How to use echocardiography to manage patients with shock? / ¿Cuál es la utilidad de la ecocardiografía en el shock?

Echocardiography enables the intensivist to assess the patient with circulatory failure. It allows the clinician to identify rapidly the type and the cause of shock in order to develop an effective management strategy. Important characteristics in the setting of shock are that it is non-invasive and can be rapidly applied. Early and repeated echocardiography is a valuable tool for the management of shock in the intensive care unit. Competency in basic critical care echocardiography is now regarded as a mandatory part of critical care training with clear guidelines available. The majority of pathologies found in shocked patients are readily identified using basic level 2D and M-mode echocardiography. The four core types of shock (cardiogenic, hypovolemic, obstructive, and septic) can readily be identified by echocardiography. Echocardiography can differentiate the different pathologies that may be the cause of each type of shock. More importantly, as a result of more complex and elderly patients, the shock may be multifactorial, such as a combination of cardiogenic and septic shock, which emphasises on the added value of transthoracic echocardiography (TTE) in such population of patients. In this review we aimed to provide to clinicians a bedside strategy of the use of TTE parameters to manage patients with shock. In the first part of this overview, we detailed the different TTE parameters and how to use them to identify the type of shock. And in the second part, we focused on the use of these parameters to evaluate the effect of treatments, in different types of shock. (AU)

La ecocardiografía permite al intensivista valorar al paciente con fallo circulatorio agudo. Esta técnica ayuda a identificar, rápidamente y de una manera no invasiva, el tipo y la causa del shock para instaurar una estrategia terapéutica. La realización de exámenes ecocardiográficos precoces y repetidos es una valiosa herramienta para el manejo del shock en la unidad de cuidados intensivos. La mayoría de patologías responsables del shock pueden ser identificadas con un nivel básico de ecocardiografía en 2D y modo M. En la actualidad, las competencias en ecocardiografía básica se consideran mandatorias en la formación de los profesionales de Medicina Intensiva. Los cuatro tipos básicos de shock (cardiogénico, hipovolémico, obstructivo y séptico) pueden ser adecuadamente identificados con la ecocardiografía. Además, la ecografía puede diferenciar las diferentes patologías que pueden ser la causa de cada uno de los tipos de shock. Es importante señalar que, dada la complejidad y la edad avanzada de muchos pacientes críticos, el shock puede ser multifactorial (p.ej.: combinación de shock séptico y cardiogénico), lo que enfatiza el valor añadido de la ecocardiografía transtorácica (ETT) en esta población de pacientes. En esta revisión, queremos proporcionar a los clínicos una estrategia, a pie de cama, del uso de los parámetros obtenidos con la ETT para manejo de los pacientes en shock. En la primera parte de este artículo, se detallan los diferentes parámetros ecocardiográficos y cómo pueden utilizarse para identificar los tipos de shock. En la segunda parte, se expone el uso de estos parámetros para evaluar el efecto de los tratamientos en los diferentes tipos de shock. (AU)

How to use echocardiography to manage patients with shock?

Echocardiography enables the intensivist to assess the patient with circulatory failure. It allows the clinician to identify rapidly the type and the cause of shock in order to develop an effective management strategy. Important characteristics in the setting of shock are that it is non-invasive and can be rapidly applied. Early and repeated echocardiography is a valuable tool for the management of shock in the intensive care unit. Competency in basic critical care echocardiography is now regarded as a mandatory part of critical care training with clear guidelines available. The majority of pathologies found in shocked patients are readily identified using basic level 2D and M-mode echocardiography. The four core types of shock (cardiogenic, hypovolemic, obstructive, and septic) can readily be identified by echocardiography. Echocardiography can differentiate the different pathologies that may be the cause of each type of shock. More importantly, as a result of more complex and elderly patients, the shock may be multifactorial, such as a combination of cardiogenic and septic shock, which emphasises on the added value of transthoracic echocardiography (TTE) in such population of patients. In this review we aimed to provide to clinicians a bedside strategy of the use of TTE parameters to manage patients with shock. In the first part of this overview, we detailed the different TTE parameters and how to use them to identify the type of shock. And in the second part, we focused on the use of these parameters to evaluate the effect of treatments, in different types of shock.

