Intra- and interindividual variability in fasted gastric content volume.

BACKGROUND: Gastric fluid plays a key role in food digestion and drug dissolution, therefore, the amount of gastric fluid present in a fasted state may influence subsequent digestion and drug delivery. We aimed to describe intra- and interindividual variation in fasted gastric content volume (FGCV) and to determine the association with age, sex, and body size characteristics. METHODS: Data from 24 MRI studies measuring FGCV in healthy, mostly young individuals after an overnight fast were pooled. The analysis included 366 participants who had up to 6 repeated measurements, with a total of 870 measurements. Linear mixed model analysis was performed to calculate intra- and interindividual variability and to assess the effects of age, sex, weight, height, weight*height as a proxy for body size, and body mass index (BMI). RESULTS: FGCV ranged from 0 to 156 mL, with a mean (± SD) value of 33 ± 25 mL. The overall coefficient of variation within the study population was 75.6%, interindividual SD was 15 mL, and the intraindividual SD was 19 mL. Age, weight, height, weight*height, and BMI had no effect on FGCV. Women had lower volumes compared to men (MD: -6 mL), when corrected for the aforementioned factors. CONCLUSION: FGCV is highly variable, with higher intraindividual compared to interindividual variability, indicating that FGCV is subject to day-to-day and within-day variation and is not a stable personal characteristic. This highlights the importance of considering FGCV when studying digestion and drug dissolution. Exact implications remain to be studied.

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.

Assessing Residual Gastric Fluid Volume after Administering Diluted Oral Contrast until One Hour Prior to Anesthesia in Children: An Observational Cohort Study.

Background: Gastric fluid volume has been used as a surrogate marker for pulmonary aspiration risk in studies evaluating fasting protocol safety. This study measured residual gastric fluid volume in children using a protocol in which diluted oral contrast medium was administered up until one hour before anesthesia. Methods: This was a single-center prospective observational cohort trial of 70 children for elective abdominal/pelvic computed tomography (CT). Imaging was performed after diluted enteral contrast medium administration, beginning two hours before and ending at least one hour before induction. For each patient, gastric fluid volume was calculated using an image region of interest. The primary outcome measure was gastric fluid volume measured using the computed tomography image. Results: The median time from the end of contrast administration to imaging was 1.5 h (range: 1.1 to 2.2 h). Residual gastric volume, measured using CT was <0.4 mL/Kg in 33%; ≥0.4 mL/Kg in 67%; and ≥1.5 mL/Kg in 44% of patients. Residual gastric volumes measured using CT and aspiration were moderately correlated (Spearman's correlation coefficient = 0.41, p = 0.0003). However, the median residual gastric volume measured using CT (1.17, IQR: 0.22 to 2.38 mL/Kg) was higher than that of aspiration (0.51, IQR: 0 to 1.58 mL/Kg, p = 0.0008 on differences in paired measures). Three cases of vomiting were reported. No evidence of pulmonary aspiration was identified. Conclusions: Children who receive large quantities of clear fluid up to one hour before anesthesia can have a significant gastric residual volume.

Nutritional Strategies for Preterm Neonates and Preterm Neonates Undergoing Surgery: New Insights for Practice and Wrong Beliefs to Uproot.

The nutrition of preterm infants remains contaminated by wrong beliefs that reflect inexactitudes and perpetuate old practices. In this narrative review, we report current evidence in preterm neonates and in preterm neonates undergoing surgery. Convictions that necrotizing enterocolitis is reduced by the delay in introducing enteral feeding, a slow advancement in enteral feeds, and the systematic control of residual gastric volumes, should be abandoned. On the contrary, these practices prolong the time to reach full enteral feeding. The length of parenteral nutrition should be as short as possible to reduce the infectious risk. Intrauterine growth restriction, hemodynamic and respiratory instability, and patent ductus arteriosus should be considered in advancing enteral feeds, but they must not translate into prolonged fasting, which can be equally dangerous. Clinicians should also keep in mind the risk of refeeding syndrome in case of high amino acid intake and inadequate electrolyte supply, closely monitoring them. Conversely, when preterm infants undergo surgery, nutritional strategies are still based on retrospective studies and opinions rather than on randomized controlled trials. Finally, this review also highlights how the use of adequately fortified human milk is strongly recommended, as it offers unique benefits for immune and gastrointestinal health and neurodevelopmental outcomes.

