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Frontiers in Veterinary Science 2024To compare the cardiopulmonary effects of apneustic anesthesia ventilation (AAV) and conventional mechanical ventilation (CMV) in anesthetized pigs and to describe a new...
OBJECTIVE
To compare the cardiopulmonary effects of apneustic anesthesia ventilation (AAV) and conventional mechanical ventilation (CMV) in anesthetized pigs and to describe a new mode of ventilation for anesthetized veterinary species.
STUDY DESIGN
Randomized, crossover design without washout.
ANIMALS
Twelve healthy, female white Landrace pigs.
METHODS
Following ketamine-midazolam premedication and anesthetic induction with propofol, the trachea was intubated, and each pig was positioned in dorsal recumbency. Anesthesia was maintained with propofol and sufentanil infusions. Pigs were instrumented and their lungs were sequentially ventilated with each mode, in random order, for 1 h according to predefined criteria [fraction of inspired oxygen (FiO) = 0.21, 10 mL kg tidal volume (V), and arterial carbon dioxide tension (PaCO) within 40-45 mmHg]. Cardiopulmonary data were collected at baseline, 30 and 60 min. In 8 pigs, thoracic computed tomography (CT) was performed following the 60 min time point for each mode of ventilation and images were analyzed to quantify lung aeration. The effects of ventilation mode, time, and order were analyzed using repeated measures ANOVA. Paired -tests were used to compare lung aeration between modes. Significance was defined as < 0.05.
RESULTS
Data from 12 pigs were analyzed. A significant effect of mode was found for heart rate, mean arterial pressure (MAP), pulmonary artery occlusion pressure, cardiac index (CI), stroke volume index, systemic vascular resistance, pulmonary vascular resistance, oxygen delivery index (DOI), oxygen extraction ratio (OER), V, arterial oxygen tension, arterial hemoglobin saturation, PaCO, end-tidal carbon dioxide tension, alveolar dead space (V/V), venous admixture ( ), mean airway pressure, and dynamic compliance index (CI). Order effects were also observed for some cardiovascular and respiratory variables. For the eight pigs that underwent thoracic CT, AAV resulted in significantly larger proportions of normally and hyperaerated lung while CMV resulted in larger proportions of hypoaerated and atelectatic lung.
CONCLUSIONS
In dorsally recumbent anesthetized pigs, ventilated with FiO = 0.21, both modes of ventilation supported adequate oxygenation while AAV resulted in higher CI, and lower V/V and , compared with CMV. AAV was also associated with lower MAP, CI, and DOI and higher OER compared with CMV. Further investigation of AAV in anesthetized animals is warranted.
PubMed: 38855412
DOI: 10.3389/fvets.2024.1378617 -
Frontiers in Veterinary Science 2024To evaluate the safety and feasibility of high flow oxygen therapy (HFOT), and to record SpO and desaturation episodes in dogs and cats receiving HFOT or conventional...
OBJECTIVES
To evaluate the safety and feasibility of high flow oxygen therapy (HFOT), and to record SpO and desaturation episodes in dogs and cats receiving HFOT or conventional oxygen therapy (COT) during bronchoscopy ± bronchoalveolar lavage (BAL).
MATERIALS AND METHODS
Dogs and cats undergoing bronchoscopy ± BAL between January and May 2023 were included in the study. Patients were randomly allocated to two groups: HFOT (HFOT group; two cats and four dogs) and COT (COT group; one cat and five dogs). HFOT and COT were started at the beginning of the bronchoscopy. HFOT was delivered with a gas flow rate of 1 L/kg/min at an FiO of 100% and a temperature of 34°C (pediatric mode) or 37°C (adult mode). COT was delivered through the working channel of the bronchoscope at a rate of 1.5 L/min. The safety and feasibility of HFOT were assessed, and peripheral oxygen saturation (SpO) was measured by pulse oximetry every 30 s throughout the procedure.
