Objective: A 15-second end-expiratory occlusion increases cardiac preload and allows detection of preload dependence. We tested whether the reliability of this test depends upon positive end-expiratory pressure.
Design: : Prospective study.
Setting: Medical ICU.
Patients: Thirty-four patients presenting with acute circulatory failure and acute respiratory distress syndrome ventilated with a tidal volume of 6.7 mL/kg (interquartile range, 6.3-7.1).
Measurements: At positive end-expiratory pressure = 5 cm H2O, we measured the changes in cardiac index induced by end-expiratory occlusion and a passive leg raising test. Preload dependence was defined by a passive leg raising-induced increase in cardiac index greater than or equal to 10%. Positive end-expiratory pressure was increased to a plateau pressure of 30 cm H2O, and end-expiratory occlusion and passive leg raising were performed again.
Main Results: At positive end-expiratory pressure = 5 cm H2O, 29% of patients were passive leg raising responders. An end-expiratory occlusion-induced increase in cardiac index greater than or equal to 5% detected a passive leg raising-induced increase in cardiac index greater than or equal to 10% with a sensitivity of 90% (95% CI, 56-100) and a specificity of 88% (95% CI, 68-97). At higher positive end-expiratory pressure (15 cm H2O [interquartile range, 13-15]), the plateau pressure - positive end-expiratory pressure difference did not change (15 mm Hg [14-17] vs 15 mm Hg [13-18] before the positive end-expiratory pressure increase). Increasing positive end-expiratory pressure significantly reduced cardiac index in passive leg raising responders (-27% [interquartile range, -6 to -56]) but not in other patients. At high positive end-expiratory pressure, passive leg raising increased cardiac index to a larger extent than at positive end-expiratory pressure = 5 cm H2O (19% [interquartile range, 15-34] vs 16% [interquartile range, 13-23], respectively). The proportion of passive leg raising responders significantly increased (34 vs 29%, respectively), meaning preload dependence had increased. At higher positive end-expiratory pressure, an end-expiratory occlusion-induced increase in cardiac index greater than or equal to 6% detected a passive leg raising-induced increase in cardiac index greater than or equal to 10% with a sensitivity of 100% (95% CI, 75-100) and a specificity of 90% (95% CI, 70-99).
Conclusions: The end-expiratory occlusion test is reliable for detecting preload dependence whatever the positive end-expiratory pressure during acute respiratory distress syndrome.
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http://dx.doi.org/10.1097/CCM.0b013e31828a2323 | DOI Listing |
J Clin Med
December 2024
Critical Care Department, University Hospital of Larissa, Faculty of Medicine, University of Thessaly, Mezourlo, 41335 Larissa, Greece.
Patients in critical condition who require mechanical ventilation experience intricate interactions between their respiratory and cardiovascular systems. These complex interactions are crucial for clinicians to understand as they can significantly influence therapeutic decisions and patient outcomes. A deep understanding of heart-lung interactions is essential, particularly under the stress of mechanical ventilation, where the right ventricle plays a pivotal role and often becomes a primary concern.
View Article and Find Full Text PDFZhonghua Jie He He Hu Xi Za Zhi
January 2025
College of Pulmonary & Critical Care Medicine, Chinese PLA General Hospital, Beijing100091, China.
This review outlines significant clinical research developments in the field of critical care respiratory medicine from October 2023 to September 2024. In the post-pandemic era, the new global definition of acute respiratory distress syndrome (ARDS) has improved practicality and early warning capabilities, although further refinement through respiratory mechanics and multi-omics approaches is required. Novel patterns of pulmonary microbiota distribution in ARDS patients have emerged, with microbiota-host immune interactions significantly influencing clinical outcomes.
View Article and Find Full Text PDFFront Physiol
December 2024
Department of Medical Physics and Medical Informatics, University of Szeged, Szeged, Hungary.
Introduction: Cerebral ischemia leads to multiple organ dysfunctions, with the lungs among the most severely affected. Although adverse pulmonary consequences contribute significantly to reduced life expectancy after stroke, the impact of global or focal cerebral ischemia on respiratory mechanical parameters remains poorly understood.
Methods: Rats were randomly assigned to undergo surgery to induce permanent global cerebral ischemia (2VO) or focal cerebral ischemia (MCAO), or to receive a sham operation (SHAM).
J Clin Monit Comput
December 2024
Department of Critical Care, Hospital Universitario de La Princesa, Madrid, Spain.
To investigate the feasibility of non-invasively estimating the arterial partial pressure of carbon dioxide (PaCO) using a computational Adaptive Neuro-Fuzzy Inference System (ANFIS) model fed by noninvasive volumetric capnography (VCap) parameters. In 14 lung-lavaged pigs, we continuously measured PaCO with an optical intravascular catheter and VCap on a breath-by-breath basis. Animals were mechanically ventilated with fixed settings and subjected to 0 to 22 cmHO of positive end-expiratory pressure steps.
View Article and Find Full Text PDFAnn Ital Chir
December 2024
Department of Anesthesiology, Institute of Anesthesia, Emergency and Critical Care, Northern Jiangsu People's Hospital Affiliated to Yangzhou University, 225002 Yangzhou, Jiangsu, China.
Aim: Intraoperative lung-protective ventilation strategies (LPVS) have been shown to improve lung oxygenation and prevent postoperative pulmonary problems in surgical patients. However, the application of positive end-expiratory pressure (PEEP)-based LPVS in emergency traumatic brain injury (TBI) has not been thoroughly explored. The purpose of this study is to evaluate the effects of drive pressure-guided individualized PEEP on perioperative pulmonary oxygenation, postoperative pulmonary complications, and recovery from neurological injury in patients with TBI.
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