The effects of wearing facemasks on oxygenation and ventilation at rest and during physical activity.

BACKGROUND: Facemasks are recommended to reduce the spread of SARS-CoV-2, but concern about inadequate gas exchange is an often cited reason for non-compliance. RESEARCH QUESTION: Among adult volunteers, do either cloth masks or surgical masks impair oxygenation or ventilation either at rest or during physical activity? STUDY DESIGN AND METHODS: With IRB approval and informed consent, we measured heart rate (HR), transcutaneous carbon dioxide (CO2) tension and oxygen levels (SpO2) at the conclusion of six 10-minute phases: sitting quietly and walking briskly without a mask, sitting quietly and walking briskly while wearing a cloth mask, and sitting quietly and walking briskly while wearing a surgical mask. Brisk walking required at least a 10bpm increase in heart rate. Occurrences of hypoxemia (decrease in SpO2 of ≥3% from baseline to a value of ≤94%) and hypercarbia (increase in CO2 tension of ≥5 mmHg from baseline to a value of ≥46 mmHg) in individual subjects were collected. Wilcoxon signed-rank was used for pairwise comparisons among values for the whole cohort (e.g. walking without a mask versus walking with a cloth mask). RESULTS: Among 50 adult volunteers (median age 33 years; 32% with a co-morbidity), there were no episodes of hypoxemia or hypercarbia (0%; 95% confidence interval 0-1.9%). In paired comparisons, there were no statistically significant differences in either CO2 or SpO2 between baseline measurements without a mask and those while wearing either kind of mask mask, both at rest and after walking briskly for ten minutes. INTERPRETATION: The risk of pathologic gas exchange impairment with cloth masks and surgical masks is near-zero in the general adult population.

Implementation of Febrile Infant Management Guidelines Reduces Hospitalization.

The clinical management of well-appearing febrile infants 7-60 days of age remains variable due in part to multiple criteria differentiating the risk of a serious bacterial infection. The purpose of this quality improvement study was to standardize risk stratification in the emergency department and length of stay in the inpatient unit by implementing an evidence-based clinical practice guideline (CPG). METHODS: The Model for Improvement was used to implement a CPG for the management of well-appearing febrile infants, with collaboration between pediatric emergency medicine and pediatric hospital medicine physicians. Interventions included physician education, process audit/feedback, and development of an electronic orderset. We used statistical process control charts to assess the primary aims of appropriate risk stratification and length of stay. RESULTS: Over a 34-month period, 168 unique encounters (baseline n = 65, intervention n = 103) were included. There was strong adherence for appropriate risk stratification in both periods: the proportion of low-risk patients admitted inappropriately decreased from 14.8% to 10.8%. Among admitted high-risk patients, the mean length of stay decreased from 49.4 to 38.2 hours, sustained for 18 months. CONCLUSION: CPG implementation using quality improvement methodology can increase the delivery of evidence-based care for febrile infants, leading to a reduction in length of stay for high-risk infants.

At the rhythm of language: brain bases of language-related frequency perception in children.

What neural mechanisms underlie language and reading acquisition? Slow rhythmic modulations in the linguistic stream (below 8 Hz) mark syllable and word boundaries in the continuous linguistic stream, potentially helping children master the words and structures of their language. Converging evidence across language and reading research suggests that children's sensitivity to these slow rhythmic modulations is important for language and reading acquisition. In infancy, children produce rhythmically alternating syllables, or babbles, at a slow frequency of ~1.5 Hz or 660 ms (Petitto et al., 2001). In early grades, children's sensitivity to slow rhythmic modulations correlates with their reading ability (Goswami, 2011). We used functional Near Infrared (fNIRS) imaging to investigate the brain bases of "language rhythm" in beginning readers (ages 6-9). Right hemisphere showed an overall greater activation toward the slow rhythmic stimuli, and left hemisphere showed greater activation toward 1.5 Hz, relative to faster and slower frequencies. The findings suggest that while right hemisphere might have an overall better ability to process rhythmic sensitivity, left hemisphere might have a select sensitivity to a preferred range of slow rhythmic modulations-a range that might be particularly salient to brain mechanisms responsible for cross-modal language processing and reading acquisition.