Objective and subjective cognition in survivors of COVID-19 one year after ICU discharge: the role of demographic, clinical, and emotional factors.

BACKGROUND: Intensive Care Unit (ICU) COVID-19 survivors may present long-term cognitive and emotional difficulties after hospital discharge. This study aims to characterize the neuropsychological dysfunction of COVID-19 survivors 12 months after ICU discharge, and to study whether the use of a measure of perceived cognitive deficit allows the detection of objective cognitive impairment. We also explore the relationship between demographic, clinical and emotional factors, and both objective and subjective cognitive deficits. METHODS: Critically ill COVID-19 survivors from two medical ICUs underwent cognitive and emotional assessment one year after discharge. The perception of cognitive deficit and emotional state was screened through self-rated questionnaires (Perceived Deficits Questionnaire, Hospital Anxiety and Depression Scale and Davidson Trauma Scale), and a comprehensive neuropsychological evaluation was carried out. Demographic and clinical data from ICU admission were collected retrospectively. RESULTS: Out of eighty participants included in the final analysis, 31.3% were women, 61.3% received mechanical ventilation and the median age of patients was 60.73 years. Objective cognitive impairment was observed in 30% of COVID-19 survivors. The worst performance was detected in executive functions, processing speed and recognition memory. Almost one in three patients manifested cognitive complaints, and 22.5%, 26.3% and 27.5% reported anxiety, depression and post-traumatic stress disorder (PTSD) symptoms, respectively. No significant differences were found in the perception of cognitive deficit between patients with and without objective cognitive impairment. Gender and PTSD symptomatology were significantly associated with perceived cognitive deficit, and cognitive reserve with objective cognitive impairment. CONCLUSIONS: One-third of COVID-19 survivors suffered objective cognitive impairment with a frontal-subcortical dysfunction 12 months after ICU discharge. Emotional disturbances and perceived cognitive deficits were common. Female gender and PTSD symptoms emerged as predictive factors for perceiving worse cognitive performance. Cognitive reserve emerged as a protective factor for objective cognitive functioning. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04422444; June 9, 2021.

Virtual Reality-Based Early Neurocognitive Stimulation in Critically Ill Patients: A Pilot Randomized Clinical Trial.

This study focuses on the application of a non-immersive virtual reality (VR)-based neurocognitive intervention in critically ill patients. Our aim was to assess the feasibility of direct outcome measures to detect the impact of this digital therapy on patients' cognitive and emotional outcomes. Seventy-two mechanically ventilated adult patients were randomly assigned to the "treatment as usual" (TAU, n = 38) or the "early neurocognitive stimulation" (ENRIC, n = 34) groups. All patients received standard intensive care unit (ICU) care. Patients in the ENRIC group also received adjuvant neurocognitive stimulation during the ICU stay. Outcome measures were a full neuropsychological battery and two mental health questionnaires. A total of 42 patients (21 ENRIC) completed assessment one month after ICU discharge, and 24 (10 ENRIC) one year later. At one-month follow-up, ENRIC patients had better working memory scores (p = 0.009, d = 0.363) and showed up to 50% less non-specific anxiety (11.8% vs. 21.1%) and depression (5.9% vs. 10.5%) than TAU patients. A general linear model of repeated measures reported a main effect of group, but not of time or group-time interaction, on working memory, with ENRIC patients outperforming TAU patients (p = 0.008, ηp2 = 0.282). Our results suggest that non-immersive VR-based neurocognitive stimulation may help improve short-term working memory outcomes in survivors of critical illness. Moreover, this advantage could be maintained in the long term. An efficacy trial in a larger sample of participants is feasible and must be conducted.

