Increased blood lactate during enteral nutrition in the critically ill: associations and treatment options.

PURPOSE OF REVIEW: To evaluate the significance of blood lactate increase during enteral nutrition in the critically ill, and to propose diagnostic and therapeutic strategies. RECENT FINDINGS: Acute mesenteric ischemia occurs in approximately 1% of critically ill patients treated with catecholamine. Recent literature suggests that enteral nutrition is a risk factor of acute mesenteric ischemia, in particular in case of low cardiac output, by a mechanism of nonocclusive mesenteric ischemia. The association of clinical, biological, and computed tomography imaging might help to evaluate the reversibility of acute mesenteric ischemia. SUMMARY: As enteral nutrition induces an increased metabolic work of the gut, the inadequation between oxygen delivery and demand exposes the gut to a phenomenon of nonocclusive mesenteric ischemia. Before initiation of enteral nutrition,, and before each increase of the enteral nutrition dose, the risk factors of nonocclusive mesenteric ischemia should be searched in order to prevent it. While under enteral nutrition, increased lactate concentration while receiving enteral nutrition requires the urgent search for nonocclusive mesenteric ischemia, and the adaptation of enteral nutrition (reduction, stop, and/or switch to parenteral nutrition or tolerate early nutrient restriction). Early signs of nonocclusive mesenteric ischemia should be searched in order to allow for a rapid diagnosis, before development of irreversible transmural necrosis. After the diagnosis of acute mesenteric ischemia, improving the balance between oxygen demand and delivery to the gut, evaluating the reversibility of the gut ischemia, and performing urgent resection in case of irreversible transmural necrosis should be the main objectives. After the resolution of acute mesenteric ischemia, the benefit risk analysis of enteral nutrition reintroduction should be evaluated.

The Angers CT Score is a Risk Factor for the Failure of the Conservative Management of Adhesive Small Bowel Obstruction: A Prospective Observational Multicentric Study.

BACKGROUND: Identifying the 30% of adhesive small bowel obstructions (aSBO) for which conservative management will require surgery is essential. The association between the previously described radiological score and failure of the conservative management of aSBO remains to be confirmed in a large prospective multicentric cohort. Our aim was to assess the risk factors of failure of the conservative management of aSBO considering the radiological score. MATERIAL AND METHODS: This prospective observational study took place in 15 French centers over 3 months. Consecutive patients experiencing aSBO with no early surgery were included. The six radiological features from the Angers radiological computed tomography (CT) score were noted (beak sign, closed loop, focal or diffuse intraperitoneal liquid, focal or diffuse mesenteric haziness, focal or diffuse mesenteric liquid, and diameter of the most dilated small bowel loop > 40 mm). RESULTS: Two hundred and seventy nine patients with aSBO were screened. Sixty patients (21.5%) underwent early surgery, and 219 (78.5%) had primary conservative management. In the end, 218 patients were included in the analysis of the risk factors for conservative treatment failure. Among them, 162 (74.3%) had had successful management while for 56 (25.7%) management had failed. In multivariate analysis, a history of surgery was not a significant risk factor for the failure of conservative treatment (OR = 0.11; 95%CI = 0-1.23). A previous episode of aSBO was protective against the failure of conservative treatment (OR = 0.36; 95%CI = 0.15-0.85) and an Angers CT score ≥ 5 as the only individual risk factor (OR = 2.39; 95%CI = 1.01-5.69). CONCLUSION: The radiological score of aSBO is a promising tool in improving the management of aSBO patients. A first episode of aSBO and/or a radiological score ≥5 should lead physicians to consider early surgical management.

Early Prediction of Acute Biliary Pancreatitis Using Clinical and Abdominal CT Features.

