Right Lateral Decubitus Positions Research Articles

A machine learning stacking model accurately estimating gastric fluid volume in patients undergoing elective sedated gastrointestinal endoscopy

ABSTRACT Background The current point-of-care ultrasound (POCUS) assessment of gastric fluid volume primarily relies on the traditional linear approach, which often suffers from moderate accuracy. This study aimed to develop an advanced machine learning (ML) model to estimate gastric fluid volume more accurately. Methods We retrospectively analyzed the clinical data and POCUS data (D1: craniocaudal diameter, D2: anteroposterior diameter) of 1386 patients undergoing elective sedated gastrointestinal endoscopy (GIE) at Nanjing First Hospital to predict gastric fluid volume using ML techniques, including six different ML models and a stacking model. We evaluated the models using the adjusted Coefficient of Determination (R2), mean absolute error (MAE) and root mean square error (RMSE). The SHapley Additive exPlanations (SHAP) method was used to interpret the importance of the variables. Finally, a web calculator was constructed to facilitate its clinical application. Results The stacking model (Linear regression + Multilayer perceptron) performed best, with the highest adjusted R2 of 0.718 (0.632 to 0.804). The mean prediction bias was 4 ml (MAE: 4.008 (3.68 to 4.336)), which is better than that of the linear model. D1 and D2 ranked high in the SHAP plot and performed better in the right lateral decubitus (RLD) than in the supine position. The web calculator can be accessed at https://cheason.shinyapps.io/Stacking_regressor/. Conclusion The stacking model and its web calculator can serve as practical tools for accurately estimating gastric fluid volume in patients undergoing elective sedated GIE. It is recommended that anesthesiologists measure D1 and D2 in the patient’s RLD position.

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

BackgroundModern 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.MethodsWe 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.ResultsThe 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).ConclusionPreoperative 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 registrationChinese Clinical Trial Registry (Registration Number ChiCTR1900024812), first registered on 29/07/2019.

Ultrasound assessment of gastric content in patients undergoing laparoscopic cholecystectomy after preoperative oral carbohydrates: a prospective, randomized controlled, double-blind study.

To evaluate the gastric volume and nature after drinking preoperative oral carbohydrates in patients undergoing laparoscopic cholecystectomy via ultrasonography. One hundred patients who had been scheduled for elective laparoscopic cholecystectomy were enrolled and randomized into the traditional fasting group (Control group, n = 50) and the carbohydrate group (CHO group, n = 50). Patients in the Control group fasted solids and drink from midnight, the day before surgery. Patients in the CHO group drank 800 ml and 400 ml of oral carbohydrates 11 and 3 h before surgery, respectively. At 2 h after oral carbohydrates (T1), all patients underwent an ultrasound examination of residual gastric contents; if the patients had a full stomach, the assessment was performed again 1 h later (T2). A stomach containing solid contents or >1.5 ml/kg of liquid was considered "full". The primary outcome was full stomach incidences at the above time points. The secondary outcomes included gastric antral CSA in the right lateral decubitus (RLD) and semi-sitting positions, as well as gastric volume (GV), GV per weight (GV/kg), and Perla's grade at T1. Compared with the Control group, the incidence of entire stomach was significantly high in the CHO group 2 h after oral carbohydrates. At the T1 time point, 6 patients (13.3%) in the Control group and 14 patients (30.4%) in the CHO group presented with a full stomach [95% confidence interval (CI), (0.96-5.41), P = 0.049]. At T2, 3 patients (6.7%) in the Control group and 4 patients (8.7%) in the CHO group had a full stomach, with no marked differences between the two groups [95% CI, (0.31-5.50), P = 0.716]. Compared with the Control group, CSA in the semi-sitting and RLD positions, GV and GV/W were significantly high in the CHO group at T1 (P < 0.05). The median (interquartile range) of the Perlas grade was 1 (0-1) in the Control group and 1(1-1.25) in the CHO group (P = 0.004). Cholecystectomy patients experience a 2 h delay in gastric emptying after receiving preoperative carbohydrates. In LC patients, the fasting window for oral carbohydrates before surgery should be adequately prolonged. Chinese Clinical Trail Registry, No: ChiCTR2200055245.

