Ultrasound assessment of gastric content and volume

Comparison of Gastric Residual Volume After Ingestion of A Carbohydrate Drink and Water in Healthy Volunteers with Obesity: A Randomized Crossover Study

INTRODUCTION

Preoperative carbohydrate intake is essential to enhance postoperative recovery. However, its safety for individuals with obesity remains unclear. This study investigated the safety of preoperative carbohydrate consumption compared to water intake in obese populations through gastric volume assessment.

METHODS

A prospective randomized crossover study enrolled 30 healthy volunteers aged 18-65 years with a body mass index ≥ 30 kg/m2, following a minimum 6-h fast. The participants received either 400 ml of a carbohydrate drink (group C) or water (group W). Gastric ultrasonography, blood glucose level, hunger, and thirst assessments were conducted at baseline (T) and various time points (T2 to T6). The protocol was repeated with reverse interventions at least 1 week later.

RESULTS

Group C had significantly higher gastric volume at T3, T4, and T5 compared to group W, with a prolonged time to empty the gastric antrum (94.4 ± 28.5 vs. 61.0 ± 33.5 min, 95% CI 33.41 [17.06,24.69]). However, glucose levels, degrees of hunger, and thirst showed no significant differences between the groups.

CONCLUSION

Administering 400 ml of preoperative carbohydrates to healthy obese individuals 2 h preoperatively is safe and comparable to water intake. These findings support the integration of carbohydrate loading into perioperative care for obese individuals, consistent with the enhanced recovery after surgery protocols. Further research is warranted to refine preoperative fasting protocols and improve surgical outcomes in this population.

Ultrasound assessment of gastrointestinal luminal contents: a narrative review

Gastro-intestinal ultrasound (GIUS) is a non-invasive and cost-effective tool, widely used as a first-line diagnostic method in patients presenting with abdominal complaints, especially in patients affected by inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis. In this setting, gastro-intestinal ultrasound has been especially used to evaluate the bowel wall features (thickening, stratification, vascularization) and complications related to IBD (fistulas, abscesses). Nevertheless, gastro-intestinal ultrasound can be also used to detect and evaluate the content of several segments of the gut. In fact, there is a growing interest in utilizing GIUS for suspected functional disorders, where assessing intestinal content may play a significant diagnostic role, as well as directing therapy. In our review, we provided a sonographic description of GIUS appearances of bowel content in various pathological and physiological conditions, offering potential applications in clinical practice and providing insights for further research.

Ultrasonic assessment of gastric solid contents in patients undergoing upper endoscope with sedation

BACKGROUND

Perioperative reflux aspiration presents a grave concern during sedation or general anesthesia, particularly when solid gastric contents prompt acute upper respiratory obstruction, potentially resulting in fatal consequences for patients. Currently, there are limited means for promptly assessing solid gastric contents in clinical settings. Therefore, this study examined the efficacy of ultrasound assessment for solid gastric contents, offering a rapid and non-invasive approach for early detection and decision-making regarding interventions.

METHODS

The study included 400 patients scheduled for upper endoscopy procedures, which encompassed both gastroscope and gastroscope combined colonoscopy examinations with sedation. Ultrasound scanning of the antrum was performed while patients were positioned semi-sitting or in the right lateral decubitus (RLD) posture. The evaluation of solid gastric contents relied on direct visual observation during endoscopy. Gastric volume measurement occurred subsequent to endoscopic suction of gastric contents. Receiver operating characteristic curves were utilized to assess the effectiveness of ultrasonography in discerning solid contents.

RESULT

Seven patients undergoing gastroscope with sedation were found to have solid gastric contents. The sensitivity, specificity, positive predictive value, and negative predictive value of the ultrasound qualitative evaluation of solid contents were 85.7%, 99%, 60%, and 99.7%, respectively.

CONCLUSION

Solid stomach contents can be evaluated qualitatively with reasonable accuracy using ultrasonography. Additionally, in patients undergoing upper endoscopy and assessed to have solid gastric contents with ultrasound, administration of mild sedation is recommended.

TRIAL REGISTRATION

www.chictr.org.cn (ChiCTR2100048994); registered 19/07/2021.

The use of point of care gastric ultrasound and anesthesia management in pediatric patients with preoperative fasting non-adherence scheduled for elective surgical procedures: a retrospective study

BACKGROUND

Failure to adhere to perioperative fasting requirements increases aspiration risk and can lead to delay or cancellation of surgery. Point of care gastric ultrasound may guide decision-making to delay, cancel or proceed with surgery.

METHODS

This study aimed to describe gastric contents using point of care gastric ultrasound in pediatric patients with known fasting guideline violations presenting for elective surgery. This was a single-center retrospectivechart review of gastric ultrasound scans in patients presenting for elective surgeries with "nothing by mouth" violation (per fasting guidelines) or unclear fasting status. The primary outcome is description of gastric contents using point of care ultrasound. The ultrasound findings were classified as low-risk for aspiration (empty, clear fluid < 1.5 ml/kg), high-risk (solids, clear fluid > 1.5 ml/kg), or inconclusive study. Gastric ultrasound findings were communicated to the attending anesthesiologist. For patients proceeding without delay the estimated time saved was defined as the difference between ultrasound scan time and presumed case start time based on American Society of Anesthesiologists fasting guidelines.

RESULTS

We identified 106 patients with a median age of 4.8 years. There were 31 patients (29.2%) that had ultrasound finding of high-risk gastric contents. These patients had cases that were delayed, cancelled or proceeded with rapid sequence intubation. Sixty-six patients (62.3%) were determined to be low-risk gastric contents and proceeded with surgery without delay. For these patients, a median of 2.6 h was saved. No aspiration events were recorded for any patients.

CONCLUSIONS

It is feasible to use preoperative point of care gastric ultrasound to determine stomach contents and risk-stratify pediatric patients presenting for elective surgical procedures with fasting non-adherence. Preoperative gastric ultrasound may have a role in determining changes in anesthetic management in this patient population.

Point-of-Care Ultrasound for Gastric Volume Measurement in a Pediatric Patient-Look Beyond the Antrum: A Case Report

Gastric ultrasound estimates stomach contents in perioperative patients. A 10-year-old boy with abdominal rhabdomyosarcoma, who received abdominal radiation, developed gastroparesis and was scheduled for endoscopic gastrointestinal pyloric dilation. Point-of-care gastric ultrasound revealed gastric antral cross-sectional area of 6.5 cm2 (estimated gastric content ~30 mL). However, dynamic right-to-left ultrasound revealed more hypoechoic material in the fundus of the stomach. On induction ~125 mL of stomach contents was suctioned. Antral measurements may not accurately predict the stomach contents in the setting of a stiff/fixed antrum. Scanning from antrum to fundus determined contents more accurately, especially with a prior history of abdominal radiation.

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.

Pre-oxygenation with high-flow oxygen through the nasopharyngeal airway compared to facemask on carbon dioxide clearance in emergency adults: a prospective randomized non-blinded clinical trial

INTRODUCTION

Before tracheal intubation, it is essential to provide sufficient oxygen reserve for emergency patients with full stomachs. Recent studies have demonstrated that high-flow nasal oxygen (HFNO) effectively pre-oxygenates and prolongs apneic oxygenation during tracheal intubation. Despite its effectiveness, the use of HFNO remains controversial due to concerns regarding carbon dioxide clearance. The air leakage and unknown upper airway obstruction during HFNO therapy cause reduced oxygen flow above the vocal cords, possibly weaken the carbon dioxide clearance.

METHODS

Patients requiring emergency surgery who had fasted < 8 h and not drunk < 2 h were randomly assigned to the high-flow group, who received 100% oxygen at 30-60 L/min through nasopharyngeal airway (NPA), or the mask group, who received 100% oxygen at 8 L/min. PaO2 and PaCO2 were measured immediately before pre-oxygenation (T0), anesthesia induction (T1), tracheal intubation (T2), and mechanical ventilation (T3). The gastric antrum's cross-sectional area (CSA) was measured using ultrasound technology at T0, T1, and T3. Details of complications, including hypoxemia, reflux, nasopharyngeal bleeding, postoperative pulmonary infection, postoperative nausea and vomiting (PONV), and postoperative nasopharyngeal pain, were recorded. The primary outcomes were PaCO2 measured at T1, T2, and T3. The secondary outcomes included PaO2 at T1, T2, and T3, CSA at T1 and T3, and complications happened during this trial.

RESULTS

Pre-oxygenation was administered by high-flow oxygen through NPA (n = 58) or facemask (n = 57) to 115 patients. The mean (SD) PaCO2 was 32.3 (6.7) mmHg in the high-flow group and 34.6 (5.2) mmHg in the mask group (P = 0.045) at T1, 45.0 (5.5) mmHg and 49.4 (4.6) mmHg (P < 0.001) at T2, and 47.9 (5.1) mmHg and 52.9 (4.6) mmHg (P < 0.001) at T3, respectively. The median ([IQR] [range]) PaO2 in the high-flow and mask groups was 404.5 (329.1-458.1 [159.8-552.9]) mmHg and 358.9 (274.0-413.3 [129.0-539.1]) mmHg (P = 0.007) at T1, 343.0 (251.6-428.7 [73.9-522.1]) mmHg and 258.3 (162.5-347.5 [56.0-481.0]) mmHg (P < 0.001) at T2, and 333.5 (229.9-411.4 [60.5-492.4]) mmHg and 149.8 (87.0-246.6 [51.2-447.5]) mmHg (P < 0.001) at T3, respectively. The CSA in the high-flow and mask groups was 371.9 (287.4-557.9 [129.0-991.2]) mm2 and 386.8 (292.0-537.3 [88.3-1651.7]) mm2 at T1 (P = 0.920) and 452.6 (343.7-618.4 [161.6-988.1]) mm2 and 385.6 (306.3-562.0 [105.5-922.9]) mm2 at T3 (P = 0.173), respectively. The number (proportion) of complications in the high-flow and mask groups is shown below: hypoxemia: 1 (1.7%) vs. 9 (15.8%, P = 0.019); reflux: 0 (0%) vs. 0 (0%); nasopharyngeal bleeding: 1 (1.7%) vs. 0 (0%, P = 1.000); pulmonary infection: 4 (6.9%) vs. 3 (5.3%, P = 1.000); PONV: 4 (6.9%) vs. 4 (7.0%, P = 1.000), and nasopharyngeal pain: 0 (0%) vs. 0 (0%).

