Computed tomography measured epicardial adipose tissue and psoas muscle attenuation: new biomarkers to predict major adverse cardiac events (MACE) and mortality in patients with heart disease and critically ill patients. Part I: Epicardial adipose tissue.

Over the last two decades, the potential role of epicardial adipocyte tissue (EAT) as a marker for major adverse cardiovascular events has been extensively studied. Unlike other visceral adipocyte tissues (VAT), EAT is not separated from the adjacent myocardium by a fascial layer and shares the same microcirculation with the myocardium. Adipocytokines, secreted by EAT, interact directly with the myocardium through paracrine and vasocrine pathways. The role of the Randle cycle, linking VAT accumulation to insulin resistance, and the relevance of blood flow and mitochondrial function of VAT, are briefly discussed. The three available imaging modalities for the assessment of EAT are discussed. The advantages of echocardiography, cardiac CT, and cardiac magnetic resonance (CMR) are compared. The last section summarises the current stage of knowledge on EAT as a clinical marker for major adverse cardiovascular events (MACE). The association between EAT volume and coronary artery disease (CAD) has robustly been validated. There is growing evidence that EAT volume is associated with computed tomography coronary angiography (CTCA) assessed high-risk plaque features. The EAT CT attenuation coefficient predicts coronary events. Many studies have established EAT volume as a predictor of atrial fibrillation after cardiac surgery. Moreover, EAT thickness has been independently associated with severe aortic stenosis and mitral annular calcification. Studies have demonstrated that EAT volume is associated with heart failure. Finally, we discuss the potential role of EAT in critically ill patients admitted to the intensive care unit. In conclusion, EAT seems to be a promising new biomarker to predict MACE.

The pathophysiological impact of intra-abdominal hypertension in pigs.

BACKGROUND: Intra-abdominal hypertension and abdominal compartment syndrome are common with clinically significant consequences. We investigated the pathophysiological effects of raised IAP as part of a more extensive exploratory animal study. The study design included both pneumoperitoneum and mechanical intestinal obstruction models. METHODS: Forty-nine female swine were divided into six groups: a control group (Cr; n = 5), three pneumoperitoneum groups with IAPs of 20mmHg (Pn20; n = 10), 30mmHg (Pn30; n = 10), 40mmHg (Pn40; n = 10), and two mechanical intestinal occlusion groups with IAPs of 20mmHg (MIO20; n = 9) and 30mmHg (MIO30; n = 5). RESULTS: There were significant changes (p<0.05) noted in all organ systems, most notably systolic blood pressure (SBP) (p<0.001), cardiac index (CI) (p = 0.003), stroke volume index (SVI) (p<0.001), mean pulmonary airway pressure (MPP) (p<0.001), compliance (p<0.001), pO2 (p = 0.003), bicarbonate (p = 0.041), hemoglobin (p = 0.012), lipase (p = 0.041), total bilirubin (p = 0.041), gastric pH (p<0.001), calculated glomerular filtration rate (GFR) (p<0.001), and urine output (p<0.001). SVV increased progressively as the IAP increased with no obvious changes in intravascular volume status. There were no significant differences between the models regarding their impact on cardiovascular, respiratory, renal and gastrointestinal systems. However, significant differences were noted between the two models at 30mmHg, with MIO30 showing worse metabolic and hematological parameters, and Pn30 and Pn40 showing a more rapid rise in creatinine. CONCLUSIONS: This study identified and quantified the impact of intra-abdominal hypertension at different pressures on several organ systems and highlighted the significance of even short-lived elevations. Two models of intra-abdominal pressure were used, with a mechanical obstruction model showing more rapid changes in metabolic and haematological changes. These may represent different underlying cellular and vascular pathophysiological processes, but this remains unclear.

Reproducibility of fluid status measured by bioelectrical impedance analysis in healthy volunteers: a key requirement to monitor fluid status in the intensive care unit.