Ultrasonographic Evaluation of Gastric Content and Volume in Pediatric Patients Undergoing Elective Surgery: A Prospective Observational Study.

Anesthesia-related complications, such as pulmonary aspiration of gastric contents, occur in approximately 0.02-0.1% of elective pediatric surgeries. Aspiration risk can be reliably assessed by ultrasound examination of the gastric antrum, making it an essential non-invasive bedside tool. In this prospective observational study, since most of our patients are immigrants and have communication problems, we wanted to investigate gastric contents and the occurrence of "high risk stomach" in children undergoing elective surgery for the possibility of pulmonary aspiration, even if the children and/or parents reported their last oral intake time. This risk is defined by ultrasound findings of solid content in the antrum and/or a calculated gastric volume exceeding 1.25 mL/kg. Children aged 2-18 were included in the study. Both supine and right lateral decubitus (RLD) ultrasound examinations were performed on the antrum before surgery. Using a qualitative grading scale from 0 to 2, we evaluated the gastric fluid content. The cross-sectional area (CSA) of the antrum was measured in the RLD position, aiding the calculation of the gastric fluid volume according to an established formula by Perlas. Ultrasound measurements of 97 children were evaluated. The median fasting duration was 4 h for liquids and 9 h for thick liquids and solids. Solid content was absent in all the children. Five children (5.2%) exhibited a grade 2 antrum, implying that fluid content was visible in both the supine and RLD positions. The median antral CSA in the RLD was 2.36 cm2, with a median gastric volume of 0.46 mL/kg. For patients with a grade 0 antrum, a moderate and positive correlation was observed between the antral CSA and BMI, and a strong and positive correlation was evident between the antral CSA and age, similar to a grade 1 antrum. Only a single child (1%) had a potentially elevated risk of aspiration of gastric contents. Hence, the occurrence of a "high risk stomach" was 1% (95% confidence interval: 0.1-4.7%) and is consistent with the literature. As a necessary precaution, we propose the regular use of ultrasound evaluations of gastric contents, given their non-invasive, bedside-friendly, and straightforward implementation, for identifying risks when fasting times are uncertain and for ruling out unknown risk factors in each potential patient.

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

Gastric ultrasound can be used to evaluate the residual gastric volume (GV) and contents before anesthetizing a patient. Autonomic gastropathy in patients with diabetes increases the risk of pulmonary aspiration of gastric contents. Therefore, the present study was conducted to assess the fasting GV among diabeticsand healthy individuals using point-of-care (POC) ultrasonography. This prospective observational study was conducted in a tertiary care hospital between January 2021 and February 2022. A total of 122 patients included in the study were divided into two groups: group D (n = 61) patients had a history of diabetes mellitus and group C (n = 61) patients were non-diabetics (control).Gastric ultrasound was performed in supine and right lateral decubitus (RLD) positions. The following parameters were measured: duration of fasting, craniocaudal (CC) diameter, anteroposterior (AP) diameter, cross-sectional area (CSA), and GVusing CC and AP diameters. The mean age of the participants was found to be 46.60 ± 13.77 years with 51.6% femalepatients and 48.4% male patients. Among the patients, there was a significantly higher mean level of CC diameter, AP diameter, and CSA in the supine position in diabetics compared to controls(p < 0.05). Similarly, there was a significantly higher mean level of CC diameter, AP diameter, and CSA in the RLD position in diabetics compared to healthy individuals (p < 0.05). The GV was significantly higher in diabetics (9.96 ± 14.520) compared to healthy individuals (-8.991 ± 20.95; p < 0.05). Fasting GV assessed using POC ultrasonography in diabetic individuals was higher when compared to non-diabetics after similar periods of fasting.

