Usability study of a new tool for nutritional and glycemic management in adult intensive care: Glucosafe 2.

The new decision support tool Glucosafe 2 (GS2) is based on a mathematical model of glucose and insulin dynamics, designed to assist caregivers in blood glucose control and nutrition. This study aims to assess end-user acceptance and usability of this bedside decision support tool in an adult intensive care setting. Caregivers were first trained and then invited to trial GS2 prototype on bedside computers. Data for qualitative analysis were collected through semi-structured interviews from twenty users after minimum three trial days. Most caregivers (70%) rated GS2 as convenient and believed it would help improving adherence to current guidelines (85%). Moreover, most nurses (80%) believed that GS2 would be timesaving. Nurses' risk perceptions and manual data entry emerged as central barriers to use GS2 in routine practice. Issues emerged from the caregivers were compiled into a list of 12 modifications of the GS2 prototype to increase end-user acceptance and usability. This usability study showed that GS2 was considered by ICU caregivers as helpful in daily clinical practice, allowing time-saving and better standardization of ICU patient's care. Important issues were raised by the users with implications for the development and deployment of GS2. Integrating the technology into existing IT infrastructure may facilitate caregivers' acceptance. Further clinical studies of the performance and potential health outcomes are warranted.

Respiratory changes in subclavian vein diameters predicts fluid responsiveness in intensive care patients: a pilot study.

The present pilot study investigated whether respiratory variation in subclavian vein (SCV) diameters correlates with fluid responsiveness in mechanically ventilated patients. Monocentric, prospective clinical study on fluid responsiveness in adult sedated, mechanically ventilated ICU patient, monitored with the PiCCO™ system (Pulsion Medical System, Germany), and requiring a fluid challenge (FC). A 10-min fluid bolus of 500 mL of 0.9% saline was administered. Cardiac output (CO) and dynamic parameters [stroke volume variation (SVV) and pulse pressure variation (PPV)] measured by transpulmonary thermodilution and pulse contour analysis (PiCCO™) as well as classical hemodynamic parameters were recorded at baseline and after FC. Fluid responsiveness was described as an increase in CO of ≥ 15%. Ultrasound measurements obtained in the subclavian long-axis view were used to calculate the SCVvariability index. A cut-off value for SCV variation for the prediction of fluid responsiveness was determined using receiver operating curve (ROC) analysis. Nine of 20 FCs (45%) induced an increase in CO of ≥ 15%. At baseline, the SCVvariability index was greater in responders than in non-responders (34.0 ± 21.4 vs. 9.0 ± 5.5; p = 0.0005). Diagnostic performance for the SCVvariability index revealed a cut-off value of 14 with a sensitivity of 100% [Confidence interval (CI) 95% (90; 100)] and a specificity of 82% [CI 95% (48; 98)] for the prediction of fluid responsiveness. Other parameters, such as SVV and PPV, could not predict fluid responsiveness. The correlation coefficient between CO variation and the SCVvariability index was 0.73 (p < 0.001). The SCVvariability index was a reliable, non-invasive parameter for the prediction of fluid responsiveness at the bedside of mechanically ventilated, critically ill patients in this pilot study.

Reproducibility of transpulmonary thermodilution cardiac output measurements in clinical practice: a systematic review.

Measuring cardiac output (CO) is an integral part of the diagnostic and therapeutic strategy in critically ill patients. During the last decade, the single transpulmonary thermodilution (TPTD) technique was implemented in clinical practice. The purpose of this paper was to systematically review and critically assess the existing data concerning the reproducibility of CO measured using TPTD (COTPTD). A total of 16 studies were identified to potentially be included in our study because these studies had the required information that allowed for calculating the reproducibility of COTPTD measurements. 14 adult studies and 2 pediatric studies were analyzed. In total, 3432 averaged CO values in the adult population and 78 averaged CO values in the pediatric population were analyzed. The overall reproducibility of COTPTD measurements was 6.1 ± 2.0 % in the adult studies and 3.9 ± 2.9 % in the pediatric studies. An average of 3 boluses was necessary for obtaining a mean CO value. Achieving more than 3 boluses did not improve reproducibility; however, achieving less than 3 boluses significantly affects the reproducibility of this technique. The present results emphasize that TPTD is a highly reproducible technique for monitoring CO in critically ill patients, especially in the pediatric population. Our findings suggest that obtaining a mean of 3 measurements for determining CO values is recommended.

