Critical Care最新文献

{"title":"Infusion of sodium DL-3-ß-hydroxybutyrate decreases cerebral injury biomarkers after resuscitation in experimental cardiac arrest","authors":"Filippo Annoni, Fuhong Su, Lorenzo Peluso, Ilaria Lisi, Enrico Caruso, Francesca Pischiutta, Elisa Gouvea Bogossian, Bruno Garcia, Hassane Njimi, Jean-Louis Vincent, Nicolas Gaspard, Lorenzo Ferlini, Jacques Creteur, Elisa R. Zanier, Fabio Silvio Taccone","doi":"10.1186/s13054-024-05106-8","DOIUrl":"https://doi.org/10.1186/s13054-024-05106-8","url":null,"abstract":"Cerebral complications after cardiac arrest (CA) remain a major problem worldwide. The aim was to test the effects of sodium-ß-hydroxybutyrate (SBHB) infusion on brain injury in a clinically relevant swine model of CA. CA was electrically induced in 20 adult swine. After 10 min, cardiopulmonary resuscitation was performed for 5 min. After return of spontaneous circulation (ROSC), the animals were randomly assigned to receive an infusion of balanced crystalloid (controls, n = 11) or SBHB (theoretical osmolarity 1189 mOsm/l, n = 8) for 12 h. Multimodal neurological and cardiovascular monitoring were implemented in all animals. Nineteen of the 20 animals achieved ROSC. Blood sodium concentrations, osmolarity and circulating KBs were higher in the treated animals than in the controls. SBHB infusion was associated with significantly lower plasma biomarkers of brain injury at 6 (glial fibrillary acid protein, GFAP and neuron specific enolase, NSE) and 12 h (neurofilament light chain, NFL, GFAP and NSE) compared to controls. The amplitude of the stereoelectroencephalograph (sEEG) increased in treated animals after ROSC compared to controls. Cerebral glucose uptake was lower in treated animals. In this experimental model, SBHB infusion after resuscitated CA was associated with reduced circulating markers of cerebral injury and increased sEEG amplitude.","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"12 1","pages":"314"},"PeriodicalIF":15.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High flow nasal cannula versus non-invasive ventilation in the treatment of acute exacerbations of COPD with acute-moderate hypercapnic respiratory failure","authors":"Rongpeng Xu, Ziqiang Shao","doi":"10.1186/s13054-024-05094-9","DOIUrl":"https://doi.org/10.1186/s13054-024-05094-9","url":null,"abstract":"<p>Dear Editor,</p><p>Recently, we read with great interest the article by Tan et al. [1], in which the authors demonstrated that compared to high-flow nasal cannula oxygen (HFNC), non-invasive ventilation (NIV) is a better choice for initial respiratory support in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) complicated by acute-moderate hypercapnic respiratory failure. Although this result highlights the efficacy of NIV in the treatment of AECOPD patients, we believe that there are still certain issues that need to be clarified in the study conducted by Tan et al.</p><p>First, the gas flow rate of HFNC during treatment needs to be noticed. Mechanically, the high gas flow rate of HFNC can wash out the dead space of chronic obstructive pulmonary disease (COPD) patients, and effectively decreases pressure of arterial carbon dioxide (PaCO<sub>2</sub>). Studies have shown that HFNC as initial respiratory support is non-inferior to NIV in decreasing PaCO<sub>2</sub> after 2 h of treatment in patients with mild-to-moderate AECOPD [2]. However, carbon dioxide retention was the most common reason for treatment failure in the HFNC group in this study. Therefore, whether raising the initial gas flow rate from 40 L/min to 60 L/min could improve the treatment success rate of HFNC. It is worth noting that study has shown that higher gas flow rate than 30 L/min not only fails to lower PaCO<sub>2</sub> but also increases inspiratory effort [3]. In short, the initial gas flow rate of 40 L/min does not seem to be an optimal setting. In addition, HFNC has the advantage of comfort and is usually used continuously after obtaining the optimal gas flow rate required by the patient. In this study, intermittent downregulation of gas flow rate or even discontinuation of HFNC was adopted in the HFNC group, which may be a key factor leading to the failure of HFNC treatment.