kg or particulate or solid contents were found in 57 patients with CKD and 36 patients with normal renal function (P = 0.004). The PADYQ scores were 6.54 ± 8.49 for CKD and 2.15 ± 5.71 for normal renal function (P < 0.0001) groups. CKD patients had a higher age (P < 0.001), lower body mass index (P = 0.005) and higher incidence of diabetes mellitus (P < 0.001). There were no incidents of gastric aspiration.

Conclusion

Renal dysfunction contributes to delayed gastric emptying. PADYQ can also help identify those at high risk of gastroparesis. Combining the questionnaire and preoperative gastric ultrasound must be considered in these patients to ensure optimum safety.

Assessment of residual gastric volume using point-of-care ultrasonography in adult patients who underwent elective surgery

BACKGROUND

Aspiration pneumonitis remains a dreaded complication that may lead to almost 9% of anaesthesia-related deaths. The presence of gastric contents has always been a contributing factor to an increased risk of aspiration. Preoperative gastric ultrasound has been suggested as a modality for determining residual volume in special populations and conditions. We conducted an observational study to determine the gastric residual volume in preoperative patients of elective surgery with gastric ultrasound and to study its correlation with patient factors.

METHODS

We enrolled 411 patients in the age group of 18-80 with ASA-PS I and II having BMI less than 35 kg/m². Patients with prior gastrointestinal surgery and parturients were excluded from the present study. Gastric antrum in both supine and right lateral decubitus positions was measured using USG in the immediate preoperative period, and gastric residual volume was calculated, which was subsequently correlated with various patient factors.

RESULTS

On qualitative assessment, 97 and 118 patients were observed to have distended stomachs in the supine and right lateral decubitus positions, respectively. On quantitative assessment, 336 had safe GRV, 60 patients were classified as having a low risk of aspiration (GRV < 1.5 ml/kg) while 13 had a high risk of aspiration (> 1.5 ml/kg). Eight patients with a fasting duration of more than ten hours and five who fasted between 6 and 10 h had a gastric residual volume of more than 1.5 ml/h. Patients who were premedicated with histamine blockers had a statistically significant higher antral cross-sectional area (p-value - 0.022*) and GRV (p-value - 0.018*) in the right lateral decubitus position compared to patients who had taken proton pump inhibitors (PPIs). As BMI increased, there was a statistically significant (p-value < 0.001) increase in mean antral CSA in both supine and right lateral decubitus positions. There was a statistically significant association found between type 2 diabetes (p-value 0.045*) with antral grade.

DISCUSSION

Patients can have significant residual volume (> 1.5 ml/kg) despite adequate fasting, and preoperative gastric ultrasound can help in assessing the same and guiding perioperative airway management. PPIs are more effective in reducing gastric residual volume as compared to histamine blockers. Patients with a BMI of more than 30 and type 2 diabetes mellitus have significant correlation with increased gastric residual volume mandating preoperative gastric ultrasound assessment for effective management.

CONCLUSIONS

Patients with BMI over 30 and type 2 diabetes may benefit from POCGUS to guide perioperative airway management by stratifying GRV. Trial registration Name of registry-Clinical Trial Registry of India. Trial registration number-2020/03/024083. Date of registration-19.3.2020. URL- http://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=39961&EncHid=&userName=.

The diagnostic accuracy of ultrasonography over manual aspiration for gastric reserve volume estimation in critically ill patients

BACKGROUND

Although gastric reserve volume (GRV) is a surrogate marker of gastrointestinal dysfunction and feeding intolerance, there is ambiguity in its estimation due to problems associated with its measurement. Introduction of point-of-care ultrasound as a tool for anesthetists kindled interest in its use for GRV estimation.

METHODS

In this prospective observational study, we recruited 57 critically ill patients and analyzed 586 samples of GRV obtained by both ultrasonography (USG) and manual aspiration.