Comparison of ultrasound measured gastric volume in term-pregnant patients posted for elective cesarean section with nonpregnant elective surgery patients---An observational study

Background: The pregnant patients undergoing anesthesia are at increased risk of aspiration due to decreased lower esophageal sphincter tone and mass effect of gravid uterus on gastric antrum. Ultrasound used as a noninvasive bedside imaging tool to measure gastric volume in term pregnant patients immediately before elective caesarian section (CS) may help in reducing aspiration induced morbidity and mortality. Methods: This observational prospective case--control study was conducted in 33 nonlaboring term pregnant patients immediately before elective CS and 30 nonpregnant patients immediately before elective surgeries, enrolled according to inclusion and exclusion criteria. A 2-5 MHz curvilinear probe was used to scan the participants in supine and right lateral decubitus (RLD) position in pre-recovery room. Visibility, qualitative grading (0,1, 2), anteroposterior (AP), and craniocaudal (CC) diameter, and cross-sectional area (CSA) of gastric antrum was measured. Gastric volume was derived from CSA using equations formulated by previous investigators. Results: Gastric antrum was visible in 27 (82%) of pregnant and 30 (100%) of nonpregnant patients in supine position (P = 0.014). In RLD position, 25 (75.7%) pregnant and 29 (96.7%) nonpregnant patients had antrum visible (P = 0.018). The qualitative grading was comparable (P = 0.064) in both the groups. In supine position, (P = 0.615), CSA in cm2 was 3.37 ± 1.31 and 3.54 ± 1.33, while in RLD position (P = 0.012), CSA was 3.98 ± 1.13 and 5.09 ± 1.85, in pregnant and nonpregnant patients, respectively. Conclusion: Gravid uterus sometimes impedes visualization of antrum by ultrasound in term pregnant patients immediately before elective CS and shows clinically similar gastric CSA when compared to nonpregnant patients, though statistically different in RLD position. Trial registration number- NCT03380637

Evaluation of Gastric Contents and Volume After Ingestion of Apple Juice versus Pure Complex Carbohydrate Using Gastric Ultrasonography: A Randomised Clinical Study

Introduction: Gastric ultrasound is a non-invasive tool for assessing gastric content and volume. Aspiration of gastric contents is a serious perioperative complication that contributes to mortality and morbidity following general anaesthesia. The Enhanced Recovery After Surgery (ERAS) protocol and Indian Society of Anaesthesiology (ISA) fasting guidelines recommend consuming a carbohydrate drink two hours before surgery in adults. However, evidence supporting this recommendation, particularly regarding volume, is still limited and variable. Aim: To examine Gastric Residual Volume (GRV) using Ultrasonography (USG) six hours after a light breakfast and compare it with GRV two hours after consuming clear liquids. Materials and Methods: A randomised clinical study was conducted involving 100 patients who were assigned randomly to two groups: Group-C (Oral Carbohydrate, CHO) and Group-A (Apple juice), with 50 patients in each group; each patient underwent gastric USG twice: once within the first six hours after a light breakfast and again two hours after consuming 400 mL of clear liquid. USG was performed with the patient in a supine position and a Right Lateral Decubitus (RLD) position, and GRV was estimated by measuring the Antral Cross-sectional Area (ACSA) using a mathematical model. The final reading was taken from the RLD position, and qualitative analysis of the antrum was conducted using the Perlas grading system. A GRV of &lt;1.5 mL/kg is considered low risk for aspiration. Statistical tests such as Chi-square, paired t-test, and one-way Analysis of Variance (ANOVA) were applied. Results: A total of 100 patients were analysed in the present study. The mean age was 41.04 years and 39.94 years in Group-A and Group-C, respectively. There was no significant difference in GRV between six hours after a light breakfast and two hours after clear liquid intake in either group (p&gt;0.05). The mean GRV was 7.75 (7.23) mL and 8.01 (7.58) mL six hours after a light breakfast, and 7.71 (8.92) mL and 8.49 (9.47) mL two hours after clear liquid intake in Group-A and Group-C, respectively, among non-CKD patients. GRV was higher in CKD patients and those with an increased Body Mass Index (BMI). Conclusion: The GRV remains within safe limits after consuming 400 mL of clear liquid two hours before surgery. This finding supports the recommended volume of preoperative clear liquid intake in the ERAS protocol and ISA fasting guidelines. However, careful consideration is necessary for patients with CKD and an increased BMI.

Ultrasound-Determined Residual Gastric Volume after Clear-Fluid Ingestion in the Paediatric Population: Still a Debatable Issue.