</p><p>Additionally, the baseline data lacks of information on the frequency of acute exacerbations in patients. The 2017 Global Strategy for the Diagnosis, Management and Prevention of COPD report noted that that the frequency of previous hospitalizations for acute exacerbations of COPD and concurrent cardiovascular disease comorbidities are associated with poor outcomes in patients [4]. Therefore, it is necessary to list the frequency of acute exacerbations and to describe the cardiovascular comorbidities such as heart failure, hypertension, and arrhythmia in the baseline data, which may significantly affect the success of respiratory therapy in each group of patients.</p><p>Furthermore, Oxygen therapy and ventilatory support are only one part of AECOPD treatment [4]. It is well known that the use of bronchodilators is critical in the treatment of AECOPD. Through dilating the bronchi and bronchioles, bronchodilators not only improve the exchange of oxygen and carbon dioxide, but also facilitate the expulsion of sputum, which is closely related to the success of o","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"12 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The procalcitonin trajectory as an effective tool for identifying sepsis patients at high risk of mortality","authors":"Xu Wang, Shilong Lin, Ming Zhong, Jieqiong Song","doi":"10.1186/s13054-024-05100-0","DOIUrl":"https://doi.org/10.1186/s13054-024-05100-0","url":null,"abstract":"<p>Sepsis is a critical condition that significantly burdens healthcare systems globally. Given the heterogeneity among sepsis patients, identifying high-risk mortality groups is crucial [1]. Procalcitonin (PCT) is a well-established biomarker for evaluating sepsis severity and guiding antibiotic therapy [2]. In practice, PCT is usually measured repeatedly during the hospital stay. While single PCT values are helpful, dynamic trends through repeated measurements offer deeper insights into patient prognosis. Traditional analysis methods often fail to fully capture the complexity of these data [3]. By employing a hierarchical linear mixed-effects (HLME) model [4], this study aims to explore distinct PCT trajectories in sepsis patients and their association with mortality, providing a refined approach to risk stratification.</p><p>We here report our main findings in this study. The medical ethics committee of Zhongshan Hospital Fudan University reviewed and approved this study (B2021-501R). Informed consent was waived because of the retrospective nature of the study and the analysis used anonymous clinical data. Between Jan 2019 and March 2024, 537 patients (167 females, 370 males; median age 69 years old [IQR 59–77]) were included. The proportion of patients with septic shock is 47.5%. Abdomen (274/51.0%) and respiratory (202/37.6%) were the two main sites of infection. The median length of stay (LOS) was 10 days [IQR 4–20] in ICU and 15 days [IQR 10–25] in hospital. One hundred sixty-five in-hospital deaths were observed.</p><p>A total of 2492 PCT measurements were available for trajectory modeling analyses. Three classes were identified using the HLME model (Fig. 1A). Class 1, also known as the “high-value-slow-decrease” class, included 43 patients (8%) and was characterized by initially high PCT values that remained stable for the first three days before gradually declining. Class 2, the “consistent-low” class, included 354 patients (66%) and displayed low initial PCT values that remained consistently low over the first 7 days in the ICU. Class 3, the “high-value-fast-decrease” class, included 140 patients (26%) and was marked by high initial PCT values that declined rapidly over time. Baseline characteristics differed significantly between the three PCT classes (Table 1). Patients in Class 1 and Class 3 had higher baseline SOFA scores and required more norepinephrine to maintain blood pressure compared to Class 2. In-hospital mortality was highest in Class 1 (42%) compared to Class 2 (32%) and Class 3 (24%) (<i>P</i> = 0.044). Baseline variables (age, sex, baseline SOFA, baseline lactate, presence of septic shock, surgical intervention, infection sites) and PCT classes were included in the Cox proportional hazards model for in-hospital mortality. With Class 1 as the reference level, Class 2 (HR: 0.507 [95% CI 0.287–0.895], <i>P</i> = 0.020) and Class 3 (HR 0.449 [95% CI 0.244–0.827], <i>P</i> = 0.011) were independent protective factors for in-","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"7 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-insufflation diaphragm contractions in patients receiving various modes of mechanical ventilation","authors":"Antenor Rodrigues, Fernando Vieira, Michael C. Sklar, L. Felipe Damiani, Thomas Piraino, Irene Telias, Ewan C. Goligher, W. Darlene Reid, Laurent