Background Assessment of the biliary origin of acute pancreatitis (AP) is crucial because it affects patient treatment to avoid recurrence. Although CT is systematically performed to determine severity in AP, its usefulness in assessing AP biliary origin has not been evaluated. Purpose To assess abdominal CT features associated with acute biliary pancreatitis (ABP) and to evaluate the predictive value of a combination of CT and clinical data for determining a biliary origin in a first episode of AP. Materials and Methods From December 2014 to May 2019, all consecutive patients who presented with a first episode of AP and with at least 6 months of follow-up were retrospectively reviewed. Evidence of gallstones was mandatory for a clinical diagnosis of ABP. Abdominal CT images were reviewed by two abdominal radiologists. Univariable and multivariable statistical analyses were performed, and a nomogram was constructed on the basis of the combination of clinical and CT features. This nomogram was validated in a further independent internal cohort of patients. Results A total of 271 patients (mean age ± standard deviation, 56 years ± 20; 160 men) were evaluated. Of these, 170 (63%) had ABP. At multivariable analysis, age (odds ratio [OR], 1.06; 95% CI: 1.03, 1.09; P < .001), alanine aminotransferase level (OR, 1.00; 95% CI: 1.00, 1.01; P = .009), gallbladder gallstone (OR, 15.59; 95% CI: 4.61, 68.62; P < .001), choledochal ring sign (OR, 5.73; 95% CI: 2.11, 17.05; P < .001), liver spontaneous attenuation (OR, 1.07; 95% CI: 1.04, 1.11; P < .001), and duodenal thickening (OR, 0.17; 95% CI: 0.03, 0.61; P = .01) were independently associated with ABP. The matching nomogram combining both clinical and CT features displayed an area under the curve of 0.94 (95% CI: 0.91, 0.97) in the study sample (n = 271) and 0.91 (95% CI: 0.84, 0.99) in the validation cohort (n = 51). Conclusion Abdominal CT provided useful features for diagnosis of acute biliary pancreatitis (ABP). Combining CT and clinical features in a nomogram showed good diagnostic performance for early diagnosis of ABP. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Chang in this issue.

Preoperative prediction of inadvertent enterotomy during adhesive small bowel obstruction surgery using combination of CT features.

OBJECTIVES: The purpose of this study was to identify the preoperative CT features that are associated with inadvertent enterotomy (IE) during adhesive small bowel obstruction (ASBO) surgery. METHODS: From January 2015 to December 2019, all patients with ASBO who underwent an abdominal CT were reviewed. Abdominal CT were retrospectively reviewed by two radiologists with a consensus read in case of disagreement. IE during ASBO surgery was retrospectively recorded. Univariate and multivariate analyses of CT features associated with IE were performed and a simple CT score was built to stratify the risk of IE. This score was validated in an independent retrospective cohort. Abdominal CT of the validation cohort was reviewed by a third independent reader. RESULTS: Among the 368 patients with ASBO during the study period, 169 were surgically treated, including 129 ASBO for single adhesive band and 40 for matted adhesions. Among these, there were 47 IE. By multivariate analysis, angulation of the transitional zone (OR = 4.19, 95% CI [1.10-18.09]), diffuse intestinal adhesions (OR = 4.87, 95% CI [1.37-19.76]), a fat notch sign (OR = 0.32, 95% CI [0.12-0.85]), and mesenteric haziness (OR = 0.13, 95% CI [0.03-0.48]) were independently associated with inadvertent enterotomy occurrence. The simple CT score built to stratify risk of IE displayed an AUC of 0.85 (95% CI [0.80-0.90]) in the study sample and 0.88 (95% CI [0.80-0.96]) in the validation cohort. CONCLUSION: A simple preoperative CT score is able to inform the surgeon about a high risk of IE and therefore influence the surgical procedure. KEY POINTS: • In this retrospective study of 169 patients undergoing abdominal surgery for adhesive small bowel obstruction, 47 (28%) inadvertent enterotomy occurred. • A simple preoperative CT score enables accurate stratification of inadvertent enterotomy risk (area under the curve 0.85). • By multivariable analysis, diffuse intestinal adhesions and angulation of the transitional zone were predictive of inadvertent enterotomy occurrence.

