A Systematic Review of Methods Used to Determine the Work of Breathing during Exercise.

INTRODUCTION: Measurement of the work of breathing (Wb) during exercise provides useful insights into the energetics and mechanics of the respiratory muscles across a wide range of minute ventilations. The methods and analytical procedures used to calculate the Wb during exercise have yet to be critically appraised in the literature. PURPOSE: The aim of this systematic review was to evaluate the quality of methods used to measure the Wb during exercise in the available literature. METHODS: We conducted an extensive search of three databases for studies that measured the Wb during exercise in adult humans. Data were extracted on participant characteristics, flow/volume and pressure devices, esophageal pressure (P oes ) catheters, and methods of Wb analysis. RESULTS: A total of 120 articles were included. Flow/volume sensors used were primarily pneumotachographs ( n = 85, 70.8%), whereas the most common pressure transducer was of the variable reluctance type ( n = 63, 52.5%). Esophageal pressure was frequently obtained via balloon-tipped catheters ( n = 114, 95.0%). Few studies mentioned calibration, frequency responses, and dynamic compensation of their measurement devices. The most popular method of measuring the Wb was pressure-volume integration ( n = 51, 42.5%), followed by the modified Campbell ( n = 28, 23.3%) and Dean & Visscher diagrams ( n = 26, 21.7%). Over one-third of studies did not report the methods used to process their pressure-volume data, and the majority (60.8%) of studies used the incorrect Wb units and/or failed to discuss the limitations of their Wb measurements. CONCLUSIONS: The findings of this systematic review highlight the need for the development of a standardized approach for measuring Wb, which is informative, practical, and accessible for future researchers.

Perceived public health threat a key factor for willingness to get the COVID-19 vaccine in Australia.

BACKGROUND: Vaccination rollout against COVID-19 is underway across multiple countries worldwide. Although the vaccine is free, rollout might still be compromised by hesitancy or concerns about COVID-19 vaccines. METHODS: We conducted two online surveys of Australian adults in April (during national lockdown; convenience cross-sectional sample) and November (very few cases of COVID-19; nationally representative sample) 2020, prior to vaccine rollout. We asked about intentions to have a potential COVID-19 vaccine (If a COVID-19 vaccine becomes available, I will get it) and free-text responses (November only). RESULTS: After adjustment for differences in sample demographics, the estimated proportion agreeing to a COVID-19 vaccine if it became available in April (n = 1146) was 76.3%. In November (n = 1941) this was estimated at 71.5% of the sample; additional analyses identified that the variation was driven by differences in perceived public health threat between April and November. Across both surveys, female gender, being younger, having inadequate health literacy and lower education were associated with reluctance to be vaccinated against COVID-19. Lower perceived susceptibility to COVID-19, belief that data on the efficacy of vaccines is 'largely made up', having lower confidence in government, and lower perception of COVID-19 as a public health threat, were also associated with reluctance to be vaccinated against COVID-19. The top three reasons for agreeing to vaccinate (November only) were to protect myself and others, moral responsibility, and having no reason not to get it. For those who were indifferent or disagreeing to vaccinate, safety concerns were the top reason, followed by indecision and lack of trust in the vaccine respectively. CONCLUSIONS: These findings highlight some factors related to willingness to accept a COVID-19 vaccine prior to one being available in Australia. Now that the vaccine is being offered, this study identifies key issues that can inform public health messaging to address vaccine hesitancy.

COVID-19 challenges faced by general practitioners in Australia: a survey study conducted in March 2021.

Limited studies at the beginning of the COVID-19 pandemic found GPs have been negatively affected by increased workload, reduced income and major concerns about staff and patient safety. This study aimed to investigate the challenges of COVID-19 in general practice 1 year since it was declared a pandemic. A national cross-sectional online survey was conducted in March 2021 of a convenience sample of 295 Australian GPs attending an online educational webcast. Twenty-five multipart and free-text questions collected information regarding GPs' main COVID-19-related issues and concerns, including COVID-19 vaccines, useful sources of information, information needs and their perceived role as GPs in COVID-19 management. Descriptive statistics were calculated for all quantitative variables. Content analysis was used to analyse text data from open-ended questions. Of the 596 eligible attendees of the online educational webcast, 295 completed the survey (49.5% response rate). One year since COVID-19 was declared a pandemic, GPs still have concerns regarding patients ignoring prescreening and presenting with flu-like symptoms, the safety of their colleagues and family and catching COVID-19 themselves, as well as concerns about the effect of the pandemic on their patients and patients delaying essential care for non-COVID-19 conditions. More education and resources about vaccines was identified as the top information need, which will assist with what GPs' perceived to be their key roles in managing the COVID-19 pandemic, namely educating the public, correcting misunderstandings and providing the COVID-19 vaccine. These findings highlight gaps in communication and information, particularly regarding COVID-19 vaccines. GPs need high-quality information and resources to support them in undertaking complex risk communication with their patients.