Brochard","doi":"10.1186/s13054-024-05091-y","DOIUrl":"https://doi.org/10.1186/s13054-024-05091-y","url":null,"abstract":"During mechanical ventilation, post-insufflation diaphragm contractions (PIDCs) are non-physiologic and could be injurious. PIDCs could be frequent during reverse-triggering, where diaphragm contractions follow the ventilator rhythm. Whether PIDCs happens with different modes of assisted ventilation is unknown. In mechanically ventilated patients with hypoxemic respiratory failure, we aimed to examine whether PIDCs are associated with ventilator settings, patients’ characteristics or both. One-hour recordings of diaphragm electromyography (EAdi), airway pressure and flow were collected once per day for up to five days from intubation until full recovery of diaphragm activity or death. Each breath was classified as mandatory (without-reverse-triggering), reverse-triggering, or patient triggered. Reverse triggering was further subclassified according to EAdi timing relative to ventilator cycle or reverse triggering leading to breath-stacking. EAdi timing (onset, offset), peak and neural inspiratory time (Tineuro) were measured breath-by-breath and compared to the ventilator expiratory time. A multivariable logistic regression model was used to investigate factors independently associated with PIDCs, including EAdi timing, amplitude, Tineuro, ventilator settings and APACHE II. Forty-seven patients (median[25%-75%IQR] age: 63[52–77] years, BMI: 24.9[22.9–33.7] kg/m2, 49% male, APACHE II: 21[19–28]) contributed 2 ± 1 recordings each, totaling 183,962 breaths. PIDCs occurred in 74% of reverse-triggering, 27% of pressure support breaths, 21% of assist-control breaths, 5% of Neurally Adjusted Ventilatory Assist (NAVA) breaths. PIDCs were associated with higher EAdi peak (odds ratio [OR][95%CI] 1.01[1.01;1.01], longer Tineuro (OR 37.59[34.50;40.98]), shorter ventilator inspiratory time (OR 0.27[0.24;0.30]), high peak inspiratory flow (OR 0.22[0.20;0.26]), and small tidal volumes (OR 0.31[0.25;0.37]) (all P ≤ 0.008). NAVA was associated with absence of PIDCs (OR 0.03[0.02;0.03]; P < 0.001). Reverse triggering was characterized by lower EAdi peak than breaths triggered under pressure support and associated with small tidal volume and shorter set inspiratory time than breaths triggered under assist-control (all P < 0.05). Reverse triggering leading to breath stacking was characterized by higher peak EAdi and longer Tineuro and associated with small tidal volumes compared to all other reverse-triggering phenotypes (all P < 0.05). In critically ill mechanically ventilated patients, PIDCs and reverse triggering phenotypes were associated with potentially modifiable factors, including ventilator settings. Proportional modes like NAVA represent a solution abolishing PIDCs.","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"61 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142236435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Further support for the intracranial compartmental syndrome concept","authors":"Daniel Agustin Godoy, Sergio Brasil, Andres M. Rubiano","doi":"10.1186/s13054-024-04974-4","DOIUrl":"https://doi.org/10.1186/s13054-024-04974-4","url":null,"abstract":"&lt;p&gt;The current approach to severe neuro-injury monitoring, especially traumatic brain injury (TBI), has experienced paradigm shifts that open a broad outlook for the future [1]. On one hand, advances in pathophysiological knowledge have made possible establishing today that intracranial pressure (ICP) control is just one more epiphenomenon within other serious events that occur simultaneously such as tissue hypoxia, metabolic crises and cerebral energy dysfunction [1]. On the other hand, the advent of new monitoring techniques (invasive and noninvasive) have allowed a deeper analysis in real time of what is happening in the injured brain [1]. One of the most important advancements in neuromonitoring was the recent popularization of the analysis of the ICP wave (ICPw) morphology. Current studies pointed the changes in ICPw as reliable markers of cerebrospinal compliance and to be followed in clinical environments. In this regard, ICPw was considered the pillar of the intracranial compartmental syndrome (ICCS) concept [2]. So, &lt;i&gt;“ICCS occurs when the compliance of the intracranial system is compromised as a result of the exhaustion of the compensating mechanisms that try to keep it within normal limits’’&lt;/i&gt;. ‘&lt;i&gt;’Perfusion, oxygenation and energy utilization compromise are its consequences’’&lt;/i&gt; [2]&lt;i&gt;.