How artificial intelligence improves radiological interpretation in suspected pulmonary embolism.

OBJECTIVES: To evaluate and compare the diagnostic performances of a commercialized artificial intelligence (AI) algorithm for diagnosing pulmonary embolism (PE) on CT pulmonary angiogram (CTPA) with those of emergency radiologists in routine clinical practice. METHODS: This was an IRB-approved retrospective multicentric study including patients with suspected PE from September to December 2019 (i.e., during a preliminary evaluation period of an approved AI algorithm). CTPA quality and conclusions by emergency radiologists were retrieved from radiological reports. The gold standard was a retrospective review of CTPA, radiological and clinical reports, AI outputs, and patient outcomes. Diagnostic performance metrics for AI and radiologists were assessed in the entire cohort and depending on CTPA quality. RESULTS: Overall, 1202 patients were included (median age: 66.2 years). PE prevalence was 15.8% (190/1202). The AI algorithm detected 219 suspicious PEs, of which 176 were true PEs, including 19 true PEs missed by radiologists. In the cohort, the highest sensitivity and negative predictive values (NPVs) were obtained with AI (92.6% versus 90% and 98.6% versus 98.1%, respectively), while the highest specificity and positive predictive value (PPV) were found with radiologists (99.1% versus 95.8% and 95% versus 80.4%, respectively). Accuracy, specificity, and PPV were significantly higher for radiologists except in subcohorts with poor-to-average injection quality. Radiologists positively evaluated the AI algorithm to improve their diagnostic comfort (55/79 [69.6%]). CONCLUSION: Instead of replacing radiologists, AI for PE detection appears to be a safety net in emergency radiology practice due to high sensitivity and NPV, thereby increasing the self-confidence of radiologists. KEY POINTS: • Both the AI algorithm and emergency radiologists showed excellent performance in diagnosing PE on CTPA (sensitivity and specificity ≥ 90%; accuracy ≥ 95%). • The AI algorithm for PE detection can help increase the sensitivity and NPV of emergency radiologists in clinical practice, especially in cases of poor-to-moderate injection quality. • Emergency radiologists recommended the use of AI for PE detection in satisfaction surveys to increase their confidence and comfort in their final diagnosis.

Post-Transplantation Cytomegalovirus Infection Interplays With the Development of Anastomotic Biliary Strictures After Liver Transplantation.

Background: Anastomotic biliary stricture (ABS) remains the most frequent complication after liver transplantation (LT). This study aimed to identify new anastomotic biliary stricture risk factors, with a specific focus on postoperative events. Additionally, ABS management and impact on patient and graft survival were assessed. Methods: All consecutive patients who underwent LT with duct-to-duct anastomosis between 2010 and 2019 were included. All patients who died within 90 days after LT due to non-ABS-related causes were excluded. Results: Among 240 patients, 65 (27.1%) developed ABS after a median time of 142 days (range, 13-1265). Median follow-up was 49 months (7-126). Upon multivariable analysis, donor BMI (OR=0.509, p = 0.037), post-LT CMV primoinfection (OR = 5.244, p < 0.001) or reactivation (OR = 2.421, p = 0.015) and the occurrence of post-LT anastomotic biliary fistula (OR = 2.691, p = 0.021) were associated with ABS. Anastomotic technical difficulty did not independently impact the risk of ABS (OR = 1.923, p = 0.051). First-line ABS treatment was systematically endoscopic (100%), and required a median of 2 (range, 1-11) procedures per patient. Repeat LT was not required in patients developing ABS. The occurrence of ABS was not associated with overall patient survival (p = 0.912) nor graft survival (p = 0.521). Conclusion: The risk of developing ABS after LT seems driven by the occurrence of postoperative events such as CMV infection and anastomotic fistula. In this regard, the role of CMV prophylaxis warrants further investigations.

Evaluating the Risk of Irreversible Intestinal Necrosis Among Critically Ill Patients With Nonocclusive Mesenteric Ischemia.