MEASUREMENTS AND MAIN RESULTS
HFOT was feasible and safe in both dogs and cats with no complications reported. While there was no significant difference in the number of desaturation episodes (SpO < 94%) between the two groups, none of the patients in the HFOT group experienced severe desaturation (SpO < 90%). In contrast, two patients in the COT group had an SpO < 90%. Mean SpO was significantly higher in the HFOT group compared to the COT group at T0 (98% ± 2% vs. 94 ± 2%), T0.5 (98% ± 2% vs. 94% ± 3%) and T1 (98% ± 2% vs. 94% ± 4%).
CONCLUSION
To the authors' knowledge, this is the largest study conducted to date using HFOT during bronchoscopy in dogs and cats. Our results suggest that HFOT is feasible and safe during bronchoscopy ± BAL. Furthermore, HFOT may reduce the risk of desaturation episodes in dogs and cats undergoing bronchoscopy and BAL.
PubMed: 38855409
DOI: 10.3389/fvets.2024.1360017 -
Future of neurocritical care: Integrating neurophysics, multimodal monitoring, and machine learning.World Journal of Critical Care Medicine Jun 2024Multimodal monitoring (MMM) in the intensive care unit (ICU) has become increasingly sophisticated with the integration of neurophysical principles. However, the... (Review)
Review
Multimodal monitoring (MMM) in the intensive care unit (ICU) has become increasingly sophisticated with the integration of neurophysical principles. However, the challenge remains to select and interpret the most appropriate combination of neuromonitoring modalities to optimize patient outcomes. This manuscript reviewed current neuromonitoring tools, focusing on intracranial pressure, cerebral electrical activity, metabolism, and invasive and noninvasive autoregulation monitoring. In addition, the integration of advanced machine learning and data science tools within the ICU were discussed. Invasive monitoring includes analysis of intracranial pressure waveforms, jugular venous oximetry, monitoring of brain tissue oxygenation, thermal diffusion flowmetry, electrocorticography, depth electroencephalography, and cerebral microdialysis. Noninvasive measures include transcranial Doppler, tympanic membrane displacement, near-infrared spectroscopy, optic nerve sheath diameter, positron emission tomography, and systemic hemodynamic monitoring including heart rate variability analysis. The neurophysical basis and clinical relevance of each method within the ICU setting were examined. Machine learning algorithms have shown promise by helping to analyze and interpret data in real time from continuous MMM tools, helping clinicians make more accurate and timely decisions. These algorithms can integrate diverse data streams to generate predictive models for patient outcomes and optimize treatment strategies. MMM, grounded in neurophysics, offers a more nuanced understanding of cerebral physiology and disease in the ICU. Although each modality has its strengths and limitations, its integrated use, especially in combination with machine learning algorithms, can offer invaluable information for individualized patient care.
PubMed: 38855276
DOI: 10.5492/wjccm.v13.i2.91397 -
BioRxiv : the Preprint Server For... May 2024GE-BOLD contrast stands out as the predominant technique in functional MRI experiments for its high sensitivity and straightforward implementation. GE-BOLD exhibits...
On the influence of the vascular architecture on Gradient Echo and Spin Echo BOLD fMRI signals across cortical depth: a simulation approach based on realistic 3D vascular networks.
GE-BOLD contrast stands out as the predominant technique in functional MRI experiments for its high sensitivity and straightforward implementation. GE-BOLD exhibits rather similar sensitivity to vessels independent of their size at submillimeter resolution studies like those examining cortical columns and laminae. However, the presence of nonspecific macrovascular contributions poses a challenge to accurately isolate neuronal activity. SE-BOLD increases specificity towards small vessels, thereby enhancing its specificity to neuronal activity, due to the effective suppression of extravascular contributions caused by macrovessels with its refocusing pulse. However, even SE-BOLD measurements may not completely remove these macrovascular contributions. By simulating hemodynamic signals across cortical depth, we gain insights into vascular contributions to the laminar BOLD signal. In this study, we employed four realistic 3D vascular models to simulate oxygen saturation states in various vascular compartments, aiming to characterize both intravascular and extravascular contributions to GE and SE signals, and corresponding BOLD signal changes, across cortical depth at 7T. Simulations suggest that SE-BOLD cannot completely reduce the macrovascular contribution near the pial surface. Simulations also show that both the specificity and signal amplitude of BOLD signals at 7T depend on the spatial arrangement of large vessels throughout cortical depth and on the pial surface.