&lt;/i&gt;&lt;/p&gt;&lt;p&gt;Further enlightenments raised from the recent study of Kazimierska et al., which evaluated a series of 130 patients who were victims of severe TBI from the CENTER-TBI database. Those authors analyzed the relationship between parameters obtained from the neuroimaging Computed Tomography (CT) scan upon admission and variables collected from invasive ICP monitoring [3]. Injury mass volume, degree of midline shift, Marshall’s and Rotterdam classifications were the data provided by the CT scans, while mean ICP values, wave amplitude and indices derived from the analysis of ICP recordings. A neural network model (previously tested with 93% accuracy) was applied in order to automatically group ICP waveforms into 4 classes [3]. As a main finding, the pulse shape index—PSI was strongly correlated with the analyzed tomographic parameters (&lt;i&gt;p&lt;/i&gt; = 0.001), while mean ICP was correlated with ICPw amplitude, indicating that the morphology of the ICP pulse wave reflects a decrease in the cerebrospinal compensatory reserve therefore of cerebral compliance [3].&lt;/p&gt;&lt;p&gt;ICP waveform is a result of complex interaction between volumes (blood, brain and cerebrospinal fluid) restrained by meninges and the bony skull box, interacting with dynamic phenomena as blood viscosity, cardiac and respiratory cycles per example [1]. Therefore, several are the ways of exploring and translating ICPw into parameters readable at the bedside to assess compensatory reserve status. Prior to PSI, the compensatory reserve index (RAP) was described by Czosnyka et al. as the moving correlation between ICP values and ICP pulse amplitude variation [4]. Both the PSI and RAP can be a","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"46 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142236434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lung ultrasound and ARDS: global collaboration is the way to go","authors":"Marry R. Smit, Maud Boumans, William Aerts, Pieter R. Tuinman","doi":"10.1186/s13054-024-05075-y","DOIUrl":"https://doi.org/10.1186/s13054-024-05075-y","url":null,"abstract":"We would like to extend our gratitude to Dr. da Hora Passos et al. for their interest in our recently published review and meta-analysis in Critical Care. In this response, we will elaborate on the points raised by the authors. We agree with the authors that LUS, like any other diagnostic technique, is valuable and safe only when utilized by trained operators. The authors expressed uncertainty regarding the sensitivity of LUS in detecting mild ARDS or ARDS at an early stage. This variance in sensitivity is more likely due to diversity in diagnostic thresholds. We advocate for global collaboration among LUS experts to align LUS methodologies and strengthen the evidence supporting LUS in the diagnosis of ARDS and its morphological subphenotypes.","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"32 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prevention of ventilator-associated pneumonia by metal-coated endotracheal tubes: a meta-analysis","authors":"Yuxin Yang, Xuan Xiong, Xiaofei Wang, Qionglan Dong, Lingai Pan","doi":"10.1186/s13054-024-05095-8","DOIUrl":"https://doi.org/10.1186/s13054-024-05095-8","url":null,"abstract":"This study aimed to evaluate whether endotracheal tubes (ETTs) with a metal coating reduce the incidence of ventilator-associated pneumonia (VAP) compared to uncoated ETTs. An extensive literature review was conducted to find studies that compared metal-coated ETT with uncoated ETT across four databases: PubMed, Embase, Cochrane Library, and Web of Science. The search parameters were set from the inception of each database until June 2024. The primary outcome measures were the rates of VAP and hospital mortality. Two independent researchers carried out the literature selection, data extraction, and quality evaluation. Data analysis was performed with RevMan 5.4.1. Furthermore, a Deeks funnel plot was used to evaluate potential publication bias in the studies included. Following the screening process, five randomized controlled trials (RCTs) encompassing a total of 2157 patients were identified. In terms of the primary outcome, the VAP incidence was found to be lower in the group utilizing metal-coated ETT compared to those with uncoated ETT, demonstrating a statistically significant difference [RR = 0.71, 95% CI (0.54–0.95), P = 0.02]. No notable difference in mortality rates was observed between the two groups [RR = 1.05, 