Evaluating Sapphire

Dismayal Performance of Sapphire PSG system.

Postby thom2my » Wed Dec 03, 2008 3:39 pm


We are currently evaluating the CleveMed Sapphire Wireless PSG system.

We set it up on an actual patient and unfortunately, the online monitoring system crashed after 3 hours of recording. It appeared to be the PC HD failure & malfunction and it could not be rebooted. However, the data was still recorded in the SD card and it was only downloaded the next morning. Neither a split-night recording nor real-time scoring were possible .

Further more, there were frequent signal loss (brief intermitent signal dropout between 3-20 seconds, occuring randomly every 4-5 minutes). The wireless unit is using 900MHz frequency and wad prone to cellphone or external interference. This was noted before it failed.

We also noted that apart from Respiratory events, auto-scoring in real-time/playback was not possible for the Sleep Staging, Snoring, Arousals, PLMS, CSA and FL - all these had to be manually scored.

What was supposed to be a wireless-experience turned out be rather disappointing and dismayal at the best.

We certainly would not using it for the next PSG case study.
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Postby SWeimer » Thu Dec 04, 2008 2:03 pm

We appreciate all of our customers' feedback. As suggested by the user the recording failure had nothing to do with the Sapphire system. The PC hard drive failed. Our IT staff will be happy to help you with all related questions including PC selection. As acknowledged by the user, despite the PC failure, the study was recoverable from the back up memory in the Sapphire. We designed the Sapphire to have a removable SD card (capable of storing at least 4 studies before a new card is needed), in order to prevent data loss in case technologists or physicians face circumstances outside their control like PC hard drive failure. Had this study been done using other PSG systems, including conventional wired PSG systems, the data would likely have been unrecoverable!

Regarding Radio Frequency (RF) interference, you have used the 900 MHz version of the Sapphire product line. Since the 900 MHz frequency shares the same band as GSM phones, RF interference is possible. That is why we recommend using the 2400MHz Sapphire version for some countries. We apologize for not receiving our recommendation before the study. However, please be advised that the backup SD card will be interference free (since it is in the Patient Unit). So, like before, the recording will not be lost. Our international sales department would be happy to assist you with a 2400 MHz demo. CleveMed prides itself that it is the ONLY sleep diagnostic company that makes wireless PSG systems with multiple frequency bands. This was done to afford our customers all the options needed to best suit their lab RF environment.

Regarding automated scoring of sleep stages, arousals, and PLMs, we are happy to let you know that our engineers are working on including them in a software upgrade to be released soon. Please be advised that we offer free software upgrades for one year after purchase.

Again, we appreciate your comments and we look forward to assisting you in the future.
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Postby somnonaut » Thu Dec 04, 2008 5:52 pm

So, then in the AM, in a system that does not crash, but yet has interference, WHICH version of the study is the one that gets used as the true "Case"? The one on the Card sans-noise, or the one inthe computer with the noise? Does it require extra time to figure out which to use. Is there a measure of RF signal quality online, and then providing the user with an oeverview to see the quality of the comptuer's recording, and if it dips below X threashold for Y amount of time, then automatically use the SD card version?

I had a trial of the Scout, and using it myself at home, I turned onto my front during the night and it pushed the off button on the front and turned itself off. Not a happy camper to say the least.
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Postby SWeimer » Mon Dec 08, 2008 5:27 pm

CleveMed offers two types of radios that use the 900 MHz band or 2400 MHz band to communicate. We help our customers evaluate what other wireless equipment is used in their facility to select the best RF band for their location. Depending on the model selected the radio will either hop to different channels to avoid interference or the user is given an indicator of the RF quality and is able to manually change the channel.

If there is an intermittent interferer our radios will attempt to retransmit the data and no data loss is seen. If the retransmission is unsuccessful there may be gaps in the data that are about 1 second long. Assuming this does not happen too frequently a 1 second gap does not prohibit scoring a sleep study.

In a situation like thom2my's where equipment like a phone causes interference on the entire band available to the radio the gaps in the data are larger and can cause whole epochs to be lost. This type of data loss is easily identified by the night tech or by a quick scan through the data.

You will be happy to know that after your experience with the SleepScout we have increased the time that the off button must be held in to help avoid accidentally turning off the system.

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Product Manager, CleveMed
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