CONCLUSIONS

Compared to facemasks, pre-oxygenation with high-flow oxygen through NPA offers improved carbon dioxide clearance and enhanced oxygenation prior to tracheal intubation in patients undergoing emergency surgery, while the risk of gastric inflation had not been ruled out.

TRIAL REGISTRATION

This trial was registered prospectively at the Chinese Clinical Research Registry on 26/4/2022 (Registration number: ChiCTR2200059192).

The relationship between gastric ultrasound findings and endoscopically aspirated volume in infants and determining the antral cutoff value for empty stomach diagnosis

BACKGROUND/AIMS

Pulmonary aspiration of gastric content is a serious perioperative complication. The objective of this prospective study was to assess the relationship between the gastric volumes suctioned endoscopically and quantitative (antral cross-section area) and qualitative (empty vs. nonempty) examination of the gastric antrum. Furthermore, the study aimed to determine the best antral cross-section area cutoff value for a truly empty antrum in infants.

METHODS

This study was performed in a pediatric gastrointestinal endoscopy unit. Antral sonography was performed in supine and right lateral decubitus positions in 46 fasted infants prior to upper gastrointestinal endoscopic evaluation. Antral cross-sectional area measurements in both positions and qualitative evaluation of the antrum (according to a three-point grading system) were recorded. Gastric contents were endoscopically suctioned and measured.

RESULTS

Forty-six patients (aged under 24 months) were included. According to the three-point qualitative grading system, 76.1% of patients were classified as grade 0. The best cutoff value for the antral cross-section area in the right lateral decubitus position, indicating an empty antrum, was determined to be 2.40 cm2. At this specific cutoff value, the sensitivity was 100%, the specificity was 68.6%, and the negative predictive value was 100%.

CONCLUSIONS

Gastric ultrasonography can confirm an empty or nearly empty stomach in healthy infants.

Gastric Volume and Antral Area in the Fasting State: A Meta-analysis of Individual Patient Data

BACKGROUND

Pulmonary aspiration of gastric content is a serious anesthetic complication. Gastric point-of-care ultrasound can determine the type and volume of gastric content when clinical information is equivocal. However, a cutoff value of either antral cross-sectional area or volume that may be considered as the upper limit of normal in fasting subjects is still controversial. The aim of this study is to characterize the distribution of baseline antral area and volume in fasting adult subjects and to identify an upper limit (95th percentile) of these distributions.

METHODS

The authors conducted a meta-analysis of individual participant data of primary studies from an academic research network of investigators collaborating in gastric ultrasound. Studies between January 2009 and December 2020 were included.

RESULTS

Twelve primary studies met inclusion criteria and were included in the analysis with a sample size of 1,203 subjects. The 95th percentile of area values (measured in the right lateral decubitus) was 9.9 cm2 (95% CI, 9.4 to 10.4), and of volume, 2.3 ml/kg (95% CI, 2.3 to 2.4). In addition, an antrum grade 0 or 1 indicates a 98% probability of an antral area below the 95th percentile.

CONCLUSIONS

An area of 10 cm2 measured in the right lateral decubitus could be a simple, data-driven upper limit of antral area that could serve as a surrogate of upper limit of normal gastric volume values in fasting adults. These results are limited by the highly selected sampling of the studies included.

EDITOR’S PERSPECTIVE

Bridging the gap: understanding Belgian anesthesiologists' proficiency and training demands in gastric point-of-care ultrasound, a case-based survey

BACKGROUND

Pulmonary aspiration syndrome remains a significant complication of general anesthesia, particularly in unfasted patients. Gastric point-of-care ultrasound (POCUS) allows for both qualitative and quantitative assessment of gastric content, providing a safe and reliable method to assess gastric emptying and reduce the risk of aspiration during general anesthesia.

METHODS

The survey was distributed to Belgian certified anesthesiologists and trainees between April 2020 and June 2021. Participants received a simulated clinical case of a patient at risk of gastric aspiration, created and approved by two certified anesthesiologists trained to perform gastric POCUS. The objectives of this study were to assess recognition of high-risk clinical situations for gastric aspiration, awareness of the gastric POCUS and its indications, and knowledge of the technical and practical conditions of the procedure among respondents trained in the technique. Furthermore, the study assessed the state of training in gastric POCUS, the desire for education, and the practical availability of ultrasound equipment. The survey used conditional branching to ensure unbiased responses to POCUS-related questions. It included multiple-choice questions, quantitative variables, and 5-point Likert scales. The margin of error was calculated using Daniel's formula, corrected for a finite population.

RESULTS

The survey was conducted among 323 anesthesiologists. Only 20.8% (27) recognized the risk of a full stomach based on the patient's history. Anesthesiologists who recognized the indication for gastric POCUS and were trained in the procedure demonstrated good recall of the practical conditions for performing the procedure and interpreting the results. Only 13.08% (31) of all respondents had received training in gastric POCUS, while 72.57% (172) expressed interest in future training. Furthermore, 80.17% (190) of participants had access to adequate ultrasound equipment and 78.90% (187) supported teaching gastric POCUS to anesthesia trainees.

CONCLUSIONS

This survey offers insight into the epidemiology, clinical recognition, knowledge, and utilization of gastric POCUS among Belgian anesthesia professionals. The results emphasize the significance of proper equipment and training to ensure the safe and effective implementation of gastric POCUS in anesthesia practice. Additional efforts should focus on improving training and promoting the integration of gastric POCUS into daily clinical practice.

Glucagon-Like Peptide-1 Agonists and General Anesthesia: Perioperative Considerations and the Utility of Gastric Ultrasound

Glucagon-like peptide-1 (GLP-1) agonists are very popular and useful medications for the treatment of type 2 diabetes mellitus and obesity. Potent gastric emptying delay is common with these medications, serving as a major contributor to the postprandial glycemic control and weight loss benefits of these medications. Recently, multiple case reports and studies indicating safety risks for these medications and their use in patients planning to undergo general anesthesia have been published, as retained gastric contents can lead to intraoperative aspiration. New guidelines for these medications have been released to guide clinical practice for anesthesiologists. Some degree of preoperative cessation of these medications is required. At this time, the ideal window for cessation of these medications to optimize clinical efficacy while reducing aspiration risks has not yet been well elaborated on. Aspiration of gastric contents can still occur despite appropriate preoperative fasting in patients taking GLP-1 agonists. Gastric ultrasound appears to be an effective and objective way of preoperatively assessing a patient's stomach contents to make decisions regarding anesthetic management for patients prescribed these medications. This practice is limited by a general lack of training and implementation in current anesthesiology practice.

Gastric Insufflation with High Flow Nasal Oxygen Therapy in Adult Patients Admitted to Intensive Care Unit: An Observational Study

Background

With the provision of a small positive end-expiratory pressure (PEEP) effect, high-flow nasal oxygen (HFNO) therapy carries a risk of stomach distension. The present study was conducted to find out the air leak in the gastric antrum leading to gastric distension in adult patients with acute respiratory failure receiving HFNO therapy.

Materials and methods

Adult patients with early hypoxemic respiratory failure requiring HFNO therapy were enrolled in this trial. Before initiation of HFNO therapy, baseline gastric volume (GV) and the average number of peristaltic contractions over one minute were measured using ultrasound. Once the patient was stabilized on HFNO therapy, a 2nd, 3rd, and 4th ultrasound scans were acquired at 10, 20, and 30 minutes respectively. Vitals and blood gas values were recorded at the baseline and after 30 min of initiation of HFNO therapy. Patient comfort, duration of HFNO therapy, and outcome were also recorded.

Results

The GV at 10, 20, and 30 minutes were significantly larger (p < 0.001) compared to baseline. This increase in GV was associated with a significantly increased number of peristaltic contractions and had a significant positive correlation with the HFNO flow (r = 0.541; p < 0.001). The HFNO therapy was well tolerated by most of the patients and led to a significant improvement in the vitals and blood gas parameters at 30 minutes after initiation of HFNO therapy.

Conclusion

In adult patients with hypoxemic respiratory failure, the use of HFNO therapy produces gas leaks into the stomach leading to increased gastric volume. The gastric distension increases the peristaltic contraction and higher flows result in more distension.

How to cite this article

Ramachandran A, Bhatia P, Mohammed S, Kamal M, Chhabra S, Paliwal B. Gastric Insufflation with High Flow Nasal Oxygen Therapy in Adult Patients Admitted to Intensive Care Unit: An Observational Study. Indian J Crit Care Med 2024;28(4):393-398.