Background: Current fasting guidelines are often exceeded in clinical practice, resulting in stressful events during anaesthesia in children. This prospective study compares residual gastric volume after 1 versus 2 h of clear fluid ingestion in fasted children. METHODS: A total of 106 patients were enrolled in the study. Ultrasonography (USG) of gastric antrum (GA) was performed in the supine and right lateral decubitus (RLD) positions. All children fasted from solid food for 6 h. Blackcurrant flavoured drink (3 mL/kg) was given following the measurement of baseline (T0) USG of GA, with follow-ups after 1 (T1) and 2 (T2) hours post-ingestion. Residual gastric volume (RGV) was calculated from the cross-sectional area of GA using a standard formula. Parental satisfaction with their children’s behaviour concerning fasting time was recorded. Results: RGV was significantly higher at T1 compared to T2 (p < 0.001). No significant difference was seen between T0 and T2 (p = 0.30). Parental satisfaction was similar at T1 and T2 (p = 0.158). Conclusions: The RGV in paediatric patients after 1 h of clear fluid ingestion was significantly higher than after 2 h of ingestion. There was no difference observed in parental satisfaction concerning the two intervals of fluid fasting. RLD and supine positions can be used reliably to measure the RGV in children.

Ultrasonographic assessment of preoperative gastric volume in patients with dyspepsia: a prospective observational study

BackgroundPatients undergoing gastroenteroscopy during sedation are prone to aspiration, and most patients with dyspepsia have delayed gastric emptying. This study aimed to investigate the feasibility of measuring the gastric antrum cross-sectional area (CSA) to supply a novel clinical diagnostic reference value in patients with dyspepsia.MethodsPatients with dyspepsia undergoing elective gastroscopy were included. The Perlas qualitative 0–2 grading scale score was determined before the operation. The anteroposterior diameter (D1) and craniocaudal diameter (D2) between gastric antrum serosal surfaces were measured perpendicular to each other in the supine and right lateral decubitus (RLD) positions. CSA values in the supine position and RLD position were determined. Gastric contents were endoscopically suctioned with the volumes measured and noted as actual gastric volume. Multiple regression analysis was used to fit a mathematical model for estimating the gastric volume. Receiver operating characteristic (ROC) curves were constructed to determine the accuracy of RLD CSA to detect gastric volumes of > 0.8 ml/kg.ResultsA total of 117 patients were enrolled and divided into a functional dyspepsia (FD) group and an organic dyspepsia group according to gastroscopy findings. For a gastric volume of > 0.8 ml/kg, cut-off values for FD and organic dyspepsia were 6.7 cm2 and 10.0 cm2, respectively. Two new modified mathematical models were derived to predict an estimated gastric volume for FD and organic dyspepsia: volume = 3.93 × RLD CSA - 0.47 × age; and volume = 6.15 × RLD CSA - 0.61 × age.ConclusionWe used the cut-off value of the antral area for the fast diagnosis of gastric volumes in patients with dyspepsia, which may assist clinicians in identifying patients at risk of aspiration.Trial registrationwww.chictr.org.cn (CHICTR-DDD-17010871); registered 15 March 2017.

Pre-anaesthetic sonographic assessment of gastric antrum in parturient scheduled for elective caesarean section - A prospective cross-sectional study.

Background and Aims:Point-of-care ultrasonography (USG) of the gastric antrum can help to evaluate the aspiration risk and improve the safety of anaesthesia. The aim was to assess the gastric antrum in term parturients scheduled for elective caesarean section using bedside USG.Methods:After obtaining institutional ethics committee approval and written informed consent, 250 term parturients (≥36 weeks gestational age) with body mass index 18.5–30 kg/m2, and scheduled for elective caesarean delivery were included in this study. The parturients were instructed to follow standard fasting guidelines. In the preoperative area, ultrasonographic examinations were performed 15 min before the scheduled time of the caesarean section. The primary outcome was the qualitative assessment (grade 0–2) of the gastric antrum, and the secondary outcome was the quantitative assessment (antral cross-sectional area [CSA]) of gastric antrum in supine and right lateral decubitus (RLD) position. Data analysis was done using Statistical Package for Social Sciences Software (version 19).Results:Among the 234 parturients who completed the study, 191 exhibited grade 0 antrum, 42 had grade 1 antrum, and one parturient had grade 2 antrum. Overall, 83% of participants had an antral CSA ≤4.25 cm2 [95% confidence interval (CI), 2.52–5.67 cm2] in the RLD position, equivalent to an estimated gastric volume of ≤43 ml (95% CI, 32–68 mL) or ≤1.5 ml/kg (95% CI, 0.49–1.23 ml/kg).Conclusion:Majority of fasted term parturients scheduled for elective caesarean section had a grade 1 gastric antrum on bedside USG. This study also establishes cutoff values of antral CSA and gastric volume in both supine and RLD position for fasted term parturients.

