So I’ve been pretty skeptical about people sewing protective face masks at home. And, as with a lot of things we don’t have all the data that we wish we had. So…I’m putting this scientific evidence out there and encouraging you to contribute to this blog by adding other scientific data.
Nevertheless, the expert opinion at CDC is that they are in the “Better Than Nothing” category and gives this additional advice. “In settings where N95 respirators are so limited that routinely practiced standards of care for wearing N95 respirators and equivalent or higher level of protection respirators are no longer possible, and surgical masks are not available, as a last resort, it may be necessary for HCP to use masks that have never been evaluated or approved by NIOSH or homemade masks. It
may be considered to use these masks for care of patients with COVID-19, tuberculosis, measles, and varicella. However, caution should be exercised when considering this option.1,2“
Anecdotally, providers are using them to extend the life of other masks or N95s. Women are also making some with little pockets for other filters, and a material called HANIBON that can be purchased online is used often on the outer layer of disposable masks and works to block out dust and fluids from entering.
- Dato, VM, Hostler, D, and Hahn, ME. Simple Respiratory Maskexternal icon, Emerg Infect Dis. 2006;12(6):1033–1034.
- Rengasamy S, Eimer B, and Shaffer R. Simple respiratory protection-evaluation of the filtration performance of cloth masks and common fabric materials against 20-1000 nm size particlesexternal icon, Ann Occup Hyg. 2010;54(7):789-98.
“Sew” there you have it. Expert opinion is that as a last resort you may use inadequately tested cloth masks if it is all you have. I am grateful for all those sewists out there responding to medical center calls to supply them with cotton and elastic homemade masks, and sending out the patterns to do so. Field medicine.
CDC also says “The filters used in modern surgical masks and respirators are considered “fibrous” in nature—constructed from flat, nonwoven mats of fine fibers” If this is true then would nonwoven interfacing improve the homemade masks?
Credible sources often disagree on technicalities. Sometimes this includes classification of research design. Some argue that there are only 2 categories of research design:
- True experiments. True experiments have 3 elements: 1) randomization to groups, 2) a control group and an 3) intervention; and
- Non-experiments. Non-experiments may have 1 to none of those 3 elements.
Fundamentally, I agree with the above. But what about designs that include an intervention and a control group, but Not randomization?
Those may be called quasi-experiments; the most often performed quasi-experiment is pre/post testing of a single group. The control group are subjects at baseline and the experimental group are the same subjects after they receive a treatment or intervention. That means the control group is a within-subjects control group (as opposed to between-group control). Quasi-experiments can be used to answer cause-and-effect hypothesis when an experiment may not be feasible or ethical.
One might even argue that a strength of pre/post, quasi-experiments is that we do Not have to Assume that control and experimental groups are equivalent–an assumption we would make about the subjects randomized (randomly assigned) to a control or experimental group. Instead the control and experimental are exactly equivalent because they are the same persons (barring maturation of subjects and similar threats to validity that are also true of experiments).
I think using the term quasi-experiments makes it clear that persons in the study receive an intervention. Adding “pre/post” means that the
researcher is using a single group as their own controls. I prefer to use the term non-experimental to mean a) descriptive studies (ones that just describe the situation) and b) correlation studies (ones without an intervention that look for whether one factor is related to another).
What do you think? 2? or 3?
Enrolled in an MSN….and wondering what to do for an evidence-based clinical project?
Recently a former student contacted me about that very question. Part of my response to her is below:
“One good place to start if you are flexible on your topic is to look through Cochrane Reviews, Joanna Briggs Institute, AHRQ Clinical Practice Guidelines, or similar for very strong evidence on a particular topic and then work to move that into practice in some way. (e.g., right now I’m involved in a project on using evidence of a Cochrane review on the benefits of music listening–not therapy–in improving patient outcomes like pain, mood, & opioid use).
Once you narrow the topic it will get easier. Also, you can apply only the best evidence you have, so if there isn’t much research or other evidence about the topic you might have to tackle the problem from a different angle” or pick an area where there IS enough evidence to apply.
Medscape just came out with Eric J. Topol article: 15 Studies that Challenged Medical Dogma in 2019. Critically check it out to practice your skills in applying evidence to practice. What are the implications for your practice? Are more or stronger studies needed before this overturning of dogma becomes simply more dogma? Are the resources and people’s readiness there for any warranted change? If not, what needs to happen? What are the risks of adopting these findings into practice?
It’s getting to be that time of year when children close their eyes and fantasize about an old, fat man breaking into their house while they sleep naïvely in false security in their bedrooms.
“Ho! Ho! Ho!” the man says to himself as he places consumer goods under a tree that for some reason has been moved to their living room.
Wait. Perhaps he says “Ho ho ho!” instead. Just how many exclamation points does this slavemaster of reindeer use?
Let’s turn to the authorities. Here’s what Merriam-Websterhas to say:
There you have it. Three hos and one exclamation point.
Ho ho ho! Merry Christmas (etc.) to you!
Erin Servais is a professional book editor who is really hoping she won’t get coal this Christmas. Learn more about how she can help you reach your publishing goals here: Dot and Dash website.
“Measure twice. Cut once!” goes the old carpenter adage. Why? Because measuring accurately means you’ll get the outcomes you want!
Same in research. A consistent and accurate measurement will get you the outcomes you want to know. Whether an instrument measures something consistently is called reliability. Whether it measures accurately is called validity. So, before you use a tool, check for its reported reliability and validity.
A good resource for understanding the concepts of reliability (consistency) and validity (accuracy) of research tools is at https://opentextbc.ca/researchmethods/chapter/reliability-and-validity-of-measurement/ Below are quoted Key Takeaways:
- Psychological researchers do not simply assume that their measures work. Instead, they conduct research to show that they work. If they cannot show that they work, they stop using them.
- There are two distinct criteria by which researchers evaluate their measures: reliability and validity. Reliability is consistency across time (test-retest reliability), across items (internal consistency), and across researchers (interrater reliability). Validity is the extent to which the scores actually represent the variable they are intended to.
- Validity is a judgment based on various types of evidence. The relevant evidence includes the measure’s reliability, whether it covers the construct of interest, and whether the scores it produces are correlated with other variables they are expected to be correlated with and not correlated with variables that are conceptually distinct.
- The reliability and validity of a measure is not established by any single study but by the pattern of results across multiple studies. The assessment of reliability and validity is an ongoing process.