Clinical practice guidelines for nutritional assessment and monitoring of adult ICU patients in China

The Chinese Society of Critical Care Medicine (CSCCM) has developed clinical practice guidelines for nutrition assessment and monitoring for patients in adult intensive care units (ICUs) in China. This guideline focuses on nutrition evaluation and metabolic monitoring to achieve optimal and personalized nutrition therapy for critically ill patients. This guideline was developed by experts in critical care medicine and evidence-based medicine methodology and was developed after a thorough review of the system and a summary of relevant trials or studies published from 2000 to July 2023. A total of 18 recommendations were formed and consensus was reached through discussions and reviews by expert groups in critical care medicine, parenteral and enteral nutrition, and surgery. The recommendations are based on currently available evidence and cover several key fields, including screening and assessment, evaluation and assessment of enteral feeding intolerance, metabolic and nutritional measurement and monitoring during nutrition therapy, and organ function evaluation related to nutrition supply. Each question was analyzed according to the Population, Intervention, Comparison, and Outcome (PICO) principle. In addition, interpretations were provided for four questions that did not reach a consensus but may have potential clinical and research value. The plan is to update this nutrition assessment and monitoring guideline using the international guideline update method within 3-5 years.

Determinants of gastric residual volume before elective surgery in diabetic patients: An observational study

Background

We investigated factors affecting the low- and high-risk groups for aspiration by measuring gastric volume with ultrasound in diabetic patients who fasted for elective surgery.

Methods

The study was conducted as an observational study. Sixty-five patients scheduled for elective surgery, aged 18-86 years, with American Society of Anesthesiologists (ASA) scores II-III, and who have diabetes were included after local ethics committee approval. Written informed consent was obtained from all participants. Demographic data of cases were recorded. Patients whose gastric residual volume (GRV) was calculated using the pupils equal, round, reactive to light, and accommodation (PERLA) formula following gastric antrum measurement in the right lateral decubitus and supine position by ultrasound were categorized as low or high risk for aspiration.

Results

Thirty-one patients were in the low-risk group, and 34 patients were in the high-risk group. Sex, weight, body mass index (BMI), hemoglobin A1c (HbA1c) values, and duration of diabetes were not statistically significant (p > 0.5). Age (p = 0.006) and fasting blood glucose (FBG) (p = 0.005) were statistically significant. The risk of aspiration decreases with age. Hyperglycemia is related to delayed gastric emptying and a high risk for aspiration. The duration of fasting, GRV, and cross-sectional area (CSA) were statistically significant (p = 0.017, p = 0.000, and p = 0.000, respectively).

Conclusion

Gastric emptying might be delayed in diabetic patients resulting in a high risk for aspiration pneumonia. The risk of aspiration increases in young diabetic patients, and preoperative FBG measurements can provide an idea about gastric emptying in diabetic patients. Gastric ultrasound (USG) may contribute to guidelines for determining more appropriate fasting times for other patient populations, such as obese, pregnant, or child patients.

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.

Gastric point-of-care ultrasonography in patients undergoing radical gastrointestinal surgery before anesthetic induction: an observational cohort study

BACKGROUND

Pulmonary aspiration of gastric contents is a serious perioperative complication. Patients with gastric cancer may experience delayed gastric emptying. However, the role of qualitative and quantitative gastric ultrasound assessments in this patient population before anesthesia induction has not yet been determined.

METHODS

Adult patients with gastrointestinal cancer were recruited and examined using gastric point-of-care ultrasound (POCUS) before anesthetic induction from March 2023 to August 2023 in a tertiary cancer center. Three hundred patients with gastric cancer were conducted with POCUS prior to induction, and three hundred patients with colorectal cancer were included as controls. The cross-sectional area (CSA) of the gastric antrum and gastric volumes (GV) were measured and calculated. We determined the nature of the gastric contents and classified the antrum using a 3-point grading system. A ratio of GV to body weight > 1.5mL/Kg was defined as a high risk of aspiration.

RESULTS

In patients with gastric cancer, 70 patients were classified as grade 2 (23%, including 6 patients with solid gastric contents) and 63 patients (21%) were identified as having a high risk of aspiration. Whereas in patients with colorectal cancer, only 11 patients were classified as grade 2 (3.7%), and 27 patients (9.7%) were identified as having a high risk of aspiration. A larger tumor size (OR:1.169, 95% CI 1.045-1.307, P = 0.006), tumor located in antrum (OR:2.304, 95% CI 1.169-4.539,P = 0.016), gastrointestinal obstruction (OR:21.633, 95% CI 4.199-111.443, P < 0.0001) and more lymph node metastasis (OR:2.261, 95% CI 1.062-4.812, P = 0.034) were found to be positively while tumor site at cardia (OR:0.096, 95% CI 0.019-0.464, P = 0.004) was negatively associated with high aspiration risk in patients with gastric cancer.

CONCLUSION

The Gastric POCUS prior to induction provides an assessment of the status of gastric emptying and can identify the patients at high risk of aspiration, especially those with gastric cancer.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ( www.chictr.org.cn ) identifier: ChiCTR2300069242; registered 10 March 2023.

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part I

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

The safety of preoperative carbohydrate drinks in extremely elderly patients assessed by gastric ultrasonography: a randomized controlled trial

BACKGROUND

Modern perioperative guidelines encourage drinking oral carbohydrates 2 h before management. Nevertheless, research on the safety of preoperative carbohydrate drinks, particularly in extremely elderly patients is lacking. We aimed to evaluate the safety of carbohydrate drinks 2 h before surgery in extremely elderly patients (≥ 80 years) using gastric ultrasonography.

METHODS

We conducted a randomized prospective comparative study of 70 patients aged over 80 years who were scheduled for total knee arthroplasty, hip fracture or humerus fracture surgery. These patients were randomly assigned to the carbohydrate group (n = 35), which fasted from midnight, except for drinking 355 mL of a carbohydrate-containing fluid 2 h before surgery, or the fasting group (n = 35), which fasted from midnight and drank no fluid before surgery. The primary outcome of the study was the cross-sectional area (CSA) of the gastric antrum in the right lateral decubitus position (RLDP) before surgery. The secondary outcomes included CSA in the supine position, intraoperative blood glucose levels and their variability coefficients, Perlas grade, and the visual analog scale of subjective feelings.

RESULTS

The CSA in the RLDP and supine positions revealed no differences between the carbohydrate and fasting groups at 0 h preoperatively (P > 0.05). In the qualitative assessment, preoperative 0-h Perlas grading did not differ significantly between the groups (P > 0.05). From 2 h before surgery to transfer out of the post-anesthesia care unit, the average blood glucose level of patients in the carbohydrate group was significantly higher than that in the fasting group (P < 0.001) but remained within the normal range. Moreover, the blood glucose variability coefficient was significantly lower in the carbohydrate group than in the fasting group (P = 0.009). Oral intake of 355 mL carbohydrates before surgery significantly relieved patients' feelings (P < 0.001).

CONCLUSION

Preoperative consumption of carbohydrate drinks 2 h before surgery is safe in "healthy" extremely elderly patients. In addition, preoperative drinking has potential value in maintaining ideal blood glucose levels and stable blood glucose fluctuations perioperatively and improving subjective perceptions of preoperative preparation. This finding warrants further investigation in clinical practice.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (Registration Number ChiCTR1900024812), first registered on 29/07/2019.

Ultrasound evaluation of gastric emptying time of standardized high-calorie liquid meals in healthy adults: A double-blind cross-over randomized study

BACKGROUND AND AIMS

Commercially available high-calorie drinks containing fat and protein can be used as dietary supplements in surgical patients. According to preoperative fasting guidelines, high-calorie drinks are non-clear fluids and should not be consumed 6 h before elective procedures. The aim of this study was to evaluate the gastric emptying time of commercially available high-calorie drink formulations in healthy adults using gastric ultrasound.

METHODS

25 healthy adult volunteers were included in this double-blind, cross-over prospective study. On three study sessions, fasted volunteers ingested one of the three study products: a solution of 75 g of glucose in 200 ml of water, a fat-free liquid meal, and a nutritionally complete liquid meal with equal volume and energy content. Gastric ultrasound examinations were performed to evaluate the gastric contents qualitatively and the volume of the gastric contents was calculated from the cross-sectional area of the gastric antrum measured in right lateral position by using a validated model. Repeated gastric ultrasounds were performed at baseline and half-hourly after ingesting the products in supine and right lateral position until the criteria for an empty stomach were met.

RESULTS

The glucose solution and the standard fat-free high-calorie drink with the same caloric content had a median gastric emptying time of 150 min. The nutritionally complete liquid meal had a median gastric emptying time of 180 min. Gastric emptying was complete in all participants before 6 h had elapsed since ingesting the study products.

CONCLUSIONS

High calorie liquid meals have a gastric emptying time longer than the recommended fasting time for clear fluids, but shorter than the recommended fasting time for solids in healthy adults.

The effect of pharyngeal packing on gastric volume in patients undergoing nasal surgery: a randomised, controlled trial

OBJECTIVE

To explore the effects of pharyngeal packing on antral cross-sectional area, gastric volume and post-operative complications.

METHODS

In this prospective, randomised, controlled study, 180 patients were randomly assigned to a control group or a pharyngeal packing group. Gastric antral dimensions were measured with pre- and post-operative ultrasound scanning. Presence and severity of post-operative nausea and vomiting and sore throat were recorded.

