Intensive Care Medicine Experimental最新文献

{"title":"Can linezolid be validly measured in endotracheal aspiration in critically ill patients? A proof-of-concept trial.","authors":"Diana Rebholz, Uwe Liebchen, Michael Paal, Michael Vogeser, Johannes Starp, Caroline Gräfe, Clara I Brozat, Felix L Happich, Katharina Habler, Christina Scharf","doi":"10.1186/s40635-024-00630-x","DOIUrl":"10.1186/s40635-024-00630-x","url":null,"abstract":"<p><strong>Background: </strong>Therapeutic drug monitoring (TDM) of anti-infectives such as linezolid is routinely performed in blood of intensive care unit (ICU) patients to optimize target attainment. However, the concentration at the site of infection is considered more important for a successful therapy. Until now, bronchoalveolar lavage (BAL) is the gold standard to measure intrapulmonary concentrations of anti-infective agents. However, it is an invasive method and unsuitable for regular TDM. The aim of this proof-of-concept study was to investigate whether it is possible to reliably determine the intrapulmonary concentration of linezolid from endotracheal aspiration (ENTA).</p><p><strong>Methods: </strong>Intubated ICU patients receiving 600 mg intravenous linezolid twice daily were examined in steady state. First, preliminary experiments were performed in six patients to investigate which patients are suitable for linezolid measurement in ENTA. In a second step, trough and peak linezolid concentrations of plasma and ENTA were determined in nine suitable patients.</p><p><strong>Results: </strong>Linezolid can validly be detected in ENTA with viscous texture and > 0.5 mL volume. The mean (SD) linezolid trough concentration was 2.02 (1.27) mg/L in plasma and 1.60 (1.36) mg/L in ENTA, resulting in a median lung penetration rate of 104%. The mean (SD) peak concentration in plasma and ENTA was 10.77 (5.93) and 4.74 (2.66) mg/L.</p><p><strong>Conclusions: </strong>Linezolid can validly be determined in ENTA with an adequate texture and volume. The penetration rate is comparable to already published BAL concentrations. This method might offer a simple and non-invasive method for TDM at the site of infection \"lung\". Due to promising results of the feasibility study, comparison of ENTA and BAL in the same patient should be investigated in a further trial.</p>","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"12 1","pages":"47"},"PeriodicalIF":3.5,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11078899/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140876342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic changes of hepatic vein Doppler velocities predict preload responsiveness in mechanically ventilated critically ill patients.","authors":"Mario Bruna, Sebastian Alfaro, Felipe Muñoz, Liliana Cisternas, Cecilia Gonzalez, Rodrigo Conlledo, Rodrigo Ulloa-Morrison, Marcos Huilcaman, Jaime Retamal, Ricardo Castro, Philippe Rola, Adrian Wong, Eduardo R Argaiz, Roberto Contreras, Glenn Hernandez, Eduardo Kattan","doi":"10.1186/s40635-024-00631-w","DOIUrl":"10.1186/s40635-024-00631-w","url":null,"abstract":"<p><strong>Background: </strong>Assessment of dynamic parameters to guide fluid administration is one of the mainstays of current resuscitation strategies. Each test has its own limitations, but passive leg raising (PLR) has emerged as one of the most versatile preload responsiveness tests. However, it requires real-time cardiac output (CO) measurement either through advanced monitoring devices, which are not routinely available, or echocardiography, which is not always feasible. Analysis of the hepatic vein Doppler waveform change, a simpler ultrasound-based assessment, during a dynamic test such as PLR could be useful in predicting preload responsiveness. The objective of this study was to assess the diagnostic accuracy of hepatic vein Doppler S and D-wave velocities during PLR as a predictor of preload responsiveness.</p><p><strong>Methods: </strong>Prospective observational study conducted in two medical-surgical ICUs in Chile. Patients in circulatory failure and connected to controlled mechanical ventilation were included from August to December 2023. A baseline ultrasound assessment of cardiac function was performed. Then, simultaneously, ultrasound measurements of hepatic vein Doppler S and D waves and cardiac output by continuous pulse contour analysis device were performed during a PLR maneuver.