Publisher Correction: Development and validation of a sample entropy-based method to identify complex patient-ventilator interactions during mechanical ventilation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Cognitive phenotypes 1 month after ICU discharge in mechanically ventilated patients: a prospective observational cohort study.

BACKGROUND: ICU patients undergoing invasive mechanical ventilation experience cognitive decline associated with their critical illness and its management. The early detection of different cognitive phenotypes might reveal the involvement of diverse pathophysiological mechanisms and help to clarify the role of the precipitating and predisposing factors. Our main objective is to identify cognitive phenotypes in critically ill survivors 1 month after ICU discharge using an unsupervised machine learning method, and to contrast them with the classical approach of cognitive impairment assessment. For descriptive purposes, precipitating and predisposing factors for cognitive impairment were explored. METHODS: A total of 156 mechanically ventilated critically ill patients from two medical/surgical ICUs were prospectively studied. Patients with previous cognitive impairment, neurological or psychiatric diagnosis were excluded. Clinical variables were registered during ICU stay, and 100 patients were cognitively assessed 1 month after ICU discharge. The unsupervised machine learning K-means clustering algorithm was applied to detect cognitive phenotypes. Exploratory analyses were used to study precipitating and predisposing factors for cognitive impairment. RESULTS: K-means testing identified three clusters (K) of patients with different cognitive phenotypes: K1 (n = 13), severe cognitive impairment in speed of processing (92%) and executive function (85%); K2 (n = 33), moderate-to-severe deficits in learning-memory (55%), memory retrieval (67%), speed of processing (36.4%) and executive function (33.3%); and K3 (n = 46), normal cognitive profile in 89% of patients. Using the classical approach, moderate-to-severe cognitive decline was recorded in 47% of patients, while the K-means method accurately classified 85.9%. The descriptive analysis showed significant differences in days (p = 0.016) and doses (p = 0.039) with opioid treatment in K1 vs. K2 and K3. In K2, there were more women, patients were older and had more comorbidities (p = 0.001) than in K1 or K3. Cognitive reserve was significantly (p = 0.001) higher in K3 than in K1 or K2. CONCLUSION: One month after ICU discharge, three groups of patients with different cognitive phenotypes were identified through an unsupervised machine learning method. This novel approach improved the classical classification of cognitive impairment in ICU survivors. In the exploratory analysis, gender, age and the level of cognitive reserve emerged as relevant predisposing factors for cognitive impairment in ICU patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier:NCT02390024; March 17,2015.

Volume Infusion Markedly Increases Femoral dP/dtmax in Fluid-Responsive Patients Only.

OBJECTIVES: To evaluate the preload dependence of femoral maximal change in pressure over time (dP/dtmax) during volume expansion in preload dependent and independent critically ill patients. DESIGN: Retrospective database analysis. SETTING: Two adult polyvalent ICUs. PATIENTS: Twenty-five critically ill patients with acute circulatory failure. INTERVENTIONS: Thirty-five fluid infusions of 500 mL normal saline. MEASUREMENTS AND MAIN RESULTS: Changes in femoral dP/dtmax, systolic, diastolic, and pulse femoral arterial pressure were obtained from the pressure waveform analysis using the PiCCO2 system (Pulsion Medical Systems, Feldkirchen, Germany). Stroke volume index was obtained by transpulmonary thermodilution. Statistical analysis was performed comparing results before and after volume expansion and according to the presence or absence of preload dependence (increases in stroke volume index ≥ 15%). Femoral dP/dtmax increased by 46% after fluid infusion in preload-dependent cases (mean change = 510.6 mm Hg·s; p = 0.005) and remained stable in preload-independent ones (mean change = 49.2 mm Hg·s; p = 0.114). Fluid-induced changes in femoral dP/dtmax correlated with fluid-induced changes in stroke volume index in preload-dependent cases (r = 0.618; p = 0.032), but not in preload-independent ones. Femoral dP/dtmax strongly correlated with pulse and systolic arterial pressures and with total arterial stiffness, regardless of the preload dependence status (r > 0.9 and p < 0.001 in all cases). CONCLUSIONS: Femoral dP/dtmax increased with volume expansion in case of preload dependence but not in case of preload independence and was strongly related to pulse pressure and total arterial stiffness regardless of preload dependence status. Therefore, femoral dP/dtmax is not a load-independent marker of left ventricular contractility and should be not used to track contractility in critically ill patients.