INTRODUCTION: To identify factors associated with irreversible transmural necrosis (ITN) among critically ill patients experiencing nonocclusive mesenteric ischemia (NOMI) and to compare the predictive value regarding ITN risk stratification with that of the previously described Clichy score. METHODS: All consecutive patients admitted to the intensive care unit between 2009 and 2019 who underwent exploratory laparotomy for NOMI and who had an available contrast-enhanced computed tomography with at least 1 portal venous phase were evaluated for inclusion. Clinical, laboratory, and radiological variables were collected. ITN was assessed on pathological reports of surgical specimens and/or on laparotomy findings in cases of open-close surgery. Factors associated with ITN were identified by univariate and multivariate analysis to derive a NOMI-ITN score. This score was further compared with the Clichy score. RESULTS: We identified 4 factors associated with ITN in the context of NOMI: absence of bowel enhancement, bowel thinning, plasma bicarbonate concentration ≤15 mmol/L, and prothrombin rate <40%. These factors were included in a new NOMI-ITN score, with 1 point attributed for each variable. ITN was observed in 6%, 38%, 65%, 88%, and 100% of patients with NOMI-ITN score ranging from 0 to 4, respectively. The NOMI-ITN score outperformed the Clichy score for the prediction of ITN (area under the receiver operating characteristics curve 0.882 [95% confidence interval 0.826-0.938] vs 0.674 [95% confidence interval 0.582-0.766], respectively, P < 0.001). DISCUSSION: We propose a new 4-point score aimed at stratifying risk of ITN in patients with NOMI. The Clichy score should be applied to patients with occlusive acute mesenteric ischemia only.

Fluorescence-based pancreas stump perfusion is associated with postoperative acute pancreatitis after pancreatoduodenectomy a prospective cohort study.

BACKGROUND: Postoperative acute pancreatitis (POAP) emerges as a distinct pancreas-specific complication increasing both the risk and the burden of POPF after pancreatoduodenectomy. Among various risk factors, pancreas stump (PS) hypoperfusion might play a role in POAP occurrence but has never been investigated. The current study aimed at evaluating the feasibility of intraoperative fluorescence angiography (IOFA) of the PS using ICG and its association with POAP. METHODS: Consecutive patients who underwent pancreatoduodenectomy for a periampullary tumor with pancreatojejunostomy and PS perfusion assessment using IOFA between January 2020 and November 2020 were prospectively included. Perioperative management and surgical strategy were standardized. IOFA of the pancreas stump was performed before fashioning pancreatojejunostomy. POAP was defined according to the Connor definition and was confirmed upon radiological blind review. Outcomes between patients with normally perfused and hypoperfused PS were compared. POAP was the primary endpoint. RESULTS: Among 30 patients, nine patients (30%) developed POAP according to the Connor definition, and six patients (20%) had CT-confirmed POAP. Upon IOFA, six patients (20%) presented PS hypoperfusion; of which one patient underwent extended pancreatectomy further to the left. PS hypoperfusion was statistically associated with the occurrence of POAP (80% vs. 16%; p = 0.011) and CT-confirmed POAP (60% vs. 12%; p = 0.041). Clinically relevant POPF rate was 40% in case of PS hypoperfusion and 4% in case of normal PS perfusion (p = 0.064). CONCLUSIONS: PS perfusion assessment using IOFA seems safe and reliable to anticipate POAP. PS IOFA could be considered as a potential tool for perioperative assessment of surgical risk after pancreatoduodenectomy.

Diagnostic performance of CT for the detection of transmural bowel necrosis in non-occlusive mesenteric ischemia.