</p><p><strong>Results: </strong>Thirty-seven patients were analyzed. 63% of the patients were preload responsive defined by a 10% increase in CO after passive leg raising. A 20% increase in the maximum S wave velocity after PLR showed the best diagnostic accuracy with a sensitivity of 69.6% (49.1-84.4) and specificity of 92.8 (68.5-99.6) to detect preload responsiveness, with an area under curve of receiving operator characteristic (AUC-ROC) of 0.82 ± 0.07 (p = 0.001 vs. AUC-ROC of 0.5). D-wave velocities showed worse diagnostic accuracy.</p><p><strong>Conclusions: </strong>Hepatic vein Doppler assessment emerges as a novel complementary technique with adequate predictive capacity to identify preload responsiveness in patients in mechanical ventilation and circulatory failure. This technique could become valuable in scenarios of basic hemodynamic monitoring and when echocardiography is not feasible. Future studies should confirm these results.</p>","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"12 1","pages":"46"},"PeriodicalIF":2.8,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11078902/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140876343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advancing acute respiratory failure management through artificial intelligence: a call for thematic collection contributions.","authors":"Zhongheng Zhang, Jakob Wittenstein","doi":"10.1186/s40635-024-00629-4","DOIUrl":"10.1186/s40635-024-00629-4","url":null,"abstract":"","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"12 1","pages":"45"},"PeriodicalIF":3.5,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11076423/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140851279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Newly innovated system to generate adjustable PEEP with a high-flow nasal cannula","authors":"Yu Onodera, Kenya Yarimizu, Tatsuya Hayasaka, Kaneyuki Kawamae, Masaki Nakane","doi":"10.1186/s40635-024-00627-6","DOIUrl":"https://doi.org/10.1186/s40635-024-00627-6","url":null,"abstract":"&lt;p&gt;&lt;b&gt;To the Editor,&lt;/b&gt;&lt;/p&gt;&lt;p&gt;A high-flow nasal cannula (HFNC) has become an essential respiratory support for patients with acute respiratory failure [1]. The physiologic effects of an HFNC include reduced dead space ventilation through the CO&lt;sub&gt;2&lt;/sub&gt; washout effect and generation of positive end-expiratory pressure (PEEP) [2]. Previous physiologic studies have shown that the PEEP produced by an HFNC is low and cannot be adjusted in a clinically relevant manner [2]. When patients with respiratory failure who are being managed with an HFNC require PEEP, the patients must be switched to continuous positive airway pressure (CPAP), non-invasive positive pressure ventilation, or invasive positive pressure ventilation [3] with loss of the ventilatory support of the HFNC generated by the CO&lt;sub&gt;2&lt;/sub&gt; washout effect.&lt;/p&gt;&lt;p&gt;Therefore, we devised a new system by merging a full-face mask and a PEEP valve with an HFNC (HFNC-P) and conducted a simulation-based experiment to determine the feasibility of further clinical experiments.&lt;/p&gt;&lt;p&gt;The experiment was conducted using a respiratory model consisting of a life-sized 3D-printed airway model connected to a Training and Test Lung ([TTL]; Michigan Instruments, USA). Breathing patterns were established as normal (compliance [C], 50 mL/cmH&lt;sub&gt;2&lt;/sub&gt;O; resistance [R], 5 cmH&lt;sub&gt;2&lt;/sub&gt;O/L/s; tidal volume [Vt], 500 mL; and respiratory rate [RR], 14/min), restrictive (C 20; R, 5; Vt, 300; and RR, 25), and obstructive (C, 80; R, 20; Vt, 700; and RR, 10). CO&lt;sub&gt;2&lt;/sub&gt; was infused into the TTL to achieve a P&lt;sub&gt;ET&lt;/sub&gt;CO&lt;sub&gt;2&lt;/sub&gt; of 40 mmHg with each breathing pattern and without interface connected to the airway model.&lt;/p&gt;&lt;p&gt;With this respiratory model, the following interfaces were attached:&lt;/p&gt;&lt;ol&gt;\u0000&lt;li&gt;\u0000&lt;span&gt;1.&lt;/span&gt;\u0000&lt;p&gt;HFNC: HFNC ([Optiflow]; F&amp;P, New Zealand) with flow rates of 20, 40, and 60 L/min.&lt;/p&gt;\u0000&lt;/li&gt;\u0000&lt;li&gt;\u0000&lt;span&gt;2.&lt;/span&gt;\u0000&lt;p&gt;CPAP mask: A full-face mask with a PEEP valve set to 5 or 10 cmH&lt;sub&gt;2&lt;/sub&gt;O and a flow rate of 20, 40, and 60 L/min was introduced.