Annals of Intensive Care最新文献

Invasive arterial blood pressure (BP) monitoring is a cornerstone of hemodynamic assessment in critically ill patients. This review explores how the individual components of BP-systolic arterial (SAP), diastolic arterial (DAP), mean arterial (MAP), and pulse pressure (PP)-offer valuable insights into cardiovascular physiology and can be leveraged as real-time therapeutic tools in intensive care settings. A strong emphasis is placed on the technical requirements for accurate BP waveform interpretation and the physiological meaning of each BP component. PP is examined as a surrogate for stroke volume and a dynamic marker of fluid responsiveness, particularly in mechanically ventilated patients. DAP is discussed as a reflection of vasomotor tone, with clinical implications for guiding the initiation of vasopressors. The concept of diastolic shock index (DSI) and the newly proposed VNERi ratio (DAP/[Heart rate × norepinephrine dose]) are introduced as potentially superior markers for assessing vascular tone and vasopressor responsiveness, respectively. These indices may facilitate earlier identification of patients requiring escalation of vasopressor therapy, including the initiation of vasopressin in addition to norepinephrine. The review advocates for a physiology-driven, individualized approach to hemodynamic management, using invasive BP not merely as a safety parameter but as an actionable guide for precision resuscitation.

Background: The spread of multidrug-resistant microorganisms (MDROs), including extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E), has increased worldwide and constitutes a significant public health challenge. International guidelines vary in their recommendations for isolation in single rooms and contact precautions regarding carriers of MDR microorganisms to mitigate cross-contamination in the ICU. The aim of this study was to investigate whether contact precautions without single-room isolation prevent cross-contamination of ESBL-E in an intensive care unit (ICU).

Methods: All patients admitted to a general ICU during a period of 19 months were included. The study began before the COVID-19 pandemic and continued, albeit interrupted during the first wave, through the second and third wave. Rectal swabs, swabs from drainages and intravenous catheters were sampled for the detection of ESBL-E in all patients at the time of admission. Swabs were also taken from all patients co-treated with an ESBL-E-positive patient (i.e., the index patient) at the time of discharge. All cross-contaminated patient bacterial isolates were analyzed with whole-genome sequencing and compared to the isolate from the corresponding index patient.

Results: Of 1042 patients admitted to the ICU, 82 patients were index patients, either known ESBL-carriers or tested positive at admission. 365 ESBL-E-negative patients (n=365) at ICU admission were co-treated in the same room as an index patient during their ICU-stay. Post-ICU discharge, three patients from the latter group tested positive for ESBL-E. No bacterial ESBLisolates from the latter patients corresponded to those of the index patients when their bacterial genomes were identified and compared.

Conclusions: Contact precautions without single-room isolation of ESBL-E-positive patients did not result in any cross-contamination between ICU-patients in an endemic setting with a short length of stay.

Background: Intensive care units (ICU) play a significant role in healthcare global greenhouse gas emissions. Ventilator-associated pneumonia (VAP) is a common ICU-acquired infection, and while microbiological confirmation is essential, the optimal sampling method remains controversial. This study compares the carbon footprint of three diagnostic techniques for VAP-tracheal aspiration (TA), blind bronchial sampling (BBS) and bronchoalveolar lavage (BAL) using single-use bronchoscopes-while also assessing their economic cost and professional impact to support more sustainable decision-making in the ICU.

Methods: The carbon footprint of each technique was estimated using a simplified Life Cycle Assessment (LCA) methodology via the "Carebone©" tool. Emission factors for drugs and devices were calculated. The economic costs of each procedure were also assessed. Finally, a survey of nursing staff was conducted to assess the professional impact of these techniques.

Results: Tracheal aspiration had the lowest emissions (0.57 kgCO₂e) and cost (€4), followed by BBS (2.82 kgCO₂e, €24) and BAL (6.60 kgCO₂e, €209). Nursing staff perceived BBS the most practical technique overall, and BAL the most technically demanding. In 2023, 341 procedures were performed in our ICU (73% BBS, 21% BAL, 6% TA), generating 1,181 kgCO2e and costing €20,835. Adopting TA exclusively in our ICU would reduce emissions by 84% and costs by 93%, whereas using BAL exclusively would increase emissions by 91% and costs by 242%.

Conclusion: Bronchoalveolar lavage was associated with the highest carbon footprint and cost. These findings can help clinicians choose more sustainable methods for microbiological confirmation of VAP.

Background: While antibiotic exposure is a known key risk factor for acquiring Carbapenem-resistant Gram-negative bacteria (CR-GNB) in the ICU, the independent contributions and relative importance of its core dimensions-spectrum, dose, and duration-remain poorly understood. This study aimed to clarify these specific relationships to inform the optimization of antibiotic stewardship strategies.