Comparison of ultrasound-guided residual gastric volume measurement between diabetic and non-diabetic patients scheduled for elective surgery under general anesthesia.

ABSTRACTBackground and Aims:The presence of gastric content increases the risk of aspiration during general anesthesia. Diabetic patients have delayed gastric emptying; however, despite adequate fasting because of diabetic gastroparesis these patients have a high risk of aspiration. This study aimed to compare ultrasound-guided measurement of residual gastric volume between diabetic and non-diabetic patients scheduled for elective surgery under general anesthesia.Methods:This prospective observational study included 80 patients divided into two groups of 40 diabetic patients with a minimum of 8 years history of diabetes and 40 nondiabetic patients aged >18 years, American Society of Anesthesiologists’ physical status I–II kept with similar fasting intervals. Before induction of general anesthesia, gastric ultrasound was performed using standard gastric scanning protocol to measure craniocaudal (CC) and anteroposterior (AP) diameters followed by calculation of antral cross-sectional area (CSA) and gastric volume in semi-sitting (SS) and right lateral decubitus (RLD) position using curved array probe. The gastric antrum volume (GV) was classified as Grade 0, 1, or 2, and risk stratification for aspiration was done. The nasogastric tube was inserted after induction of anesthesia to aspirate and compare the gastric content.Results:In the semi-sitting position, the mean CC and AP diameters were 16.38 ± 3.31 mm and 10.1 ± 2.53 mm in the non-diabetic group and 25.19 ± 4.08 mm and 15.8 ± 3.51 mm in the diabetic group, respectively. In RLD, CC was 1.91 ± 0.38 cm and AP was 1.19 ± 0.34 cm in the non-diabetic group as compared to the CC of 2.78 ± 0.4 cm and AP of 1.81 ± 0.39 cm in the diabetic group. The calculated CSA of 318.23 ± 97.14 mm2 and 4 ± 1.1 cm2 in diabetic were significantly higher than 133.12 ± 58.56 mm2 and 1.83 ± 0.83 cm2 of non-diabetic, in SS (p < 0.0001) and RLD (p < 0.0001) positions, respectively. The GV of 15.48 ± 11.18 ml in the diabetic group was significantly higher than (-) 9.77 ± 18.56 ml in the non-diabetic group (p < 0.0001). Despite the differences in CSA and GV between diabetic and non-diabetic groups, both groups showed a low gastric residual volume (<1.5 ml/kg). The gastric tube aspirate in the non-diabetic and diabetic groups was 0.3 ± 0.78 ml and 1.24 ± 1.46 ml, respectively, and was statistically significant (p = 0.0006).Conclusion:Patients with long-standing diabetes showed higher gastric residual and antral CSA when compared with non-diabetic patients. The clinical significance of these findings needs further evidence for the formulation of specific guidelines for diabetic patients.

Gastric emptying of preoperative carbohydrate in elderly assessed using gastric ultrasonography: A randomized controlled study.

Background:Preoperative carbohydrate loading enhances postoperative recovery and reduces patient discomfort. However, gastric emptying of liquids can be delayed in elderly populations. Therefore, this study aimed to evaluate the gastric emptying of 400 mL of a carbohydrate drink ingested 2 hours before surgery in elderly patients.Methods:In this prospective, randomized controlled study, patients aged >65 years were allocated to either fast from midnight (nil per os [NPO] group, n = 29) or drink 400 mL of a carbohydrate drink 2 hours before surgery (carbohydrate group, n = 29). The gastric antrum was assessed using ultrasonography in the supine position, followed by the right lateral decubitus (RLD) position. The gastric antrum was graded as grade 0 (fluid not seen in both positions), grade 1 (fluid only seen in the RLD position), and grade 2 (fluid seen in both positions). The gastric antral cross-sectional area (CSA) and aspirated residual gastric volume were measured.Results:In 58 patients, the incidence of grade 2 stomach was 13.8% in NPO group and 17.2% in carbohydrate group (P = .790). The gastric antral CSA in the supine position was larger in carbohydrate group than in NPO group (4.42 [3.72–5.18] cm2 vs 5.31 [4.35–6.92] cm2, P = .018). The gastric antral CSA in the RLD position was not different in NPO and carbohydrate groups (P = .120). There was no difference in gastric volume (2 [0–7.5] vs 3 [0–13.4], P = .331) in NPO group versus carbohydrate group.Conclusion:The incidence of grade 2 stomach was not different between NPO group and carbohydrate group in elderly patients.