RESULTS

Post-operative antral cross-sectional area and gastric volume were significantly larger in the pharyngeal packing group compared to the control group. The incidence and severity of post-operative nausea and vomiting were significantly less in the pharyngeal packing group. More frequent and severe sore throat was observed in the control group within the ward. An increased Apfel simplified risk score and post-operative antral cross-sectional area were associated with post-operative nausea and vomiting during the first 2 hours, whereas septorhinoplasty and functional endoscopic sinus surgery, absent pharyngeal packing, and lower American Society of Anesthesiologists' physical status were associated with post-operative nausea and vomiting within the ward.

CONCLUSION

Regardless of operation type, pharyngeal packing use resulted in smaller gastric volume, which was associated with reduced post-operative nausea and vomiting frequency and severity, and lower sore throat incidence.

Rapid Evaluation of Gastric Content With Ultrasound: An Educational Tool

Pulmonary aspiration is a severe complication in patients receiving anesthesia for surgical procedures. The risk and severity of aspiration are significantly higher in the presence of substantial gastric contents. Bedside ultrasound imaging of the gastric antrum is emerging as a rapid and valuable method to evaluate gastric contents before surgery. Rapid gastric ultrasound using a three-category grading system promotes timely decision-making to help in emergent or urgent surgeries by identifying patients with potentially high gastric volumes or solid food contents. In emergent cases with limited time, a single ultrasound view of the gastric antrum is still likely to yield helpful information. In this report, we argue that bedside ultrasound offers a more reliable assessment of gastric contents than assumptions based on time-based fasting guidelines.

Pre-operative gastric ultrasound in patients at risk of pulmonary aspiration: a prospective observational cohort study

Point-of-care gastric sonography offers an objective approach to assessing individual pulmonary aspiration risk before induction of general anaesthesia. We aimed to evaluate the potential impact of routine pre-operative gastric ultrasound on peri-operative management in a cohort of adult patients undergoing elective or emergency surgery at a single centre. According to pre-operative gastric ultrasound results, patients were classified as low risk (empty, gastric fluid volume ≤ 1.5 ml.kg-1 body weight) or high risk (solid, mixed or gastric fluid volume > 1.5 ml.kg-1 body weight) of aspiration. After sonography, examiners were asked to indicate changes in aspiration risk management (none; more conservative; more liberal) to their pre-defined anaesthetic plan and to adapt it if patient safety was at risk. We included 2003 patients, 1246 (62%) of which underwent elective and 757 (38%) emergency surgery. Among patients who underwent elective surgery, 1046/1246 (84%) had a low-risk and 178/1246 (14%) a high-risk stomach, with this being 587/757 (78%) vs. 158/757 (21%) among patients undergoing emergency surgery, respectively. Routine pre-operative gastric sonography enabled changes in anaesthetic management in 379/2003 (19%) of patients, with these being a more liberal approach in 303/2003 (15%). In patients undergoing elective surgery, pre-operative gastric sonography would have allowed a more liberal approach in 170/1246 (14%) and made a more conservative approach indicated in 52/1246 (4%), whereas in patients undergoing emergency surgery, 133/757 (18%) would have been managed more liberally and 24/757 (3%) more conservatively. We showed that pre-operative gastric ultrasound helps to identify high- and low-risk situations in patients at risk of aspiration and adds useful information to peri-operative management. Our data suggest that routine use of pre-operative gastric ultrasound may improve individualised care and potentially impact patient safety.

Diagnostic accuracy of a simple qualitative ultrasound assessment for the diagnosis of empty stomach in the adult: A supplementary analysis of a prospective observer-blind randomized crossover study

BACKGROUND

It has been reported that qualitative ultrasound assessment performed in the semi-upright position had high sensitivity to detect gastric fluid volume >1.5 mL.kg-1 . Nevertheless, the diagnostic accuracy of qualitative assessment for the diagnosis of empty stomach (fluid volume <0.8 mL.kg-1 ) has not been assessed. We aimed to assess the diagnostic accuracy of simple qualitative ultrasound assessment with and without head-of-bed elevation to 45° for the diagnosis of an empty stomach. We also aimed to determine the diagnostic accuracy of a composite ultrasound scale and clinical algorithm.

METHODS

We performed a supplementary analysis of a prospective observer-blind randomized crossover trial in which adult fasting volunteers attended two distinct sessions, with the head-of-bed angled either at 0° or 45°, in a randomized order. Three tests were performed within each session, each corresponding to a different (either 0, 50, 100, 150 or 200 mL) and randomized volume of water; the same volumes were ingested in both sessions, in a randomized order. Ultrasounds were performed 3 min after water ingestion, blindly to the volume ingested.

RESULTS

We included 20 volunteers in whom 120 measurements were analyzed. The sensitivity and specificity of the qualitative assessment in the semirecumbent position were 93% (95% CI: 68-100) and 89% (95% CI: 76-96), respectively. The composite scale and clinical algorithm did not have better diagnostic accuracy than the qualitative assessment performed with head-of-bed elevation. Without head-of-bed elevation, the clinical algorithm had significantly higher specificity (98% [95% CI: 88-100]) than qualitative assessment (67% [95% CI: 51-80]; p < 0.05).

CONCLUSION

These results suggest that qualitative assessment in the semirecumbent position had high diagnostic accuracy for the diagnosis of fluid volume <0.8 mL.kg-1 ; this method can be used in clinical practice for reliable diagnosis of empty stomach.

Point of care gastric ultrasound to predict aspiration in patients undergoing urgent endotracheal intubation in the emergency medicine department

BACKGROUND

One significant cause of morbidity and mortality in patients undergoing endotracheal intubation is the aspiration of gastric contents. Its prevalence is more in the emergency than in elective settings. Point-of-care gastric ultrasound (GUS) is a non-invasive bedside ultrasonogram that provides both qualitative and quantitative information about the stomach contents. The diagnostic accuracy of GUS in terms of gastric parameters (measured antral diameters, antral cross-sectional area, and calculated gastric volume) to predict aspiration is yet unknown. We aim to determine this in the patients undergoing urgent emergency intubation (UEI) in the emergency department.

METHODOLOGY

A prospective observational study was conducted at the emergency department of a tertiary healthcare center in India. Patients requiring UEI were identified and a bedside gastric ultrasound was done in the right lateral decubitus position using low frequency curved array probe. The qualitative data and the antral diameters (anteroposterior and craniocaudal) were assessed. The patient's clinical parameters and history regarding the last meal were noted. The cross-sectional area of gastric antrum was calculated using CSA = (AP × CC) π/4. The gastric volume is estimated using Perla's formula: GV = 27.0 + 14.6(RLD CSA) -1.28(age).

RESULTS

A hundred patients requiring urgent endotracheal intubation were enrolled in the study. Visible aspiration was more in participants with a distended gastric status (χ2 = 16.880, p =  < 0.001). The median gastric volume in the patients who aspirated was 146.37 mL, and it ranged from 111.59 mL-201.01 mL. Using ROC analysis, a cut-off of CC diameter ≥ 2.35 cm (sensitivity 88%, specificity 91%) and AP diameter ≥ 5.15 cm (sensitivity 88%, specificity 87%) predicts aspiration. A calculated USG CSA cut-off ≥ 9.27cm2 (sensitivity 100%, specificity 87%) and an USG gastric volume ≥ 111.594 mL (sensitivity 100%, a specificity 92%) predicts aspiration.

CONCLUSION

Point-of-care gastric ultrasound is an useful non-invasive bedside tool for risk stratification for aspiration in busy emergency rooms. We present threshold gastric antral parameters that can be used to predict aspiration along with its diagnostic accuracy. This can help the treating ED physician take adequate precautions, decide on intubation techniques and treatment modifications to aid in better patient management.

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.

Effect of trans-nasal humidified rapid insufflation ventilatory exchange on reflux and microaspiration in patients undergoing laparoscopic cholecystectomy during induction of general anesthesia: a randomized controlled trial

Background

Reflux aspiration is a rare but serious complication during induction of anesthesia. The primary aim of this study is to compare the incidence of reflux and microaspiration in patients undergoing laparoscopic cholecystectomy during induction of general anesthesia using either a facemask or trans-nasal humidified rapid insufflation ventilatory exchange.

Methods

We conducted a single-center, randomized, controlled trial. Thirty patients were allocated to either a facemask or a trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) group. Pre-oxygenation for 5 min with a facemask or THRIVE, positive pressure ventilation for 2 min or THRIVE for 2 min after anesthesia induction was followed. Before endotracheal intubation, the secretion above and below the glottis was collected to measure pepsin content and analyze blood gas. The ELISA assay for supra- and subglottic human pepsin content was used to detect the presence of reflux and microaspiration. The primary outcome was the incidence of reflux and microaspiration. Secondary outcomes were apnea time, PaO2 before tracheal intubation, and the end-expiratory carbon dioxide partial pressure.

Results

Patients in the THRIVE group had a significantly longer apnea time (379.55 ± 94.12 s) compared to patients in the facemask group (172.96 ± 58.87 s; p < 0.001). There were no differences observed in PaO2 between the groups. A significant difference in gastric insufflation, reflux, and microaspiration was observed between the groups. Gastric insufflation was 6.9% in the THRIVE group vs. 28.57% kPa in the facemask group (p = 0.041); reflux was 10.34% in the THRIVE group vs. 32.14% kPa in the facemask group (p = 0.044); and microaspiration was 0% in the THRIVE group vs. 17.86% kPa in the facemask group (p = 0.023).

Conclusion

The application of THRIVE during induction of general anesthesia reduced the incidence of reflux and microaspiration while ensuring oxygenation and prolonged apnea time in laparoscopic cholecystectomy patients. THRIVE may be an optimal way to administer oxygen during the induction of general anesthesia in laparoscopic cholecystectomy patients.