Effects of acute hemorrhage on intrapulmonary shunt in a pig model of acute respiratory distress-like syndrome.

BACKGROUND: In acute respiratory distress syndrome (ARDS), gas exchange and respiratory system mechanics (compliance) are severely impaired. Besides ventilatory parameters, the degree of respiratory abnormality can be influenced by the circulatory state. This study investigated the influence of acute hypovolemia on the respiratory system. METHODS: We performed a secondary analysis of a previous study including 8 pigs with ARDS-like syndrome induced by lung lavage and surfactant depletion method (ARDS group) and 10 mechanically ventilated pigs with no intervention (CTRL group). Animals of both groups were subjected to hemorrhage and retransfusion successively. We reanalyzed the effect of acute blood volume variations on intrapulmonary shunt (shunt), arterial oxygenation (PaO2:FiO2), global oxygen delivery (DO2) and respiratory system compliance (Crs). RESULTS: In the ARDS group, after hemorrhage, shunt decreased (-28 +/- 3.5 % (p < 0.001)), respiratory system compliance (Crs) increased (+5.1 +/- 1.0 ml/cm H2O (p < 0.001)) moreover, there was a concurrent increase in PaO2:FiO2 (+113 +/- 19.1 mmHg; p < 0.001) but this did not prevent a reduction in DO2 (-317 +/- 49.8 ml/min; p < 0.001). Following retransfusion, shunt and Crs return towards pre-hemorrhage values. Similar changes, but of smaller magnitude were observed in the CTRL group, except that no significant changes in oxygenation occurred. CONCLUSIONS: The present analysis suggests that an acute decrease in blood volume results in a decrease in shunt with a parallel improvement in arterial oxygenation and an increase in Crs during ARDS-like syndrome. Our results strengthen the importance to integrate the circulatory condition in the analysis of the state of the respiratory system. However, the translation of this physiological model in a clinical perspective is not straightforward because our model of acute and severe hemorrhage is not strictly equivalent to a progressive hypovolemia, as could be obtained in ICU by diuretic. Furthermore, the present model does not consider the impact of blood loss induced decrease of DO2 on other vital organs function. TRIAL REGISTRATION: 'Not applicable'.

Massive pulmonary embolism leading to cardiac arrest: one pathology, two different ECMO modes to assist patients.

Massive acute pulmonary embolism (MAPE) represents a significant risk for morbidity and mortality. The potential for sudden and fatal deterioration highlights the need for a prompt diagnosis and appropriate intervention. Using two cases reports, we describe two different modes of successful ECMO implantation (VA-ECMO vs. VV-ECMO) for MAPE leading to cardiac arrest. A 27-year-old patient with a severe trauma presented with a MAPE leading to cardiac arrest. In this case, which had absolute contraindications of thrombolysis, a VA-ECMO was successfully implanted. Additionally, a 56-year-old patient presented with a MAPE leading to cardiac arrest. Although intravenous thrombolysis allowed for hemodynamic stabilization, the patient remained severely hypoxemic with RV dilation. A VV-ECMO was successfully implemented, leading to a rapid improvement in both oxygenation and RV function. ECMO can provide lifesaving hemodynamic and respiratory support in critically ill patients with a MAPE who are too unstable to tolerate other interventions or have failed other therapies. An important determinant of success in the use of ECMO for MAPE is the return of adequate RV function, which allows physicians to appropriately identify which type of ECMO to implant.

The LUCAS 2 chest compression device is not always efficient: an echographic confirmation.

Survival after cardiac arrest depends on prompt and effective cardiopulmonary resuscitation (CPR). Resuscitative teams are more frequently using mechanical chest compression devices, as documented in physiologic and experimental data, suggesting that these devices are more effective than manual CPR. A 41-year-old male patient presented with an ST-elevation myocardial infarction with cardiac arrest. The patient was immediately resuscitated by manual chest compressions; CPR was continued with a mechanical chest compression device (LUCAS 2). The patient had experienced a 15-minute period of "low-flow" without "no-flow" episode. After a discussion with the heart team, we decided that the patient was a candidate for extracorporeal membrane oxygenation (ECMO) therapy. During the ECMO implantation, we noticed that while performing transesophageal echocardiography, chest compressions were ineffective with the machine. After the ECMO implantation, we observed myocardial damage in the right-sided heart cavities. The present case report illustrates the likelihood that the mechanical chest compression device has limitations that might contribute to inadequate CPR. Therefore, rescuers should consider the efficacy of their chest compression through a continuous hemodynamic monitoring during CPR.