The Influence of Social Distancing Behaviors and Psychosocial Factors on Physical Activity During the COVID-19 Pandemic: Cross-sectional Survey Study.

BACKGROUND: The COVID-19 pandemic has arguably facilitated a shift toward increased sedentariness and reduced physical activity. Moreover, there is mounting evidence that mental health has also declined during the pandemic. However, it remains unknown to what extent social distancing (SD) behaviors and mental health have affected the physical activity levels of the general population. OBJECTIVE: The purpose of this study was to determine the influence of SD behaviors and prevailing mental health on the odds of being physically active during the early COVID-19 pandemic response. METHODS: A total of 4819 adults (2474/4819, 51.3%, female) from the US population with a median age of 46 (IQR 35-59) completed an online survey during the early pandemic response (April-June 2020). The survey included questions on adherence to 11 SD behaviors, and validated questionnaires which assessed self-reported physical activity, depression, anxiety, and mental well-being. Respondents were categorized into 2 physical activity groups: inactive (0-599 metabolic equivalent of task [MET]-minutes/week) and active (≥600 MET-minutes/week). A logistic generalized additive model (GAM) was used to determine which SD factors and mental health outcomes were associated with physical activity level. RESULTS: The GAM analysis revealed that wearing a facemask in public (odds ratio [OR] 1.46, 95% CI 1.14-1.79; P=.003), limiting the use of public transport (OR 1.47, 95% CI 1.19-1.83; P=.001), and restricting travel outside the house (OR 1.56, 95% CI 1.19-2.05; P=.002) were SD behaviors associated with higher odds of being more physically active. Conversely, avoiding physical activity outside the house was associated with higher odds of being inactive (OR 0.52, 95% CI 0.46-0.63; P<.001). Leaving the house more frequently, and a higher mental well-being were associated with increasing odds of being physically active (P<.001). Engaging with a moderate number of SD behaviors (3-7 total) was positively associated with physical activity, whereas a very high SD vigilance (ie, engaging with ≥10 total behaviors) decreased the odds of being active during the early pandemic response. CONCLUSIONS: Based on the findings of our study, we suggest that future public health messaging of SD guidelines should include (1) a clear portrayal of the benefits of regular exercise on mental health; and (2) a specific focus on how to be physically active outdoors in a COVID-safe manner.

Self-reported physical activity before a COVID-19 'lockdown': is it just a matter of opinion?

There are growing concerns that the COVID-19 pandemic has facilitated a sedentary shift in our physical activity habits. A reduction in physical activity during the pandemic may be secondary to restrictive policies implemented at the government-level, typically those policies which limit interpersonal contact; for example, physical/social distancing. It is without question that social distancing is a necessary measure to mitigate community transmission of the novel virus; however, these policies often limit the public's opportunities to engage in physical activity. The strictest enforcement of social distancing occurs during an authority-mandated 'lockdown' (also known as a 'shelter-in-place' or 'stay-at-home' order). This Viewpoint focuses on the current evidence demonstrating that physical activity declines during a COVID-19 'lockdown'. We highlight the point that most of the available evidence stems from investigations using non-validated, self-reported measures of physical activity and discuss the caveats therewith. This Viewpoint explores whether current evidence reflects an 'actual' or rather a 'perceived' reduction in physical activity, and raises the question of whether this distinction matters in the end.

Contextualising COVID-19 prevention behaviour over time in Australia: Patterns and long-term predictors from April to July 2020 in an online social media sample.