Development and validation of a sample entropy-based method to identify complex patient-ventilator interactions during mechanical ventilation.

Patient-ventilator asynchronies can be detected by close monitoring of ventilator screens by clinicians or through automated algorithms. However, detecting complex patient-ventilator interactions (CP-VI), consisting of changes in the respiratory rate and/or clusters of asynchronies, is a challenge. Sample Entropy (SE) of airway flow (SE-Flow) and airway pressure (SE-Paw) waveforms obtained from 27 critically ill patients was used to develop and validate an automated algorithm for detecting CP-VI. The algorithm's performance was compared versus the gold standard (the ventilator's waveform recordings for CP-VI were scored visually by three experts; Fleiss' kappa = 0.90 (0.87-0.93)). A repeated holdout cross-validation procedure using the Matthews correlation coefficient (MCC) as a measure of effectiveness was used for optimization of different combinations of SE settings (embedding dimension, m, and tolerance value, r), derived SE features (mean and maximum values), and the thresholds of change (Th) from patient's own baseline SE value. The most accurate results were obtained using the maximum values of SE-Flow (m = 2, r = 0.2, Th = 25%) and SE-Paw (m = 4, r = 0.2, Th = 30%) which report MCCs of 0.85 (0.78-0.86) and 0.78 (0.78-0.85), and accuracies of 0.93 (0.89-0.93) and 0.89 (0.89-0.93), respectively. This approach promises an improvement in the accurate detection of CP-VI, and future study of their clinical implications.

Patient-ventilator asynchronies during mechanical ventilation: current knowledge and research priorities.

BACKGROUND: Mechanical ventilation is common in critically ill patients. This life-saving treatment can cause complications and is also associated with long-term sequelae. Patient-ventilator asynchronies are frequent but underdiagnosed, and they have been associated with worse outcomes. MAIN BODY: Asynchronies occur when ventilator assistance does not match the patient's demand. Ventilatory overassistance or underassistance translates to different types of asynchronies with different effects on patients. Underassistance can result in an excessive load on respiratory muscles, air hunger, or lung injury due to excessive tidal volumes. Overassistance can result in lower patient inspiratory drive and can lead to reverse triggering, which can also worsen lung injury. Identifying the type of asynchrony and its causes is crucial for effective treatment. Mechanical ventilation and asynchronies can affect hemodynamics. An increase in intrathoracic pressure during ventilation modifies ventricular preload and afterload of ventricles, thereby affecting cardiac output and hemodynamic status. Ineffective efforts can decrease intrathoracic pressure, but double cycling can increase it. Thus, asynchronies can lower the predictive accuracy of some hemodynamic parameters of fluid responsiveness. New research is also exploring the psychological effects of asynchronies. Anxiety and depression are common in survivors of critical illness long after discharge. Patients on mechanical ventilation feel anxiety, fear, agony, and insecurity, which can worsen in the presence of asynchronies. Asynchronies have been associated with worse overall prognosis, but the direct causal relation between poor patient-ventilator interaction and worse outcomes has yet to be clearly demonstrated. Critical care patients generate huge volumes of data that are vastly underexploited. New monitoring systems can analyze waveforms together with other inputs, helping us to detect, analyze, and even predict asynchronies. Big data approaches promise to help us understand asynchronies better and improve their diagnosis and management. CONCLUSIONS: Although our understanding of asynchronies has increased in recent years, many questions remain to be answered. Evolving concepts in asynchronies, lung crosstalk with other organs, and the difficulties of data management make more efforts necessary in this field.