Clinical trial registration

Chinese Clinical Trial Registry, No: ChiCTR2100054086, https://www.chictr.org.cn/indexEN.html.

Effects of ultrasound monitoring of gastric residual volume on feeding complications, caloric intake and prognosis of patients with severe mechanical ventilation

BACKGROUND

Monitoring of gastric residual is an important approach for assessing gastric emptying in patients with mechanical ventilation. By monitoring gastric contents, the enteral nutrition scheme can be adjusted in time to ensure feeding safety.

AIM

To investigate the effects of ultrasound monitoring on the incidence of feeding complications, daily caloric intake and prognosis of patients with severe mechanical ventilation. To analyze the clinical significance of ultrasound monitoring of gastric residual volume (GRV) up to 250 mL to provide a theoretical basis for clinical practice.

METHODS

Patients admitted to the department of emergency medicine of the Affiliated Hospital of Nantong University from January 2018 to June 2022 who received invasive mechanical ventilation and continuous enteral nutrition support within 24-48 h after admission were enrolled in this study. Medical records for patients within 7 d of hospitalization were retrospectively analyzed to compare the incidence of feeding complications, daily caloric intake and clinical prognosis between patients with gastric residual ≥ 250 mL and < 250 mL, as monitored by ultrasound on the third day.

RESULTS

A total of 513 patients were enrolled in this study. Incidences of abdominal distension, diarrhea, and vomiting in the < 250 mL and ≥ 250 mL groups were: 18.4% vs 21.0%, 23.9% vs 32.3% and 4.0% vs 6.5%, respectively; mortality rates were 20.8% vs 22.65%; mechanical ventilation durations were 18.30 d vs 17.56 d while lengths of stay in the intensive care units (ICU) were 19.87 d vs 19.19 ± 5.19 d. Differences in the above factors between groups were not significant. Gastric residual ≥ 250 mL was not an independent risk factor for death and prolonged ICU stay. However, target feeding time of patients in the ≥ 250 mL group was longer than that of patients in the ≥ 250 mL group, and caloric intake (22.0, 23.6, 24.8, 25.3 kcal/kg/d) for patients in the ≥ 250 mL group from the 4^th day to the 7^th day of hospitalization was lower than that of patients in the ≥ 250 mL group (23.2, 24.8, 25.7, 25.8 kcal/kg/d). On the 4^th day (Z = 4.324, P = 0.013), on the 5^th day (Z = 3.376, P = 0.033), while on the 6^th day (Z = 3.098, P = 0.04), the differences were statistically significant.

CONCLUSION

The use of ultrasound to monitor GRV and undertaking clinical interventions when the monitoring value is ≥ 250 mL has no significant effects on incidences of feeding complications and clinical prognostic outcomes, however, it significantly prolongs the time to reach target feeding, reduces the daily intake of calories during ICU hospitalization, and increases the risk of insufficient nutrition of patients. The accuracy and necessity of monitoring gastric remnants and monitoring frequencies should be investigated further.

Ultrasonographic Assessment of Gastric Volume in Fasted Patients Undergoing Gastrointestinal Endoscopy Under Sedation

Purpose

In this prospective observational study, an ultrasonographic measurement of antral cross-sectional area (ACSA) was conducted to evaluate the gastric content and volume as well as to identify high-risk stomach in non-pregnant adult surgical patients adhering to preanesthetic fasting guidelines.

Patients and Methods

Fasted patients undergoing gastrointestinal endoscopy under sedation were included. Ultrasonographic measurements of ACSA were conducted in both semi-recumbent and right lateral decubitus positions before endoscopic procedures. Gastroscopy was employed to guide the measurement of suctioned gastric volume (GV). Ultrasonography was performed to assess gastric contents and identify patients with high-risk stomach. The relationship between ACSA and suctioned GV was also evaluated.

Results

ACSA was evaluated in 736 out of 782 patients. A significant positive correlation was discovered between ACSA in the right lateral decubitus position and suctioned GV, which was more reliable than in the semi-recumbent position. To analyze high-risk stomach with a GV > 100 mL, the cutoff value of ACSA in the right lateral decubitus was found to be 7.5 cm2, with the AUC, sensitivity and specificity of 0.80 (95% CI, 0.76-0.82; P<0.001), 82.4% and 67.3%, respectively. A novel mathematical model based on ACSA to estimate GV in non-pregnant fasted adults was presented.

Conclusion

Ultrasonographic measurement of ACSA can assist anesthesiologists in estimating the risk of pulmonary aspiration of gastric contents during general anesthesia and sedation.

Determining residual gastric volume in healthy children using ultrasound

PURPOSE

Fasting guidelines for children recommend restricting clear fluids for one or two hours before a procedure to reduce pulmonary aspiration. Gastric volumes < 1.5 mL·kg-1 do not seem to present an increased risk of pulmonary aspiration. Our aim was to quantify the time to achieve a gastric volume < 1.5 mL·kg-1 after clear fluid ingestion in children.

METHODS

We conducted a prospective observational study in healthy volunteers aged 1-14 yr. Participants followed American Society of Anesthesiologists fasting guidelines prior to data collection. Gastric ultrasound (US) was performed in the right lateral decubitus (RLD) position to determine the antral cross-sectional area (CSA). Following baseline measurements, participants consumed 250 mL of a clear fluid. We then performed gastric US at four time intervals: 30, 60, 90, and 120 min. Data were collected following a predictive model for gastric volume estimation using the formula: volume (mL) = -7.8 + (3.5 × RLD CSA) + (0.127) × age (months).

RESULTS

We recruited 33 healthy children aged 2-14 yr. The mean gastric volume per weight (mL·kg-1) at baseline was 0.51 mL·kg-1 (95% confidence interval [CI], 0.46 to 0.57). The mean gastric volume was 1.55 mL·kg-1 (95% CI, 1.36 to 1.75) at 30 min, 1.17 mL·kg-1 (95% CI, 1.01 to 1.33) at 60 min, 0.76 mL·kg-1 (95% CI, 0.67 to 0.85) at 90 min, and 0.58 mL·kg-1 (95% CI, 0.52 to 0.65) at 120 min.

CONCLUSION

Our results show that total gastric fluid volume was < 1.5 mL·kg-1 after 60 min, suggesting that current fasting guidelines for children could be liberalized.

Influence of semaglutide use on the presence of residual gastric solids on gastric ultrasound: a prospective observational study in volunteers without obesity recently started on semaglutide

PURPOSE

Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RAs) have become increasingly popular as both diabetic and weight loss therapies. One effect of this class of medication is delayed gastric emptying, which may impact the risk of aspiration during anesthesia delivery.

METHODS

In this prospective study, we used gastric ultrasound to evaluate the presence of solid gastric contents in both supine and lateral positions after an eight-hour fast in those taking GLP-1RA compared with controls. Participants underwent a second ultrasound evaluation two hours later after drinking 12 fluid ounces of water (approximately 350 mL).

RESULTS

Twenty adults voluntarily enrolled, giving a total of ten participants in each group. In the supine position, 70% of semaglutide participants and 10% of control participants had solids present on gastric ultrasound (risk ratio [RR], 3.50; 95% confidence interval [CI], 1.26 to 9.65; P = 0.02.) In the lateral position, 90% of semaglutide participants and 20% of control participants had solids identified on gastric ultrasound (RR, 7.36; 95% CI, 1.13 to 47.7; P = 0.005). Two hours after drinking clear liquids, the two groups did not differ in the lateral position, but in the supine position, 90% of control group participants were rated as empty compared with only 30% of semaglutide group participants (P = 0.02).

CONCLUSIONS

This study provides preliminary evidence that GLP-1RAs may affect gastric emptying and residual gastric contents following an overnight fast and two hours after clear liquids, which may have implications for aspiration risk during anesthetic care.

The correlation between patient satiety sensation and total gastric fluid volume: a prospective observational study

PURPOSE

Surgical patients are asked to adhere to preoperative fasting guidelines to minimize gastric contents. Large fluid volumes or solid content can still be present as shown with gastric ultrasound. It has been suggested that additional rating of patients' satiety, measured as the feeling of hunger and thirst, could help clinicians to better judge emptying of the stomach.

METHODS

We performed a prospective observational study in fasted elective surgical patients. The primary objective was to investigate the correlation between hunger measured on a 0-10 numeric rating scale and total gastric fluid volume measured with gastric ultrasonography. Secondary objectives included the correlation between 1) thirst and total gastric fluid volume and 2) hunger, thirst, and the Perlas grading scale score.

RESULTS

We included 515 patients. The exam was inconclusive in 14 individuals (2.7%). The Spearman correlation coefficient between gastric fluid volumes and hunger was 0.11 (95% confidence interval [CI], 0.02 to 0.20) (P = 0.01). The correlation between gastric fluid volumes and thirst was 0.11 (95% CI, 0.02 to 0.20) (P = 0.02). Between antral grades and numeric rating scale, the correlation coefficient was 0.00 (95% CI, -0.09 to 0.09) (P = 1.00) for thirst and 0.00 (95% CI, -0.08 to 0.09) (P = 0.94) for hunger. Ten patients (2.0%) had solid content, 24 presented a grade 2 antrum (4.8%).

CONCLUSION

This study suggests that the correlation between total gastric fluid volume and satiety sensation is very weak. Satiety did not reliably predict total gastric fluid volume.

STUDY REGISTRATION

ClinicalTrials.gov (NCT04884373); registered 13 May 2021.