Monitoring CO2 in shock states.

The primary end point when treating acute shock is to restore blood circulation, mainly by reaching macrocirculatory parameters. However, even if global haemodynamic goals can be achieved, microcirculatory perfusion may remain impaired, leading to cellular hypoxia and organ damage. Interestingly, few methods are currently available to measure the adequacy of organ blood flow and tissue oxygenation. The rise in tissue partial pressure of carbon dioxide (CO2) has been observed when tissue perfusion is decreased. In this regard, tissue partial pressure of CO2 has been proposed as an early and reliable marker of tissue hypoxia even if the mechanisms of tissue partial pressure in CO2 rise during hypoperfusion remain unclear. Several technologies allow the estimation of CO2 content from different body sites: vascular, tissular (in hollow organs, mucosal or cutaneous), and airway. These tools remain poorly evaluated, and some are used but are not widely used in clinical practice. The present review clarifies the physiology of increasing tissue CO2 during hypoperfusion and underlines the specificities of the different technologies that allow bedside estimation of tissue CO2 content.

Respiratory change in ECG-wave amplitude is a reliable parameter to estimate intravascular volume status.

Electrocardiogram (ECG) is a standard type of monitoring in intensive care medicine. Several studies suggest that changes in ECG morphology may reflect changes in volume status. The "Brody effect", a theoretical analysis of left ventricular (LV) chamber size influence on QRS-wave amplitude, is the key element of this phenomenon. It is characterised by an increase in QRS-wave amplitude that is induced by an increase in ventricular preload. This study investigated the influence of changes in intravascular volume status on respiratory variations of QRS-wave amplitudes (ΔECG) compared with respiratory pulse pressure variations (ΔPP), considered as a reference standard. In 17 pigs, ECG and arterial pressure were recorded. QRS-wave amplitude was measured from the Biopac recording to ensure that in all animals ECG electrodes were always at the same location. Maximal QRS amplitude (ECGmax) and minimal QRS amplitude (ECGmin) were determined over one respiratory cycle. ΔECG was calculated as 100 × [(ECGmax - ECGmin)/(ECGmax + ECGmin)/2]. ΔECG and ΔPP were simultaneously recorded. Measurements were performed at different time points: during normovolemic conditions, after haemorrhage (25 mL/kg), and following re-transfusion (25 mL/kg) with constant tidal volume (10 mL/kg) and respiration rate (15 breath/min). At baseline, ΔPP and ΔECG were both <12 %. ΔPP were significantly correlated with ΔECG (r(2) = 0.89, p < 0.001). Volume loss induced by haemorrhage increased significantly ΔPP and ΔECG. Moreover, during this state, ΔPP were significantly correlated with ΔECG (r(2) = 0.86, p < 0.001). Re-transfusion significantly decreased ΔPP and ΔECG, and ΔPP were significantly correlated with ΔECG (r(2) = 0.90, p < 0.001). The observed correlations between ΔPP and ΔECG at each time point of the study suggest that ΔECG is a reliable parameter to estimate the changes in intravascular volume status and provide experimental confirmation of the "Brody effect."

Clinical validation of a new thermodilution system for the assessment of cardiac output and volumetric parameters.