BACKGROUND: In Australia in March 2020 a national public health directive required that non-essential workers stay at home, except for essential activities. These restrictions began easing in May 2020 as community transmission slowed. OBJECTIVES: This study investigated changes in COVID prevention behaviours from April-July 2020, and psychosocial predictors of these behaviours. METHODS: An Australia-wide (national) survey was conducted in April, with monthly follow-up over four months. Participants who were adults (18+ years), currently residing in Australia and who could read and understand English were eligible. Recruitment was via online social media. Analysis sample included those who provided responses to the baseline survey (April) and at least one subsequent follow-up survey (N = 1834 out of a possible 3216 who completed the April survey). 71.7% of the sample was female (n = 1,322). Principal components analysis (PCA) combined self-reported adherence across seven prevention behaviours. PCA identified two behaviour types: 'distancing' (e.g. staying 1.5m away) and 'hygiene' (e.g. washing hands), explaining 28.3% and 24.2% of variance, respectively. Distancing and hygiene behaviours were analysed individually using multivariable regression models. RESULTS: On average, participants agreed with statements of adherence for all behaviours (means all above 4 out of 7). Distancing behaviours declined each month (p's < .001), whereas hygiene behaviours remained relatively stable. For distancing, stronger perceptions of societal risk, self-efficacy to maintain distancing, and greater perceived social obligation at baseline were associated with adherence in June and July (p's<0.05). For hygiene, the only significant correlate of adherence in June and July was belief that one's actions could prevent infection of family members (p < .001). CONCLUSION: High adherence to COVID prevention behaviours were reported in this social media sample; however, distancing behaviours tended to decrease over time. Belief in social responsibility may be an important aspect to consider in encouraging distancing behaviours. These findings have implications for managing a shift from government-imposed restrictions to individual responsibility.

Measurement of muscle blood flow and O2 uptake via near-infrared spectroscopy using a novel occlusion protocol.

We describe here a novel protocol that sequentially combines venous followed by arterial occlusions to determine muscle blood flow and O2 uptake from a single measurement point using near-infrared spectroscopy (NIRS) during handgrip exercise. NIRS data were obtained from the flexor digitorum superficialis (FDS) muscle on the dominant arm of 15 young, healthy adults (3 women; 26 ± 7 years; 78.6 ± 9.1 kg). Participants completed a series of 15-s static handgrip contractions at 20, 40 and 60% of maximal voluntary contraction (MVC) immediately followed by either a: (i) venous occlusion (VO); (ii); arterial occlusion (AO); or venous then arterial occlusion (COMBO). Each condition was repeated 3 times for each exercise-intensity. The concordance correlation coefficient (CCC) and robust linear mixed effects modeling were used to determine measurement agreement between vascular occlusion conditions. FDS muscle blood flow ([Formula: see text]) and conductance ([Formula: see text]) demonstrated strong absolute agreement between VO and COMBO trials from rest up to 60%MVC, as evidenced by high values for CCC (> 0.82) and a linear relationship between conditions that closely approximated the line-of-identity (perfect agreement). Conversely, although FDS muscle O2 uptake ([Formula: see text]) displayed "substantial" to "near perfect" agreement between methods across exercise intensities (i.e., CCC > 0.80), there was a tendency for COMBO trials to underestimate [Formula: see text] by up to 7%. These findings indicate that the COMBO method provides valid estimates of [Formula: see text] and, to a slightly lesser extent, [Formula: see text] at rest and during static handgrip exercise up to 60%MVC. Practical implications and suggested improvements of the method are discussed.

COVID-19 Misinformation Trends in Australia: Prospective Longitudinal National Survey.

BACKGROUND: Misinformation about COVID-19 is common and has been spreading rapidly across the globe through social media platforms and other information systems. Understanding what the public knows about COVID-19 and identifying beliefs based on misinformation can help shape effective public health communications to ensure efforts to reduce viral transmission are not undermined. OBJECTIVE: This study aimed to investigate the prevalence and factors associated with COVID-19 misinformation in Australia and their changes over time. METHODS: This prospective, longitudinal national survey was completed by adults (18 years and above) across April (n=4362), May (n=1882), and June (n=1369) 2020. RESULTS: Stronger agreement with misinformation was associated with younger age, male gender, lower education level, and language other than English spoken at home (P<.01 for all). After controlling for these variables, misinformation beliefs were significantly associated (P<.001) with lower levels of digital health literacy, perceived threat of COVID-19, confidence in government, and trust in scientific institutions. Analyses of specific government-identified misinformation revealed 3 clusters: prevention (associated with male gender and younger age), causation (associated with lower education level and greater social disadvantage), and cure (associated with younger age). Lower institutional trust and greater rejection of official government accounts were associated with stronger agreement with COVID-19 misinformation. CONCLUSIONS: The findings of this study highlight important gaps in communication effectiveness, which must be addressed to ensure effective COVID-19 prevention.

