8 research outputs found

    Assessment of a Wearable Device for Minute Ventilation in Detecting Different States of Ventilation

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    Introduction: Minute ventilation (MV) and breathing status are valuable vital signs to measure in patients clinically such as in detecting opioid induced respiratory depression. However, there are few devices capable of continuously monitoring MV in an accurate fashion. RTM Vital Signs, LLC and TJU are developing a non-invasive wearable Tracheal Sound Sensor to determine if a device can accurately and continuously measure respiratory rate (RR), tidal volume (TV), MV, and changes in ventilation patterns based on sound recordings of breathing. Methods: Tracheal breathing sounds were recorded in six researchers using a prototype sensor placed on the skin above the sternal notch. Simultaneously, researcher’s RR and MV were recorded in minute long intervals using a pneumotach. Researchers were asked to mimic various breathing patterns by adjusting breathing rate and breathing depth. A variety of signal processing methods and algorithms were used to analyze the data to produce RR, TV, and breathing pattern estimates. Results: Researchers tolerated use of the sensor and breathing apparatus system without difficulty and data was successfully obtained. Initial signal processing and analysis methods applied to this data were able to accurately measure the respiratory rate (~ 98% sensitivity/specificity), and accurately characterize normal breathing from hyperventilation and hypoventilation (~ 98% sensitivity/specificity). The sensor’s algorithm estimated tidal volume with ± 100 ml accuracy compared with the commercial pneumotach. Discussion: Based on the results, a non-invasive wearable device could obtain accurate measures of RR and classify breathing patterns based solely on measurements of breathing sounds. Although the TV results were not as accurate as we expected, this may be due in part to systematic error from the pneumotach device used for the reference TV. With the satisfactory sensor and data acquisition system, future trials are planned in volunteers and hospitalized patients using this system with more accurate pneumotach devices

    Detecting Different States of Ventilation with a Wearable Device through Minute Ventilation

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    Introduction: Detecting changes in respiration are essential to monitoring a patient’s vital signs. Few devices accomplish this in a non-invasive manner. We are developing a wearable Trachea Sound Sensor that measures respiratory rate (RR), tidal volume (TV), minute ventilation (MV = RR x TV). A prototypical Trachea Sound Sensor (TSS) was created and compared to a reference pneumotachometer. Both were used to record the sounds of breathing with research team members. Methods:The TSS recording device was tested on six research team members and breath sounds were recorded. Simultaneously, the member’s RR and MV was recorded using a calibrated pneumotachometer. The researchers were instructed to adjust their breathing rate and depth while intervals were recorded. Signal processing techniques were used to analyze and produce measurements of RR, TV, and characterize hyperventilatory or hypoventilatory states. Results: Based on the results, we found that it is possible to obtain accurate measures of RR and identify breathing patterns through the TSS. Signal processing and analysis calculated RR, states of hyperventilation and hypoventilation with 98% sensitivity and specificity. Results obtained for measuring TV were less accurate (±100 mL). Discussion: Our results suggest that it is viable to obtain accurate measures of RR and classify breathing sounds solely on measurements of breathing sounds from the TSS. The inaccuracy in TV measurements may be partly due to the systematic error from the pneumotachometer used. The prototypical TSS are suitable for upcoming NIH-funded clinical trials to test the TSS in volunteers and hospitalized patients

    Connective Tissue Growth Factor Overexpression in Cardiomyocytes Promotes Cardiac Hypertrophy and Protection against Pressure Overload