Effects of sedatives and opioids on trigger and cycling asynchronies throughout mechanical ventilation: an observational study in a large dataset from critically ill patients.

BACKGROUND: In critically ill patients, poor patient-ventilator interaction may worsen outcomes. Although sedatives are often administered to improve comfort and facilitate ventilation, they can be deleterious. Whether opioids improve asynchronies with fewer negative effects is unknown. We hypothesized that opioids alone would improve asynchronies and result in more wakeful patients than sedatives alone or sedatives-plus-opioids. METHODS: This prospective multicenter observational trial enrolled critically ill adults mechanically ventilated (MV) > 24 h. We compared asynchronies and sedation depth in patients receiving sedatives, opioids, or both. We recorded sedation level and doses of sedatives and opioids. BetterCare™ software continuously registered ineffective inspiratory efforts during expiration (IEE), double cycling (DC), and asynchrony index (AI) as well as MV modes. All variables were averaged per day. We used linear mixed-effects models to analyze the relationships between asynchronies, sedation level, and sedative and opioid doses. RESULTS: In 79 patients, 14,166,469 breaths were recorded during 579 days of MV. Overall asynchronies were not significantly different in days classified as sedatives-only, opioids-only, and sedatives-plus-opioids and were more prevalent in days classified as no-drugs than in those classified as sedatives-plus-opioids, irrespective of the ventilatory mode. Sedative doses were associated with sedation level and with reduced DC (p < 0.0001) in sedatives-only days. However, on days classified as sedatives-plus-opioids, higher sedative doses and deeper sedation had more IEE (p < 0.0001) and higher AI (p = 0.0004). Opioid dosing was inversely associated with overall asynchronies (p < 0.001) without worsening sedation levels into morbid ranges. CONCLUSIONS: Sedatives, whether alone or combined with opioids, do not result in better patient-ventilator interaction than opioids alone, in any ventilatory mode. Higher opioid dose (alone or with sedatives) was associated with lower AI without depressing consciousness. Higher sedative doses administered alone were associated only with less DC. TRIAL REGISTRATION: ClinicalTrial.gov, NCT03451461.

Influence of changes in ventricular systolic function and loading conditions on pulse contour analysis-derived femoral dP/dtmax.

BACKGROUND: Femoral dP/dtmax (maximum rate of the arterial pressure increase during systole) measured by pulse contour analysis has been proposed as a surrogate of left ventricular (LV) dP/dtmax and as an estimator of LV systolic function. However, femoral dP/dtmax may be influenced by LV loading conditions. In this study, we evaluated the impact of variations of LV systolic function, preload and afterload on femoral dP/dtmax in critically ill patients with cardiovascular failure to ascertain its reliability as a marker of LV systolic function. RESULTS: We performed a prospective observational study to evaluate changes in femoral dP/dtmax, thermodilution-derived variables (PiCCO2-Pulsion Medical Systems, Feldkirchen, Germany) and LV ejection fraction (LVEF) measured by transthoracic echocardiography during variations in dobutamine and norepinephrine doses and during volume expansion (VE) and passive leg raising (PLR). Correlations with arterial pulse and systolic pressure, effective arterial elastance, total arterial compliance and LVEF were also evaluated. In absolute values, femoral dP/dtmax deviated from baseline by 21% (201 ± 297 mmHg/s; p = 0.013) following variations in dobutamine dose (n = 17) and by 15% (177 ± 135 mmHg/s; p < 0.001) following norepinephrine dose changes (n = 29). Femoral dP/dtmax remained unchanged after VE and PLR (n = 24). Changes in femoral dP/dtmax were strongly correlated with changes in pulse pressure and systolic arterial pressure during dobutamine dose changes (R = 0.942 and 0.897, respectively), norepinephrine changes (R = 0.977 and 0.941, respectively) and VE or PLR (R = 0.924 and 0.897, respectively) (p < 0.05 in all cases). Changes in femoral dP/dtmax were correlated with changes in LVEF (R = 0.527) during dobutamine dose variations but also with effective arterial elastance and total arterial compliance in the norepinephrine group (R = 0.638 and R = - 0.689) (p < 0.05 in all cases). CONCLUSIONS: Pulse contour analysis-derived femoral dP/dtmax was not only influenced by LV systolic function but also and prominently by LV afterload and arterial waveform characteristics in patients with acute cardiovascular failure. These results suggest that femoral dP/dtmax calculated by pulse contour analysis is an unreliable estimate of LV systolic function during changes in LV afterload and arterial load by norepinephrine and directly linked to arterial waveform determinants.

