Gastrointestinal Biomarkers and Their Association with Feeding in the First Five Days of Pediatric Critical Illness

OBJECTIVES

Predicting the patients' tolerance to enteral nutrition (EN) would help clinicians optimize individual nutritional intake. This study investigated the course of several gastrointestinal (GI) biomarkers and their association with EN advancement (ENA) longitudinally during pediatric intensive care unit (PICU) admission.

METHODS

This is a secondary analysis of the Early versus Late Parenteral Nutrition in the Pediatric Intensive Care Unit randomized controlled trial. EN was started early and increased gradually. The cholecystokinin (CCK), leptin, glucagon, intestinal fatty acid-binding protein 2 (I-FABP2), and citrulline plasma concentrations were measured upon PICU admission, day 3 and day 5. ENA was defined as kcal EN provided as % of predicted resting energy expenditure. The course of the biomarkers and ENA was examined in patients with samples on all time points using Friedman and Wilcoxon signed-rank tests. The association of ENA with the biomarkers was examined using a 2-part mixed-effects model with data of the complete population, adjusted for possible confounders.

RESULTS

For 172 patients, median age 8.6 years (first quartile; third quartile: 4.2; 13.4), samples were available, of which 55 had samples on all time points. The median ENA was 0 (0; 0) on admission, 14.5 (0.0; 43.8) on day 3, and 28.0 (7.6; 94.8) on day 5. During PICU stay, CCK and I-FABP2 concentrations decreased significantly, whereas glucagon concentrations increased significantly, and leptin and citrulline remained stable. None of the biomarkers was longitudinally associated with ENA.

CONCLUSIONS

Based on the current evidence, CCK, leptin, glucagon, I-FABP2, and citrulline appear to have no added value in predicting ENA in the first 5 days of pediatric critical illness.

Nutrition and autophagy deficiency in critical illness

PURPOSE OF REVIEW

Critical illness imposes a severe insult on the body, with various stressors triggering pronounced cell damage. This compromises cellular function, leading to a high risk of multiple organ failure. Autophagy can remove damaged molecules and organelles but appears insufficiently activated during critical illness. This review discusses insight into the role of autophagy in critical illness and the involvement of artificial feeding in insufficient autophagy activation in critical illness.

RECENT FINDINGS

Animal studies manipulating autophagy have shown its protective effects against kidney, lung, liver, and intestinal injury after several critical insults. Autophagy activation also protected peripheral, respiratory, and cardiac muscle function, despite aggravated muscle atrophy. Its role in acute brain injury is more equivocal. Animal and patient studies showed that artificial feeding suppressed autophagy activation in critical illness, particularly with high protein/amino acid doses. Feeding-suppressed autophagy may explain short and long-term harm by early enhanced calorie/protein feeding in large randomized controlled trials.

SUMMARY

Insufficient autophagy during critical illness is at least partly explained by feeding-induced suppression. This may explain why early enhanced nutrition failed to benefit critically ill patients or even induced harm. Safe, specific activation of autophagy avoiding prolonged starvation opens perspectives for improving outcomes of critical illness.

C-reactive protein rise in response to macronutrient deficit early in critical illness: sign of inflammation or mediator of infection prevention and recovery

PURPOSE

Withholding parenteral nutrition (PN) early in critical illness, late-PN, has shown to prevent infections despite a higher peak C-reactive protein (CRP). We investigated whether the accentuated CRP rise was caused by a systemic inflammatory effect mediated by cytokines or arose as a consequence of the different feeding regimens, and whether it related to improved outcome with late-PN.

METHODS

This secondary analysis of the EPaNIC-RCT first investigated, with multivariable linear regression analyses, determinants of late-PN-induced CRP rise and its association with cytokine responses (IL-6, IL-10, TNF-α) in matched early-PN and late-PN patients requiring intensive care for ≥ 3 days. Secondly, with multivariable logistic regression and Cox proportional-hazard analyses, we investigated whether late-PN-induced CRP rises mediated infection prevention and enhanced recovery or reflected an adverse effect counteracting such benefits of late-PN.

RESULTS

CRP peaked on day 3, higher with late-PN [216(152-274)mg/l] (n = 946) than with early-PN [181(122-239)mg/l] (n = 946) (p < 0.0001). Independent determinants of higher CRP rise were lower carbohydrate and protein intakes (p ≤ 0.04) with late-PN, besides higher blood glucose and serum insulin concentrations (p ≤ 0.01). Late-PN did not affect cytokines. Higher CRP rises were independently associated with more infections and lower likelihood of early ICU discharge (p ≤ 0.002), and the effect size of late-PN versus early-PN on these outcomes was increased rather than reduced after adjusting for CRP rise, not confirming a mediating role.

CONCLUSIONS

The higher CRP rise with late-PN, explained by the early macronutrient deficits, did not relate to cytokine responses and thus did not reflect more systemic inflammation. Instead of mediating clinical benefit on infection or recovery, the accentuated CRP rise appeared an adverse effect reducing such late-PN benefits.