PubMed: 38853905
DOI: 10.1101/2024.05.30.596593 -
The International Journal of Artificial... Jun 2024A feared complication of an acute myocardial infarction (AMI) is cardiac arrest (CA). Even if return of spontaneous circulation is achieved, cardiogenic shock (CS) is...
INTRODUCTION
A feared complication of an acute myocardial infarction (AMI) is cardiac arrest (CA). Even if return of spontaneous circulation is achieved, cardiogenic shock (CS) is common. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) supports patients with CS and is often used in conjunction with an Impella device (2.5 and CP) to off-load the left ventricle, although limited evidence supports this approach.
METHODS
The goal of this study was to determine whether a mortality difference was observed in VA-ECMO alone versus VA-ECMO with Impella (ECPELLA) in patients with CS from AMI and CA. A retrospective chart review of 50 patients with AMI-CS and CA and were supported with VA-ECMO ( = 34) or ECPELLA ( = 16) was performed. The primary outcome was all-cause mortality at 6-months from VA-ECMO or Impella implantation. Secondary outcomes included in-hospital mortality and complication rates between both cohorts and intensive care unit data.
RESULTS
Baseline characteristics were similar, except patients with ST-elevation myocardial infarction were more likely to be in the VA-ECMO group ( = 0.044). The ECPELLA cohort had significantly worse survival after VA-ECMO (SAVE) score ( = 0.032). Six-month all-cause mortality was not significantly different between the cohorts, even when adjusting for SAVE score. Secondary outcomes were notable for an increased rate of minor complications without an increased rate of major complications in the ECPELLA group.
CONCLUSIONS
Randomized trials are needed to determine if a mortality difference exists between VA-ECMO and ECPELLA platforms in patients with AMI complicated by CA and CS.
PubMed: 38853663
DOI: 10.1177/03913988241254978 -
Chest Jun 2024A 57-year-old man was admitted to our hospital via the ED presenting in reduced general condition because of an infection of unknown origin, generalized edema, and...
A 57-year-old man was admitted to our hospital via the ED presenting in reduced general condition because of an infection of unknown origin, generalized edema, and dyspnea at rest (peripheral capillary oxygen saturation, 89%) that required 2 L/min intranasal oxygen. Anamnesis was complicated by an infection-triggered delirium, but his wife reported an increasing physical decay that had led to bed confinement. The BP was reduced at 88/55 mm Hg with a normal heart rate of 86 beats/min. Lung auscultation showed mild bipulmonal rales. Previous comorbidities were a BMI of 42 kg/m, an insulin-dependent type 2 diabetes mellitus with a severe diabetes-related chronic kidney disease stage G4A3, and systemic arterial hypertension.
Topics: Humans; Male; Middle Aged; Pulmonary Artery; Vascular Calcification; Tomography, X-Ray Computed; Diagnosis, Differential
PubMed: 38852977
DOI: 10.1016/j.chest.2024.02.022 -
Bioelectrochemistry (Amsterdam,... May 2024Intracellular reactive oxygen species (ROS) generation is widely suggested as a trigger for biological consequences of electric field exposures, such as those in...
