Tesla's (TSLA 1.50%) CEO Elon Musk stunned the country on March 23 when he announced he had -- as if by magic -- procured 1,255 ventilators from China, and was shipping them to medical centers in the U.S. 

But according to a story first reported by the Financial Times, it seems that the "ventilators" Musk promised aren't the type of ventilators that are most needed...and in fact aren't usually called "ventilators" at all! They're actually BPAP machines, typically used to treat sleep apnea. 

A man lies in bed with a CPAP mask on, and a CPAP machine in the background.

This CPAP machine is similar to the BPAP machines procured by Tesla. It forces air into the lungs through an external mask as opposed to an internal tube, technically making it a type of "non-invasive" ventilator. Image source: Getty Images.

Invasive vs. non-invasive

The U.S. medical system is dangerously short on invasive ventilators -- machines that supply the lungs with oxygen via a tube inserted into the body. They are a critical life support tool for people with severe respiratory infections, like COVID-19. A single device can cost tens of thousands of dollars. 

On Wednesday, a group called NYC Health + Hospitals tweeted a photo of their Tesla "ventilator" shipment, which clearly showed a BPAP machine, a type of non-invasive ventilator. Non-invasive ventilators like BPAP and CPAP machines push pressurized air into the lungs from outside the body. They aren't life-support devices, and usually cost less than $1,000. 

Also pictured was a stack of boxes with the ResMed (RMD -0.64%) logo. Mick Farrell, ResMed's CEO, has confirmed these appeared to be a discontinued model of BPAP machine that ResMed developed five years ago. 

Useful or not

In tweets, Musk has referred to his shipment as "FDA-approved" ventilators, and it's true that the FDA has issued an emergency policy approving non-invasive ventilators like these as potential -- if inferior -- substitutes for invasive ventilators when the latter isn't available. 

So, while Tesla's donation may still be useful in some situations, it's not what it initially seemed to be.