95% CI (0.86–1.27), P = 0.65]. Concerning secondary outcomes, two studies were evaluated to compare the mechanical ventilation duration (RR = 0.60, 95% CI (− 0.52, 1.72), P = 0.29, I2 = 97%) and intensive care unit (ICU) stay for both patient groups (RR = 0.47, 95% CI (− 1.02, 1.95), P = 0.54, I2 = 50%). Due to the marked heterogeneity, a comparison of mechanical ventilation length between the two patient groups was not feasible. However, both studies suggested no significant difference in ventilation duration between patients using metal-coated ETT and those with uncoated ETT. Metal-coated ETT show a lower occurrence of VAP compared to the uncoated ETT. Nevertheless, they do not considerably decrease the length of mechanical ventilation, the duration of ICU admission, nor do they reduce hospital mortality rates. Systematic review registration: https://www.crd.york.ac.uk/prospero/ , identifier CRD42024560618.","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"329 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142236438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time course of electrical activity of the diaphragm (EAdi) in the peri extubation period and its role as predictor of extubation failure in difficult to wean patients","authors":"Francisco José Parrilla-Gómez, Ferran Roche-Campo, Stefano Italiano, Andrés Parrilla-Gómez, Indalecio Morán, Jordi Mancebo, Tommaso Maraffi","doi":"10.1186/s13054-024-05092-x","DOIUrl":"https://doi.org/10.1186/s13054-024-05092-x","url":null,"abstract":"Weaning patients from mechanical ventilation is crucial in the management of acute respiratory failure (ARF). Spontaneous breathing trials (SBT) are used to assess readiness for extubation, but extubation failure remains a challenge. Diaphragmatic function, measured by electrical activity of the diaphragm (EAdi), may provide insights into weaning outcomes. This prospective, observational study included difficult-to-wean patients undergoing invasive mechanical ventilation. EAdi was recorded before, during, and after extubation. Patients were categorized into extubation success and failure groups based on reintubation within 48 h. Statistical analysis assessed EAdi patterns and predictive value. Thirty-one patients were analyzed, with six experiencing extubation failure. Overall, EAdi increased significantly between the phases before the SBT, the SBT and post-extubation period, up to 24 h (p < 0.001). EAdi values were higher in the extubation failure group during SBT (p = 0.01). An EAdi > 30 μV during SBT predicted extubation failure with 92% sensitivity and 67% specificity. Multivariable analysis confirmed EAdi as an independent predictor of extubation failure. In difficult-to-wean patients, EAdi increases significantly between the phases before the SBT, the SBT and post-extubation period and is significantly higher in patients experiencing extubation failure. An EAdi > 30 μV during SBT may enhance extubation failure prediction compared to conventional parameters. Advanced monitoring of diaphragmatic function could improve weaning outcomes in critical care settings.","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"13 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142236436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Testing preload responsiveness by the tidal volume challenge assessed by the photoplethysmographic perfusion index","authors":"Chiara Bruscagnin, Rui Shi, Daniela Rosalba, Gaelle Fouqué, Julien Hagry, Christopher Lai, Katia Donadello, Tài Pham, Jean-Louis Teboul, Xavier Monnet","doi":"10.1186/s13054-024-05085-w","DOIUrl":"https://doi.org/10.1186/s13054-024-05085-w","url":null,"abstract":"To detect preload responsiveness in patients ventilated with a tidal volume (Vt) at 6 mL/kg of predicted body weight (PBW), the Vt-challenge consists in increasing Vt from 6 to 8 mL/kg PBW and measuring the increase in pulse pressure variation (PPV). However, this requires an arterial catheter. The perfusion index (PI), which reflects the amplitude of the photoplethysmographic signal, may reflect stroke volume and its respiratory variation (pleth variability index, PVI) may estimate PPV. We assessed whether Vt-challenge-induced changes in PI or PVI could be as reliable as changes in PPV for detecting preload responsiveness defined by a PLR-induced increase in cardiac index (CI) ≥ 10%. In critically ill patients ventilated with Vt = 6 mL/kg PBW and no spontaneous breathing, haemodynamic (PICCO2 system) and photoplethysmographic (Masimo-SET technique, sensor