Pan-alimentary assessment of motility, luminal content, and structures: an MRI-based framework

BACKGROUND

Gastrointestinal symptoms originating from different segments overlap and complicate diagnosis and treatment. In this study, we aimed to develop and test a pan-alimentary framework for the evaluation of gastrointestinal (GI) motility and different static endpoints based on magnetic resonance imaging (MRI) without contrast agents or bowel preparation.

METHODS

Twenty healthy volunteers (55.6 ± 10.9 years, BMI 30.8 ± 9.2 kg/m2) underwent baseline and post-meal MRI scans at multiple time points. From the scans, the following were obtained: Gastric segmental volumes and motility, emptying half time (T50), small bowel volume and motility, colonic segmental volumes, and fecal water content. Questionnaires to assess GI symptoms were collected between and after MRI scans.

KEY RESULTS

We observed an increase in stomach and small bowel volume immediately after meal intake from baseline values (p<.001 for the stomach and p=.05 for the small bowel). The volume increase of the stomach primarily involved the fundus (p<.001) in the earliest phase of digestion with a T50 of 92.1 ± 35.3 min. The intake of the meal immediately elicited a motility increase in the small bowel (p<.001). No differences in colonic fecal water content between baseline and 105 min were observed.

CONCLUSION & INFERENCES

We developed a framework for a pan-alimentary assessment of GI endpoints and observed how different dynamic and static physiological endpoints responded to meal intake. All endpoints aligned with the current literature for individual gut segments, showing that a comprehensive model may unravel complex and incoherent gastrointestinal symptoms in patients.

Ultrasound Assessment of Gastric Volume in Parturients After High-Flow Nasal Oxygen Therapy

BACKGROUND

High-flow nasal oxygen (HFNO) therapy is widely used in critical care obstetrics to improve oxygenation. Much of the benefit of HFNO is linked to the creation of modest levels of positive airway pressure. Pregnant women are generally considered to be at high risk of regurgitation and aspiration. It is unknown whether HFNO may cause gas insufflation into the stomach and further increase this risk. Therefore, this study aimed to systematically evaluate the possible safety effects of HFNO on gastric volume in healthy fasted parturients.

METHODS

Sixty fasted parturients scheduled for elective cesarean delivery were enrolled in an observer-blinded, prospective, interventional study. We used ultrasonography to assess changes of antral cross-sectional area (CSA) and gastric volume before and after a 20-minute treatment with HFNO at a rate of 50 L·min -1 . The primary outcome was the change in gastric volume from before to after HFNO therapy, and the secondary outcome was the distribution of antral grades.

RESULTS

In semirecumbent right lateral position, the antral CSA at baseline and after treatment with HFNO was 3.81 (3.01-4.72) cm 2 and 3.79 (3.03-4.54) cm 2 , respectively. The estimated fluid volume at baseline and after treatment with HFNO was 38.51 (33.39-54.62) mL and 39.71 (32.00-52.82) mL, respectively. All participants had either a grade 0 or grade 1 antrum, and most of them had a grade 0 antrum. There was no significant difference in gastric volume and distribution of antral grades before and after HFNO therapy. Gastric air distension was not shown in any of the parturients either at baseline or after treatment with HFNO.

CONCLUSIONS

Treatment with HFNO for 20 minutes at flow rates up to 50 L·min -1 did not increase gastric volume in term pregnant women breathing spontaneously when evaluated by gastric ultrasonography.

Safety and effectiveness for oral intake of carbohydrate-rich drink at preoperative 2 hours before painless colonoscopy

The aim of this study was to evaluate the feasibility, safety, and optimal dose of oral intake of carbohydrate-rich drinks 2 hours before painless colonoscopy. All patients receiving painless colonoscopy were randomly divided into 3 groups: control group (no carbohydrate-rich drink, n = 33), low-dose group (5 mL/kg carbohydrate-rich drink, n = 30), and high-dose group (8 mL/kg carbohydrate-rich drink, n = 30). Use of vasoactive drugs, the visual analog scale including thirst and hunger, degree of satisfaction, the time required for Modified Post Anesthetic Discharge Scoring System scale, first urination time, electrolyte level (sodium, potassium, and calcium), and blood glucose level were also determined. A total of 93 patients were recruited in this study. No significant difference was observed in the cross-sectional area (CSA) of the gastric antrum area at T0 between low- and high-dose groups (P = .912). There was a significant difference in CSA of gastric antrum at 120 minutes after oral intake between the low- and high-dose groups (P = .015). No significant difference was observed in the CSA of gastric antrum at 0 minutes and 120 minutes in the low-dose group (P = .177). In the high-dose group, the CSA of gastric antrum significantly differed at 0 minutes and 120 minutes (P < .001). There was a significant difference in the visual analog scale scores of thirst and hunger at 4 and 5 hours after bowel preparation among 3 groups (P = .001, P = .029, P < .001, P = .001). The degree of satisfaction in low- and high-dose groups was significantly higher than that in the control group (both P < .001). In conclusion, it is feasible and safe to deliver an oral intake of 5 mL/kg carbohydrate-rich drink 2 hours before painless colonoscopy. The comfort level and degree of satisfaction of patients can be further improved.

Gastric Emptying Velocity After Labor Analgesia Assessed by Sonography: A Prospective Controlled Observational Study

Objective

The effect of labor analgesia on gastric emptying rate will affect the management of fasting during the perinatal period. To evaluate gastric emptying after labor analgesia using the gastric antrum ultrasound examination.

Methods

From September 2022 to January 2023, a prospective controlled observational study was conducted. The Study group (epidural analgesia group) and Observation group (pharmacological and non-pharmacological interventions group) were successively enrolled and grouped using the random envelope method. However, labor analgesia was supplied according to maternal women's wishes, and intention-to-treat (ITT) and per-protocol (PP) analyses were performed to establish its effect on stomach emptying. The gastric emptying rate during the first stage of labor was considered to be the primary outcome.

Results

From September 2022 to January 2023, 120 persons were studied, 90 in the Study group and 30 in the Observation group. 33 people's analgesic selection was discordant with the grouped one. ITT analysis showed that the Study group's cross-sectional area (CSA) fell from baseline (624.19 ± 92.70 mm²) to 334.64 ± 46.32 mm² after 1 hour and to 217.26 ± 29.90 mm² after 2 hours. In the Observation group, the CSA similarly dropped from 620.10 ± 100.73 mm² to 331.30 ± 51.19 mm² and 214.70 ± 28.73 mm², p<0.001. CSA was not significantly different between groups, p>0.05. The PP analysis also indicated no significant changes in the CSA between the two groups at 3 time-points, p>0.05. At the first hour, the Study and Observation group had stomach emptying speeds of 300.05 ± 103.74 mm²/h and 259.50 ± 125.25 mm²/h, respectively, which were greater than those at the second hour (115.75 ± 43.51 mm²/h vs 124.36 ± 58.98 mm²/h), p<0.001.

Conclusion

Epidural analgesia, pharmacological, and non-pharmacological labor analgesia had little effect on gastric emptying, and gastric antrum ultrasonography can be utilized to monitor maternal gastric volume changes.

Ultrasonic evaluation of metoclopramide's effect on gastric motility in emergency trauma patients

Objective: The present study aimed to use bedside ultrasound to evaluate the effects of metoclopramide on gastric motility in patients being treated for trauma in the emergency department. Methods: Fifty patients underwent an ultrasound immediately after attending the emergency department of Zhang Zhou Hospital due to trauma. The patients were randomly divided into two groups: a metoclopramide group (group M, n = 25) and a normal saline group (group S, n = 25). The cross-sectional area (CSA) of the gastric antrum was measured at 0, 30, 60, 90, and 120 min (T = time). The gastric emptying rate (GER, GER=-AareaTn/AareaTn-30-1×100), GER/min (GER divided by the corresponding interval time), gastric content properties, Perlas grade at different time points, T120 gastric volume (GV), and GV per unit of body weight (GV/W) were evaluated. The risk of vomiting, reflux/aspiration, and type of anesthetic treatment were also evaluated. Results: The differences between the two groups in the CSA of the gastric antrum at each time point were statistically significant (p < 0.001). The CSAs of the gastric antrum in group M were lower than those in group S, and the greatest difference between the two groups occurred at T30 (p < 0.001). The differences between the two groups in GER and GER/min were also statistically significant (p < 0.001); those differences in group M were higher than those in group S, and the greatest differences between the two groups occurred at T30 (p < 0.001). There were no obvious change trends in the properties of the gastric contents and the Perlas grades in either group, and the differences between the two groups were not statistically significant (p = 0.97). The differences between the two groups in the GV and GV/W at T120 were statistically significant (p < 0.001), as was the risk of reflux and aspiration at T120 (p < 0.001). Conclusion: When metoclopramide was used in satiated emergency trauma patients, it accelerated gastric emptying within 30 min and reduced the risk of accidental reflux. However, a normal gastric emptying level was not achieved, which can be attributed to the delaying effect of trauma on gastric emptying.

Conditioning by a Previous Experience Impairs the Rewarding Value of a Comfort Meal

BACKGROUND

Meal ingestion induces a postprandial experience that involves homeostatic and hedonic sensations. Our aim was to determine the effect of aversive conditioning on the postprandial reward of a comfort meal.

METHODS

A sham-controlled, randomised, parallel, single-blind study was performed on 12 healthy women (6 per group). A comfort meal was tested before and after coupling the meal with an aversive sensation (conditioning intervention), induced by infusion of lipids via a thin naso-duodenal catheter; in the pre- and post-conditioning tests and in the control group, a sham infusion was performed. Participants were instructed that two recipes of a tasty humus would be tested; however, the same meal was administered with a colour additive in the conditioning and post-conditioning tests. Digestive well-being (primary outcome) was measured every 10 min before and 60 min after ingestion using graded scales.