Trends in the incidence and mortality of patients with community-acquired septic shock 2003-2016.

PURPOSE: To evaluate the incidence and mortality of adult patients with community-acquired septic shock (CASS) and the influence of source control (SC) and other risk factors on the outcome. MATERIAL AND METHODS: The study included patients with CASS admitted to the ICU at a university hospital (2003-2016). Multivariate analyses were performed to identify risk factors of ICU mortality. RESULTS: A total of 625 patients were included. The incidence showed an average annual increase of 4.9% and the mortality an average annual decrease of 1.4%. The patients who required SC showed a lower mortality (20.4%) than patients who did not require SC (31.3%) (p = 0.002). However, the evolution in mortality was different: Mortality decreased in patients who did not require SC (from 56.3% to 20%; p = 0.02), but did not differ in those who required SC (from 21.4% to 27.6%; p = 0.43). In the multivariate analysis, severity at admission, age, alcoholism, cirrhosis, ARDS, neutropenia and thrombocytopenia were associated with worse outcome, whereas appropriate antibiotic treatment and adequate SC were independently associated with better survival. CONCLUSIONS: The incidence of CASS increased and the ICU mortality decreased during the study period. The mortality was mainly due to a decrease in mortality in infections not requiring SC.

Echocardiographic diagnosis of pulmonary artery occlusion pressure elevation during weaning from mechanical ventilation.

OBJECTIVE: Weaning-induced pulmonary edema is a cause of weaning failure in high-risk patients. The diagnosis may require pulmonary artery catheterization to demonstrate increased pulmonary artery occlusion pressure (PAOP) during weaning. Transthoracic echocardiography can estimate left ventricular filling pressures using early (E) and late (A) peak diastolic velocities measured with Doppler transmitral flow, and tissue Doppler imaging of mitral annulus velocities including early (Ea) peak diastolic velocity. We tested the hypothesis that E/A and E/Ea could be used to detect weaning-induced PAOP elevation defined by a PAOP > or =18 mm Hg during a spontaneous breathing trial (SBT). MEASUREMENTS AND MAIN RESULTS: We included 39 patients who previously failed two consecutive SBTs. A third SBT was performed over a maximum 1-hour period using a T-piece. The PAOP, E/A, and E/Ea were measured before and during this SBT. Receiver operating characteristic curves were constructed to determine the optimal sensitivity and specificity values of E/A and E/Ea obtained at the end of the SBT for predicting a weaning-induced PAOP elevation. Weaning-induced PAOP elevation occurred in 17 patients. A value of E/A >0.95 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 88% and a specificity of 68%. A value of E/Ea >8.5 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 94% and a specificity of 73%. The combination of E/A >0.95 and E/Ea >8.5 predicted a weaning-induced PAOP elevation with a sensitivity of 82% and a specificity of 91%. CONCLUSION: At the end of an SBT, the combination of E/A >0.95 and E/Ea >8.5 measured with transthoracic echocardiography allowed an accurate noninvasive detection of weaning-induced PAOP elevation.