INTRODUCTION: Transpulmonary thermodilution is used to measure cardiac output (CO), global end-diastolic volume (GEDV) and extravascular lung water (EVLW). A system has been introduced (VolumeView/EV1000™ system, Edwards Lifesciences, Irvine CA, USA) that employs a novel algorithm for the mathematical analysis of the thermodilution curve. Our aim was to evaluate the agreement of this method with the established PiCCO™ method (Pulsion Medical Systems SE, Munich, Germany, clinicaltrials.gov identifier: NCT01405040) METHODS: Seventy-two critically ill patients with clinical indication for advanced hemodynamic monitoring were included in this prospective, multicenter, observational study. During a 72-hour observation period, 443 sets of thermodilution measurements were performed with the new system. These measurements were electronically recorded, converted into an analog resistance signal and then re-analyzed by a PiCCO2™ device (Pulsion Medical Systems SE). RESULTS: For CO, GEDV, and EVLW, the systems showed a high correlation (r(2) = 0.981, 0.926 and 0.971, respectively), minimal bias (0.2 L/minute, 29.4 ml and 36.8 ml), and a low percentage error (9.7%, 11.5% and 12.2%). Changes in CO, GEDV and EVLW were tracked with a high concordance between the two systems, with a traditional concordance for CO, GEDV, and EVLW of 98.5%, 95.1%, and 97.7% and a polar plot concordance of 100%, 99.8% and 99.8% for CO, GEDV, and EVLW, respectively. Radial limits of agreement for CO, GEDV and EVLW were 0.31 ml/minute, 81 ml and 40 ml, respectively. The precision of GEDV measurements was significantly better using the VolumeView™ algorithm compared to the PiCCO™ algorithm (0.033 (0.03) versus 0.040 (0.03; median (interquartile range), P = 0.000049). CONCLUSIONS: For CO, GEDV, and EVLW, the agreement of both the individual measurements as well as measurements of change showed the interchangeability of the two methods. For the VolumeView method, the higher precision may indicate a more robust GEDV algorithm. TRIAL REGISTRATION: clinicaltrials.gov NCT01405040.

Demonstration of inferior vena cava compression by probe pressure during subxiphoid echocardiography.

We sought to compare the inferior vena cava diameter measured by transthoracic echocardiography and by transesophageal echocardiography in human and animals. Transthoracic echocardiography yielded lower inferior vena cava diameter values than transesophageal echocardiography. Adult and pediatric intensivists should pay attention to the risk of false measurement of the inferior vena cava anterior-posterior diameter that may be due to compression of the inferior vena cava by the sonographic probe when the subxiphoid view is used.

Transpulmonary thermodilution assessments: precise measurements require a precise procedure.

When incorporating the values of a hemodynamic parameter into the care of patients, the precision of the measurement method should always be considered. A prospective analysis in the previous issue of Critical Care showed that the precision of transpulmonary thermodilution (TPTD) allows for reliable mean values if a standardised procedure is used. The present finding has a physiological basis, as TPTD requires a more prolonged transit time, which in turn reduces the effects that airway pressure and arrhythmia have on venous return-cardiac output steady states. Moreover, this result suggests that the current accepted threshold value of a 15% increase in cardiac output to identify a positive response to a fluid challenge could be reduced in the future. Indeed, this value is mainly related to the precision of the pulmonary artery catheter.

Pre-ejection period to estimate cardiac preload dependency in mechanically ventilated pigs submitted to severe hemorrhagic shock.

BACKGROUND: Respiratory change in pre-ejection period (ΔPEP) has been described as a potential parameter for monitoring cardiac preload dependency in critically ill patients. This study was designed to describe the relationship between ΔPEP and pulse pressure variation (PPV) in pigs submitted to severe hemorrhagic shock. METHODS: In 17 paralyzed, anesthetized mechanically ventilated pigs, electrocardiography, arterial pressure, and cardiac output derived from pulmonary artery catheter were recorded. Hemorrhagic shock was induced by removal of blood volume followed by restoration. PEP was defined as the time interval between the beginning of the Q wave on the electrocardiogram and the upstroke of the invasive radial arterial pressure curve. RESULTS: At baseline, ΔPEP and PPVs were both <12% with PPV significantly correlated with ΔPEP (r = 0.96, p < 0.001). Volume loss induced by hemorrhage significantly increased PPV and ΔPEP values (p < 0.05). During severe hemorrhage, PPV correlated well with ΔPEP (r = 0.88, p < 0.001) with PPV values significantly higher than ΔPEP (p < 0.05). However, the reproducibility of ΔPEP measurements was significantly better than PPV during this step (p < 0.05). Retransfusion significantly decreased PPV and ΔPEP (p < 0.05) with PPV significantly correlated to ΔPEP (r = 0.94, p < 0.001). CONCLUSION: Available correlations between PPV and ΔPEP at each time of the study were observed, meaning that ΔPEP is a reliable parameter to estimate and track the changes in cardiac preload dependency. Moreover, during the severe hemorrhagic shock period, ΔPEP measurements were more reproducible than PPV values.

