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.
There is a positive correlation between the use of alteplase for malfunctioning central venous catheters and the development of a CASBI. This is likely associated with the presence of an intraluminal fibrin sheath or thrombus. This study adds evidence linking thrombus formation to CBSI.
In this external cohort, the DPT is clinically relevant in predicting time from withdrawal of life support to death. In our patients, the DPT is more useful in predicting death within 60 min of withdrawal of life support than within 30 min. Furthermore, our analysis suggests optimal cut-off scores. Additional calibration and modifications of this important tool could help guide the intensive care team and families considering DCD.
The mortality in the ICU for pediatric HSCT recipients remains high. Early pulmonary complications continue to be an obstacle to the survival. We hypothesize OI is a predictor for mortality in critically ill pediatric HSCT recipients. Retrospective review of pediatric HSCT recipients between 2002 and 2010 who required intensive care during the same hospital admission as their transplant. Twenty-eight patients accounted for 31 ICU admissions. Twenty-six (84%) admissions required mechanical ventilation. Ten (38%) mechanically ventilated admissions were placed on HFOV. Mortality of those mechanically ventilated was 70%. An OI ≥ 20 at any point during ventilation was associated with 94% mortality, while an OI ≥ 25 had 100% mortality. There was a significant association between maximum OI at any point during mechanical ventilation and ICU mortality, with the odds of dying increasing by 13% for each unit increase of max OI (OR = 1.13, 95% CI = 1.01-1.26, p = 0.03). An OI of 20 had a sensitivity of 0.89 and specificity of 0.83 for predicting mortality. OI has a strong association with ICU mortality among pediatric stem cell recipients.
In children hospitalized with bronchiolitis, hyponatremia may be a modifiable risk factor for severe disease that may be mitigated by avoiding use of severely hypotonic IVF.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.