RESULTS

In the aversive conditioning group, the comfort meal in the pre-conditioning test induced a pleasant postprandial experience, which was significantly lower in the post-conditioning test; the effect of aversive conditioning (change from pre- to post-conditioning) was significant as compared to sham conditioning in the control group, which showed no differences between study days.

CONCLUSION

The hedonic postprandial response to a comfort meal in healthy women is impaired by aversive conditioning.

CLINICALTRIALS

gov ID: NCT04938934.

The Year in Perioperative Echocardiography: Selected Highlights From 2022

THIS SPECIAL article is part of an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan, and the Editorial Board for the opportunity to continue this series, which focuses on the past year's research highlights that pertain to perioperative echocardiography in relation to cardiothoracic and vascular anesthesia. The major selected themes for 2022 include (1) updates on mitral valve assessments and interventions, (2) training and simulation updates, (3) outcomes and complications of transesophageal echocardiography, and (4) point-of-care cardiac ultrasound. The themes selected for this special article are just a sample of the advances in perioperative echocardiography during 2022. An appreciation and understanding of these highlights will help to ensure and improve the perioperative outcomes for patients with cardiovascular disease undergoing cardiac surgery.

Differences in preoperative gastric ultrasound findings in elderly compared to the mid-aged surgical patients: A retrospective observational study

This study aimed to compare gastric ultrasound assessments between young and elderly patients, to determine whether the cross-section area (CSA) cutoff values for elderly and young patients should be different, and to suggest CSA cutoff values for elderly patients. This study evaluated the data of 120 patients who underwent elective surgery under general anesthesia between July 2019 and August 2020. Demographic and gastric ultrasound assessment data were retrieved. Patients were divided into the elderly group (n = 58, age: ≥65 years) and young group (n = 62, age: <65 years). The CSAs in the supine and right lateral decubitus positions (RLDP), semiquantitative 3-point Perlas grade (grades 0, 1, and 2), and gastric volume (GV) were determined. CSAs according to different Perlas grades were compared between the 2 groups. To compare normally and non-normally distributed continuous data, Student t test and the Mann-Whitney U test were used, respectively. Categorical data were compared using the chi-square test or Fisher exact test, as appropriate. The receiver operating characteristic (ROC) curves were built for the CSAs to predict pulmonary aspiration. The CSA cutoff values for predicting a high risk of pulmonary aspiration in both the groups were determined. Among patients with Perlas grade 0, the CSAsupine (P = .002) and CSARLDP (P = .002) were greater in the elderly group than in the young group. The specificity, positive predictive value, and accuracy of the CSA decreased when the CSA cutoff value for the young group was applied to the elderly group. The CSA cutoff values for the elderly group were: CSAsupine, 6.92 cm2 and CSARLDP, 10.65 cm2. The CSA of the empty stomach was greater in elderly patients than in young patients. We suggest that the following CSA cutoff values should be used for predicting pulmonary aspiration risk in elderly patients: CSAsupine, 6.92 cm2 and CSARLDP, 10.65 cm2.

Postoperative Handheld Gastric Point-of-Care Ultrasound and Delayed Bowel Function

BACKGROUND

Delayed bowel function (DBF) following intra-abdominal surgery is a common problem that contributes to postoperative complications and prolonged length of stay. Use of a handheld gastric point-of-care ultrasound (GPOCUS) can identify a full vs empty stomach in the postoperative period. We hypothesized that the findings of a full stomach identified on a postoperative day 1 (POD1) GPOCUS exam would predict an increased risk of delayed bowel function.

STUDY DESIGN

A blinded, prospective cohort study was performed. Postoperative colorectal surgery patients were identified as having either a full or empty stomach based on previously published definitions. GPOCUS examinations were performed on POD1 using a handheld ultrasound device, and the clinicians were blinded to the results. Demographic and perioperative data were collected. The primary outcome variable was gastrointestinal-3 (GI-3) recovery, defined as time to tolerance of diet and either flatus or bowel movement.

RESULTS

Fifty-six patients agreed to participate in the study; fifty were eligible and included. Eighteen patients' stomachs were identified as full on POD1 GPOCUS examination, and thirty-two were identified as empty. No significant demographic or perioperative differences existed between groups. Patients with full stomachs had significantly delayed GI-3 recovery (4 vs 1 days, p < 0.0001) and longer length of stay (5 vs 3 days, p < 0.0001). Full-stomach patients also had significantly more emesis and nasogastric tube (NGT) placement (both p < 0.05).

CONCLUSIONS

GPOCUS performed on POD1 can predict DBF, length of stay, likelihood of emesis, and NGT placement. Use of handheld devices for GPOCUS showed promise for the identification of patients at high risk for DBF and could provide an opportunity for pre-emptive intervention.

Ultrasound Assessment of Gastric Fluid Volume in Children Scheduled for Elective Surgery After Clear Fluid Fasting for 1 Versus 2 Hours: A Randomized Controlled Trial

BACKGROUND

This study aimed to compare the gastric fluid volume (GFV) in children who fasted 1 versus 2 hours using ultrasound, after ingestion of a defined volume of clear fluid.

METHODS

Children scheduled for elective surgery were enrolled in this randomized, double-blinded, controlled trial. After receiving 3 mL kg -1 clear fluid, participants were randomized to have a gastric ultrasound after fasting for either 1 hour (1-hour group, n = 116) or 2 hours (2-hour group, n = 111). Our primary outcome was the GFV. Other outcomes included the antral cross-sectional area, frequency of high risk and low risk of aspiration, and qualitative grading for the gastric antrum.

RESULTS

Two hundred and twenty-seven children were available for final analysis. The median (Q1-Q3) GFV was higher in the 1-hour group versus the 2-hour group (0.61 [0.41-0.9] mL kg -1 vs 0.32 [0.23-0.47] mL kg -1 ; P value = .001). None of the study groups had GFV ≥1.5 mL kg -1 . The frequency (%) of GFV ≥1.25 mL kg -1 was comparable between both groups (2 [1.7%] vs 0 [0%], P value = .165). However, the frequency of GFV ≥0.8 mL kg -1 was higher in 1-hour group than in 2-hour group (34.5% vs 4.5%), and grade 2 antral grading score was 56.9% in 1-hour group vs 0.9% in 2-hour group ( P value <.001).

CONCLUSIONS

In healthy children scheduled for elective surgery receiving 3 mL kg -1 clear fluid, the median GFV after 1-hour fasting was double the volume after conventional 2-hour fasting. These findings should be considered whether weighting the risk/benefit of a liberal approach to preoperative fasting versus the risk of pulmonary aspiration.

Ultrasound assessment of residual gastric volume in older adults undergoing staged-bilateral total knee arthroplasty after consuming carbohydrate-containing fluids: a prospective observational study

BACKGROUND

We compared preoperative residual gastric volume (GV) between the first and second stages of total knee arthroplasty (TKA) in older adults after drinking carbohydrate-containing fluid 2 h prior to surgery.

METHODS

In this study, 36 patients, aged > 65 years, scheduled for staged bilateral TKA with one-week interval, were enrolled. The patients consumed 400 ml of carbohydrate-containing fluid 2 h prior to surgery. Before the induction of spinal anesthesia, the gastric antral cross-sectional area was measured at the first and second TKA using ultrasound, and the residual GV was calculated. The primary outcome was the residual GV. Qualitative GV (grades 0, 1, and 2) and analgesic consumption after the first TKA were assessed as secondary outcomes.

RESULTS

The GV (median [Q1, Q3]) was greater in the second-stage TKA (41.1 [22.5, 62.8] ml) than in the first-stage TKA (10.3 [0.0, 27.1] ml) (P < 0.001). In the qualitative assessment, the distribution was not different between the two stages of TKA (P = 0.219) and only one patient showed grade 2 gastric content in the second TKA. When opioid consumption was converted to an equivalent dose of morphine, an average of 53.9 mg of morphine was required after the first TKA.

CONCLUSIONS

Residual GV after drinking carbohydrate-containing fluid differed according to the stage of TKA, showing a larger residual GV in the second TKA than in the first one. In older adults scheduled to undergo bilateral staged TKA, caution is required in preoperative fasting practice, especially in second-stage surgery.

Inter-observer and intra-observer variability in ultrasound assessment of gastric content and volume in critically ill patients receiving enteral nutrition

BACKGROUND

The assessment of gastric content and volume using bedside ultrasound (US) has become a useful tool in emergency departments, anesthesiology departments and inpatient wards, as it provides a rapid and dynamic assessment of the gastric content of patients, which, allows making decisions regarding the risk of regurgitation or the need to adjust the strategy used to induce general anesthesia in patients with a full stomach. This assessment consists of two evaluations: a qualitative one, in which the status of the antrum, in terms of gastric content, is classified into three categories (empty, liquid content and full), and a quantitative one, where gastric volume is estimated. The objective of this study was to estimate the intra-observer and inter-observer agreement in ultrasound assessment of gastric content and volume in critically ill patients receiving enteral nutrition.