&lt;/p&gt;\u0000&lt;/li&gt;\u0000&lt;li&gt;\u0000&lt;span&gt;3.&lt;/span&gt;\u0000&lt;p&gt;HFNC-P: HFNC combined with a full-face mask (Cough Ventec Japan, Inc., Japan) and a PEEP valve set to 5 or 10 cmH&lt;sub&gt;2&lt;/sub&gt;O (Fig. 1).&lt;/p&gt;\u0000&lt;/li&gt;\u0000&lt;/ol&gt;&lt;figure&gt;&lt;figcaption&gt;&lt;b data-test=\"figure-caption-text\"&gt;Fig. 1&lt;/b&gt;&lt;/figcaption&gt;&lt;picture&gt;&lt;img alt=\"figure 1\" aria-describedby=\"Fig1\" height=\"418\" loading=\"lazy\" src=\"//media.springernature.com/lw685/springer-static/image/art%3A10.1186%2Fs40635-024-00627-6/MediaObjects/40635_2024_627_Fig1_HTML.png\" width=\"685\"/&gt;&lt;/picture&gt;&lt;p&gt;HFNC-P attached to the respiratory model. For HFNC only setting, the full-face mask was removed and for the CPAP setting, gas from the flow generator was directly infused into the full-face mask. A one-way valve was attached to the mask to accommodate external air inflow for CPAP and HFNC-P if the inspiratory flow surpassed the flow from the flow generator&lt;/p&gt;&lt;span&gt;Full size image&lt;/span&gt;&lt;svg aria-hidden=\"true\" focusable=\"false\" heig","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"7 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140799255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immediate inflammatory response to mechanical circulatory support in a porcine model of severe cardiogenic shock","authors":"Emilie Gregers, Peter H. Frederiksen, Nanna L. J. Udesen, Louise Linde, Ann Banke, Amalie L. Povlsen, Jeppe P. Larsen, Christian Hassager, Lisette O. Jensen, Jens F. Lassen, Henrik Schmidt, Hanne B. Ravn, Peter M. H. Heegaard, Jacob E. Møller","doi":"10.1186/s40635-024-00625-8","DOIUrl":"https://doi.org/10.1186/s40635-024-00625-8","url":null,"abstract":"In selected cases of cardiogenic shock, veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is combined with trans valvular micro axial flow pumps (ECMELLA). Observational studies indicate that ECMELLA may reduce mortality but exposing the patient to two advanced mechanical support devices may affect the early inflammatory response. We aimed to explore inflammatory biomarkers in a porcine cardiogenic shock model managed with V-A ECMO or ECMELLA. Fourteen landrace pigs had acute myocardial infarction-induced cardiogenic shock with minimal arterial pulsatility by microsphere embolization and were afterwards managed 1:1 with either V-A ECMO or ECMELLA for 4 h. Serial blood samples were drawn hourly and analyzed for serum concentrations of interleukin 6 (IL-6), IL-8, tumor necrosis factor alpha, and serum amyloid A (SAA). An increase in IL-6, IL-8, and SAA levels was observed during the experiment for both groups. At 2–4 h of support, IL-6 levels were higher in ECMELLA compared to V-A ECMO animals (difference: 1416 pg/ml, 1278 pg/ml, and 1030 pg/ml). SAA levels were higher in ECMELLA animals after 3 and 4 h of support (difference: 401 ng/ml and 524 ng/ml) and a significant treatment-by-time effect of ECMELLA on SAA was identified (p = 0.04). No statistical significant between-group differences were observed in carotid artery blood flow, urine output, and lactate levels. Left ventricular unloading with Impella during V-A ECMO resulted in a more extensive inflammatory reaction despite similar end-organ perfusion.","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"17 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140635835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ineffectiveness of hemoadsorption in large animals with abdominal sepsis: a randomized controlled porcine study","authors":"Vaclav Tegl, Jan Horak, Lukas Nalos, Michala Horakova, Milan Stengl, Martin Matejovic, Jan Benes","doi":"10.1186/s40635-024-00622-x","DOIUrl":"https://doi.org/10.1186/s40635-024-00622-x","url":null,"abstract":"The use of hemoadsorption (HA) has become popular in the treatment of vasoplegic states associated with massive cytokine release, including septic shock. However, this approach does not seem to be based on robust evidence, and it does not follow international guidelines. To understand the pathophysiological rationale and timing of HA, we conducted a large animal septic shock experiment. Prospective randomized large-animal peritoneal septic shock experiment. Laboratory investigation. Twenty-six