The syringe potentiometer: a low-cost device for pneumotachograph calibration.

The purpose of this report was to 1) detail the construction of a low-cost device that provides a "reference" flow waveform for pneumotachograph (PNT) calibration, i.e., the "syringe potentiometer" (SP), and to compare the 2) accuracy and 3) practical performance of "calibration curves" obtained with the SP device to other more established methods of PNT calibration, i.e., the weighted averaging (WA) and polynomial least-squares (PolyLS) methods. Volume and flow waveforms obtained via the SP device were validated against a motion capture system and were deemed accurate surrogates of actual syringe volume and flows. The SP device was used to construct a calibration curve of a PNT by dividing the flow waveform of the SP by the analog output of the PNT amplifier. A total of 187 inspiratory and 187 expiratory strokes were collected. When the entire data set of expiratory strokes was used, the SP, WA, and PolyLS methods together demonstrated acceptable volume and flow errors as per American Thoracic Society/European Respiratory Society recommendations (less than ±3.5% and less than ±5.0% errors, respectively). The "practical" performance of each method was assessed with a nested subsampling procedure, whereby volume and flow errors were evaluated as the number of strokes was increased (in blocks of 5 strokes). To this end, the SP method demonstrated practical performance superior to that of the WA and PolyLS approaches, whereby acceptable volume and flow errors were achieved after only 5 calibration strokes; the WA and PolyLS methods required 15 and 20 strokes, respectively, to achieve the same level of volume and flow accuracy.NEW & NOTEWORTHY This report describes the construction and validation of a low-cost device for the purposes of pneumotachograph (PNT) calibration: the "syringe potentiometer" (SP). Calibration of a PNT with the SP device yielded acceptable volume and flow errors (<3.5% and 5%, respectively) across a wide range of flows (<0.5 to 15 L/s). The SP device offered superior "practical performance" over other established PNT calibration methods, whereby acceptable volume and flow errors were achieved after only five calibration strokes.

Validity of Nutritional Screening Tools for Community-Dwelling Older Adults: A Systematic Review and Meta-Analysis.

OBJECTIVES: The aim of this systematic review was to summarize the validity of nutritional screening tools to detect the risk of malnutrition in community-dwelling older adults. DESIGN: A systematic review and meta-analysis. The protocol for this systematic review was registered in the PROSPERO database (CRD42017072703). SETTING AND PARTICIPANTS: A literature search was performed in PubMed, EMBASE, CINAHL, and Cochrane using the combined terms "malnutrition," "aged," "community-dwelling," and "screening." The time frame of the literature reviewed was from January 1, 2001, to May 18, 2018. Older community-dwellers were defined as follows: individuals with a mean/median age of >65 years who were community-dwellers or attended hospital outpatient clinics and day hospitals. All nutritional screening tools that were validated in community-dwelling older adults against a reference standard to detect the risk of malnutrition, or with malnutrition, were included. MEASURES: Meta-analyses were performed on the diagnostic accuracy of identified nutritional screening tools validated against the Mini Nutritional Assessment-Long Form (MNA-LF). The symmetric hierarchical summary receiver operating characteristic models were used to estimate test performance. RESULTS: Of 7713 articles, 35 articles were included in the systematic review, and 9 articles were included in the meta-analysis. Seventeen nutritional screening tools and 10 reference standards were identified. The meta-analyses showed average sensitivities and specificities of 0.95 (95% confidence interval [CI] 0.75-0.99) and 0.95 (95% CI 0.85-0.99) for the Mini Nutritional Assessment-Short Form (MNA-SF; cutoff point ≤11), 0.85 (95% CI 0.80-0.89) and 0.87 (95% CI 0.86-0.89) for the MNA-SF-V1 (MNA-SF using body mass index, cutoff point ≤11), 0.85 (95% CI 0.77-0.89) and 0.84 (95% CI 0.79-0.87) for the MNA-SF-V2 (MNA-SF using calf circumference instead of body mass, cutoff point ≤11), respectively, using MNA-LF as the reference standard. CONCLUSIONS AND IMPLICATIONS: The MNA-SF, MNA-SF-V1, and MNA-SF-V2 showed good sensitivity and specificity to detect community-dwelling older adults at risk of malnutrition validated against the MNA-LF. Clinicians should consider the use of the cutoff point ≤11 on the MNA-SF, MNA-SF-V1, and MNA-SF-V2 to identify community-dwelling older adults at risk of malnutrition.