The Effect of Body Posture on Resting-State Functional Connectivity.

Introduction: An important but under-investigated confound of functional magnetic resonance imaging (fMRI) is body posture. Although it is well established that body position changes cerebral blood flow, the amount of cerebrospinal fluid in the brain, intracranial pressure, and even the firing rate of certain cell types, there is currently no study that directly examines its effect on fMRI measurements. Moreover, fMRI is typically done in a supine position, which often does not correspond to how these processes are performed in everyday settings. Methods: In this study, 20 healthy adults underwent resting-state fMRI under three body positions: supine, right lateral decubitus (RLD), and left lateral decubitus (LLD). We first investigated whether there were differences in overall organization of whole-brain connectivity between conditions using graph theory. Second, we examined whether functional connectivity of two most studied default mode network (DMN) seeds to the rest of the brain was altered as a function of body position. Results: Nonparametric statistical analyses revealed that global network measures differed among conditions, with the supine and LLD showing identical results which differed when compared to the RLD. There was decreased connectivity for DMN seeds in the RLD condition compared to the supine and LLD, but there were no significant differences between the latter two conditions. Discussion: Potential mechanisms underlying these alterations include gravity, changes in physiology, and body anatomy. Our results suggest that, compared to supine and LLD, the RLD position leads to changes in whole-brain and DMN connectivity. Finally, depending on the research question, combining imaging modalities that allow for more naturalistic settings provides a better understanding of certain phenomena. Impact statement Functional connectivity is sensitive to several confounds, including motion, heart rate, and respiration. Body posture is also an important but under-investigated confound. In this study, healthy adults were scanned in three different positions to investigate whether posture results in changes in connectivity. We found that connectivity was identical if participants were facing up or lying on their left, but it was altered when they were lying on their right. Results suggest that posture can lead to connectivity changes and, in some cases, the combined use of functional magnetic resonance imaging with other techniques might provide a better understanding of the phenomenon of interest.

RETRACTED ARTICLE: Routine point-of-care ultrasound (POCUS) assessment of gastric antral content in traumatic emergency surgical patients for prevention of aspiration pneumonitis: an observational clinical trial

BackgroundPolytrauma patients are at a higher risk of delayed gastric emptying. To assess the gastric volume, a reliable diagnostic tool is needed to prevent the occurrence of aspiration pneumonia, which remains a serious complication associated with anesthesia. Gastric antral ultrasound can provide reliable information about the size of the gastric antrum in traumatized patients undergoing emergency surgery.MethodsA prospective observational study of 45 polytrauma patients undergoing emergency surgery under general anesthesia was carried out. Prior to induction of anesthesia in the emergency department, gastric ultrasound was performed for qualitative and quantitative assessment of the gastric antrum in a supine position and right lateral decubitus (RLD) position. This was followed by routine placement of the nasogastric tube to aspirate and calculate the volume of the stomach contents.ResultsOf the 45 polytrauma patients, the risk assessment of aspiration and the anesthesia technique changed in 14 patients (31.1%) after the gastric ultrasound examination.A very good relationship existed between the expected stomach volume at the RLD position and the suction volume in the nasogastric tube. In all cases, no aspirations were documented.ConclusionUltrasound examination of the stomach in polytrauma patients allows assessing the size and type of stomach contents. The data obtained can influence the choice of anesthesia technique and reduce the risk of aspiration pneumonia.Trial registrationThis trial was registered at ClinicalTrials.gov. registry number: NCT04083677 on September 6, 2019.