Echocardiographic prediction of volume responsiveness in critically ill patients with spontaneously breathing activity.

OBJECTIVE: In hemodynamically unstable patients with spontaneous breathing activity, predicting volume responsiveness is a difficult challenge since the respiratory variation in arterial pressure cannot be used. Our objective was to test whether volume responsiveness can be predicted by the response of stroke volume measured with transthoracic echocardiography to passive leg raising in patients with spontaneous breathing activity. We also examined whether common echocardiographic indices of cardiac filling status are valuable to predict volume responsiveness in this category of patients. DESIGN AND SETTING: Prospective study in the medical intensive care unit of a university hospital. PATIENTS: 24 patients with spontaneously breathing activity considered for volume expansion. MEASUREMENTS: We measured the response of the echocardiographic stroke volume to passive leg raising and to saline infusion (500 ml over 15 min). The left ventricular end-diastolic area and the ratio of mitral inflow E wave velocity to early diastolic mitral annulus velocity (E/Ea) were also measured before and after saline infusion. RESULTS: A passive leg raising induced increase in stroke volume of 12.5% or more predicted an increase in stroke volume of 15% or more after volume expansion with a sensitivity of 77% and a specificity of 100%. Neither left ventricular end-diastolic area nor E/Ea predicted volume responsiveness. CONCLUSIONS: In our critically ill patients with spontaneous breathing activity the response of echocardiographic stroke volume to passive leg raising was a good predictor of volume responsiveness. On the other hand, the common echocardiographic markers of cardiac filling status were not valuable for this purpose.

The fully automatic external cardioverter defibrillator: reality of a new meaningful scenario for in-hospital cardiac arrests.

Sudden cardiac death is an unresolved problem which causes significant mortality and morbidity in both the community and in-hospital setting. Cardiac arrest is often caused by ventricular tachyarrhythmias which may be mostly interrupted by cardioversion or defibrillation. The single most critical factor for survival is the response time. Over the last 30 years, there have been virtually no procedural changes in the way hospitals address in-hospital resuscitation. A unique device has been developed that eliminates human intervention and assures defibrillation therapy is administered in seconds. This is accomplished with a fully automatic, external bedside monitor defibrillator designed to be prophylactically attached to hospitalized patients at risk of ventricular tachyarrhythmia. The safety and efficacy of the device has been demonstrated in multicenter US and European trials. Thus, this device allows a new scenario which may increase survival and enables meaningful redistribution of health resources.

Systemic inflammatory response and progression to severe sepsis in critically ill infected patients.

RATIONALE: The systemic inflammatory response syndrome has low specificity to identify infected patients at risk of worsening to severe sepsis or shock. OBJECTIVE: To examine the incidence of and risk factors for worsening sepsis in infected patients. METHODS: A 1-year inception cohort study in 28 intensive care units of patients (n = 1,531) having a first episode of infection on admission or during the stay. MEASUREMENTS AND MAIN RESULTS: The cumulative incidence of progression to severe sepsis or shock was 20% and 24% at Days 10 and 30, respectively. Variables independently associated (hazard ratio [HR]) with worsening sepsis included: temperature higher than 38.2 degrees C (1.6), heart rate greater than 120/minute (1.3), systolic blood pressure higher than 110 mm Hg (1.5), platelets higher than 150 x 109/L (1.5), serum sodium higher than 145 mmol/L (1.5), bilirubin higher than 30 mumol/L (1.3), mechanical ventilation (1.5), and five variables characterizing infection (pneumonia [HR 1.5], peritonitis [1.5], primary bacteremia [1.8], and infection with gram-positive cocci [1.3] or aerobic gram-negative bacilli [1.4]). The 12 weighted variables were included in a score (Risk of Infection to Severe Sepsis and Shock Score, range 0-49), summarized in four classes of "low" (score 0-8) and "moderate" (8.5-16) risk (9% and 17% probability of worsening, respectively), and of "high" (16.5-24) and "very high" (score > 24) risk (31% and 55% probability, respectively). CONCLUSIONS: One of four patients presenting with infection/sepsis worsen to severe sepsis or shock. A score estimating this risk, using objectively defined criteria for systemic inflammatory response syndrome, could be used by physicians to stratify patients for clinical management and to test new interventions.