ScvO(2) as a marker to define fluid responsiveness.

BACKGROUND: Definition of the hemodynamic response to volume expansion (VE) could be useful in shocked critically ill patients in absence of cardiac index (CI) measurements. The aim of this study is to evaluate whether central venous oxygen saturation variations (ΔScvO(2)) after VE could be an alternative to classify responders (R) and nonresponders (NR) to volume therapy. METHODS: A total of 30 patients requiring VE were included in this prospective cohort study, all equipped with radial arterial line and pulmonary artery catheters. CI, mixed venous oxygen saturation (SvO(2)) and ScvO(2) were measured before and after VE. CI, SvO(2), and ScvO(2) changes after volume were analyzed using linear regression. Receiver operating characteristics curve analysis was used to test their ability to distinguish R and NR. RESULTS: ΔScvO(2) and SvO(2) variations after VE (ΔSvO(2)) were significantly correlated with CI changes (ΔCI) after VE (r = 0.67 and r = 0.49, p < 0.001, respectively). A ΔScvO(2) threshold value of 4% allowed the definition of R and NR patients with 86% sensitivity (95%CI; 57-98%) and 81% specificity (95%CI; 54-96%). CONCLUSIONS: ScvO2 variations after VE was able to categorize VE efficiently and could be suggested as an alternative marker to define fluid responsiveness in absence of invasive CI measurement.

Decreased CRRT Filter Lifespan in COVID-19 ICU Patients.

(1) Background: Increased thromboembolic events and an increased need for continuous renal replacement therapy (CRRT) have been frequently reported in COVID-19 patients. Our aim was to investigate CRRT filter lifespan in intensive care unit (ICU) COVID-19 patients. (2) Methods: We compared CRRT adjusted circuit lifespan in COVID-19 patients admitted for SARS-CoV-2 infection to a control group of patients admitted for septic shock of pulmonary origin other than COVID-19. Both groups underwent at least one session of CRRT for AKI. (3) Results: Twenty-six patients (13 in each group) were included. We analysed 117 CRRT circuits (80 in the COVID-19 group and 37 in the control group). The adjusted filter lifespan was shorter in the COVID-19 group (17 vs. 39 h, p < 0.001). This trend persisted after adjustment for confounding factors (-14 h, p = 0.037). Before CRRT circuit clotting, the COVID-19 group had a more procoagulant profile despite higher heparin infusion rates. Furthermore, we reported a decreased relation between activated partial thromboplastin time (aPTT) and cumulative heparin dose in COVID-19 patients when compared to historical data of 23,058 patients, suggesting a heparin resistance. (4) Conclusion: COVID-19 patients displayed a shorter CRRT filter lifespan that could be related to a procoagulant profile and heparin resistance.

Validation of a new transpulmonary thermodilution system to assess global end-diastolic volume and extravascular lung water.

INTRODUCTION: A new system has been developed to assess global end-diastolic volume (GEDV), a volumetric marker of cardiac preload, and extravascular lung water (EVLW) from a transpulmonary thermodilution curve. Our goal was to compare this new system with the system currently in clinical use. METHODS: Eleven anesthetized and mechanically ventilated pigs were instrumented with a central venous catheter and a right (PulsioCath; Pulsion, Munich, Germany) and a left (VolumeView™; Edwards Lifesciences, Irvine, CA, USA) thermistor-tipped femoral arterial catheter. The right femoral catheter was used to measure GEDV and EVLW using the PiCCO(2)™ (Pulsion) method (GEDV(1) and EVLW(1), respectively). The left femoral catheter was used to measure the same parameters using the new VolumeView™ (Edwards Lifesciences) method (GEDV(2) and EVLW(2), respectively). Measurements were made during inotropic stimulation (dobutamine), during hypovolemia (bleeding), during hypervolemia (fluid overload), and after inducing acute lung injury (intravenous oleic acid). RESULTS: One hundred and thirty-seven paired measurements were analyzed. GEDV(1) and GEDV(2) ranged from 701 to 1,629 ml and from 774 to 1,645 ml, respectively. GEDV(1) and GEDV(2) were closely correlated (r(2) = 0.79), with mean bias of -11 ± 80 ml and percentage error of 14%. EVLW(1) and EVLW(2) ranged from 507 to 2,379 ml and from 495 to 2,222 ml, respectively. EVLW(1) and EVLW(2) were closely correlated (r(2) = 0.97), with mean bias of -5 ± 72 ml and percentage error of 15%. CONCLUSIONS: In animals, and over a very wide range of values, a good agreement was found between the new VolumeView™ system and the PiCCO™ system to assess GEDV and EVLW.