Changes in the Bronchial Cuff Pressure of Left-Sided Double-Lumen Endotracheal Tube by Lateral Positioning: A Prospective Observational Study.

Proper bronchial cuff pressure (BCP) is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. As positional change during endotracheal tube placement could alter cuff pressure, we aim to evaluate the change in BCP of DLT from the supine to the lateral decubitus position during thoracic surgery. A total of 69 patients aged 18–70 years who underwent elective lung surgery were recruited. BCP was measured at a series of time points in the supine and lateral decubitus positions after confirming the DLT placement. The primary outcome was change in the initial established BCP (BCPi), which is the maximum pressure at which the BCP did not exceed 40 cmH2O without air leak in the supine position, after lateral decubitus positioning. As the primary outcome, the BCPi increased from 25.4 ± 9.0 cmH2O in the supine position to 29.1 ± 12.2 cmH2O in the lateral decubitus position (p < 0.001). Out of the 69 participants, 43 and 26 patients underwent surgery in the left-lateral decubitus position (LLD group) and the right-lateral decubitus position (RLD group) respectively. In the LLD group, the BCPi increased significantly (p < 0.001) after lateral positioning and the beginning of surgery and the difference value, ∆BCPi, from supine to lateral position was significantly higher in the LLD group than in the RLD group (p = 0.034). Positional change from supine to lateral decubitus could increase the BCPi of DLT and the increase was significantly greater in LLD that in RLD.

Ultrasound assessment of gastric volumes of thick fluids: Validating a prediction model.

Enteral nutrition is essential in the treatment of critically ill patients. Current methods to monitor enteral nutrition such as aspiration of residual volume may be inaccurate. Gastric ultrasonography estimates total gastric fluid volume using the Perlas model, but this model is validated for clear fluids only, and its accuracy for measuring thick fluids is unknown. The primary aim of this study was to evaluate the Perlas model for gastric volume estimation of enteral nutrition, a thick fluid product. A single-centre, single blinded, randomised controlled study. Single university hospital, from May to July 2019. Seventy-two healthy fasted volunteers were randomly allocated to different fluid volume groups. Participants randomly ingested predetermined volumes between 50 and 400 ml of a feeding-drink (Nutricia Nutridrink). Following a standardised gastric ultrasound scanning protocol, a blinded sonographer measured the antral cross-sectional area in the supine and right-lateral decubitus positions. Measurements were performed at baseline, 5 min postingestion and 20 min postingestion. Gastric volumes were predicted using the previously established Perlas model and compared with total gastric fluid volumes after ingestion of the study drink. The Perlas model underestimated the volume of thick gastric fluid and yielded a suboptimal fit for our data. However, antral cross-sectional area and total gastric thick fluid volumes were significantly correlated (Pearson's correlation coefficient 0.73, P < 0.01). A new model was fitted to predict gastric volumes of thick fluids, using the antral cross-sectional area (cm2) in the right-lateral decubitus position: Volume (ml) = 79.38 + 13.32 x right-lateral cross-sectional area. The Perlas model for clear gastric fluid volume estimation is suboptimal for thick fluid volume assessment and an alternative model is presented. Netherlands Trial Register Trial NL7677, Registration date: 16 April 2019; https://www.trialregister.nl/trial/7677.

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

Background and Aims:Gastroparesis despite standard fasting in diabetic patients may increase the aspiration risk. This study aimed to compare fasting gastric volume (GV) of diabetic with non-diabetic patients scheduled for elective surgery using USG.Methods:This prospective observational study included 53 diabetic and 50 non-diabetic patients aged >18 years, American Society of Anesthesiologists' physical status I-III having similar fasting intervals. Before induction, using standard gastric scanning protocol, qualitative and quantitative assessments of gastric antrum in supine and right lateral decubitus (RLD) positions were performed with a curved array probe. USG grade, cross-sectional area (CSA) of the antrum and GV were calculated. The gastric antrum was classified as Grade 0, 1 or 2, signifying empty antrum, fluid in RLD position only and antral fluid in both supine and RLD positions, respectively.Results:In supine position, CC and AP diameters were 1.96 ± 0.41 cm and 0.9 ± 0.57 cm in control group and 2.28 ± 0.50 cm and 1.39 ± 0.44 cm in diabetic group, respectively. In RLD, CC was 2.28 ± 0.57 cm and AP was 1.24 ± 0.42 cm in control group as compared to CC 2.54 ± 0.56 cm and AP 1.82 ± 0.56 cm in diabetic group. The CSA of 2.57 ± 1.19 cm2 and 3.73 ± 1.61 cm2 in diabetic were significantly higher (P = 0.001) than 1.41 ± 0.55 cm2 and 2.30 ± 1.18 cm2 of control, in supine and RLD positions, respectively. GV was 4.20 ± 22.26 ml in control group and 9.15 ± 25.70 ml in diabetic group.Conclusion:Diabetic patients have higher gastric antral cross-sectional area and gastric volumes as observed by gastric ultrasound than the non-diabetic patients.

