Publications by authors named "J Lynn Fink"

1,469 Publications

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Optimizing high-flow nasal cannula flow settings in adult hypoxemic patients based on peak inspiratory flow during tidal breathing.

Ann Intensive Care 2021 Nov 27;11(1):164. Epub 2021 Nov 27.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA.

Background: Optimal flow settings during high-flow nasal cannula (HFNC) therapy are unknown. We investigated the optimal flow settings during HFNC therapy based on breathing pattern and tidal inspiratory flows in patients with acute hypoxemic respiratory failure (AHRF).

Methods: We conducted a prospective clinical study in adult hypoxemic patients treated by HFNC with a fraction of inspired oxygen (FO) ≥ 0.4. Patient's peak tidal inspiratory flow (PTIF) was measured and HFNC flows were set to match individual PTIF and then increased by 10 L/min every 5-10 min up to 60 L/min. FO was titrated to maintain pulse oximetry (SpO) of 90-97%. SpO/FO, respiratory rate (RR), ROX index [(SpO/FO)/RR], and patient comfort were recorded after 5-10 min on each setting. We also conducted an in vitro study to explore the relationship between the HFNC flows and the tracheal FO, peak inspiratory and expiratory pressures.

Results: Forty-nine patients aged 58.0 (SD 14.1) years were enrolled. At enrollment, HFNC flow was set at 45 (38, 50) L/min, with an FO at 0.62 (0.16) to obtain an SpO/FO of 160 (40). Mean PTIF was 34 (9) L/min. An increase in HFNC flows up to two times of the individual patient's PTIF, incrementally improved oxygenation but the ROX index plateaued with HFNC flows of 1.34-1.67 times the individual PTIF. In the in vitro study, when the HFNC flow was set higher than PTIF, tracheal peak inspiratory and expiratory pressures increased as HFNC flow increased but the FO did not change.

Conclusion: Mean PTIF values in most patients with AHRF were between 30 and 40 L/min. We observed improvement in oxygenation with HFNC flows set above patient PTIF. Thus, a pragmatic approach to set optimal flows in patients with AHRF would be to initiate HFNC flow at 40 L/min and titrate the flow based on improvement in ROX index and patient tolerance.

Trial Registration: ClinicalTrials.gov (NCT03738345). Registered on November 13th, 2018. https://clinicaltrials.gov/ct2/show/NCT03738345?term=NCT03738345&draw=2&rank=1.
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http://dx.doi.org/10.1186/s13613-021-00949-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8626729PMC
November 2021

Aerosol particle concentrations with different oxygen devices and interfaces for spontaneous breathing patients with tracheostomy: a randomised crossover trial.

ERJ Open Res 2021 Oct 22;7(4). Epub 2021 Nov 22.

Dept of Cardiopulmonary Sciences, Division of Respiratory Care, Rush University Medical Center, Chicago, IL, USA.

https://bit.ly/2Y1HSO2.
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http://dx.doi.org/10.1183/23120541.00486-2021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8607113PMC
October 2021

Obesity Surgery-Weight Loss, Metabolic Changes, Oncological Effects, and Follow-up.

Dtsch Arztebl Int 2022 Feb 4(Forthcoming). Epub 2022 Feb 4.

Background: In 2017, the prevalence of obesity (BMI ≥ 30 kg/m2) in Germany was approximately 16%. Obesity increases an individual's risk of developing type 2 diabetes (T2DM) and arterial hypertension; it also increases overall mortality. Consequently, effective treatment is a necessity. Approximately 20 000 bariatric operations are performed in Germany each year.

Methods: This review is based on pertinent publications retrieved by a selective search in the PubMed and Cochrane databases and on current German clinical practice guidelines.

Results: The types of obesity surgery most commonly performed in Germany, Roux-en-Y gastric bypass and sleeve gastrectomy, lead to an excess weight loss of 27-69% ≥ 10 years after the procedure. In obese patients with T2DM, the diabetes remission rate ≥ 10 years after these procedures ranges from 25% to 62%. Adjusted regression analyses of data from large registries have shown that the incidence of malignancies is 33% lower in persons who have undergone obesity surgery compared to control subjects with obesity (unadjusted incidence 5.6 versus 9.0 cases per 1000 person-years). The operation can cause vitamin deficiency, surgical complications, gastroesophageal reflux, and dumping syndrome. Therefore, lifelong follow-up is necessary.