RESULTS

The analysis showed that USG-guided GRV was significantly correlated (r=0.788, P<0.001) and in positive agreement with manual aspiration based on Bland-Altman plot, with a mean difference of 8.50±14.84 (95% confidence interval, 7.389-9.798). The upper and lower limits of agreement were 37.7 and -20.5, respectively, within the ±1.96 standard deviation (P<0.001). The respective sensitivity and positive predictive value, specificity and negative predictive value, and area under the curve of USG for feeding intolerance were 66.67%, 98.15%, and 0.82%, with 96.49% diagnostic accuracy.

CONCLUSIONS

Ultrasonographic estimation of GRV was positively, significantly correlated and in agreement with the manual aspiration method and estimated feeding intolerance earlier. Routine use of gastric USG could avoid clinical situations where feeding status is unclear and there is high risk of aspiration and could become a standard practice of critical care.

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.

Comparison of Gastric Insufflation Volume Between Ambu AuraGain and ProSeal Laryngeal Mask Airway Using Ultrasonography in Patients Undergoing General Anesthesia: A Randomized Controlled Trial

Introduction: Ambu AuraGain and ProSeal laryngeal mask airway are second-generation supraglottic airway devices (SADs) with added advantage of gastric drain and better oropharyngeal sealing pressure. The primary objective was to study the difference in the gastric insufflation volume between Ambu AuraGain and ProSeal LMA in patients undergoing general anesthesia.

Methods: This randomized controlled trial involving 120 adult patients scheduled under general anesthesia were randomized into either Ambu AuraGain or LMA ProSeal group. Gastric cross-sectional area was measured using ultrasonography at baseline, after mask ventilation, and at the end of surgery. Gastric volume was calculated from the measured cross-sectional area. Oropharyngeal sealing pressure, peak airway pressure, and postoperative complications were noted. Statistical analysis was done using SPSS version 22 (Armonk, NY: IBM Corp.) and p < 0.05 was considered statistically significant.

Results: Demographic profile of the study groups was comparable. There was a significant difference in gastric volume between the groups at the end of surgery with 5.91 ml (±9.68 ml) in Ambu AuraGain group and 12.28 ml (±13.05 ml) in the LMA ProSeal group (p = 0.001). Similarly, there was a difference in volume between baseline and at the end of the surgery within the groups also (Ambu AuraGain group, p=0.0012; LMA ProSeal group, p=0.0015, respectively). Though the oropharyngeal sealing pressure and peak airway pressures were comparable, increased incidence of postoperative complications was observed with LMA ProSeal.

Conclusion: Thus, Ambu AuraGain resulted in a lower gastric insufflation volume than LMA ProSeal with lesser incidence of postoperative complications.

Ultrasound-guided estimation of gastric residual volume using Perlas's formula: A validation study in patients

Background and Aims:

Bedside ultrasound (US) is used to evaluate gastric residual volume (GRV) and assess aspiration risk. We examined the accuracy of US-guided measurement of GRV using Perlas’s formula, by two trained anaesthesiologists, in patients who had consumed different types and volumes of fluids.

Methods:

Patients with no risk factors for delayed gastric emptying were included. Each assessor independently determined the baseline US-guided GRV. The patients were randomly allocated to receive no drink or 100 or 200 mL of water or milk. US-guided GRV was re-assessed within 5 min after the intervention. Investigators were blinded to the measurements performed by each other and to the randomisation arm. The primary outcome was the agreement between actual volumes consumed and estimated change in GRV.

Results:

Agreement between actual volume consumed and estimated change in GRV was poor [Intra-class correlation coefficient (ICC) 0.46, 95% confidence interval (CI) 0.09 to 0.72; P = 0.09 for assessor 1 and ICC 0.37; 95% CI 0.02 to 0.66; P = 0.03 for assessor 2].

Conclusion:

US-guided GRV measurements using Perlas’s formula, performed by trained anaesthesiologists may not be a reliable measure of GRV.

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.

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.