To create a low-cost ventilator that could be constructed with readily-available hospital equipment for use in emergency or low-resource settings. Main methods: The novel ventilator consists of an inspiratory limb composed of an elastic flow-inflating bag encased within a non-compliant outer sheath and an expiratory limb composed of a series of two, one-way bidirectional splitter valves derived from a self-inflating bag system. An Arduino Uno microcontroller controls a solenoid valve that can be programmed to open and close to produce a set respiratory rate and inspiratory time. Using an ASL 5000 Lung Simulator, we obtained flow, pressure, and volume waveforms at different lung compliances. Key findings: At a static lung compliance of 50 mL/cm H 2 O and an airway resistance of 6 cm H 2 O/L/s, ventilated at a PIP and PEEP of 16 and 5 cm H 2 O, respectively, tidal volumes of approximately 540 mL were achieved. At a static lung compliance of 20 mL/cm H 2 O and an airway resistance of 6 cm H 2 O/L/s, ventilated at a PIP and PEEP of 38 and 15 cm H 2 O, respectively, tidal volumes of approximately 495 mL were achieved. Significance: This novel ventilator is able to safely and reliably ventilate patients with a range of pulmonary disease in a simulated setting. Opportunities exist to utilize our ventilator in emergency situations and lowresource settings.
Background-Sinus venosus defects (SVD) of the inferior vena cava (IVC) type, or inferior SVDs, are an uncommon form of atrial communication located outside the confines of the fossa ovalis and involve override of the IVC. Despite numerous studies describing the anatomical and echocardiographic features of the inferior SVD, distinguishing this defect from a large secundum atrial septal defect (ASD) by echocardiography is often challenging. Accurate diagnosis of an inferior SVD and correct differentiation from a secundum ASD is essential for appropriate presurgical planning. Absence of the posterior rim in the parasternal short axis views may serve as a useful clue in diagnosing inferior SVDs. We sought to determine the utility of using the presence or absence of a posterior atrial rim in the parasternal short axis view to help distinguish an inferior SVD from a secundum ASD. This sign may help clinch the diagnosis when subcostal imaging is suboptimal.
Aims
We hypothesized left atrial (LA) stiffness may serve as a surrogate marker in children to differentiate elevated pulmonary capillary wedge pressure (PCWP) from normal and help detect diastolic dysfunction in myocardial injury due to multisystem inflammatory syndrome in children (MIS-C).
Methods and results
We validated LA stiffness in 76 patients (median age 10.5 years), 33 had normal PCWP (<12 mmHg) and 43 had elevated PCWP (≥12 mmHg). LA stiffness was applied to 42 MIS-C patients [28 with myocardial injury (+) and 14 without myocardial injury (−)], defined by serum biomarkers. The validation group consisted of a group with and without cardiomyopathies, whose PCWP values ranged from normal to severely elevated. Peak LA strain was measured by speckle-tracking and E/e′ from apical four chamber views. Noninvasive LA stiffness was calculated as: LAStiffness=E/e′LAPeakStrain (%−1). Patients with elevated PCWP showed significantly elevated LA stiffness [median 0.71%−1 vs. 0.17%−1, P < 0.001]. Elevated PCWP group showed significantly decreased LA strain (median: 15.0% vs. 38.2%, P < 0.001). Receiver operator characteristic (ROC) curve for LA stiffness yielded an area under the curve (AUC) of 0.88 and cutoff value of 0.27%−1. In MIS-C group, ROC curve yielded an AUC of 0.79 and cutoff value of 0.29%−1 for identifying myocardial injury.
Conclusion
In children with elevated PCWP, LA stiffness was significantly increased. When applied to children with MIS-C, LA stiffness classified myocardial injury accurately. LA stiffness and strain may serve as noninvasive markers of diastolic function in the pediatric population.
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