Ventricular flow analysis and its association with exertional capacity in repaired tetralogy of Fallot: 4D flow cardiovascular magnetic resonance study

Background Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) allows quantification of biventricular blood flow by flow components and kinetic energy (KE) analyses. However, it remains unclear whether 4D flow parameters can predict cardiopulmonary exercise testing (CPET) as a clinical outcome in repaired tetralogy of Fallot (rTOF). Current study aimed to (1) compare 4D flow CMR parameters in rTOF with age- and gender-matched healthy controls, (2) investigate associations of 4D flow parameters with functional and volumetric right ventricular (RV) remodelling markers, and CPET outcome. Methods Sixty-three rTOF patients (14 paediatric, 49 adult; 30 ± 15 years; 29 M) and 63 age- and gender-matched healthy controls (14 paediatric, 49 adult; 31 ± 15 years) were prospectively recruited at four centers. All underwent cine and 4D flow CMR, and all adults performed standardized CPET same day or within one week of CMR. RV remodelling index was calculated as the ratio of RV to left ventricular (LV) end-diastolic volumes. Four flow components were analyzed: direct flow, retained inflow, delayed ejection flow and residual volume. Additionally, three phasic KE parameters normalized to end-diastolic volume (KEiEDV), were analyzed for both LV and RV: peak systolic, average systolic and peak E-wave. Results In comparisons of rTOF vs. healthy controls, median LV retained inflow (18% vs. 16%, P = 0.005) and median peak E-wave KEiEDV (34.9 µJ/ml vs. 29.2 µJ/ml, P = 0.006) were higher in rTOF; median RV direct flow was lower in rTOF (25% vs. 35%, P < 0.001); median RV delayed ejection flow (21% vs. 17%, P < 0.001) and residual volume (39% vs. 31%, P < 0.001) were both greater in rTOF. RV KEiEDV parameters were all higher in rTOF than healthy controls (all P < 0.001). On multivariate analysis, RV direct flow was an independent predictor of RV function and CPET outcome. RV direct flow and RV peak E-wave KEiEDV were independent predictors of RV remodelling index. Conclusions In this multi-scanner multicenter 4D flow CMR study, reduced RV direct flow was independently associated with RV dysfunction, remodelling and, to a lesser extent, exercise intolerance in rTOF patients. This supports its utility as an imaging parameter for monitoring disease progression and therapeutic response in rTOF. Clinical Trial Registrationhttps://www.clinicaltrials.gov. Unique identifier: NCT03217240.

Estimating the time point for nutritional failure in patients suffering from acute brain attacks in the intensive care unit

Background: Severe brain attack patients demonstrate hypermetabolic state and gastrointestinal dysfunction, leading to faster onset of nutritional failure. Aim: To estimate the time point where the development of nutritional failure is more probable among patients with acute brain attacks in the intensive care unit (ICU). Methods: Direct bedside observation for selected nutritional parameters was performed. When enteral nutrition was initiated, observation was performed at five points over 9 days. Findings: 84 patients with 55% mortality risk and on mechanical ventilation were included. Over the observation period, gastric residual volume increased (144 ml vs 196 ml), body weight decreased (79.4 kg vs 74.3 kg), and serum albumin reduced (3.6 g/dl to 3.1 g/dl). Caloric attainment and malnutrition score deteriorated, and feeding-related complications increased. Nutritional failure was evidently prevalent between the third and fifth day of observation. Conclusion: An earlier period of enteral nutrition entails higher probability of nutritional failure among severe brain attack patients in the ICU.

FLGS-02. What is the role of intraoperative MRI when performing a high-grade glioma resection using 5-ALA? A single center series reporting extent of resection of contrast-enhancing tumor and FLAIR signal abnormality with clinical outcomes