Community-acquired bloodstream infection in critically ill adult patients: impact of shock and inappropriate antibiotic therapy on survival.

DESIGN: The objectives were to characterize the prognostic factors and evaluate the impact of inappropriate empiric antibiotic treatment and systemic response on the outcome of critically ill patients with community-acquired bloodstream infection (BSI). PATIENTS: A prospective, multicenter, observational study was carried out in 339 patients admitted in 30 ICUs for BSI. RESULTS: Crude mortality was 41.5%. Septic shock was present in 184 patients (55%). The pathogens most frequently associated with septic shock or death were Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae, which accounted for approximately half of the deaths. Antibiotic treatment was found to be inappropriate in 14.5% of episodes. Patients in septic shock with inappropriate treatment had a survival rate below 20%. Multivariate analysis identified a significant association between septic shock and four variables: age > or = 60 years (odds ratio [OR], 1.96), previous corticosteroid therapy (OR, 2.58), leukopenia (OR, 2.32), and BSI secondary to intra-abdominal (OR, 2.38) and genitourinary tract (OR, 2.29) infections. The variables that independently predicted death at ICU admission were APACHE (acute physiology and chronic health evaluation) II score > or = 15 (OR, 2.42), development of septic shock (OR, 3.22), and inappropriate empiric antibiotic treatment (OR, 4.11). This last variable was independently associated with an unknown source of sepsis (OR, 2.49). Mortality attributable to inappropriate antibiotic treatment increased with the severity of illness at ICU admission (10.7% for APACHE II score < 15 and 41.8% for APACHE II score > or = 25, p < 0.01). CONCLUSIONS: Inappropriate antimicrobial treatment is the most important influence on outcome in patients admitted to the ICU for community-acquired BSI, particularly in presence of septic shock or high degrees of severity. Initial broad-spectrum therapy should be prescribed to septic patients in whom the source is unknown or in those requiring vasopressors.

Evaluation of a noninvasive method for cardiac output measurement in critical care patients.

OBJECTIVE: Thermodilution (TD) is the gold standard to monitor cardiac output (CO) in critical care. However, there is concern about the safety of right-ventricular catheterization. The CO(2) rebreathing technique allows noninvasive CO determination by means of the indirect Fick principle. Our objectives were: (a) to assess the accuracy of a new system of CO measurement using the CO(2) partial rebreathing method (PRCO); (b) to evaluate whether the PRCO itself may induce changes in CO. DESIGN AND SETTING: Prospective study in the intensive care department in a university-affiliated hospital. PATIENTS: Twenty-two mechanically ventilated critically ill patients. INTERVENTIONS: CO measured simultaneously by PRCO and TDCO. MEASUREMENTS AND RESULTS: PRCO and TDCO values were compared by concordance analysis. Stability of cardiac output during PRCO was evaluated by comparing the TDCO measurements before, during, and after the partial rebreathing period using analysis of variance. From a total of 79 valid sets of measurements, bias and precision was calculated at -0.18+/-1.39 l/min. The concordance analysis of lower and intermediate CO values (<7 l/min) yielded a bias and precision calculation of -0.07+/-0.91 l/min. No changes in hemodynamics were observed during the partial rebreathing period. CONCLUSIONS: The noninvasive partial CO(2) rebreathing technique may be an alternative method for CO determination in mechanically ventilated critically ill patients. The rebreathing maneuver alone does not induce changes in CO.