Methods: We prospectively enrolled consecutive adult patients admitted to 4 ICUs at a university hospital between March 2024 and January 2025. Patients were screened for CR-GNB upon admission and weekly. Antibiotic exposure was quantified by spectrum (Antibiotic Spectrum Index per antibiotic day [ASI]), dose (Defined Daily Doses [DDDs]), and duration (Length of Therapy [LOT]). The primary outcome was ICU-acquired CR-GNB. We used interval-censored Cox regression to assess associations. Restricted cubic splines were used to explore potential non-linear relationships, and relative importance analysis was performed to compare the impact of the exposure metrics.

Results: Overall, 151 of 422 patients (35.8%) acquired CR-GNB during their ICU stay, with a median follow-up of 12.0 days (interquartile range, 8.0-17.0). ASI per antibiotic day was independently associated with an increased risk of ICU-acquired CR-GNB (adjusted Hazard Ratio [aHR] per 1-unit increase, 1.14; 95% Confidence Interval [CI] 1.09-1.19; P < 0.001), exhibiting a non-linear J-shaped relationship (P for nonlinearity = 0.027). In contrast, after full adjustment, DDDs were not significantly associated with CR-GNB acquisition (aHR per 1-unit increase, 0.89; 95% CI 0.69-1.15; P = 0.374), despite displaying a non-linear inverted U-shaped relationship (P for nonlinearity < 0.001). Similarly, LOT showed no significant independent association in the fully adjusted model (aHR per 1-day increase, 1.03; 95% CI 0.97-1.11; P = 0.214), although a non-linear trend suggested increasing risk with longer durations (P for nonlinearity < 0.001). Relative importance analysis identified ASI per antibiotic day as the most critical factor (P < 0.001), significantly outweighing both DDDs and LOT (P > 0.05).

Conclusions: This study identifies ASI per antibiotic day as the principal independent risk factor for ICU-acquired CR-GNB, significantly outweighing the adjusted impact of DDDs or LOT. Therefore, prioritizing antibiotic spectrum optimization is crucial for stewardship strategies targeting CR-GNB prevention in the ICU.

Trial registration: Chinese Clinical Trial Registry Identifier ChiCTR2400081352. Registered 28 February 2024.

Ventilatory management of acute respiratory distress syndrome (ARDS) requires a careful balance between achieving adequate gas exchange and minimizing ventilator-induced lung injury (VILI). Recent advances in bedside monitoring of respiratory mechanics have created new opportunities to individualize mechanical ventilation by aligning ventilator settings with the patient's dynamic pathophysiology. This review synthesizes current evidence on key respiratory mechanics parameters - such as driving pressure, respiratory system compliance, airway resistance, mechanical power - and examines how they can guide titration of tidal volume, positive end-expiratory pressure (PEEP), and respiratory rate. By integrating real-time assessments of respiratory mechanics, clinicians can reduce stress and strain, limit alveolar overdistension and collapse, and optimize oxygenation and ventilation. Moreover, practical strategies are discussed for implementing physiology-guided ventilation in the intensive care unit, with attention to patient-specific characteristics and the heterogeneity of ARDS subphenotypes. Respiratory mechanics-guided ventilation represents a pragmatic, individualized strategy that enhances lung protection, complements established protocols and may contribute to improve survival. Further experimental and clinical studies are required to validate these approaches and translate them into precision medicine for ARDS.

Background: Awake prone positioning (APP) reduces the risk of endotracheal intubation and mortality in COVID-19-related acute respiratory failure (ARF) receiving high-flow nasal oxygen (HFNO). However, a significant proportion of patients undergoing APP are ultimately intubated, and mortality in this subgroup remains high. We aimed to develop a predictive model to be applied within the first 24 h of APP to identify patients at higher risk of progressing to intubation within 72 h of APP initiation.

Methods: We conducted a secondary analysis of a prospective multicenter cohort including adult patients with COVID-19-related ARF admitted to six intensive care units in Argentina between June 2020 and January 2021. Eligible patients received HFNO and APP for at least 6 h per day. Physiological variables were collected at ICU admission (baseline) and 24 h after APP initiation. Two multivariable logistic regression models were developed using baseline and 24-hour variables, respectively. Predictors were selected based on clinical relevance and univariable associations. A final model was constructed by integrating variables retained from both time points.

Results: Of 400 patients included, 136 (34%) required intubation within the first 72 h. Patients who required intubation were older, had lower PaO₂ and PaO₂/FiO₂ ratios, and higher respiratory rates both at baseline and after 24 h. The final predictive model included five variables: age, respiratory rate, PaO₂, FiO₂, and SaO₂/FiO₂ ratio, all measured 24 h after APP initiation. A nomogram was developed based on this model to estimate the individual risk of early intubation.

Conclusion: In patients with COVID-19-related ARF treated with HFNO and APP, a model combining baseline characteristics and early physiological response can help predict the need for intubation within 72 h. This tool may support clinicians in identifying high-risk patients and making timely, individualized decisions about escalation of care.