OBJECTIVE Use of intraoperative MRI (iMRI) and 5-ALA together is poorly investigated although both appear individually superior to standard resection alone in meta-analyses. METHODS We identified 54 patients who underwent 5-ALA guided resection of an intracranial high-grade glioma. Intraoperative ultrasound and frameless stereotactic neuronavigation with tractography were used in all cases. iMRI was selectively used in 33 cases. MRI scans were used to measure extent of resection (EOR) of T1-weighted contrast enhancing (T1WCE) tumor and FLAIR signal abnormality. Clinical data were collected prospectively and survival data retrospectively. RESULTS The mean EOR of T1WCE tumor was 93.7% (range 38 – 100%) with mean residual volume of 2.2 cc. The mean EOR of FLAIR signal abnormality was 59% (range 15–100%) with mean residual volume of 35.7 cc. Compared to using 5-ALA alone, using iMRI+5-ALA did not reduce the volume of residual T1WCE tumor (Mann-Whitney U, p = 0.557) and no more patients achieved complete resection (14/21 vs. 24/33, Chi-Square, p = 0.634). The volume of residual FLAIR signal abnormality was no different (Mann-Whitney U, p= 0.081) but more patients in the 5-ALA+iMRI group achieved resection of &gt;53.21% of the FLAIR signal abnormality, which is known to be a predictor of improved prognosis (20/31 vs 5/21, Chi-Square, p = 0.004*). There was no difference in new neurological deficits at 30 days (Fisher’s exact test, p=0.549). Median OS was 14.3 months and median PFS was 5.2 months. There were no significant differences in OS or PFS between patients operated with iMRI in addition to 5-ALA. CONCLUSIONS 5-ALA and iMRI both assist in safely maximizing EOR when combined with adjuncts such as awake craniotomy and cortical/subcortical mapping. The role and interaction of these two technologies needs further study to understand whether they are additive and what their influence on clinical outcomes is.

ITVT-04. Management of intraoperative technological advances [intraoperative MRI, neuronavigation system using PET, and 5-aminolevulinic acid (5-ALA)–induced fluorescence image-guided surgery] for glioblastoma

OBJECTIVE The maximum resection of Glioblastoma (GBM) is the standard therapy and is expected to improve prognosis. Image-guided surgery using a neuronavigation system is the standard technique for glioma. However, due to the brain shift during surgery, intraoperative technologies, such as 5-ALA fluorescence and intraoperative MRI (IoMRI), are employed. Radiotracers are used during positron emission tomography (PET) for metabolic imaging and assist the evaluation of glioma metabolism. We compared the effectiveness of these intraoperative technologies. METHODS Between January 2016 and May 2021, 52 patients with gliomas underwent IoMRI. 21 patients were selected for 5-ALA fluorescence-guided resection of GBM and underwent multiple PET studies (MET, FLT, and FMISO). We graded fluorescence level as strong, vague, or none. Following tumor resection, we identified the fluorescence level and evaluated the residual volume of gadolinium-enhanced T1WI (T1-Gd) on IoMRI and at each PET study. After calculating the extent of resection (EOR) for T1-Gd, we compared the residual volume on T1-Gd for IoMRI and each PET study, between EOR ≥ 93% and EOR &lt; 93%. RESULTS We detected strong 5-ALA fluorescence during induction and before tumor resection in all 21 (100%) patients with a newly-diagnosed and histopathologically-confirmed GBM. Following tumor resection, we noted an EOR ≥ 93% for T1-Gd in 12 cases (vague, 4; none, 8) and an EOR &lt; 93% for T1-Gd in 9 cases (vague, 5; none, 4). The compared median residual volume (mL) with no fluorescence between EOR ≥ 93% and EOR &lt; 93% for T1-Gd were T1-Gd (0.22, 0.74), MET (0.29, 3.31), FLT (0.24, 1.77), and FMISO (0.22, 1.02). CONCLUSIONS GBM cells are difficult to distinguish in cases without 5-ALA fluorescence. For cases without 5-ALA fluorescence, we were able to maximize the resection of GBM by extracting the area of MET accumulation.

Preventive Strategies for Feeding Intolerance in Patients with Severe Traumatic Brain Injury in China: An Online Cross-Sectional Survey