anesthetized, mechanically ventilated, and instrumented pigs randomly assigned into (1) sham-operated group with HA (SHAM, n = 5); (2) sepsis animals without HA (SEPSIS, n = 5); (3) sepsis group with HA at norepinephrine initiation (EARLY, n = 8); and (4) sepsis group with HA initiated at norepinephrine rate reaching 0.5 μg/kg/min (LATE, n = 8). Peritoneal sepsis was induced by cultivated autologous feces inoculation. A CytoSorb cartridge (200 g) with a blood flow rate of 200 mL/min and heparin anticoagulation was used to perform HA. The animals received sedation and intensive organ support up to 48 h or until they experienced cardiovascular collapse. Systemic hemodynamics, multiple-organ functions, and immune-inflammatory response were measured at predefined periods. The HA treatment was not associated with any measurable benefit in terms of systemic hemodynamics and organ support. The systemic inflammatory markers were unaffected by any of the treatment timings. In contrast, the HA resulted in higher vasopressor load and decreased 36-h survival (5 animals in SHAM (100%), 4 (80%) in SEPSIS, 4 (57%) in EARLY, and 2 (25%) in LATE; p = 0.041). The HA exposure in healthy animals was associated with hemodynamic deterioration, systemic inflammatory response, and cytopenia. In this large-animal-controlled fulminant sepsis study, the HA was unable to counteract the disease progression in the early or advanced septic shock phase. However, findings from the HA-exposed sham animals suggest potential safety concerns. Question: To understand hemoadsorption using CytoSorb device pathophysiological rationale and timing on disease progression in septic subjects. Findings: In this large-animal-controlled fulminant sepsis study, the CytoSorb hemoadsorption did not counteract the disease progression in the early or advanced septic shock phase. However, findings from the hemoadsorption-exposed sham animals suggest potential safety concerns. Meaning: Considering the limited evidence, the clinical use of CytoSorb for hemoadsorption in septic patients should be limited to well-designed interventional studies.","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"27 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140616121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperoxemia and hypoxemia impair cellular oxygenation: a study in healthy volunteers","authors":"Bashar N. Hilderink, Reinier F. Crane, Bas van den Bogaard, Janesh Pillay, Nicole P. Juffermans","doi":"10.1186/s40635-024-00619-6","DOIUrl":"https://doi.org/10.1186/s40635-024-00619-6","url":null,"abstract":"Administration of oxygen therapy is common, yet there is a lack of knowledge on its ability to prevent cellular hypoxia as well as on its potential toxicity. Consequently, the optimal oxygenation targets in clinical practice remain unresolved. The novel PpIX technique measures the mitochondrial oxygen tension in the skin (mitoPO2) which allows for non-invasive investigation on the effect of hypoxemia and hyperoxemia on cellular oxygen availability. During hypoxemia, SpO2 was 80 (77–83)% and PaO2 45(38–50) mmHg for 15 min. MitoPO2 decreased from 42(35–51) at baseline to 6(4.3–9)mmHg (p < 0.001), despite 16(12–16)% increase in cardiac output which maintained global oxygen delivery (DO2). During hyperoxic breathing, an FiO2 of 40% decreased mitoPO2 to 20 (9–27) mmHg. Cardiac output was unaltered during hyperoxia, but perfused De Backer density was reduced by one-third (p < 0.01). A PaO2 < 100 mmHg and > 200 mmHg were both associated with a reduction in mitoPO2. Hypoxemia decreases mitoPO2 profoundly, despite complete compensation of global oxygen delivery. In addition, hyperoxemia also decreases mitoPO2, accompanied by a reduction in microcirculatory perfusion. These results suggest that mitoPO2 can be used to titrate oxygen support.","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"46 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140561642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oxygenation and ventilation during prolonged experimental cardiopulmonary resuscitation with either continuous or 30:2 compression-to-ventilation ratios together with 10 cmH20 positive end-expiratory pressure","authors":"Jukka Kopra, Erik Litonius, Pirkka T. Pekkarinen, Merja Laitinen, Juho A. Heinonen, Luca Fontanelli, Markus