Emergency Medical Services Responder Manual Ventilation Performance.

OBJECTIVE: Manual ventilation is a basic skill that every emergency medical services (EMS) responder is expected to perform proficiently. Improper manual ventilation may result in significant morbidity; however, there is no feedback mechanism or method of control for the volume, pressure, or frequency during manual ventilation. In this study, we aimed to quantify the volume and peak pressures of manually delivered breaths using a simulated lung. METHODS: One hundred ninety-nine volunteer EMS responders from the EMS World Expo 2019 and EMS Today 2020 participated in this study. Each volunteer manually ventilated a simulated lung using a bag-valve-mask (BVM) for 18 breaths. Descriptive statistics were computed for peak pressures (Ppeak) and tidal volumes (VT)), and a multivariable linear regression was conducted to determine whether there was an independent correlation between Ppeak or VT and seven different variables. RESULTS: Both Ppeak and VT delivered by EMS responders had a high level of variability; 82.9% of clinicians delivered at least one breath exceeding the recommended safety thresholds; and 98.0% delivered at least one breath that was inadequate or excessive. Our results showed no likely clinical significant role of sex, hand size, frequency of use, or years of experience in determining Ppeak and VT. Tidal volumes were significantly higher in males (p < 0.001), those using two-hand manual ventilation (p < 0.001), shorter hand length (p = 0.013), higher confidence (p < 0.001), and more years of experience (p < 0.001). Peak pressures were significantly higher in those using two-hand manual ventilation (p < 0.001), wider hand width (p = 0.004), higher confidence (p < 0.001), less frequent use of the BVM per month (p < 0.001), more experience (p < 0.001). CONCLUSIONS: Our study demonstrated large variability of VT and Ppeak within and, to a lesser degree, between clinicians. Of the seven variables that might have affected tidal volume or peak pressures, only the use of two hands versus one hand had a potentially clinically significant effect. Our study identifies a clear need for BVM improvement to ensure every practitioner can deliver breaths at appropriate volumes and safe pressures.

Increased "absence" of telomeres may indicate Alzheimer's disease/dementia status in older individuals with Down syndrome.

We have reported previously that telomeres (ends of chromosomes consisting of highly conserved TTAGGG repeats) were shorter in metaphase and interphase preparations in T lymphocytes from short-term whole blood cultures of women with Down syndrome (DS) and dementia compared to age-matched women with DS but without dementia [E.C. Jenkins, M.T. Velinov, L. Ye, H. Gu, S. Li, E.C. Jenkins Jr., S.S. Brooks, D. Pang, D.A. Devenny, W.B. Zigman, N. Schupf, W.P. Silverman, Telomere shortening in T lymphocytes of older individuals with Down syndrome and dementia, Neurobiol. Aging 27 (2006) 41-45]. Our previous study was carried out by measuring changes in fluorescence intensity [using an FITC-labeled peptide nucleic acid (PNA) probe (Applied Biosystems; DAKO) and Applied Imaging software], and we now report on a substantially simpler metric, counts of signals at the ends of chromosomes. Nine adults with DS and dementia plus four who are exhibiting declines in cognition analogous to mild cognitive impairment in the general population (MCI-DS) were compared to their pair-matched peers with DS but without dementia or MCI-DS. Results indicated that the number of chromosome ends that failed to exhibit fluorescent signal from the PNA telomere probe was higher for people with dementia or mild cognitive impairment (MCI-DS). Thus, a simple count of chromosome ends for the "presence/absence" of fluorescence may provide a valid biomarker of dementia status. If this is the case, then after additional research for validation to assure high specificity and sensitivity, the test may be used to identify and ultimately guide treatment for people at increased risk for developing mild cognitive impairment and/or dementia.

Shorter telomeres may indicate dementia status in older individuals with Down syndrome.

We have recently reported reduced telomere length in T lymphocytes of individuals with Down syndrome (DS) and dementia due to Alzheimer's disease (AD). We have now replicated and extended that study by finding that people with DS and mild cognitive impairment (MCI-DS) also have shorter telomeres than people with DS without MCI-DS. Additional new findings demonstrated that light intensity measurements from chromosome 21 alone, or in concert with chromosomes 1, 2, and 16, exhibited shorter telomeres in adults with DS and with either dementia or MCI-DS compared to aging per se. Chromosome 21 measurements appeared to be especially promising for use as a biomarker because there was no overlap in the distribution of light intensity measurement scores between demented or MCI-DS and non-demented participants. Given that early clinical symptoms of AD can be very difficult to recognize in this population of adults due to their pre-existing cognitive impairments, a valid biomarker would be of great value. Early detection is especially important because it would allow treatments to begin before significant damage to the central nervous system has occurred. Our findings suggest that it may be feasible to use telomere shortening as a biomarker for accurately inferring dementia status.