Intracellular reactive oxygen species (ROS) generation is widely suggested as a trigger for biological consequences of electric field exposures, such as those in electroporation applications. ROS are linked with membrane barrier function degradation, genetic damage, and complex events like immunological cell death. Dihydroethidium (DHE) is commonly used to monitor ROS in cells. DHE is linked to intracellular ROS by a primary oxidation product, Ethidium (Eth), that shows increased fluorescence upon binding to polynucleotides. We observed changes in DHE-derived fluorescence in Chinese hamster ovary (CHO) cells post 300-ns electric pulse exposures, comparing them to tert-butyl-hydroperoxide (t-BHP) induced oxidative stress. Immediate intracellular fluorescence changes were noted in both cases, but with distinct localization patterns. After electrical stress, cytosolic DHE-derived fluorescence intensity decreases, and nucleolar intensity increases. Conversely, t-BHP exposure increases DHE-derived fluorescence uniformly across the cell. Surprisingly, fluorescence patterns after electrical stress in Eth-loaded cells is identical to those in DHE-loaded cells, in kinetics and localization patterns. These findings indicate that DHE-derived fluorescence changes after pulsed electric field stress are not due to intracellular ROS generation leading to DHE oxidation, but rather indicate stress-induced intracellular microenvironment alterations affecting Eth fluorescence.
PubMed: 38851174
DOI: 10.1016/j.bioelechem.2024.108751 -
Journal of Rehabilitation Medicine Jun 2024Wheelchair basketball (WCB) demands high-intensity training due to its intermittent nature. However, acute oxygen uptake (V˙O2) in handcycling is restricted. Combining... (Randomized Controlled Trial)
Randomized Controlled Trial
Handcycling with concurrent lower body low-frequency electromyostimulation significantly increases acute oxygen uptake in elite wheelchair basketball players: an acute crossover trial.
OBJECTIVE
Wheelchair basketball (WCB) demands high-intensity training due to its intermittent nature. However, acute oxygen uptake (V˙O2) in handcycling is restricted. Combining handcycling with low-frequency electromyostimulation (LF-EMS) may enhance V˙O2 in elite WBC athletes.
DESIGN
Randomized crossover trail.
SUBJECTS
Twelve German national team WCB players (age: 25.6 [5.6] years, height: 1.75 [0.16] m, mass: 74.0 [21.7] kg, classification: 2.92 [1.26]).
METHOD
Participants underwent 2×5 min of handcycling (60 rpm, ¾ bodyweight resistance in watts) (HANDCYCLE) and 2×5 min of handcycling with concurrent LF-EMS (EMS_HANDCYCLE). LF-EMS (4Hz, 350µs, continuous stimulation) targeted gluteal, quadriceps, and calf muscles, adjusted to individual pain thresholds (buttocks: 69.5 [22.3] mA, thighs: 66.8 [20.0] mA, calves: 68.9 [31.5] mA).
RESULTS
Significant mode-dependent differences between HANDCYCLE and EMS_HANDCYCLE were found in V˙O2 (17.60 [3.57] vs 19.23 [4.37] ml min-1 kg-1, p = 0.001) and oxygen pulse (16.69 [4.51] vs 18.41 [5.17] ml, p = 0.002). ΔLactate was significantly lower in HANDCYCLE (0.04 [0.28] vs 0.31 [0.26] mmol l-1). Although perceived effort did not differ (p = 0.293), discomfort was rated lower in HANDCYCLE (1.44 [1.28] vs 3.94 [2.14], p = 0.002).
CONCLUSION
LF-EMS applied to the lower extremities increases oxygen demand during submaximal handcycling. Thus, longitudinal application of LF-EMS should be investigated as a potential training stimulus to improve aerobic capacity in wheelchair athletes.
Topics: Humans; Cross-Over Studies; Wheelchairs; Adult; Basketball; Oxygen Consumption; Male; Young Adult; Muscle, Skeletal; Athletes
PubMed: 38850087
DOI: 10.2340/jrm.v56.40028 -
Journal of Rehabilitation Medicine Jun 2024To determine the physical strain of walking and assess its relationship with daily steps and intensity of daily activity in people with neuromuscular diseases.
OBJECTIVE
To determine the physical strain of walking and assess its relationship with daily steps and intensity of daily activity in people with neuromuscular diseases.