INTRODUCTION: Little is known about the use of bioelectrical impedance analysis (BIA) in critically ill patients. The objective of this study was to evaluate the reproducibility of BIA measurements by comparing non-dominant versus dominant body-side measurements at 2 separate time points in healthy volunteers in order to extrapolate key elements that may be of relevance in critically ill patients. MATERIAL AND METHODS: A prospective observational validation experiment was carried out in healthy volunteers. Full-body and segmental multiple frequency BIA measurements were carried out at the non-dominant and the dominant body side, consecutively, and on 2 separate occasions within 1 week. Parameters of interest were both raw data (impedance and phase angle) at the individual frequencies (5-50-100-200 kHz) and body fluid compartment volume estimations (total body water, extracellular water volume, intracellular water volume, volume excess). RESULTS: A total of 42 measurements were performed in 22 volunteers. Median (interquartile range) age and time between measurements was 26 years (24; 35) and 2.07 days (1.00; 2.99), respectively. The intraclass-correlation coefficients (ICCs) for body fluid compartment volumes estimated by full-body BIA, were greatly above 90%, showing excellent agreement, except for volume excess which showed moderate agreement. Full-body raw impedance and phase angle measurements showed highly variable and much lower ICCs. For both estimated body fluid compartment volumes and raw measurements, segmental BIA showed also highly variable and low ICCs. CONCLUSIONS: Overall this study showed that in healthy volunteers, BIA-derived fluid parameters are reproducible, and differences can be attributed to the changes in clinical status.

Aiming for zero fluid accumulation: First, do no harm.

Critically ill patients are often presumed to be in a state of "constant dehydration" or in need of fluid, thereby justifying a continuous infusion with some form of intravenous (IV) fluid, despite their clinical data suggesting otherwise. Overzealous fluid administration and subsequent fluid accumulation and overload are associated with poorer outcomes. Fluids are drugs, and their use should be tailored to meet the patient's individualized needs; fluids should never be given as routine maintenance unless indicated. Before prescribing any fluids, the physician should consider the patient's characteristics and the nature of the illness, and assess the risks and benefits of fluid therapy. Decisions regarding fluid therapy present a daily challenge in many hospital departments: emergency rooms, regular wards, operating rooms, and intensive care units. Traditional fluid prescription is full of paradigms and unnecessary routines as well as malpractice in the form of choosing the wrong solutions for maintenance or not meeting daily requirements. Prescribing maintenance fluids for patients on oral intake will lead to fluid creep and fluid overload. Fluid overload, defined as a 10% increase in cumulative fluid balance from baseline weight, is an independent predictor for morbidity and mortality, and thus hospital cost. In the last decade, increasing evidence has emerged supporting a restrictive fluid approach. In this manuscript, we aim to provide a pragmatic description of novel concepts related to the use of IV fluids in critically ill patients, with emphasis on the different indications and common clinical scenarios. We also discuss active deresuscitation, or the timely cessation of fluid administration, with the intention of achieving a zero cumulative fluid balance.

Human factors and ergonomics to improve performance in intensive care units during the COVID-19 pandemic.

The COVID-19 pandemic has tested the very elements of human factors and ergonomics (HFE) to their maximum. HFE is an established scientific discipline that studies the interrelationship between humans, equipment, and the work environment. HFE includes situation awareness, decision making, communication, team working, leadership, managing stress, and coping with fatigue, empathy, and resilience. The main objective of HF is to optimise the interaction of humans with their work environment and technical equipment in order to maximise patient safety and efficiency of care. This paper reviews the importance of HFE in helping intensivists and all the multidisciplinary ICU teams to deliver high-quality care to patients in crisis situations.

Comprehensive assessment of the aortic valve in critically ill patients for the non-cardiologist. Part I: Aortic stenosis of the native valve.

Aortic stenosis (AS) causes left ventricular outflow obstruction. Severe AS has major haemodynamic implications in critically ill patients, in whom increased cardiac output and oxygen delivery are often required. Transthoracic echocardiography (TTE) plays a key role in the AS severity grading. In this review, we will give an overview of how to use the simplified Bernoulli equation to convert the echo Doppler measured velocities (cm s-1) to AS peak and mean gra-dient (mm Hg) and how to calculate the aortic valve area (AVA), using the continuity equation, based on the principle of preservation of flow. TTE allows quantification of compensatory left ventricular (LV) hypertrophy, assessment of LV systolic function, and determination of LV diastolic function and LV loading. Subsequently, the obtained results from the TTE study need to be integrated to establish the AS severity grading. The pitfalls of echocardiographic AS severity assessment are explained, and how to deal with inconsistency between AVA and mean gradient. The contribution of transoesophageal echocardiography, low-dose dobutamine stress echo (in case of low-flow low-gradient AS), echocardiography strain imaging, cardiac magnetic resonance imaging, cardiac multidetector computed tomography and the relatively new concept of Flow Pressure Gradient Classification to the work-up for aortic stenosis is discussed. Finally, the treatment of AS is overviewed. Elective aortic valve replacement is indicated in patients with severe symptomatic AS. In the ICU, afterload reduction by vasodilator therapy and treatment of pulmonary and venous congestion by diuretics could be considered.

Comprehensive assessment of the aortic valve in critically ill patients for the non-cardiologist. Part II: Chronic aortic regurgitation of the native valve.