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.

[Evaluation of gastric emptying after drinking carbohydrates before cesarean section by gastric ultrasonography].

OBJECTIVE: To investigate the effect of gastric antrum ultrasonography in evaluating gastric emptying after oral administration of 300 mL carbohydrates two hours before cesarean section, and to analyze the risk factors of gastric emptying in pregnant women. METHODS: From August 2020 to February 2021, a total of 80 patients, aged 22-43 years, body mass index (BMI) < 35 kg/m2, gestational age≥36 weeks, falling into American Society of Anesthesiologists (ASA) physical status Ⅰ or Ⅱ, scheduled for cesarean sections in Peking University International Hospital were recruited and divided into two groups: the intervention group (n=40)and the control group (n=40). In the intervention group, solid food was restricted after 22:00, the patients were required to take 300 mL carbohydrates two hours before cesarean section. In the control group, solid food and liquid intake were restricted after 22:00 the night before surgery. All the patients received assessment of preoperative feeling of thirst and starvation with visual analogue scale (VAS). The cross-sectional area (CSA)of gastric antrum was measured in supine position and right supine position before anesthesia, the gastric volume (GV)and the gastric volume/weight(GV/W)of the two groups was further calculated. Perlas A semi-quantitative grading assessments were performed in each patient. The blood pressure and heart rate were recorded at admission(T0), 5 minutes after anesthesia (T1), immediately after fetal delivery (T2) and at the end of the surgery (T3). The occurrence of nausea and vomiting during the operation and 24 hours after the operation were recorded. RESULTS: One case in each group was excluded because the antrum was not clearly identified during the ultrasound assessments. In the semi-sitting position, the CSA was (5.07±1.73) cm2 in the intervention group vs. (5.24±1.96) cm2 in the control group, respectively; in the right lateral decubitus position, CSA was (7.32±2.17) cm2 in the intervention group vs. (7.25±2.24) cm2 in the control group, GV was (91.74±32.34) mL vs. (90.07±31.68) mL, GV/W was (1.27±0.40) mL/kg vs. (1.22±0.41) mL/kg, respectively; all the above showed no significant difference between the two groups (P > 0.05). Perlas A semi-quantitative grading showed 0 in 20 patients (51.3%), 1 in 16 (41%), 2 in 3 (7.7%)in the intervention group and 0 in 22 (56.4%), 1 in 15 (38.5%), 2 in 2 (5.1%)in the control group, the proportion of Perlas A semi-quantitative grading showed no significant difference between the two groups (P > 0.05). For the patients with Perlas A semi-quantitative grade 2 (3 cases in the intervention group and 2 cases in the control group), metoclopramide 0.2 mg/kg was intravenously injected before anesthesia. No aspiration case was observed in this study. The intervention group was endured less thirst and hunger (P < 0.05). There was no significant difference in blood pressure and heart rate between the two groups at each time point (P > 0.05). There was no significant difference in the incidence of intraoperative hypotension between the two groups (P > 0.05). There was no significant difference in the incidence of nausea intraoperatively and postoperatively between the two groups (P > 0.05). CONCLUSION: Ultrasonography of gastric antrum can provide objective basis for evaluating gastric emptying of pregnant women perioperatively. 300 mL carbohydrates intake two hours before surgery, which does not increase GV and the risk of reflux aspiration, and is helpful in minimizing disturbance to the patient's physiological status, therefore leading to better clinical outcome.

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

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

[Effect of preoperative carbohydrates intake on the gastric volume and the risk of reflux aspiration in patients positioning in trendelenburg undergoing gynecological laparoscopic procedures].