DESIGN
Cross-sectional study.
SUBJECTS/PATIENTS
Sixty-one adults with neuromuscular diseases.
METHODS
Physical strain of walking, defined as oxygen consumption during comfortable walking relative to peak oxygen uptake. Daily step count and daily time spent in moderate and vigorous physical activity were assessed using accelerometry and heart rate measurements, respectively. Regression analyses assessed the relationships between log daily step count and log daily time spent in moderate and vigorous physical activity, and physical strain of walking.
RESULTS
The mean (standard deviation) physical strain of walking was 73 (20)% Log daily step count and physical strain were negatively associated (β = -0.47). No association was found with log daily time spent in moderate and vigorous physical activity.
CONCLUSIONS
The highly increased physical strain of comfortable walking indicates that walking is very demanding for people with neuromuscular diseases and is associated with a reduction in daily step activity. The absence of a relationship between intensity of activities and physical strain indicates that, despite a reduction in daily step activity, strenuous daily activities may still be performed.
Topics: Humans; Neuromuscular Diseases; Walking; Cross-Sectional Studies; Male; Female; Activities of Daily Living; Middle Aged; Adult; Accelerometry; Oxygen Consumption; Heart Rate; Aged; Exercise
PubMed: 38850055
DOI: 10.2340/jrm.v56.40026 -
BMC Medical Informatics and Decision... Jun 2024This study aimed to develop a higher performance nomogram based on explainable machine learning methods, and to predict the risk of death of stroke patients within 30...
A novel higher performance nomogram based on explainable machine learning for predicting mortality risk in stroke patients within 30 days based on clinical features on the first day ICU admission.
BACKGROUND
This study aimed to develop a higher performance nomogram based on explainable machine learning methods, and to predict the risk of death of stroke patients within 30 days based on clinical characteristics on the first day of intensive care units (ICU) admission.
METHODS
Data relating to stroke patients were extracted from the Medical Information Marketplace of the Intensive Care (MIMIC) IV and III database. The LightGBM machine learning approach together with Shapely additive explanations (termed as explain machine learning, EML) was used to select clinical features and define cut-off points for the selected features. These selected features and cut-off points were then evaluated using the Cox proportional hazards regression model and Kaplan-Meier survival curves. Finally, logistic regression-based nomograms for predicting 30-day mortality of stroke patients were constructed using original variables and variables dichotomized by cut-off points, respectively. The performance of two nomograms were evaluated in overall and individual dimension.
RESULTS
A total of 2982 stroke patients and 64 clinical features were included, and the 30-day mortality rate was 23.6% in the MIMIC-IV datasets. 10 variables ("sofa (sepsis-related organ failure assessment)", "minimum glucose", "maximum sodium", "age", "mean spo2 (blood oxygen saturation)", "maximum temperature", "maximum heart rate", "minimum bun (blood urea nitrogen)", "minimum wbc (white blood cells)" and "charlson comorbidity index") and respective cut-off points were defined from the EML. In the Cox proportional hazards regression model (Cox regression) and Kaplan-Meier survival curves, after grouping stroke patients according to the cut-off point of each variable, patients belonging to the high-risk subgroup were associated with higher 30-day mortality than those in the low-risk subgroup. The evaluation of nomograms found that the EML-based nomogram not only outperformed the conventional nomogram in NIR (net reclassification index), brier score and clinical net benefits in overall dimension, but also significant improved in individual dimension especially for low "maximum temperature" patients.
CONCLUSIONS
The 10 selected first-day ICU admission clinical features require greater attention for stroke patients. And the nomogram based on explainable machine learning will have greater clinical application.
Topics: Humans; Nomograms; Male; Female; Machine Learning; Aged; Middle Aged; Intensive Care Units; Stroke; Risk Assessment; Aged, 80 and over; Prognosis
PubMed: 38849903
DOI: 10.1186/s12911-024-02547-7