RESULTS

A total of 41 patients were included and each examiner performed 64 gastric US (n = 128). Participants' average age was 56.5 years (SD ± 12.6) and 63.4% were men. Regarding the qualitative evaluation of the antrum, in supine position both examiners classified the gastric content as grade 0 in 1 gastric US (1.5%), grade 1 in 4 gastric US (6.2%) and grade 2 in 59 (92.1%). Regarding intra-observer variability in the measurement of the area of the antrum, Lin's concordance correlation coefficient (CCC), the difference of means between measurements and the 95% limits of agreement of Bland and Altman values were 0.95 (95% CI 0.940-0.977), - 0.47 cm² (SD ± 1.64) and - 3.70 cm² to 2.75 cm², respectively, in EC1, and 0.94 (95% CI 0.922-0.973), - 0.18 cm² (SD ± 2.18) and - 4.47 cm² to 4.09 cm² in EC2. Concerning to inter-observer variability (EC1 vs EC2) in the measurement of the area of the antrum and of gastric volume, the following CCC, mean difference between measurements and 95% limits of agreement of Bland and Altman values were obtained: measurement of the area of the antrum: 0.84 (95% CI 0.778-0.911), - 0.86 cm² (SD ± 3.38) and - 7.50 cm² to 5.78 cm²; gastric volume measurement: 0.84 (95% CI 0.782-0.913), - 12.3 mL (SD ± 49.2) and - 108.8 mL to 84.0 mL.

CONCLUSIONS

The assessment of gastric content and volume using bedside US in critically ill patients on mechanical ventilation and receiving enteral nutrition showed a good intra and inter-rater reliability. Most of the patients included in the study had a high risk of pulmonary aspiration, since, according to the results of the gastric US evaluation, they had gastric volumes > 1.5 mL/kg.

Gastric Cross-Sectional Area to Predict Gastric Intolerance in Critically Ill Patients: The Sono-ICU Prospective Observational Bicenter Study

To evaluate the correlation between gastric cross-sectional area (GCSA) and the occurrence of gastric intolerance in critically ill patients within 24 hours of the measurement.

DESIGN

Two-center prospective observational study.

SETTING

Two academic ICUs in France between June 2020 and August 2021.

PATIENTS

All surgical intubated ICU patients greater than or equal to 18 years old receiving enteral feeding for greater than 12 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Forty-four patients were included, 11 (25%) of whom presented digestive intolerance. Primary outcome was assessment of the association between GCSA and the occurrence of gastric intolerance within 24 hours of the measurement. GCSA value was significantly higher in patients with upper digestive intolerance compared to those without (553 mm² [interquartile range (IQR), 500-649 mm²] vs 970 mm² [IQR, 777-1,047]; p < 0.001, respectively). The optimal threshold for predicting upper digestive intolerance was 720 mm² (area under the receiver operating characteristic curve 0.86; positive predictive value 62.5%; negative predictive value 96.4%; sensibility 0.91; and specificity 0.81). Multivariate analysis (weighted by propensity score), including known risk factors, showed that GCSA above the 720 mm² threshold was independently associated with the occurrence of upper digestive intolerance (odds ratio, 1.85; 1.37-2.49; p < 0.0002). Measurement quality was "good" (i.e., liver, aorta, superior mesenteric vein, and pancreas were all visualized) in 81% of cases.

CONCLUSIONS

Measurement of GCSA by ultrasound would allow prediction of gastric intolerance in critically ill patients. This should be confirmed by a prospective score validation and interventional trials.

Role of gastric ultrasound to guide enteral nutrition in the critically ill

PURPOSE OF REVIEW

Early initiation of enteral nutrition (EN) is often not feasible due to the high prevalence of gastrointestinal dysfunction that constitutes one of the leading nonavoidable causes for discontinuing or delaying enteral feeding in critically ill. This review summarizes current evidence on the role of gastric ultrasound as a management and monitoring tool for enteral nutrition in critically ill patients.

RECENT FINDINGS

The ultrasound meal accommodation test, the gastrointestinal and urinary track sonography (GUTS), and other gastric ultrasound protocols used to diagnose and treat gastrointestinal dysfunction in critically ill patients have not changed the outcome. However, this intervention could help clinicians with accurate daily clinical decisions. The dynamic changes in the cross-sectional area (CSA) diameter could help to access gastrointestinal dynamics results immediately, provide a valuable guide to initiate EN, predict feeding intolerance (FI), and aid in following treatment response. More studies are necessary to determine the complete scope and true added clinical value of these tests in critically ill patients.

SUMMARY

Using gastric point of care ultrasound (POCUS) is a noninvasive, radiation-free, and inexpensive method. Implementing the ultrasound meal accommodation test in ICU patients might become a step forward to ensure safe early enteral nutrition in critically ill patients.

Association of a Liberal Fasting Policy of Clear Fluids Before Surgery With Fasting Duration and Patient Well-being and Safety

Importance

Current fasting guidelines for procedures under anesthesia are poorly implemented, leading to negative metabolic sequelae. Recent studies in children showed support of liberal clear fluid intake; adult physiology can support clear fluid intake, but implementation studies are lacking.

Objective

To evaluate the successfulness of implementation of a liberal clear fluid policy with regard to fasting duration, well-being, and safety in adults scheduled for anesthesia.

Design, Setting, and Participants

This was a quality improvement study conducted from January 2016 to July 2021 at a tertiary referral hospital in the Netherlands. Adults scheduled for nonemergency procedures under anesthesia were included in the study. Patients undergoing obstetrics procedures or those who were intubated preoperatively were excluded.

Interventions

Stepwise introduction of a liberal fluid fasting policy, allowing for ingestion of clear fluids until arrival at the operating room.

Main Outcomes and Measures

The primary outcome was change in fasting duration. Secondary outcomes were patient well-being, measured as preoperative thirst, amount of fluid ingested, postoperative nausea and vomiting (PONV), and administration of antiemetics. Safety was measured as incidence of regurgitation and aspiration (pneumonia).

Results

Of the 76 451 patients (mean [SD] age, 56 [17] years; 39 530 male individuals [52%] 36 921) included in the study, 59 036 (78%) followed the standard policy, and 16 815 (22%) followed the liberal policy. Time series analysis showed an estimated fasting duration decrease of 3:07 hours (IQR, 1:36-7:22; P < .001) after implementation of the liberal policy. Postimplementation median (IQR) fasting duration was 1:20 (0:48-2:24) hours. The incidence of regurgitation changed from 18 (95% CI, 14-21) to 24 (95% CI, 17-32) in 10 000 patients, and the incidence of aspiration changed from 1.7 (95% CI, 0.6-2.7) to 2.4 (95% CI, 0.5-4.7) in 10 000 patients. In the liberal policy, thirst feelings decreased (37% [4982 of 8615] vs 46% [3373 of 7362]; P < .001). PONV incidence decreased from 10.6% (6339 of 59 636) to 9.4% (1587 of 16 815; P < .001) and antiemetic administration decreased from 11.0% (6538 of 59 636) to 9.5% (1592 of 16 815; P < .001).

Conclusions and Relevance

Results of this quality improvement study suggest that a liberal fasting policy was associated with a clinically relevant reduction in fasting duration and improved patient well-being with regard to preoperative thirst and PONV. Although a slightly higher incidence of regurgitation could not be ruled out, wider implementation of such a policy may be advocated as results are still within the clinically accepted risks margins. Results suggest that surgical procedures in patients who drink clear fluids within 2 hours before anticipated anesthesia should not be postponed or canceled.

Effects of preoperative oral enzyme-hydrolyzed rice flour solution on gastric emptying and insulin resistance in patients undergoing laparoscopic cholecystectomy: a prospective randomized controlled trial

BACKGROUND

The effect of preoperative oral carbohydrates (POC) on insulin resistance (IR) of laparoscopic cholecystectomy (LC) remains debatable. Enzyme-hydrolyzed rice flour (EHR) is a kind of water-soluble micromolecular carbohydrates. This study aimed to investigate the impact of preoperative oral EHR solution on gastric emptying and IR in patients undergoing LC.

METHODS

Patients (n = 100) undergoing LC were divided into oral-water group (group C) or oral-EHR solution (group E) randomly (n = 50 each), and the patients drank 300 ml water or EHR solution 2-3 h before surgery respectively. Gastric emptying which was quantized by gastric volume (GV) from antrum ultrasonography, IR indicators, subjective comfort indicators, handgrip strength, postoperative recovery indexes, and complications were recorded.

RESULTS

There were no differences in GV between the two groups before oral administration (V₀), immediately after oral administration (V₁) and before anesthesia induction(V₂). The GV at V₂ (GV₂) reduced to the level of V₀ (GV₀) in the two groups. Fasting glucose (FG), fasting insulin (FINS) and Homa-IR in the two groups increased at postoperative day 1 (Pos 1d) compared with those at preoperative day 1(Pre 1d). Homa-IS and Homa-β in the two groups decreased at Pos 1d compared with those at Pre 1d. FG, FINS and Homa-IR in group E were lower than those in group C at Pos 1d, and Homa-IS and Homa-β were higher in group E than those in group C at Pos 1d. Subjective comfort indictors (hunger, fatigue and anxiety) in group E were lower than those in group C at preoperative 15 min (Pre 15 min) and postoperative 1 h (Pos 1 h). Handgrip strength in group E was raised compared with that in group C at Pre 15 min, Pos 1 h and Pos 1d. There was a lower incidence of nausea and earlier exhaust time in group E.

CONCLUSION

Oral 300 ml EHR solution 2-3 h before LC surgery did not increase the occurrence of reflux and aspiration during anesthesia induction with a normal gastric emptying, ameliorated postoperative IR, improved subjective comfort, and promoted postoperative gastrointestinal function recovery.

TRIAL REGISTRATION

Prospectively registered at the China Clinical Trial Registry, registration number: ChiCTR2000039939, date of registration:14/11/2020.