Monocyte-driven atypical cytokine storm and aberrant neutrophil activation as key mediators of COVID-19 disease severity

Epidemiological and clinical reports indicate that SARS-CoV-2 virulence hinges upon the triggering of an aberrant host immune response, more so than on direct virus-induced cellular damage. To elucidate the immunopathology underlying COVID-19 severity, we perform cytokine and multiplex immune profiling in COVID-19 patients. We show that hypercytokinemia in COVID-19 differs from the interferon-gamma-driven cytokine storm in macrophage activation syndrome, and is more pronounced in critical versus mild-moderate COVID-19. Systems modelling of cytokine levels paired with deep-immune profiling shows that classical monocytes drive this hyper-inflammatory phenotype and that a reduction in T-lymphocytes correlates with disease severity, with CD8+ cells being disproportionately affected. Antigen presenting machinery expression is also reduced in critical disease. Furthermore, we report that neutrophils contribute to disease severity and local tissue damage by amplification of hypercytokinemia and the formation of neutrophil extracellular traps. Together our findings suggest a myeloid-driven immunopathology, in which hyperactivated neutrophils and an ineffective adaptive immune system act as mediators of COVID-19 disease severity.

Prevalence of hypophosphatemia in the ICU - Results of an international one-day point prevalence survey

BACKGROUND & AIMS

Hypophosphatemia (HypoP) is associated with organ dysfunction and mortality. Despite its potential severe consequences, HypoP remains poorly characterized in terms of real prevalence and timing of onset. The primary objective was to determine the prevalence of HypoP defined as blood phosphate <0.8 and < 0.65 mmol/l on one particular day at international level.

METHODS

One-day point prevalence survey conducted by the Section of Metabolism, Endocrinology and Nutrition (MEN) of the European Society of Intensive Care Medicine (ESICM) during week 11-2020.

RESULTS

In total, 56 adult and 4 paediatric ICUs, from 22 countries participated: 41 ICUs were mixed medico surgical, the 19 others being cardiac, medical or surgical. Phosphate measurements were performed daily in 21 ICUs, and 1-3 times per week in 39 ICUs. On D-Day 909 patients (883 adults) were present and 668/883 (75.7%) had serum/plasma phosphate determined, revealing a HypoP in 103 (15.4%) patients aged 62 [18 to 85] years. Of those, 49 patients presented phosphate <0.65 mmol/l: cases of hypophosphatemia were detected at any time of patient's ICU stay. No HypoP was observed in children. A treatment protocol existed only in 41.1% of adult ICUs, independently of ICU type, or size. Only 41/98 of the HypoP patients (29/41 of patients with phosphate <0.65 mmol/l) were receiving phosphate.

CONCLUSION

HypoP is present at least in 15.4% of ICU patients, and may occur at any time during the ICU stay. The absence of phosphate repletion protocols in 60% of participating ICUs is an unexpected finding, and confirms the necessity for the development of ICU phosphate protocols and guidelines.

CLINICALTRIALS IDENTIFIER

NCT04201899.

OR16-4 The Growth Hormone Axis in Relation to Muscle Weakness in the ICU: Effect of Early Macronutrient Deficit

Background: The activity of the growth hormone (GH) axis is altered by critical illness. In the acute phase, GH resistance, as reflected by increased GH and decreased insulin-like growth factor-I (IGF-I), mimics fasting-induced changes in health. Although early full feeding in ICU has long been assumed to prevent muscle wasting and weakness, the EPaNIC RCT observed fewer complications and faster recovery with accepting the macronutrient deficit in the first ICU week, as compared with early full feeding, including less acquired muscle weakness [1,2]. We previously observed that accepting the early macronutrient deficit attenuated rather than aggravated the rise in GH as compared with early full feeding [3]. We have now further characterized its impact on the GH axis, in relation to the risk of acquiring muscle weakness in ICU. Methods: This was a preplanned sub-analysis of the EPaNIC RCT. For 10 matched patients per group, serum GH was quantified every 10 min between 9 PM and 6 AM, followed by deconvolution analyses to estimate GH secretion. For 564 patients per group, matched for baseline characteristics, and for all patients investigated for muscle weakness (n=600), serum IGF-I, IGF binding protein 3 (IGFBP3) and IGFBP1 were measured upon ICU admission, at day 4 (if still in ICU), and on the last ICU day (LD). Matched healthy subjects (n=65) were included as controls. Groups were compared with Wilcoxon test or repeated-measures ANOVA. Associations between changes in concentrations from baseline to day 4 or LD for patients with shorter ICU stay (d4/LD) and risk of muscle weakness were assessed with nominal logistic regression analysis, adjusted for baseline risk factors, baseline hormone concentrations and randomization. Results: Upon ICU admission, patients revealed low IGF-I and IGFBP3 and high IGFBP1 as compared with controls (p<0.001). Tolerating an early macronutrient deficit in ICU decreased basal (non-pulsatile) GH secretion (p=0.005) without affecting pulsatile GH secretion. From admission to d4/LD IGF-I and IGFBP3 increased, whereas IGFBP1 decreased (all p<0.001) in the fully fed group. Compared to full feeding, tolerating the early macronutrient deficit prevented the rise in IGF-I (p<0.001), did not affect IGFBP3 and attenuated the decrease in IGFBP1 (p<0.001). A stronger rise in GH and IGF-I from admission to d4/LD was independently associated with a lower risk of acquiring muscle weakness (OR (95%CI) per ng/ml change 0.88 (0.81-0.96) for GH, p=0.001; 0.98 (0.97-0.99) for IGF-I, p=0.002). Conclusion: Tolerating the early macronutrient deficit suppresses basal but not pulsatile GH secretion and alters IGF-I bioavailability during critical illness. These effects may counteract the protection of the intervention against the development of muscle weakness. 1. Casaer et al. N Engl J Med 2011;365:506-17 2. Hermans et al. Lancet Respir Med 2013;1:621-9 3. Van Dyck et al. ENDO 2018;SUN601