B. Skrifvars","doi":"10.1186/s40635-024-00620-z","DOIUrl":"https://doi.org/10.1186/s40635-024-00620-z","url":null,"abstract":"In refractory out-of-hospital cardiac arrest, the patient is commonly transported to hospital with mechanical continuous chest compressions (CCC). Limited data are available on the optimal ventilation strategy. Accordingly, we compared arterial oxygenation and haemodynamics during manual asynchronous continuous ventilation and compressions with a 30:2 compression-to-ventilation ratio together with the use of 10 cmH2O positive end-expiratory pressure (PEEP). Intubated and anaesthetized landrace pigs with electrically induced ventricular fibrillation were left untreated for 5 min (n = 31, weight ca. 55 kg), after which they were randomized to either the CCC group or the 30:2 group with the the LUCAS® 2 piston device and bag-valve ventilation with 100% oxygen targeting a tidal volume of 8 ml/kg with a PEEP of 10 cmH2O for 35 min. Arterial blood samples were analysed every 5 min, vital signs, near-infrared spectroscopy and electrical impedance tomography (EIT) were measured continuously, and post-mortem CT scans of the lungs were obtained. The arterial blood values (median + interquartile range) at the 30-min time point were as follows: PaO2: 180 (86–302) mmHg for the 30:2 group; 70 (49–358) mmHg for the CCC group; PaCO2: 41 (29–53) mmHg for the 30:2 group; 44 (21–67) mmHg for the CCC group; and lactate: 12.8 (10.4–15.5) mmol/l for the 30:2 group; 14.7 (11.8–16.1) mmol/l for the CCC group. The differences were not statistically significant. In linear mixed models, there were no significant differences between the groups. The mean arterial pressures from the femoral artery, end-tidal CO2, distributions of ventilation from EIT and mean aeration of lung tissue in post-mortem CTs were similar between the groups. Eight pneumothoraces occurred in the CCC group and 2 in the 30:2 group, a statistically significant difference (p = 0.04). The 30:2 and CCC protocols with a PEEP of 10 cmH2O resulted in similar gas exchange and vital sign outcomes in an experimental model of prolonged cardiac arrest with mechanical compressions, but the CCC protocol resulted in more post-mortem pneumothoraces.","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"41 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140561572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of respiratory cycle during mechanical ventilation on beat-to-beat right ventricle stroke volume estimation by pulmonary artery pulse wave analysis","authors":"Arnoldo Santos, M. Ignacio Monge-García, João Batista Borges, Jaime Retamal, Gerardo Tusman, Anders Larsson, Fernando Suarez-Sipmann","doi":"10.1186/s40635-024-00618-7","DOIUrl":"https://doi.org/10.1186/s40635-024-00618-7","url":null,"abstract":"The same principle behind pulse wave analysis can be applied on the pulmonary artery (PA) pressure waveform to estimate right ventricle stroke volume (RVSV). However, the PA pressure waveform might be influenced by the direct transmission of the intrathoracic pressure changes throughout the respiratory cycle caused by mechanical ventilation (MV), potentially impacting the reliability of PA pulse wave analysis (PAPWA). We assessed a new method that minimizes the direct effect of the MV on continuous PA pressure measurements and enhances the reliability of PAPWA in tracking beat-to-beat RVSV. Continuous PA pressure and flow were simultaneously measured for 2–3 min in 5 pigs using a high-fidelity micro-tip catheter and a transonic flow sensor around the PA trunk, both pre and post an experimental ARDS model. RVSV was estimated by PAPWA indexes such as pulse pressure (SVPP), systolic area (SVSystAUC) and standard deviation (SVSD) beat-to-beat from both corrected and non-corrected PA signals. The reference RVSV was derived from the PA flow signal (SVref). The reliability of PAPWA in tracking RVSV on a beat-to-beat basis was enhanced after accounting for the direct impact of intrathoracic pressure changes induced by MV throughout the respiratory cycle. This was evidenced by an increase in the correlation between SVref and RVSV estimated by PAPWA under healthy conditions: rho between SVref and non-corrected SVSD – 0.111 (0.342), corrected SVSD 0.876 (0.130), non-corrected SVSystAUC 0.543 (0.141) and corrected SVSystAUC 0.923 (0.050). Following ARDS, correlations were SVref and