OBJECTIVE: To investigate the effect of 300 mL carbohydrates intake two hours before sur-gery on the gastric volume (GV) in patients positioning in trendelenburg undergoing gynecological laparoscopic procedures by using gastric antrum sonography, and further assess the risk of reflux aspiration. METHODS: From June 2020 to February 2021, a total of 80 patients, aged 18-65 years, body mass index (BMI) 18-35 kg/m2, falling into American Society of Anesthesiologists (ASA) physical status Ⅰ or Ⅱ, scheduled for gynecological laparoscopic procedures positioning in trendelenburg were recruited and divided into two groups: the observation group (n =40) and the control group (n=40). In the observation group, solid food was restricted after 24:00, the patients were required to take 300 mL carbohydrates two hours before surgery. In the control group, solid food and liquid intake were restricted after 24:00 the night before surgery. The cross-sectional area (CSA) of gastric antrum was measured in supine position and right lateral decubitus position before anesthesia. Primary outcome was gastric volume (GV) in each group. Secondary outcome included Perlas A semi-quantitative grading and gastric volume/weight (GV/W). All the patients received assessment of preoperative feeling of thirsty and hunger with visual analogue scale (VAS). RESULTS: Complete data were available in eighty patients. GV was (58.8±23.6) mL in the intervention group vs. (56.3±22.1) mL in the control group, GV/W was (0.97±0.39) mL/kg vs. (0.95±0.35) mL/kg, respectively; all the above showed no significant difference between the two groups (P > 0.05). Perlas A semi-quantitative grading showed 0 in 24 patients (60%), 1 in 15 patients (37.5%), 2 in 1 patient (2.5%) in the intervention group and 0 in 25 (62.5%), 1 in 13 (32.5%), 2 in 2 (5%) in the control group, the proportion of Perlas A semi-quantitative grading showed no significant difference between the two groups (P > 0.05). A total of 3 patients (1 in the intervention group and 2 in the control group) with Perlas A semi-quantitative grading 2 were treated with special intervention, no aspiration case was observed in this study. The observation group endured less thirst and hunger (P＜0.05). CONCLUSION: Three hundred mL carbohydrates intake two hours before surgery along with ultrasound guided gastric content monitoring does not increase gastric volume and the risk of reflux aspiration in patients positioning in trendelenburg undergoing gynecological laparoscopic surgery, and is helpful in minimizing disturbance to the patient's physiological needs, therefore leading to better clinical outcome.

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.

Effect of preoperative oral rehydration before cesarean section on ultrasound assessment of gastric volume and intraoperative hemodynamic changes: a randomized controlled trial.

BACKGROUND: Cesarean section often requires an urgent transfusion load due to decreased blood pressure after spinal anesthesia. This prospective randomized study aimed to investigate whether a preoperative oral rehydration solution (ORS) stabilized perioperative circulatory dynamics. METHODS: Sixty-three parturients scheduled for cesarean section under combined spinal epidural anesthesia (CSEA) were randomly allocated to one of three groups: Group O received 500 mL ORS before bedtime and 500 mL 2 h before CSEA; Group M received mineral water instead of ORS; and Group C had no fluid intake (controls). After entering the operating room, stomach size was measured using ultrasound. Blood samples were obtained, and CSEA was induced. Vasopressors were administered when systolic blood pressure was < 90 mmHg or decreased by > 20%. As a vasopressor, phenylephrine (0.1 mg) was administered at ≥ 60 beats/min heart rate or ephedrine (5 mg) at < 60 beats/min heart rate. The primary outcome was the total number of vasopressor boluses administered. Secondary outcomes were the cross-sectional area of the stomach antrum, maternal plasma glucose levels, serum sodium levels, total intravenous fluid, bleeding volume, urine volume, operative time, and cord blood gas values after delivery. RESULTS: The total number of vasopressor boluses was lower in Group O than in Group C (P < 0.05). Group O had lower total dose of phenylephrine than Group C (P < 0.05). There were no significant differences between Group M and other groups. No differences were detected regarding secondary outcomes. CONCLUSIONS: In women scheduled for cesarean section, preoperative ORS stabilized perioperative circulatory dynamics. Neither ORS nor mineral water consumption increased the stomach content volume. TRIAL REGISTRATION: This trial is registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000019825: Date of registration 17/11/2015).

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.

Gastric emptying times of obese and non-obese school-aged children after preoperative clear fluid intake: A prospective observational study.