AKIpredictor, an online prognostic calculator for acute kidney injury in adult critically ill patients: development, validation and comparison to serum neutrophil gelatinase-associated lipocalin

PURPOSE

Early diagnosis of acute kidney injury (AKI) remains a major challenge. We developed and validated AKI prediction models in adult ICU patients and made these models available via an online prognostic calculator. We compared predictive performance against serum neutrophil gelatinase-associated lipocalin (NGAL) levels at ICU admission.

METHODS

Analysis of the large multicenter EPaNIC database. Model development (n = 2123) and validation (n = 2367) were based on clinical information available (1) before and (2) upon ICU admission, (3) after 1 day in ICU and (4) including additional monitoring data from the first 24 h. The primary outcome was a comparison of the predictive performance between models and NGAL for the development of any AKI (AKI-123) and AKI stages 2 or 3 (AKI-23) during the first week of ICU stay.

RESULTS

Validation cohort prevalence was 29% for AKI-123 and 15% for AKI-23. The AKI-123 model before ICU admission included age, baseline serum creatinine, diabetes and type of admission (medical/surgical, emergency/planned) and had an AUC of 0.75 (95% CI 0.75-0.75). The AKI-23 model additionally included height and weight (AUC 0.77 (95% CI 0.77-0.77)). Performance consistently improved with progressive data availability to AUCs of 0.82 (95% CI 0.82-0.82) for AKI-123 and 0.84 (95% CI 0.83-0.84) for AKI-23 after 24 h. NGAL was less discriminant with AUCs of 0.74 (95% CI 0.74-0.74) for AKI-123 and 0.79 (95% CI 0.79-0.79) for AKI-23.

CONCLUSIONS

AKI can be predicted early with models that only use routinely collected clinical information and outperform NGAL measured at ICU admission. The AKI-123 models are available at http://akipredictor.com/ . Trial registration Clinical Trials.gov NCT00512122.

Pruritus in patients with small burn injuries

OBJECTIVE

To document incidence of pruritus and the presence of predisposing factors after small burns and their (subjective) impact on daily life.

METHODS

Retrospective study interviewing all patients treated in an outpatient burn clinic during 2004. Patients were contacted by phone and questioned on aspects of the burn and the presence, intensity and impact of pruritus. Predisposing factors for pruritus were analysed by multivariate logistic regression analysis.

RESULTS

Eighty-five percent of the 318 outpatients consented to the interview. Median total burned surface area (TBSA) was 2% (interquartile range of 1-4%). Thirty-five percent of patients recalled moderate pruritus, 14% severe pruritus. Impact on daily life was reported in 42% of patients suffering from moderate pruritus and 92% of patients suffering from severe pruritus. A multi variant logistic regression model based on baseline parameters (TBSA, age and anatomical region burned) only predicted 16.8% of experienced pruritus.

CONCLUSION

Recovery from small burns is associated with a high incidence of pruritus, which has substantial impact on daily life. It is difficult to identify patients at risk at the time of injury, as baseline demographic and injury related parameters only play a minor role. Future studies are needed to assess the effect of prevention and treatment and to define predictors for the incidence of pruritus.

Gallbladder wall sonolucency in acute cholecystitis

The usual ultrasound findings in acute cholecystitis include diffuse hyperreflective wall thickening, hazy wall delineation and gallbladder distension. In 11 patients with acute cholecystitis, an additional sign was seen consisting of a hyporeflective or sonolucent layer, continuous or interrupted, within the hyperreflective, thickened gallbladder wall. Anatomic-pathologic correlation, comparative CT scans and clinical follow-up studies showed subserosal edema and necrosis to be the most probable cause of this finding.