Background The application of preventive strategies for feeding intolerance in severe traumatic brain injury (STBI) patients is discrepant among different hospitals. We aim to investigate the application status of preventive measures of feeding intolerance in China. Method A cross-sectional study was carried out among 996 clinicians and nurses working in intensive care units of 89 hospitals in China (response rate of 89.81%). Data were collected by means of an online survey. Descriptive statistics were used to analyze respondents’ characteristics and questionnaire responses. Results Clinicians and nurses usually applied several methods simultaneously to assess gastrointestinal functions and risk of feeding intolerance among STBI patients, including assessment scales, gastrointestinal symptoms, etc. Furthermore, initiating enteral nutrition (EN) within 24-48 hours (61.45%), < 500 ml initial volume of EN solution (50.00%), using non-nutritional preparations as initial EN formula (65.56%), nasogastric tube EN (91.16%), continuous feeding by pump (72.89%), 30°-45° of head-of-bed elevation during EN (89.46%), monitoring gastric residual volume by syringe (93.67%), assessing gastric residual volume every 4 hours (51.51%), EN solution temperature of 38℃-40℃ (65.46%), prokinetic agents (73.29%), enema (73.59%), probiotics (79.01%), and antacid agents (84.13%), were mostly applied strategies in clinical practice for preventing feeding intolerance among STBI patients. Conclusions The data from the survey showed that medical staffs in China are closely concerned with the gastrointestinal functions of STBI patients and EN delivery protocol, and have a positive attitude towards preventive strategies for feeding intolerance. Meanwhile, there are still many points need to be paid attention to and solved, and researchers, clinicians, nurses and dietitians should strengthen the cooperation to explore more valuable preventive strategies for feeding intolerance in STBI patients.

Sonographic Evaluation of Gastric Residual Volume during Enteral Nutrition in Critically Ill Patients Using a Miniaturized Ultrasound Device

Background: To assess the risk of aspiration, nutrient tolerance, and gastric emptying of patients in ICUs, gastric ultrasound can provide information about the gastric contents. Using established formulas, the gastric residual volume (GRV) can be calculated in a standardized way by measuring the gastric antrum. The purpose of this study was to determine the GRV in a cohort of enterally fed patients using a miniaturized ultrasound device to achieve knowledge about feasibility and the GRV over time during the ICU stay. The findings could contribute to the optimization of enteral nutrition (EN) therapy. Methods: A total of 217 ultrasound examinations with 3 measurements each (651 measurements in total) were performed twice daily (morning and evening) in a longitudinal observational study on 18 patients with EN in the interdisciplinary surgical ICU of Saarland University Medical Center. The measured values of the GRV were analyzed in relation to the clinical course, the nutrition, and other parameters. Results: Measurements could be performed without interrupting the flow of clinical care and without pausing EN. The GRV was significantly larger with sparsely auscultated bowel sounds than with normal and excited bowel sounds (p < 0.01). Furthermore, a significantly larger GRV was present when using a high-caloric/low-protein nutritional product compared to an isocaloric product (p = 0.02). The GRV at the morning and evening measurements showed no circadian rhythm. When comparing the first and last ultrasound examination of each patient, there was a tendency towards an increased GRV (p = 0.07). Conclusion: The GRV measured by miniaturized ultrasound devices can provide important information about ICU patients without restricting treatment procedures in the ICU. Measurements are possible while EN therapy is ongoing. Further studies are needed to establish gastric ultrasound as a management tool in nutrition therapy.

Comparison of Gastric Residual Volume and pH between Single and Split-Dose Bowel Preparation in Patients Undergoing Esophago-Gastro-Duodenoscopy and Colonoscopy: A Randomized Controlled Trial

Background: Colonoscopy is an effective surveillance for the diagnosis and screening of colorectal cancer (CRC). Prior to the procedure, people would take laxatives for a good visualization of bowel texture. Although a split-dose bowel preparation has become popular, many anesthesiologists are concerned about pulmonary aspiration. Objective: To study the gastric residual volume and pH in patients taking split-dose bowel preparation as compared to those having laxatives on the day before the procedure. Materials and Methods: One hundred patients were randomized equally into two groups, as A for a single-dose, and B for a split-dose regimen. All patients underwent endoscopy under standard anesthetic care. The total gastric residual volume was suctioned, and pH was measured through the endoscope. The surgical team was unaware of the study protocol. The quality of bowel cleansing was assessed by the endoscopist using the Boston Bowel Preparation Scale (BBPS). Results: The bowel cleansing, the latency period, the endoscopist and patients’ satisfaction of single-and split-dose group were 7.06±1.4 and 8.14±1.1, 13.3±1.1 and 4.2±0.4 hours, 62.0% and 94.0%, and 90.0% and 74.0%, respectively. They all showed statistically significant differences between the two groups (p<0.05). Conclusion: The gastric residual volume and pH were not different between the split and single-dose preparations. Therefore, it might not increase the risk of aspiration pneumonitis. However, the split-dose technique was more effective in colon cleansing, patients’ tolerability, acceptability, and compliance than the preparations administered entirely the day or evening before the surgical procedure. Keywords: Gastro-colonoscopy; Single-dose bowel preparation; Split-dose bowel preparation; Gastric residual volume; Anesthesia