non-corrected SVSD – 0.033 (0.262), corrected SVSD 0.839 (0.077), non-corrected SVSystAUC 0.483 (0.114) and corrected SVSystAUC 0.928 (0.026). Correction also led to reduced limits of agreement between SVref and SVSD and SVSystAUC in the two evaluated conditions. In our experimental model, we confirmed that correcting for mechanical ventilation induced changes during the respiratory cycle improves the performance of PAPWA for beat-to-beat estimation of RVSV compared to uncorrected measurements. This was demonstrated by a better correlation and agreement between the actual SV and the obtained from PAPWA.","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"17 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140561644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The ongoing journey in targeting hemodynamic interventions: missing miles for missing the last micron?","authors":"Johannes Heymer, Daniel Raepple","doi":"10.1186/s40635-024-00621-y","DOIUrl":"https://doi.org/10.1186/s40635-024-00621-y","url":null,"abstract":"&lt;p&gt;With great interest we followed the original work by Bruno et al. [1] assessing sublingual microcirculatory perfusion variables in shock and the following discussion by Hilty et al. [2]. The authors critique the study for its use of unvalidated software and the absence of an effective, hemodynamic monitoring-based treatment plan. They also highlight the study's failure to address different shock types and their unique microcirculatory characteristics, crucial for appropriate treatment decisions.&lt;/p&gt;&lt;p&gt;In the last decades, therapy guided by either macrocirculatory or microcirculatory targets in patients with shock has not yet shown satisfactory results to demonstrate benefits in directing treatment for these patients.&lt;/p&gt;&lt;p&gt;In our response, we aim to explore an alternative perspective by examining acid–base homeostasis to evaluate shock progression or resuscitation success. We propose to focus on the dynamics of Base Excess (BE) as an indicator of successful resuscitation in shock scenarios. BE is a calculated parameter that determines the amount of acid or base required to restore the blood's pH to 7.40 under standardized conditions, assuming normal CO&lt;sub&gt;2&lt;/sub&gt; levels. A negative BE, coupled with acidemia, indicates that the primary cause of the blood's acidity is metabolic in nature. This could be due to deranged physiological buffer systems, such as loss of bicarbonate through the gastrointestinal tract, reduced bicarbonate synthesis in the case of acute kidney injury (AKI) secondary to shock, or an increase in the strong ion difference, such as that seen in hyperchloremic acidosis resulting from resuscitation with isotonic saline. Although these elements can lead to acid–base disturbances during shock, we contend that a more crucial contributing factor is the accumulation of protons arising from impaired adenosine triphosphate (ATP) regeneration.&lt;/p&gt;&lt;p&gt;The daily turnover of ATP in the human body is remarkably high, underscoring ATP's crucial role as the primary energy carrier in biological processes. Typically, the human body contains about 0.1 mol of ATPa at any given moment, which is continuously cycled. The human body synthesizes and degrades an amount of ATP approximately equal to its own weight each day. We propose that the pronounced acidosis following cardiac arrest is a manifestation of this abrupt metabolic shift, in contrast to the effects or confounders mentioned above, which take some time to manifest.&lt;/p&gt;&lt;p&gt;Traditionally, shock has been characterized by a discrepancy between oxygen delivery (DO&lt;sub&gt;2&lt;/sub&gt;) and consumption (VO&lt;sub&gt;2&lt;/sub&gt;). However, we suggest to see DO&lt;sub&gt;2&lt;/sub&gt;/VO&lt;sub&gt;2&lt;/sub&gt; as a partial aspect of some forms of shock but broadening this definition to encompass shock more generally as an imbalance between ATP consumption and regeneration, which results in proton accumulation during acute imbalances. This viewpoint is supported by studies showing that not all shock states display a VO&lt;sub&gt;2&lt;/sub&gt;/DO&lt;sub&gt;2","PeriodicalId":13750,"journal":{"name":"Intensive Care Medicine Experimental","volume":"5 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140561456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}