BACKGROUND: Liberal fasting regimens, which support clear fluid intake up to 1 h before surgery in children scheduled for elective surgery, are taking their place in guidelines. However, because of the lack of publications that investigate the gastric emptying time in preoperative obese children, the practice of 1-hour clear fluid fasting in obese children remained at the level of recommendation with weak evidence. AIMS: The primary aim was to investigate whether there is a difference in gastric emptying times between obese and non- obese children after preoperative intake of 3 mL/kg clear liquid containing 5% dextrose by using ultrasound. METHODS: A total of 70 children were included in the study in two groups, 35 obese and 35 non-obese, aged 6-14 years, who were scheduled for elective surgery. The baseline antral cross-sectional area measurements of the children in the groups were made using ultrasound. 3 mL/kg 5% dextrose was consumed. Ultrasound was repeated immediately after fluid intake and every 5 min until the antral cross-sectional area was at the baseline level. RESULTS: The difference in median (IQR [range]) gastric emptying times (minutes) of non-obese {35 [30.0-45.0 (20-60)]} and obese children {35 [30.0-40.0 (25-60)]} were not statistically significant (median of differences 0.0, 95% CI -5.0 to 5.0; p = .563). The antral cross-sectional area and weight-adjusted gastric volumes returned to the baseline level within 60 min after the intake of clear liquid with 3 mL/kg 5% dextrose in all children in both groups. CONCLUSIONS: Obese and non-obese children have similar gastric emptying times, and these groups can be offered clear fluids containing 3 mL/kg 5% dextrose 1 h before the surgery.

Residual unabsorbed midazolam: a case report.

BACKGROUND: Oral midazolam is commonly administered to reduce anxiety in children presenting for medical procedures or surgery. It is unclear what volume of medication remains unabsorbed in the stomach when the child presents for anesthetic induction prior to these procedures. The presence of any significant residual medication in the stomach has significant clinical implications in the postoperative period. CASE PRESENTATION: A 5-year-old white Caucasian boy presented for upper gastrointestinal endoscopy after receiving oral midazolam liquid. Insertion of the endoscope into the stomach revealed a significant amount of unabsorbed medication remaining within the gastric cavity. CONCLUSION: Clinicians should be aware that the sedative effects of midazolam may be present before the medication is fully absorbed. A significant amount of unabsorbed medication may be present in the stomach during medical procedures/surgery. This may continue to be absorbed in the intraoperative and postoperative period, with unwanted clinical effect.

Three-Dimensional Multi-detector Computed Tomography (3D-MDCT) Gastric Volumetry in Patients with obesity and Normal-Weight Individuals.

BACKGROUND: Obesity is a widely prevalent medical and socioeconomic problem. Bariatric surgery is indicated for patients with clinically severe obesity. Reduction of gastric volume is an important factor that contributes to weight loss after laparscopic sleeve gastrectomy (LSG). The impact of the gastric volume on weight after LSG has been studied. AIM OF THE STUDY: This study was designed to assess the gastric volume in patients with obesity prior to LSG and in the normal-weight patients, using three-dimensional multi-detector computer tomography (3D-MDCT), and to evaluate the potential correlation of the gastric volume with body mass index (BMI). PATIENTS AND METHODS: A total of 100 patients were equally enrolled in two groups: one group for patients with obesity scheduled for LSG and another one for normal-weight patients scheduled for non-bariatric surgery. The study patients underwent 3D-MDCT gastric volumetry. RESULTS: The gastric volume ranged from 525 to 1170 mL in patients with obesity and from 312 to 676 mL in the normal-weight group. Statistically significant difference was found between the two groups. Age, weight, and BMI were found to be predictors for the gastric volume in normal-weight patients only. CONCLUSION: MDCT gastric volumetry is a feasible method to assess the stomach volume. Higher volumes were evident in patients with obesity. Age, weight, and BMI are predictors for the gastric volume in normal-weight patients with linear regression equations that could help during the preoperative planning of bariatric surgeries.

