Background: Simulated exhaled nitric oxide (eNO) depends on ventilatory settings used in different experimental conditions.
Objectives: To normalize the simulated minute exhaled nitric oxide according to different ventilatory settings.
Working Hypothesis: Different ventilatory settings influence the concentrations of exhaled nitric oxide and these results can be normalized. METHODOLOGY AND STUDY DESIGN: We used a rubber lung model (50 ml) with an orifice through which a 3 mm endotracheal tube was introduced. The NO, which simulated that of endogenous production, was delivered through the base of the lung using a unidirectional rotameter and obtaining a concentration of around 25 ppb. The sample of gas was recorded through a 6 F arterial catheter introduced into the endotracheal tube to its tip. The ventilator used was a Babylog 8000. Air delivered was compressed and filtered and had an NO content of under 0.3 ppb. The NO level assessed was the plateau value given by the software of the Sievers NOA apparatus. Each experiment involved sampling during 1 min, three times. Normalization was done using a multiple cubic regression formula.
Results: An increase in respiratory frequency or in peak of inspiratory pressure were accompanied by a decrease in eNO (ppb). Minute volume was adjusted for the percentage of leakage given by the ventilator. Normalization was obtained analyzing 518 respirations with different ventilatory settings. The coefficient of variation fell from 15.5% to 0.27%. Validation of the normalization formula was performed in other three groups (320, 372, and 372 respirations) with different simulated NO concentrations (25, 16, and 50 ppb), resulting in reduction of the coefficient of variation from 42.7% to 9.3%, from 42.3% to 10.6% and from 45.2% to 9.6%, respectively.
Conclusions: Normalization of simulated minute eNO according to ventilatory settings is possible using the equipment and experimental set-up reported. Extrapolation to patients is not possible without constraints.
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http://dx.doi.org/10.1002/ppul.20893 | DOI Listing |
Heart
December 2024
Centro Cardiologico Monzino, IRCCS, Milan, Italy.
Background: Little evidence is available about heart rate (HR) response to exercise as well as its relationship with functional capacity in amyloid cardiomyopathy. Then, in a multicentre cohort of patients with amyloid cardiomyopathy, we investigated the prevalence of chronotropic incompetence (CI) and its relationships with cardiopulmonary exercise testing (CPET) variables.
Methods: Data from 172 outpatients with amyloid cardiomyopathy who performed a maximal CPET and who had no significant rhythm disorders were analysed.
Neurocrit Care
January 2025
Division of Neuroscience Critical Care, Departments of Neurology, Neurosurgery, and Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Background: Invasive mechanical ventilation can present complex challenges for patients with acute brain injury (ABI) in middle-income countries (MICs). We characterized the impact of country income level on weaning strategies and outcomes in patients with ABI.
Methods: A secondary analysis was performed on a registry of critically ill patients with ABI admitted to 73 intensive care units (ICUs) in 18 countries from 2018 to 2020.
ASAIO J
November 2024
From the Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota.
A 40 year old woman who underwent combined heart-lung transplant for familial severe pulmonary hypertension experienced episodes of nonsustained ventricular tachycardia followed by sudden ventricular fibrillation arrest 8 days after transplant. Postarrest investigations revealed left lower lobe herniation into the right lower hemithorax, prompting emergent reoperation, and hernia reduction. Arrhythmias resolved following reduction of the herniated lung and facilitated rapid weaning from vasopressor and ventilatory support.
View Article and Find Full Text PDFJ Cardiothorac Vasc Anesth
December 2024
Department of Anesthesiology, Thomas Jefferson University, Philadelphia, PA.
Objectives: Following cardiac surgery, patients often require ventilatory support during transport to the intensive care unit (ICU). Manual ventilation using a bag valve mask (BVM) is commonly employed; however, mechanical ventilation may sometimes be preferred due to concerns regarding oxygenation, ventilation, and hemodynamic stability. The decision between manual and mechanical ventilation is typically based on clinical experience and surgical factors, as there is no established consensus or robust clinical evidence to guide this choice.
View Article and Find Full Text PDFJ 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.
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