Does the hip positioning matter for oblique lumbar interbody fusion approach? A morphometric study.

To evaluate whether left hip positioning widened the access corridor using oblique lateral interbody fusion (OLIF) approach during right lateral decubitus (RLD). Ten healthy adult volunteers underwent a T2 lumbosacral MRI (1.5T) in the supine position, RLD position with left hip in extension and then in flexion. L2-L3 to L5-S1 disc spaces were identified. At each level, left psoas surface (in cm2), access corridor (in mm) and vessel movement were calculated in the three positions. Paired t test was used for comparison. The mean surface of the left psoas ranged from 7.83 to 17.19cm2 in the three positions (p>0.05). From L2-3 to L4-5, in RLD, when the left hip shifted from extension to flexion, nor the access corridor nor vessel movements were significantly different. When the volunteers shifted from supine to RLD position with hip in extension, arteries moved 3.66-5.61mm to the right (p<0.05 at L2-3, L3-4 and L5-S1), while the venous structures moved 0.92-4.96mm (p<0.05 at L2-3) to the right. When the position shifted from supine to RLD with hip in flexion, the arterial structures moved 0.47-4.88mm (p<0.05 at L2-3 and L3-4) to the right, while the venous structures moved -0.94 to 4.13mm (p<0.05 at L2-3 and L3-4) to the right. Hip positioning was not associated with a significant widening of the surgical corridor. To perform OLIF, we advocate for RLD position with left hip in extension to move away the vascular structures and reduce the psoas volume. These slides can be retrieved under Electronic Supplementary Material.

Serial echocardiographic changes with different body positions and sleeping side preference in heart failure patients.

The sleeping position plays an important role in overall health in both healthy individuals and heart failure (HF) patients, which complain of increasing dyspnea when adopting left lateral decubitus position (LLDP) that improves when turning over to the right lateral decubitus position (RLDP). Several theories have been proposed to explain this preference of HF patients; however, the underlying mechanisms remain unclear. We evaluated consecutive dilated cardiomyopathy (DCMP) patients with regard to whether they had a sleeping position preference and analyzed early and late left ventricular filling velocities, tissue Doppler recordings, tricuspid annular plane systolic excursion (TAPSE), and left ventricular outflow tract time-velocity integral (LVOT-TVI). Baseline echocardiographic parameters were obtained first by LLDP, followed by the supine position (SP) and finally RLDP in each position for 10minutes to ensure a stabilized hemodynamic milieu. A total of 26 DCMP patients were included in this study and a 78 echocardiographic examination performed. We detected that many HF patients preferred the right lateral decubitus sleeping position (RLDSP, 54%) and avoided from the left lateral decubitus sleeping position (LLDSP, 40%); the echocardiographic LVOT TVI and TAPSE parameters were statistically higher in RLDP compared to SP and LLDP. The echocardiographic LVOT TVI and TAPSE values as functional parameters of left and right ventricular function change with body position, and these hemodynamic changes may explain why HF patients willingly adopt RLDSP.

PP-449 - Serial Echocardiographic Changes With Different Body Positions and Sleeping Side Preference in Heart Failure Patients

Background: The sleeping position plays an important role in overall health in both healthy individuals and heart failure (HF) patients, which complaint of increasing dyspnea when adopting left lateral decubitus position (LLDP) that improves when turning over to the right lateral decubitus position (RLDP). Several theories have been proposed to explain this preference of HF patients; however, the underlying mechanisms remain unclear.