Pulmonary fluid status monitoring with intrathoracic impedance.

Various pacemakers can now track diverse hemodynamic parameters that are useful in the management of patients with heart failure. Among these indicators, pulmonary fluid status can be monitored. To the best of our knowledge, this is the first case describing an agreement between a simultaneous detection of an increase in lung water by transthoracic impedance monitoring (OptiVol™ (Medtronic, Inc., Minneapolis, MN), and the transpulmonary thermodilution method (PiCCO™, Pulsion Medical Systems, Munich, Germany) in a patient with acute pulmonary oedema. The present case suggests that transthoracic impedance monitoring could be a useful tool to guide therapy in critically ill patients with implanted devices and lung fluid congestion.

Preparedness and Reorganization of Care for Coronavirus Disease 2019 Patients in a Swiss ICU: Characteristics and Outcomes of 129 Patients.

OBJECTIVES: In many countries, large numbers of critically ill patients with coronavirus disease 2019 are admitted to the ICUs within a short period of time, overwhelming usual care capacities. Preparedness and reorganization ahead of the wave to increase ICU surge capacity may be associated with favorable outcome. The purpose of this study was to report our experience in terms of ICU organization and anticipation, as well as reporting patient characteristics, treatment, and outcomes. DESIGN: A prospective observational study. SETTING: The division of intensive care at the Geneva University Hospitals (Geneva, Switzerland). PATIENTS: All consecutive adult patients with acute respiratory failure due to coronavirus disease 2019 admitted in the ICU between March 9, 2020, and May 19, 2020, were enrolled. Patients' demographic data, comorbidities, laboratory values, treatments, and clinical outcomes were collected. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The ICU was reorganized into cells of six to eight patients under the care of three physicians and five nurses. Its capacity increased from 30 to 110 beds, fully equipped and staffed, transforming the surgical intermediate care unit, the postoperative care facility, and operating theaters into ICUs. Surge capacity has always exceeded the number of patients hospitalized. Among 129 critically ill patients with severe acute hypoxemic respiratory failure, 96% required invasive mechanical ventilation. A total of 105 patients (81%) were discharged alive and 24 died, corresponding to a mortality of 19%. Patients who died were significantly older, with higher severity scores at admission, had higher levels of d-dimers, plasma creatinine, high-sensitive troponin T, C-reactive protein, and procalcitonin, and required more frequent prone sessions. CONCLUSIONS: A rapid increase in ICU bed capacity, including adequate equipment and staffing, allowed for a large number of critically ill coronavirus disease 2019 patients to be taken care of within a short period of time. Anticipation and preparedness ahead of the wave may account for the low mortality observed in our center. These results highlight the importance of resources management strategy in the context of the ongoing coronavirus disease 2019 pandemic.

[Evaluation of practical skills in echocardiography for intensivists]. / Evaluation des compétences requises pour la pratique de l'echo- cardiographie aux soins intensifs.

In 2009, the Critical Care NetWork of the American College of Chest Physicians (ACCP) in partnership with La Société de réanimation de langue française (SRLF) selected a panel of experts to characterize competence in critical care ultrasonography (CCUS) and suggest a consensus statement on competence in CCUS. CCUS may be divided into general CCUS (thoracic, abdominal, and vascular), and echocardiography (basic and advanced). For each component, the experts defined the specific skills that the intensivist should acquire to be competent in that aspect of CCUS. They, also, defined a reasonable minimum standard statement to serve as a guide for the intensivist in achieving proficiency in the field. The present article focuses on the consensus statement concerning the evaluation of the competences (basic level) in critical care echocardiography.