Conclusion: In view of an increasing number of patients undergoing bariatric surgery, it will probably not be feasible in the future for lifelong follow-up to be provided exclusively in specialized centers.
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http://dx.doi.org/10.3238/arztebl.m2021.0359DOI Listing
February 2022

Mitigating Fugitive Aerosols during Aerosol Delivery via High-Flow Nasal Cannula Devices.

Respir Care 2021 Nov 17. Epub 2021 Nov 17.

Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee, USA.

Aerosol delivery via high-flow nasal cannula (HFNC) has attracted clinical interests in recent years. However, both HFNC and nebulization are categorized as aerosol generating procedures (AGPs). In-vitro studies raised concerns that AGPs had high transmission risk. Very few in-vivo studies examined fugitive aerosols with HFNC and nebulization via HFNC, and effective methods to mitigate aerosol dispersion are unknown. Two HFNC devices (Airvo2 and Vapotherm) with or without a vibrating mesh nebulizer (VMN) were compared; HFNC alone, surgical mask over HFNC interface, and HFNC with face tent scavenger were used in a random order for nine healthy volunteers. Fugitive aerosol concentrations at sizes of 0.3-10 µm were continuously measured by particle sizers placed at one and three feet from participants. On a different day, six of the nine participants received six additional nebulizer treatments via VMN or small volume nebulizer (SVN) with mouthpiece with/without an expiratory filter or facemask. In-vitro simulation was employed to quantify inhaled dose with VMN via Airvo2 and Vapotherm. Compared to baseline, neither HFNC device generated higher aerosol concentrations. Compared to HFNC alone, VMN via Airvo2 generated higher 0.3-1.0 µm particles (all p<.05) but VMN via Vapotherm did not. Concentrations of 1.0-3.0 µm particles with VMN via Airvo2 were similar with VMN and a mouthpiece/facemask but lower than SVN with a mouthpiece/facemask (all p<.05). Placing a surgical mask over HFNC during nebulization reduced 0.5-1.0 µm particles (all p<.05) to levels similar to the use of a nebulizer with mouthpiece and expiratory filter. In-vitro the inhaled dose with VMN via Airvo2 was ≥6 times higher than VMN via Vapotherm. During aerosol delivery via HFNC, Airvo2 generated higher inhaled dose and consequently higher fugitive aerosols than Vapotherm. Simple measures, such as placing a surgical mask over nasal cannula during nebulization via HFNC, could effectively reduce fugitive aerosol concentrations.
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http://dx.doi.org/10.4187/respcare.09589DOI Listing
November 2021

Efficacy of Various Mitigation Devices in Reducing Fugitive Emissions from Nebulizers.

Respir Care 2021 Nov 9. Epub 2021 Nov 9.

Department of Cardiopulmonary Sciences, Division of Respiratory Care, Rush University, Chicago, IL.

Fugitive aerosol concentrations generated by different nebulizers and interfaces , and mitigation of aerosol dispersion into the environment with various commercially available devices are not known. Nine healthy volunteers were given 3 mL saline with a small volume nebulizer (SVN) or vibrating mesh nebulizer (VMN) with a mouthpiece, a mouthpiece with an exhalation filter, an aerosol mask with open ports for SVN and a valved facemask for VMN, and a facemask with a scavenger (Exhalo) in random order. Five of the participants received treatments using a face tent scavenger (Vapotherm) and a mask with exhalation filter with SVN and VMN in a random order. Treatments were performed in an ICU room, with 2 particle counters positioned 1 and 3 feet from participants measuring aerosol concentrations at sizes of 0.3-10 µm at baseline, before, during and after each treatment. The Ethics Committee at Rush University approved this study. Fugitive aerosol concentrations were higher with SVN than VMN and higher with a facemask than a mouthpiece. Adding an exhalation filter to a mouthpiece reduced aerosol concentrations of 0.3-1.0 µm in size for VMN and 0.3-3.0 µm for SVN (all p<0.05). An Exhalo scavenger over the mask reduced 0.5-3.0 µm sized particle concentrations for SVN (all p<0.05) but not VMN. Vapotherm scavenger and filter facemask reduced fugitive aerosol concentrations regardless of the nebulizer type. SVN produced higher fugitive aerosol concentrations than VMN, while facemasks generated higher aerosol concentrations than mouthpieces. Adding an exhalation filter to the mouthpiece or a scavenger to the facemask reduced aerosol concentrations for both SVN and VMN. Vapotherm scavenger and filter facemask reduced fugitive aerosol as effectively as a mouthpiece with an exhalation filter. This study provides guidance for reducing fugitive aerosol emissions from nebulizers in clinical practice.
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http://dx.doi.org/10.4187/respcare.09546DOI Listing
November 2021
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