Inadequate diastolic closure of the aortic valve causes aortic regurgitation (AR). Diastolic regurgitation towards the left ventricle (LV) causes LV volume overload, resulting in eccentric LV remodelling. Transthoracic echocardiography (TTE) is the first line examination in the work-up of AR. TTE allows quantification of left ventricular end-diastolic diameter and volume and left ventricular ejection fraction, which are key elements in the clinical decision making regarding the timing of valve surgery. The qualitative echocardiographic features contributing to the AR severity grading are discussed: fluttering of the anterior mitral valve leaflet, density and shape of the continuous wave Doppler signal of the AR jet, colour flow imaging of the AR jet width, and holodiastolic flow reversal in the descending thoracic aorta and abdominal aorta. Volumetric assessment of the AR is performed by measuring the velocity time integral of the left ventricular outflow tract (LVOT) and transmitral valve (MV) plane, and diameters of LVOT and MV. We explain how the regurgitant fraction and effective regurgitant orifice area (EROA) can be calculated. Alternatively, the proximal isovelocity surface area can be used to determine the EROA. We overview the utility of pressure half time and vena contracta width to assess AR severity. Further, we discuss the role of transoesophageal echocardiography, echocardiography speckle tracking strain imaging, cardiac magnetic resonance imaging and computed tomography of the thoracic aorta in the work-up of AR. Finally, we overview the criteria for valve surgery in AR.

Prognostic value of bioelectrical impedance analysis for assessment of fluid overload in ICU patients: a pilot study.

INTRODUCTION: The non-invasive analysis of body fluid composition with bio-electrical impedance analysis (BIA) provides additional information allowing for more persona-lised therapy to improve outcomes. The aim of this study is to assess the prognostic value of fluid overload (FO) in the first week of intensive care unit (ICU) stay. MATERIAL AND METHODS: A retrospective, observational analysis of 101 ICU patients. Whole-body BIA measurements were performed, and FO was defined as a 5% increase in volume excess from baseline body weight. RESULTS: Baseline demographic data, including severity scores, were similar in both the fluid overload-positive (FO+, n = 49) patients and in patients without fluid overload (FO-, n = 52). Patients with FO+ had significantly higher cumulative fluid balance during their ICU stay compared to those without FO (8.8 ± 7.0 vs. 5.5 ± 5.4 litres; P = 0.009), VE (9.9 ± 6.5 vs. 1.5 ± 1.5 litres; P < 0.001), total body water (63.0 ± 9.5 vs. 52.8 ± 8.1%; P < 0.001), and extracellular water (27.0 ± 7.3 vs. 19.6 ± 3.7 litres; P < 0.001). The presence of 5%, 7.5%, and 10% fluid overload was directly associated with increased ICU mortality rates. The percentage fluid overload (P = 0.039) was an independent predictor for hospital mortality. CONCLUSIONS: A higher mortality rate in ICU-patients with FO was observed. FO is an independent prognostic factor because neither APACHE-II, SOFA, nor SAPS-II significantly differed on admission between survivors and non-survivors. Further research is needed to confirm these data prospectively and to evaluate whether BIA-guided deresuscitation in the subacute phase will improve mortality rates.

Energy expenditure of patients on ECMO: A prospective pilot study.

BACKGROUND: An optimal nutritional approach sustained by convenient monitoring of metabolic status and reliable assessment of energy expenditure (EE) may improve the outcome of critically ill patients on extracorporeal membrane oxygenation (ECMO). We previously demonstrated the feasibility of indirect calorimetry (IC)-the standard of care technique to determine caloric targets-in patients undergoing ECMO. This study aims to compare measured with calculated EE during ECMO treatment. We additionally provide median EE values for use in settings where IC is not available. METHODS: IC was performed in seven stable ECMO patients. Gas exchange was analyzed at the ventilator, and ECMO side and values were introduced in a modified Weir formula to calculate resting EE. Results were compared with EE calculated with the Harris-Benedict equation and with the 25 kcal/kg/day ESPEN recommendation. RESULTS: Total median oxygen consumption rate was 196 (Q1-Q3 158-331) mL/min, and total median carbon dioxide production was 150 (Q1-Q3 104-203) mL/min. Clinically relevant differences between calculated and measured EE were observed in all patients. The median EE was 1334 (Q1-Q3 1134-2119) kcal/24 hours or 18 (Q1-Q3 15-27) kcal/kg/day. CONCLUSION: Compared with measured EE, calculation of EE both over- and underestimated caloric needs during ECMO treatment. Despite a median EE of 21 kcal/kg/day, large variability in metabolic rate was found and demands further investigation.