A pressure distends blood vessels even when the heart is not beating and there is no blood flow. This is called mean circulatory filling pressure (MCFP). We will first discuss why it is physiologically necessary to have this base pressure. Although all pressures in the vasculature are the same when there is no flow, blood volume distributes based on the compliance of the walls in each compartment. The compliance of systemic venous compartment is by far the largest and contain most of the blood volume. When flow starts, volume redistributes among the vascular regions based on the compliance and resistance draining them. Because of it dominates the total compliance, pressure in the systemic venous compartment changes very little; it is called mean systemic filling pressure (MSFP). Under normal hemodynamic conditions, differences between MCFP and MSFP are trivial because venous compliance is so large compared to all other vascular regions. When cardiac function is maximal, MCFP determines the maximum possible cardiac output. MSFP is significant for two reasons. It is the upstream pressure driving blood back to the right heart. Importantly, it also is the downstream pressure for systemic capillary drainage. Thus, a high MSFP increases the risk of tissue edema. From our review of the studies, the pressure difference from MSFP to the right atrium (RAP) is generally in the 3 to 6 mmHg range so that MSFP can be approximated by adding values in this range to properly measured RAP. Ideally, MSFP should be less than 10 mmHg to limit capillary drainage.

Background: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used in patients with cardiogenic shock. It results in cardiopulmonary shunting with reduced native cardiac output. Volume expansion is usually administered to increase native cardiac output, in order to improve peripheric perfusion or to avoid thromboembolic complications in cardiac cavities. End-tidal carbon dioxide (EtCO₂) is known to be related to native cardiac output. Our hypothesis was that EtCO₂ changes induced by passive leg raising predict fluid responsiveness in patients under VA-ECMO.

Methods: In this prospective, interventional study, patients under VA-ECMO support were included, provided they required volume expansion. The protocol included three sequential steps: (1) Baseline in supine position (2) Passive leg raising (3) Volume expansion in basal position. Hemodynamic parameters were recorded at each step. Fluid responsiveness was defined as a velocity time integral at the left ventricle outflow tract increase of 15% or more after volume expansion. The ability of passive leg raising induced changes in EtCO₂ to predict fluid responsiveness was evaluated with area under the receiver operating characteristics curve (AUC).

Results: 41 patients were studied; 58 passive leg raising - volume expansion tests were recorded. Fluid responsiveness was observed in 38 of the 58 measurements (65%). Passive leg raising test has correctly mimicked volume expansion (intraclass correlation coefficient 0.83 [0.73-0.9]). Considering all measurements, AUC of passive leg raising-changes in velocity time integral to predict fluid responsiveness was 0.89 [0.79-0.99] and remained good whatever the basal native cardiac output. Sensitivity and specificity were 92% [85-100] and 80% [69-90] respectively for a threshold of 15%. AUC of passive leg raising-induced changes in EtCO₂ for predicting fluid responsiveness was good (0.98 [0.95-1]) only when basal native cardiac output was ≤ 1 L/min.

Conclusion: Passive leg raising test can predict fluid responsiveness under VA-ECMO. EtCO₂ changes induced by passive leg raising test can be used to detect fluid responsiveness in patients with native cardiac output ≤ 1 L/min under VA-ECMO. This test is easy to perform, reliable and may help to avoid unnecessary and potentially harmful fluid loading.

Background: Assessing sources of job stress in intensive care units is a critical issue for preventing many occupational health and care-related issues, such as burnout, voluntary turnover and decrease in quality and safety of care. Accordingly, this French nation-wide multicentre study aims to provide supplementary evidence regarding the validity of a recent tool: the Perceived Stressors in Intensive Care Units (PS-ICU) scale. More precisely, this study has three main objectives: to 1) confirm the metrological properties of the PS-ICU scale on a large sample of professionals; 2) test its measurement invariance between nurses, physicians and residents (initial population targeted by the scale); 3) examine whether the scale would also be suited for use with nursing auxiliaries. In addition, depending on the results (which may suggest the removal of several items), this study offers the possibility to shorten the scale to facilitate its use.

Method and results: 2241 ICU professionals (1135 nurses, 308 physicians, 179 residents, and 619 nursing auxiliaries; overall participation rate of 58.10%) from 42 ICUs in France, voluntarily completed an online questionnaire collecting socio-demographic data and perceived job stressors (PS-ICU). Exploratory structural equation modelling (ESEM), unidimensional reliability (McDonald's Omega) and item response theory (IRT) analyses overall confirmed the metrological properties of the scale, while several items were removed and the sixth factor ("lack of support and resources from the organisation") measured by the scale was revised. Results regarding measurement invariance show that the PS-ICU scale can be used to compare occupational groups, including nursing auxiliaries. Finally, all analyses resulted in a reduction of the scale to a 26-item version.

Conclusions: The PS-ICU scale, which measures generic and ICU-specific job stress factors, is a valid and reliable scale that can be used to collect data from nurses, physicians and residents, as well as from nursing auxiliaries. With 26 items, it can be used by researchers and managers in ICUs to assess the extent and type of stress factors perceived by healthcare professionals.