OBJECTIVES: To evaluate the diagnostic performance of CT for transmural necrosis (TN) in non-occlusive mesenteric ischemia (NOMI) according to the bowel segment involved. METHODS: From January 2009 to December 2019, all patients admitted to the intensive care unit (ICU) and requiring laparotomy for NOMI were retrospectively studied. CT had to have been performed within 24 h prior to laparotomy and were reviewed by two abdominal radiologists, with a consensus reading in case of disagreement. A set of CT features of mesenteric ischemia were assessed, separating the stomach, jejunum, ileum, and right (RC) and left colon (LC). Univariate and multivariate analyses were performed to identify features associated with TN. Its influence on overall survival (OS) was assessed. RESULTS: Among 145 patients, 95 (66%) had ≥ 1 bowel segment with TN, including 7 (5%), 31 (21%), 43 (29%), 45 (31%), and 52 (35%) in the stomach, jejunum, ileum, RC, and LC, respectively. Overall inter-reader agreement of CT features was significantly lower in the colon than in the small bowel (0.59 [0.52-0.65] vs 0.74 [0.70-0.77] respectively). The absence of bowel wall enhancement was the only CT feature associated with TN by multivariate analysis, whatever the bowel segment involved. Proximal TN was associated with poorer OS (p < 0.001). CONCLUSIONS: The absence of bowel wall enhancement remains the most consistent CT feature of transmural necrosis, whatever the bowel segment involved in NOMI. Inter-reader agreement of CT features is lower in the colon than in the small bowel. Proximal TN seems to be associated with poorer OS. KEY POINTS: • The absence of bowel wall enhancement is the most consistent CT feature associated with transmural necrosis in NOMI, whatever is the bowel segment involved. • Inter-reader agreement is lower in the colon than in the small bowel in NOMI. • In NOMI, the more proximal the bowel necrosis, the worse the prognosis.

Acute Pulmonary Embolism Associated with COVID-19 Pneumonia Detected with Pulmonary CT Angiography.

Online supplemental material is available for this article.

Transmural Bowel Necrosis From Acute Mesenteric Ischemia and Strangulated Small-Bowel Obstruction: Distinctive CT Features.

OBJECTIVE. The purpose of this study was to assess whether transmural bowel necrosis has distinct CT features based on the three main causes: occlusive acute mesenteric ischemia (AMI), nonocclusive AMI, and strangulated small-bowel obstruction (SBO). MATERIALS AND METHODS. From January 2010 to December 2017, the records of all patients with a pathologic diagnosis of transmural bowel necrosis were extracted from the pathology department database of a university hospital. The inclusion criteria for the study were presence of transmural bowel necrosis at pathologic examination and available contrast-enhanced CT images obtained within the 24 hours before surgery. Seventy-seven patients were finally included. The CT scans were retrospectively independently reviewed by two abdominal radiologists to identify the classic CT findings of transmural bowel necrosis. Statistical analyses were performed. RESULTS. Pneumatosis intestinalis was statistically more frequent in nonocclusive AMI (59%) than in occlusive AMI (29%) and strangulated SBO (7%) (p < 0.01), as were superior mesenteric venous gas (55%, 29%, and 0%; p < 0.01) and portal venous gas (48%, 10%, and 0%; p < 0.01). Decreased or absent bowel wall enhancement was more frequent in AMI than in SBO (nonocclusive AMI, 83%; occlusive AMI, 81%; SBO, 56%; p = 0.02), as was thinned bowel wall (nonocclusive AMI, 52%; occlusive AMI, 48%; SBO, 18%; p = 0.02). Spontaneous hyperattenuation of the bowel wall was more frequent in strangulated SBO (41%) than in nonocclusive AMI (10%) and occlusive AMI (14%) (p < 0.01). CONCLUSION. Transmural bowel necrosis has distinct CT findings according to its three main causes. Occlusive AMI is characterized by an absence of bowel wall enhancement and less mesenteric fat stranding, nonocclusive AMI by a high prevalence of pneumatosis intestinalis and portal venous gas, and strangulated SBO by spontaneous hyperattenuation of the bowel wall and an absence of pneumatosis intestinalis and portal venous gas.

Contrast-Enhanced CT for the Diagnosis of Acute Mesenteric Ischemia.