Effect of preoperative carbohydrates intake on the gastric volume and the risk of reflux aspiration in patients positioning in trendelenburg undergoing gynecological laparoscopic procedures / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effect of 300 mL carbohydrates intake two hours before sur-gery on the gastric volume (GV) in patients positioning in trendelenburg undergoing gynecological laparoscopic procedures by using gastric antrum sonography, and further assess the risk of reflux aspiration.@*METHODS@#From June 2020 to February 2021, a total of 80 patients, aged 18-65 years, body mass index (BMI) 18-35 kg/m2, falling into American Society of Anesthesiologists (ASA) physical status Ⅰ or Ⅱ, scheduled for gynecological laparoscopic procedures positioning in trendelenburg were recruited and divided into two groups: the observation group (n =40) and the control group (n=40). In the observation group, solid food was restricted after 24:00, the patients were required to take 300 mL carbohydrates two hours before surgery. In the control group, solid food and liquid intake were restricted after 24:00 the night before surgery. The cross-sectional area (CSA) of gastric antrum was measured in supine position and right lateral decubitus position before anesthesia. Primary outcome was gastric volume (GV) in each group. Secondary outcome included Perlas A semi-quantitative grading and gastric volume/weight (GV/W). All the patients received assessment of preoperative feeling of thirsty and hunger with visual analogue scale (VAS).@*RESULTS@#Complete data were available in eighty patients. GV was (58.8±23.6) mL in the intervention group vs. (56.3±22.1) mL in the control group, GV/W was (0.97±0.39) mL/kg vs. (0.95±0.35) mL/kg, respectively; all the above showed no significant difference between the two groups (P > 0.05). Perlas A semi-quantitative grading showed 0 in 24 patients (60%), 1 in 15 patients (37.5%), 2 in 1 patient (2.5%) in the intervention group and 0 in 25 (62.5%), 1 in 13 (32.5%), 2 in 2 (5%) in the control group, the proportion of Perlas A semi-quantitative grading showed no significant difference between the two groups (P > 0.05). A total of 3 patients (1 in the intervention group and 2 in the control group) with Perlas A semi-quantitative grading 2 were treated with special intervention, no aspiration case was observed in this study. The observation group endured less thirst and hunger (P＜0.05).@*CONCLUSION@#Three hundred mL carbohydrates intake two hours before surgery along with ultrasound guided gastric content monitoring does not increase gastric volume and the risk of reflux aspiration in patients positioning in trendelenburg undergoing gynecological laparoscopic surgery, and is helpful in minimizing disturbance to the patient's physiological needs, therefore leading to better clinical outcome.

Evaluation of gastric emptying after drinking carbohydrates before cesarean section by gastric ultrasonography / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effect of gastric antrum ultrasonography in evaluating gastric emptying after oral administration of 300 mL carbohydrates two hours before cesarean section, and to analyze the risk factors of gastric emptying in pregnant women.@*METHODS@#From August 2020 to February 2021, a total of 80 patients, aged 22-43 years, body mass index (BMI) < 35 kg/m2, gestational age≥36 weeks, falling into American Society of Anesthesiologists (ASA) physical status Ⅰ or Ⅱ, scheduled for cesarean sections in Peking University International Hospital were recruited and divided into two groups: the intervention group (n=40)and the control group (n=40). In the intervention group, solid food was restricted after 22:00, the patients were required to take 300 mL carbohydrates two hours before cesarean section. In the control group, solid food and liquid intake were restricted after 22:00 the night before surgery. All the patients received assessment of preoperative feeling of thirst and starvation with visual analogue scale (VAS). The cross-sectional area (CSA)of gastric antrum was measured in supine position and right supine position before anesthesia, the gastric volume (GV)and the gastric volume/weight(GV/W)of the two groups was further calculated. Perlas A semi-quantitative grading assessments were performed in each patient. The blood pressure and heart rate were recorded at admission(T0), 5 minutes after anesthesia (T1), immediately after fetal delivery (T2) and at the end of the surgery (T3). The occurrence of nausea and vomiting during the operation and 24 hours after the operation were recorded.@*RESULTS@#One case in each group was excluded because the antrum was not clearly identified during the ultrasound assessments. In the semi-sitting position, the CSA was (5.07±1.73) cm2 in the intervention group vs. (5.24±1.96) cm2 in the control group, respectively; in the right lateral decubitus position, CSA was (7.32±2.17) cm2 in the intervention group vs. (7.25±2.24) cm2 in the control group, GV was (91.74±32.34) mL vs. (90.07±31.68) mL, GV/W was (1.27±0.40) mL/kg vs. (1.22±0.41) mL/kg, respectively; all the above showed no significant difference between the two groups (P > 0.05). Perlas A semi-quantitative grading showed 0 in 20 patients (51.3%), 1 in 16 (41%), 2 in 3 (7.7%)in the intervention group and 0 in 22 (56.4%), 1 in 15 (38.5%), 2 in 2 (5.1%)in the control group, the proportion of Perlas A semi-quantitative grading showed no significant difference between the two groups (P > 0.05). For the patients with Perlas A semi-quantitative grade 2 (3 cases in the intervention group and 2 cases in the control group), metoclopramide 0.2 mg/kg was intravenously injected before anesthesia. No aspiration case was observed in this study. The intervention group was endured less thirst and hunger (P < 0.05). There was no significant difference in blood pressure and heart rate between the two groups at each time point (P > 0.05). There was no significant difference in the incidence of intraoperative hypotension between the two groups (P > 0.05). There was no significant difference in the incidence of nausea intraoperatively and postoperatively between the two groups (P > 0.05).@*CONCLUSION@#Ultrasonography of gastric antrum can provide objective basis for evaluating gastric emptying of pregnant women perioperatively. 300 mL carbohydrates intake two hours before surgery, which does not increase GV and the risk of reflux aspiration, and is helpful in minimizing disturbance to the patient's physiological status, therefore leading to better clinical outcome.