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    Connective tissue growth factor (CTGF) is a secreted protein that is strongly induced in human and experimental heart failure. CTGF is said to be profibrotic; however, the precise function of CTGF is unclear. We generated transgenic mice and rats with cardiomyocyte-specific CTGF overexpression (CTGF-TG). To investigate CTGF as a fibrosis inducer, we performed morphological and gene expression analyses of CTGF-TG mice and rat hearts under basal conditions and after stimulation with angiotensin II (Ang II) or isoproterenol, respectively. Surprisingly, cardiac tissues of both models did not show increased fibrosis or enhanced gene expression of fibrotic markers. In contrast to controls, Ang II treated CTGF-TG mice displayed preserved cardiac function. However, CTGF-TG mice developed age-dependent cardiac dysfunction at the age of 7 months. CTGF related heart failure was associated with Akt and JNK activation, but not with the induction of natriuretic peptides. Furthermore, cardiomyocytes from CTGF-TG mice showed unaffected cellular contractility and an increased Ca2+ reuptake from sarcoplasmatic reticulum. In an ischemia/reperfusion model CTGF-TG hearts did not differ from controls

    Incidence and Risk Factors for Retinal Detachment and Retinal Tear after Cataract Surgery

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    Objective: To report the incidence of and evaluate demographic, ocular comorbidities, and intraoperative factors for rhegmatogenous retinal detachment (RRD) and retinal tear (RT) after cataract surgery in the American Academy of Ophthalmology IRIS® Registry (Intelligent Research in Sight). Design: Retrospective cohort study. Participants: Patients aged ≥ 40 years who underwent cataract surgery between 2014 and 2017. Methods: Multivariable logistic regression was used to evaluate demographic, comorbidity, and intraoperative factors associated with RRD and RT after cataract surgery. Main Outcome Measures: Incidence and risk factors for RRD or RT within 1 year of cataract surgery. Results: Of the 3 177 195 eyes of 1 983 712 patients included, 6690 (0.21%) developed RRD and 5489 (0.17%) developed RT without RRD within 1 year after cataract surgery. Multivariable logistic regression odds ratios (ORs) showed increased risk of RRD and RT, respectively, among men (OR 3.15; 95% confidence interval [CI], 2.99–3.32; P 70, peaking at age 40 to 50 for RRD (8.61; 95% CI, 7.74–9.58; P 40 years within 1 year of surgery. The presence of LD conferred the highest odds for RRD and RT after surgery. Additional risk factors for RRD included male gender, younger age, hypermature cataract, PVD, and high myopia. These data may be useful during the informed consent process for cataract surgery and help identify patients at a higher risk of retinal complications. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article

    Characterizations of myosin essential light chain’s N-terminal truncation mutant Δ43 in transgenic mouse papillary muscles by using tension transients in response to sinusoidal length alterations

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    Cross-bridge kinetics were studied at 20 °C in cardiac muscle strips from transgenic (Tg) mice expressing N-terminal 43 amino acid truncation mutation (Δ43) of myosin essential light chain (ELC), and the results were compared to those from Tg-wild type (WT) mice. Sinusoidal length changes were applied to activated skinned papillary muscle strips to induce tension transients, from which two exponential processes were deduced to characterize the cross-bridge kinetics. Their two rate constants were studied as functions of ATP, phosphate (Pi), ADP, and Ca(2+) concentrations to characterize elementary steps of the cross-bridge cycle consisting of six states. Our results demonstrate for the first time that the cross-bridge kinetics of Δ43 are accelerated owing to an acceleration of the rate constant k(2) of the cross-bridge detachment step, and that the number of strongly attached cross-bridges are decreased because of a reduction of the equilibrium constant K(4) of the force generation step. The isometric tension and stiffness of Δ43 are diminished compared to WT, but the force per cross-bridge is not changed. Stiffness measurement during rigor induction demonstrates a reduction in the stiffness in Δ43, indicating that the N-terminal extension of ELC forms an extra linkage between the myosin cross-bridge and actin. The tension-pCa study demonstrates tht there is no Ca(2+) sensitivity change with Δ43, but the cooperativity is diminished. These results demonstrate the importance of the N-terminal extension of ELC in maintaining the myosin motor function during force generation and optimal cardiac performance

    A second update on mapping the human genetic architecture of COVID-19

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