OBJECTIVE. The purpose of this article is to provide an overview of the diagnostic and prognostic roles of CT in the management of acute mesenteric ischemia. CONCLUSION. Acute mesenteric ischemia is defined as inadequate blood supply to the gastrointestinal tract resulting in ischemic and inflammatory injury. The prognosis is poor without treatment. Contrast-enhanced CT has become the cornerstone of diagnosis to identify features of vascular disorders and of intestinal ischemic injury and to visualize bowel necrosis.

AE hepatic lesions: correlation between calcifications at CT and FDG-PET/CT metabolic activity.

PURPOSE: To correlate the presence of calcifications in alveolar echinococcosis (AE) hepatic lesions to the metabolic activity in 18 fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT). METHODS: Our institutional review board approved this study. 61 patients (29 women, 32 men, aged from 15 to 86 years) were included in the study. Images of FDG-PET/CT were interpreted by two independent nuclear medicine physicians. AE hepatic lesions were classified as AE lesions with or without hypermetabolic activity. The presence of calcifications was assessed on unenhanced CT scans by two independent radiologists blinded with regard to the metabolic activity of the AE hepatic lesions. Every single calcification the size of which was < 3 mm and non-measurable calcifications which were forming areas with a powdery appearance were considered as microcalcifications. All other types of calcifications were reported as macrocalcifications. Statistical analysis was performed and p value < 0.05 was considered as statistically significant. RESULTS: Microcalcifications and macrocalcifications were present at CT in 95% (58/61) AE hepatic lesions and 43% (26/61) AE hepatic lesions, respectively. Hypermetabolic activity was present at FDG-PET/CT in 93% (57/61) AE hepatic lesions. 98% (56/57) of the AE hepatic lesions presenting with hypermetabolic activity at FDG-PET/CT showed microcalcifications at CT (p = 0.01) when only 40% (23/57) showed macrocalcifications at CT (p = 0.3). 100% (23/23) of the AE hepatic lesions with hypermetabolic activity at FDG-PET/CT and macrocalcifications at CT showed also microcalcifications at CT. CONCLUSIONS: Hypermetabolic activity of AE hepatic lesions at FDG-PET/CT is strongly correlated to the presence of microcalcifications at CT, independently of the presence of macrocalcifications.

Correlation between a continent ileocecal valve and CT signs of severity in patients presenting with obstructive colonic cancer.

OBJECTIVE: To study the association of a continent ileocecal valve and the degree of severity of the CT signs in patients presenting with large bowel obstruction due to colonic cancer. PATIENTS AND METHODS: Sixty-six patients undergoing emergency surgery for confirmed obstructive colonic cancer were included. The CT examinations were analyzed without consultation of the surgical results. For each patient, the diameter of the cecum at its widest point and that of the last ileal loop were measured. The ileocecal valve was considered incontinent when there was a distension of the last ileal loop greater than or equal to 25 mm. Below 25 mm, the ileocecal valve was considered continent. The presence of CT signs of severity of the LBO was noted, i.e., intestinal pneumatosis, absence of contrast enhancement of the large bowel wall, defect in the large bowel wall, and presence of extra-digestive air and ascites. RESULTS: Among the 66 patients included, 42 had an incontinent ileocecal valve and 24 had a continental ileocecal valve. There was a statistically significant difference between the two groups in the diametrical measurements of the cecum's widest point (mean diameter measured at 10.3 cm in patients with continent ileocecal valve vs 8.4 cm in patients with incontinent ileocecal valve, P = 0.0023). Patients with a continent valve had statistically higher rates of CT severity (79% vs 40%, P < 0.005). Perforation of the cecum remained rare (8%) and was only observed in patients with continent ileocecal valve in our series. CONCLUSION: Continence of the ileocecal valve appears to be statistically correlated both with cecum distension and the presence of CT signs of severity in patients with obstructive colonic cancer. As such, its presence must be retained as a risk factor for a pejorative evolution of this type of LBO and must be specified in the CT report of these patients.