Effect of facemask oxygenation with and without positive pressure ventilation on gastric volume during anesthesia induction in patients undergoing laparoscopic cholecystectomy or partial hepatectomy: a randomized controlled trial.

BACKGROUND: Studies focusing on the relationship between gastric volume and facemask oxygenation without ventilation during apnea in anesthesia induction are scarce. This study compared the change in gastric volume during apnea in anesthesia induction using facemask ventilation and facemask oxygenation without ventilation in adults undergoing laparoscopic surgery. METHODS: In this prospective, randomized, double-blinded trial, 70 adults undergoing laparoscopic surgery under general anesthesia were divided into two groups to receive facemask oxygenation with and without ventilation for 60 seconds after loss of consciousness. Before anesthesia induction and after endotracheal intubation, the gastric antral cross-sectional area was measured with ultrasound imaging. Arterial blood gases were tested at baseline (T1), after preoxygenation (T2), after loss of consciousness (T3), and before and after endotracheal intubation (T4 and T5, respectively). RESULTS: Sixty patients were included (ventilation n = 30; non ventilation n = 30, 10 patients were excluded). The median [IQR] change of gastric antral cross-sectional area in ventilation group was significantly higher than in non ventilation group (0.83 [0.20 to 1.54] vs. 0.10 [- 0.11 to 0.56] cm2, P = 0.001). At T4 and T5, the PaO2 in ventilation group was significantly higher than in non ventilation group (T4: 391.83 ± 61.53 vs. 336.23 ± 74.99 mmHg, P < 0.01; T5: 364.00 ± 58.65 vs. 297.13 ± 86.95 mmHg, P < 0.01), while the PaCO2 in non ventilation group was significantly higher (T4: 46.57 ± 5.78 vs. 37.27 ± 6.10 mmHg, P < 0.01; T5: 48.77 ± 6.59 vs. 42.63 ± 6.03 mmHg, P < 0.01) and the pH value in non ventilation group was significantly lower (T4: 7.35 ± 0.029 vs 7.42 ± 0.047, P < 0.01; T5: 7.34 ± 0.033 vs 7.39 ± 0.044, P < 0.01). At T4, the HCO3- in non ventilation group was significantly higher (25.79 ± 2.36 vs. 23.98 ± 2.18 mmol l- 1, P < 0.01). CONCLUSIONS: During apnoea, the increase in gastric volume was milder in patients undergoing facemask oxygenation without ventilation than with positive pressure ventilation. TRIAL REGISTRATION: ChiCTR2100054193, 10/12/2021, Title: "Effect of positive pressure and non-positive pressure ventilation on gastric volume during induction of general anesthesia in laparoscopic surgery: a randomized controlled trial". Website: https://www.chictr.ogr.cn .

Hard-Candy Consumption Does Not Have an Effect on Volume and pH of Gastric Content in Patients Undergoing Elective Gastrointestinal Endoscopic Procedures: A Randomized Controlled Trial.