placed on the finger or the forehead) data were recorded during a Vt-challenge and a PLR test. Among 63 screened patients, 21 (33%) were excluded because of an unstable PI signal and/or atrial fibrillation and 42 were included. During the Vt-challenge in the 16 preload responders, CI decreased by 4.8 ± 2.8% (percent change), PPV increased by 4.4 ± 1.9% (absolute change), PIfinger decreased by 14.5 ± 10.7% (percent change), PVIfinger increased by 1.9 ± 2.6% (absolute change), PIforehead decreased by 18.7 ± 10.9 (percent change) and PVIforehead increased by 1.0 ± 2.5 (absolute change). All these changes were larger than in preload non-responders. The area under the ROC curve (AUROC) for detecting preload responsiveness was 0.97 ± 0.02 for the Vt-challenge-induced changes in CI (percent change), 0.95 ± 0.04 for the Vt-challenge-induced changes in PPV (absolute change), 0.98 ± 0.02 for Vt-challenge-induced changes in PIforehead (percent change) and 0.85 ± 0.05 for Vt-challenge-induced changes in PIfinger (percent change) (p = 0.04 vs. PIforehead). The AUROC for the Vt-challenge-induced changes in PVIforehead and PVIfinger was significantly larger than 0.50, but smaller than the AUROC for the Vt-challenge-induced changes in PPV. In patients under mechanical ventilation with no spontaneous breathing and/or atrial fibrillation, changes in PI detected during Vt-challenge reliably detected preload responsiveness. The reliability was better when PI was measured on the forehead than on the fingertip. Changes in PVI during the Vt-challenge also detected preload responsiveness, but with lower accuracy.","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"53 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142234501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The pleural gradient does not reflect the superimposed pressure in patients with class III obesity","authors":"Stefano Spina, Lea Mantz, Yi Xin, David C. Moscho, Roberta Ribeiro De Santis Santiago, Luigi Grassi, Alice Nova, Sarah E. Gerard, Edward A. Bittner, Florian J. Fintelmann, Lorenzo Berra, Maurizio Cereda","doi":"10.1186/s13054-024-05097-6","DOIUrl":"https://doi.org/10.1186/s13054-024-05097-6","url":null,"abstract":"The superimposed pressure is the primary determinant of the pleural pressure gradient. Obesity is associated with elevated end-expiratory esophageal pressure, regardless of lung disease severity, and the superimposed pressure might not be the only determinant of the pleural pressure gradient. The study aims to measure partitioned respiratory mechanics and superimposed pressure in a cohort of patients admitted to the ICU with and without class III obesity (BMI ≥ 40 kg/m2), and to quantify the amount of thoracic adipose tissue and muscle through advanced imaging techniques. This is a single-center observational study including ICU-admitted patients with acute respiratory failure who underwent a chest computed tomography scan within three days before/after esophageal manometry. The superimposed pressure was calculated from lung density and height of the largest axial lung slice. Automated deep-learning pipelines segmented lung parenchyma and quantified thoracic adipose tissue and skeletal muscle. N = 18 participants (50% female, age 60 [30–66] years), with 9 having BMI < 30 and 9 ≥ 40 kg/m2. Groups showed no significant differences in age, sex, clinical severity scores, or mortality. Patients with BMI ≥ 40 exhibited higher esophageal pressure (15.8 ± 2.6 vs. 8.3 ± 4.9 cmH2O, p = 0.001), higher pleural pressure gradient (11.1 ± 4.5 vs. 6.3 ± 4.9 cmH2O, p = 0.04), while superimposed pressure did not differ (6.8 ± 1.1 vs. 6.5 ± 1.5 cmH2O, p = 0.59). Subcutaneous and intrathoracic adipose tissue were significantly higher in subjects with BMI ≥ 40 and correlated positively with esophageal pressure and pleural pressure gradient (p < 0.05). Muscle areas did not differ between groups. In patients with class III obesity, the superimposed pressure does not approximate the pleural pressure gradient, which is higher than in patients with lower BMI. The quantity and distribution of subcutaneous and intrathoracic adiposity also contribute to increased pleural pressure gradients in individuals with BMI ≥ 40. This study introduces a novel physiological concept that provides a solid rationale for tailoring mechanical ventilation in patients with high BMI, where specific guidelines recommendations are lacking.","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":"36 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}