*** Pulse Oxygen Units for Search & Rescue *** From: "Keith Conover, M.D., FACEP" To: Cc: ; Subject: Pulse Ox units for SAR use. Date: March 18, 2000 15:19 Thanks for all the advice and comments. To summarize them: 1. COLD AND PRACTICAL CLINICAL ISSUES. Pulse ox units don't sense well on a cold extremity or when someone's poorly perfused, or someone's wiggling a lot (Iike my daughter sometimes!) and are only one more diagnostic parameter that a good medic can use along with other factors to monitor the patient. To deal with a cold extremity, one can (a) warm it up, (b) put a little nitropaste on the finger to cause dilation, or (c) use a forehead sensor that is less susceptible to poor perfusion of extremities. Nonin makes such a forehead sensor, and I'd like to hear of anyone with experience with different brands of forehead sensor. And, the units themselves, especially the LEDs, don't work in the cold. The solution is to keep the unit packaged with the patient and just bring it out to check the readings. 1. NONIN ONYX. Nonin makes the Onyx tiny unit that fits on a finger -- but is a bit fragile, not very water resistant, and doesn't offer various sizes and types of sensor. Sounded neat but I decided against it. 3. NONIN 8500. Nonin also makes the Model 8500 which seems designed for EMS and helicopter use (meets MilSpec 801). It uses 6 AA alkaline cells, and will work fine on 6 disposable Eveready Lithium AA cells, which provide lighter weight, longer life (about 2-3x longer), and work fine even when it's so cold the LEDs won't light. The unit with AA lithium cells and case and leads and such weighs about half a pound (8 oz=240g). They give a battery life of 200 hours if your're using alkalines and keep the brightness turned all the way down. The unit is small (3"x6"x1"=8x15x2 cm), sturdy but not bombproof nor waterproof, but comes with a nice zipper padded Cordura case which has room for leads and sensors, and unzips in a way that shows the entire face of the unit through some clear plastic, allowing access to controls by pressing through th clear vinyl. The lead for the sensor comes out through a double-zipper slit at the top; the zipper can be snugged up around the lead but it's really only rain- resistant, not waterproof. There is no audio alarm, but if you're with the patient constantly as in EMS, an audio alarm is more a pain and battery drain than anything. You can get add-ons that have a memory, alarm and printer, but I wasn't interested in these add-ons I decided to get one of these for my own use. For more information: http://www.nonin.com/m8500_1.html 4. Nellcor N-20. These units are in constant use in our ED for spot checks, so I'm quite familiar with them, and generally happy with their performance. They're much heavier than the Nonin 8500 (about twice the size and three times the weight). They do have audio alarms and printers available, and work on C cells (no exact match lithium disposable cells available, though you could get 3V lithium C cells and use dummy cells to replace half the batteries). They are water-resistant about like the Nonin, but their "case" is realy a rubber thing that snaps around them and protect them when you drop them on a rock, but do nothing to protect the unit from water. May be a good choice for street EMS but too big and heavy for wilderness use. There are several other units on the market but these three stood out in my evaluation as the most likely to be used for SAR/Wilderness EMS. Hope this is of some use to you. Thanks again for all the comments. --Keith Conover, M.D., FACEP http://www.pitt.edu/~kconover