Purpose: This study aimed to determine the effect of hard candies on gastric content volume and pH in patients undergoing elective esophagogastroduodenoscopy and colonoscopy. Additionally, the study evaluated the difficulty of the procedure, complications, and satisfaction levels of the endoscopist and patient. Patients and Methods: A randomized controlled study equally recruited 108 outpatients to candy and control groups. The patients in the candy group could consume sugar-free candies within 2 hours before anesthesia, while the controls remained fasted. The endoscopic procedure began under topical pharyngeal anesthesia and intravenous sedation. A blinded endoscopist suctioned the gastric volume through an endoscope. A blinded anesthesia provider tested the gastric pH with a pH meter. The primary outcome variables were gastric volume and pH. The secondary outcome variables were complications, the difficulty of the procedure, and endoscopist and patient satisfaction. Results: The characteristics of both patient groups were comparable. The mean gastric volume of the candy group (0.43 [0.27-0.67] mL/kg) was not significantly different from that of the control group (0.32 [0.19-0.55] mL/kg). The gastric pH of both groups was similar: 1.40 (1.10-1.70) for the candy group and 1.40 (1.20-1.90) for the control group. The procedure-difficulty score of the candy group was higher than that of the control group. The satisfaction scores rated by the endoscopist and the patients in both groups were comparable. In addition, most endoscopists and patients in the candy and control groups reported being "very satisfied". No complications were observed in either group. Conclusion: Hard candies did not affect gastric volume or pH. Elective gastrointestinal endoscopic procedures in adult patients who preoperatively consume candies could proceed to prevent delays and disruption of workflows.

Reinforcing the valuable role of gastric ultrasound for volume and content assessment: an observational study

Abstract Background Pulmonary aspiration is one of the most important complications in anesthesiology. Assessment of gastric content by ultrasound is a good method to quantify gastric volume and to determine the risk of intraoperative pulmonary aspiration. The aim of this study is to determine the accuracy of the gastric ultrasonography in the qualitative analysis of gastric content, mainly in the analysis of small amounts of liquid content. Methods Gastric ultrasound was performed to 36 patients before upper gastrointestinal endoscopy (UGI), making two longitudinal scans at the epigastric level, one in supine position and the other in right lateral decubitus position, measuring two diameters and the area of the gastric antrum and assessing the content characteristics determining whether it was an empty stomach or contained fluid or solid content. Subsequently, the ultrasound findings were compared with UGI findings. Results Gastric areas were analyzed by the trace and the lengths of the craniocaudal and anteroposterior axes concluding that there are no significant differences between the two methods. No statistically significant difference was found between UGI and US assessment technics. No statistically significant difference was found between the estimated volume by UGI and US. Conclusions Though our study has some limitations, qualitative analysis of gastric content using ultrasound followed by endoscopy enabled the conclusion that there are no differences in the qualitative assessment regarding these two techniques, supporting the important role of point-of-care gastric ultrasound (POCGUS) in the assessment of pulmonary aspiration risk by the anesthesiologist in the perioperative period.

Impact of preoperative carbohydrate loading on gastric volume in patients with type 2 diabetes.

BACKGROUND: Enhanced recovery after surgery advocates that consuming carbohydrates two hours before anesthesia is beneficial to the patient's recovery. Patients with diabetes are prone to delayed gastric emptying. Different guidelines for preoperative carbohydrate consumption in patients with diabetes remain controversial due to concerns about the risk of regurgitation, aspiration and hyperglycemia. Ultrasonic gastric volume (GV) assessment and blood glucose monitoring can comprehensively evaluate the safety and feasibility of preoperative carbohydrate intake in type 2 diabetes (T2D) patients. AIM: To evaluate the impact of preoperative carbohydrate loading on GV before anesthesia induction in T2D patients. METHODS: Patients with T2D receiving surgery under general anesthesia from December 2019 to December 2020 were included. A total of 78 patients were randomly allocated to 4 groups receiving 0, 100, 200, or 300 mL of carbohydrate loading 2 h before anesthesia induction. Gastric volume per unit weight (GV/W), Perlas grade, changes in blood glucose level, and risk of reflux and aspiration were evaluated before anesthesia induction. RESULTS: No significant difference was found in GV/W among the groups before anesthesia induction (P > 0.05). The number of patients with Perlas grade II and GV/W > 1.5 mL/kg did not differ among the groups (P > 0.05). Blood glucose level increased by > 2 mmol/L in patients receiving 300 mL carbohydrate drink, which was significantly higher than that in groups 1 and 2 (P < 0.05). CONCLUSION: Preoperative carbohydrate loading < 300 mL 2 h before induction of anesthesia in patients with T2D did not affect GV or increase the risk of reflux and aspiration. Blood glucose levels did not change significantly with preoperative carbohydrate loading of < 200 mL. However, 300 mL carbohydrate loading may increase blood glucose levels in patients with T2D before induction of anesthesia.