Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

Bad Advice on Masimo’s RAD-57 – Part I

Also posted over at Paramedicine 101 (now at EMS Blogs). Go check out the rest of the excellent material there.

Here is some bad advice from a review of the RAD-57 study. Research that showed just how flawed Masimo’s CO (Carbon monOxide) measuring technology is –

Medic Marshall: I’m not entirely sure how I feel about this study. I’m afraid people will look at it as saying the RAD-57 doesn’t really work, and a valuable tool for evaluating potential CO exposures for patients and firefighters in rehab will be discarded.[1]

Is the RAD-57 a valuable tool for evaluating potential CO exposures for patients and firefighters in rehab?

What would make it valuable?

Assume that we use the RAD-57 to measure the CO levels of firefighters in rehab. We want to determine if the firefighter should –

1. Go to the hospital.

2. Go back to the station/home/to the next fire, depending on dispatch.

3. Go back to fighting this fire.

How do we determine which category the firefighter falls into?

1. Go to the hospital.

If the number on the RAD-57 is above whatever limit is established for the Go to the hospital decision, then there should be no question.

There is not a clear danger level for carboxyhemoglobin (COHb – CO bound to hemoglobin in the blood). In the study 15% was used. Whatever level is used, the important thing to know is whether the readings are accurate.

Most of the time, when the blood level of CO was over 15%, the RAD-57 was not accurate.

Most of the time, the RAD-57 missed the readings over 15%.

With a 15% carboxyhemoglobin level, the firefighter is presumed to be toxic. That toxicity probably occurred fighting this fire.

Most of the time, firefighters who should be told Go to the hospital, will be told, Everything’s OK. Go back and knock down that fire.

Most of the time, poisoned firefighters will be given bad advice if we trust the RAD-57.

Is this safe?

Compared to what? Compared with juggling hand grenades with the pins pulled it is very safe, but that is not what I would call safe.

A laboratory value of 15% carboxyhemoglobin was selected as the cutoff for determination of these performance characteristics according to proposed use of this RAD level for out-of-hospital triage of patients with possible carbon monoxide exposure in New York City.13[2]

The RAD device correctly identified 11 of 23 patients with laboratory values greater than or equal to 15% carboxyhemoglobin (sensitivity 48%; 95% CI 27% to 69%).[2]

Less than half of the patients with elevated COHb were correctly identified.

If we consider screening any fire fighter for COHb, then we should send that fire fighter to the hospital and do it the right way.

Or do firefighters not deserve accurate screening?

If you’re evaluating a patient who happens to be a firefighter, and they’re exhibiting signs and symptoms of CO exposure but the RAD-57 device is reading in a normal range, you aren’t (or at least you shouldn’t) allow that firefighter to return to duty.[1]

This is true, but –

If you’re evaluating a patient who happens to be a firefighter, and they’re exhibiting signs and symptoms of CO exposure, then stop playing with the RAD-57 and take them to the hospital.

If you’re evaluating a patient who happens to be a firefighter, and they’re exhibiting signs and symptoms of CO exposure the RAD-57 provides an excuse to send that firefighter back to fighting that fire.

The RAD-57 could justify refusing to cover illness due to on the job exposure to carbon monoxide.

If there were signs of CO toxicity, why didn’t the firefighter go to the hospital? The RAD-57 indicated no serious exposure, but it is inaccurate.

Without the RAD-57, the firefighter stays safe.

With the RAD-57, the firefighter is in danger.

This is exactly the opposite of what we want.

The problem is that CO toxicity does not present with clear symptoms. What is a symptom of CO toxicity could be any of dozens of other things. A low reading on the RAD-57 can convince people that the symptoms are due to something else.

The RAD-57 is dangerous.

To be continued in Bad Advice on Masimo’s RAD-57 – Part II and later continued in Bad Advice on Masimo’s RAD-57 – Part III and finished in Bad Advice on Masimo’s RAD-57 – Part IV.

Footnotes:

[1] RAD-57 Pulse Oximeter Performance – Study measures device’s readings comared with lab measurement
JEMS Street Science
by Keith Wesley, MD, FACEP and Marshall J. Washick, BAS, NREMT-P
Tuesday, February 15, 2011
Article

[2] Performance of the RAD-57 pulse CO-oximeter compared with standard laboratory carboxyhemoglobin measurement.
Touger M, Birnbaum A, Wang J, Chou K, Pearson D, Bijur P.
Ann Emerg Med. 2010 Oct;56(4):382-8. Epub 2010 Jun 3.
PMID: 20605259 [PubMed – indexed for MEDLINE]

Free Full Text Article from Ann Emerg Med with links to Free Full Text PDF download

.

Trackbacks

  1. […] from Bad Advice on Masimo’s RAD-57 – Part I and from Bad Advice on Masimo’s RAD-57 – Part […]

  2. […] from Bad Advice on Masimo’s RAD-57 – Part I from Bad Advice on Masimo’s RAD-57 – Part II and from Bad Advice on Masimo’s […]

Speak Your Mind