This month’s Editor’s Choice is an evaluation of over-the-counter portable oxygen concentrators (POCs) by Casaburi et al. They note that direct-to-consumer advertising of POCs has led to the online sale of low cost POCs not cleared by the FDA. Using a bench model simulating a patient at exertion, they measured the delivered oxygen with 3 POCs and compared those to an oxygen cylinder. They used end-tidal partial pressure of oxygen (PETO2) as a surrogate for alveolar PO2. They reported that the highest PO2 was obtained with the cylinder, while only the FDA-cleared POC produced meaningful increases in delivered oxygen. They concluded that caregivers and patients should avoid over-the-counter POC devices due to lack of efficacy. Branson opines that direct-to-consumer sales of POCs, while well intended, place patients at risk in the absence of respiratory therapy guidance.
Battaglini et al evaluated the effects of physiotherapy on hemodynamics, gas exchange and cerebral physiology in ventilated subjects with and without COVID-19. They found improved gas exchange in subjects with COVID with no impact on cerebral dynamics measured by ultrasound. Of note, none of the subjects studied had intracranial pathology. They concluded that protocolized physiotherapy improved gas exchange in subjects with COVID-19 while improving cerebral oxygenation in subjects without COVID-19. Ntoumenopoulos provides accompanying commentary. He suggests that while these short-term physiologic changes provide evidence of clinical benefit, important patient outcomes such as length of stay require investigation in subjects with cerebral pathophysiology.
Terzi and others performed a bench study of mechanical insufflation-exsufflation (MI-E) and the impact of simulated airway collapse on cough peak flow (CPF). They evaluated 4 MI-E devices and modeled airway collapse with a flexible tube in a rigid chamber. They report that CPF differed significantly between MI-E devices, highlighting the limitations of using CPF alone to determine effectiveness.
Fossat and others evaluated the measurement of CPF in mechanically ventilated subjects without disconnecting them from the ventilator. They compared CPF measured with the ventilator’s expiratory flow sensor and a handheld peak flow meter. In 61 subjects, they found that CPF was readily measured using the ventilator. Willis considers both the Terzi and Fossat papers in an accompanying editorial. She notes that with increasing use of MI-E and the measurement of CPF, our understanding of the complexities of MI-E use in varying scenarios requires further research.
Macedo et al performed a randomized crossover study in COPD subjects comparing a 20-min session of intermittent intrapulmonary deflation technique and positive expiratory pressure therapy on separate days. Lung volumes were measured via body plethysmography and helium dilution techniques, and spirometry results were reviewed before and after each therapy. They found no differences in functional residual capacity or trapped gas volume. Residual volume was lower with the deflation technique but the importance of these differences is unclear.
Essay and others conducted a cross-sectional observational study to evaluate the ability of deep recurrent neural network models (long short-term memory, gated recurrent unit, and gated recurrent unit with trainable decay) to predict failure of noninvasive respiratory support (NRS). Data from a large Southwestern U.S. health network over 7 years was used to create the model. Input variables included laboratory, gas exchange, and cardiopulmonary values. In over 22,000 subjects they found the long short-term memory model had the best accuracy for predicting NRS failure. Accurate predictions were made 12 hours after admission and well preceded clinical signs of NRS failure.
Danesh et al performed a retrospective, multicenter observational cohort study of 15,361 consecutive hospitalizations of patients with COVID-19 at 25 adult hospitals as part of the Society of Critical Care Medicine VIRUS COVID-19 registry. They reported that the majority of subjects received oxygen via nasal cannula with increasing numbers requiring invasive ventilation in the first week. At 4 weeks, 70% of subjects required high-flow nasal cannula, noninvasive ventilation (NIV), or invasive ventilation. These data help to describe respiratory support requirements across a wide range of facilities.
Linares et al conducted a cross-sectional study of spirometry tests over 3 years in children 5–15 y old with diagnostic suspicion of asthma who had a methacholine and/or exercise test. In 20% of tests, bronchodilator response was identified in the forced expiratory flow (FEF)25–75. They concluded that assessment of FEF25–75 alone is not always reliable for ruling in or ruling out airway hyperresponsiveness in the setting of normal spirometry results in suspected asthma.
Chang and others evaluated the association between self-management behaviors and psychological resilience in subjects with COPD. Subjects completed a questionnaire based on the 20-item COPD Self-Management Scale and 25-item Connor-Davidson Resilience Scale through a face-to-face interview. They found that self-management and psychological resilience were positively correlated and significantly associated in a linear regression model.
Ambati and coworkers performed a retrospective chart review of new onset vocal cord dysfunction in a children’s hospital during the COVID-19 pandemic. One year prior to the pandemic, vocal cord dysfunction was seen in 5% of subjects compared to 10% of subjects during the first year of the pandemic. They suggest that this doubling of the vocal cord dysfunction incidence must be accounted for during evaluations of patients to prevent unnecessary therapy.
Bianchi and others present a short report on the impact of awake prone positioning and NIV on respiratory effort in severe COVID-19. They found the combination of therapies reduced respiratory effort. Liu and colleagues describe the use of 3D printing to develop a high-fidelity bronchial tree for bronchoscopy training.
Veldhoen and others provide a systematic review on MI-E use in subjects with neuromuscular disease. They included 25 studies that enrolled 608 subjects and reported that MI-E was associated with improved CPF and high patient satisfaction. They note that evidence is lacking to make any definitive conclusions.
- Copyright © 2023 by Daedalus Enterprises