Hoping this helps:

How To Make A Hospital Mask:

First, I want to say that these are NOT surgical grade masks. They are meant to be used when nothing else is available and you are left using a bandana. They may be used alone or over an N95 mask you might be forced to re-use. It is a last resort as something is better than nothing. That said, let's begin:

I got my instructions from a link my friend, Paula, suggested and watched this video. 

CLICK HERE FOR THE VIDEO

And...

CLICK HERE FOR THE PATTERN

(There are other patterns on her site, too.)

Then, I added a little pocket and a twister tie so you can pinch the top of the mask over the bridge of your nose. 

Let's Get Started:

I gathered up fabric (100% cotton is best), 1/4" elastic, & twister ties.

Cut rectangles of fabric 9"X7" for adults (children size = 7"X5").

Cut 2 pieces of elastic 7" long for each mask.

Cut a twister tie pocket 1/2" longer than your twister tie and 3/4" wide.

I centered the twister tie pocket on the wrong side of one of the 9" edges of the rectangle and stitched 3 of the pocket edges leaving the bottom edge open. Backstitch all of your sewing.

Tuck in a twister tie and pin the opening closed.

Flip it over to the right side and attach one elastic piece on the 7" edge of the rectangle, about 1/2" down from the 9" edge. Do the same on the other 7" side. 

Now, pin the loose ends of the elastic 1/2" from the bottom on each side.

Repeat on the other side.

Place the 2nd rectangle over the first one with right sides together and elastic bands inside. Pin and stitch leaving a 3" opening at the bottom for turning. Be sure to use catch the twister tie pocket while stitching so you enclose the twister tie inside the small pocket. See both photos below before stitching.

(The 2nd rectangle is peeking out from under the dotted one.
It it a white fabric with a black design so this mask will be reversible.)

Now, clip corners close to stitching and turn right sides out. 

Iron flat. Then, fold in half (hot dog style) and iron a crease. Open and fold both long ends in (hot dog style again) to the center crease. Photos of this on on the Sweet Red Poppy web site. CLICK HERE.

Fold, pin, and iron 3 pleats towards the top (where the twister tie is), and stitch in place. Continue stitching along the bottom edge which will close the 3" opening. 

Here, you ca see how the twister tie allows the fabric to bend and stay in place over your nose.

I made 18 of these today. I plan to make more tomorrow. 

I made lots of happy, colorful ones, but now I'm making lots of the more popular plain ones. 

Hospitals will wash these. I washed mine with Tide Free & Gentle (which is not free and not particularly gentle, but it's fragrance free) and they did fine in a dryer on the low (delicate) setting. Since they are cotton, an iron helps, but I kept it off of the area by the plastic-coated twister tie. 

Do check with your local health care providers as not all are accepting these. For those of you who live near me, our local hospital is requesting a different pattern which I plan to work on tomorrow. Thanks to my friend, Kathy, for sharing this link with me: CLICK HERE for another pattern.

Thank you for helping your friends, community, and fellow humans. We are all in this together! Stay strong. We can do this!