chbare Posted December 20, 2009 Author Posted December 20, 2009 I respect your opinion however disagree that the time difference is worth it. You have a ground assett ready to transport, why go through the trouble of setting up an LZ and wait for a helicopter? I could see if the boat was still at sea and you could arrange the transport from the dock, I agree that a helicopter "could" be a safe mode of transport, I just think it isn't warranted here. You actually have no idea. We do not know how long the ground unit waited. However, I must impress that this is a time critical situation in some cases. While little time was spent on a comprehensive assessment, if there are any neurological problems, AGE is assumed until ruled out. This would be an emergency. While not part of the concept for my scenario, I do think discussing the transport considerations of dive emergencies is a good way to proceed. Rock shoes, you are very close. Helium does in fact have a very high level of thermal conductivity. In addition, gas inhaled from a tank will be quite cold at the depths mentioned. This changes with rebreather diving; however, this patient was in fact breathing open circuit. Take care, chbare.
p3medic Posted December 20, 2009 Posted December 20, 2009 You actually have no idea. We do not know how long the ground unit waited. However, I must impress that this is a time critical situation in some cases. While little time was spent on a comprehensive assessment, if there are any neurological problems, AGE is assumed until ruled out. This would be an emergency. While not part of the concept for my scenario, I do think discussing the transport considerations of dive emergencies is a good way to proceed. Rock shoes, you are very close. Helium does in fact have a very high level of thermal conductivity. In addition, gas inhaled from a tank will be quite cold at the depths mentioned. This changes with rebreather diving; however, this patient was in fact breathing open circuit. Take care, chbare. No idea? It's your senario, feel free to fill in the blanks. You indicate an intercept with a ground ambulance, I have to assume they have the patient. The time required to land, tranfer care, transport, land, and hand off the patient in your senario v.s. transport 30 minutes via ground is pretty much the same. The flight crew has nothing more to offer this patient other than speed. I do a fair amount of mixed gas diving, never been 400 but been close to 300, in very cold, dark north atlantic water. I appreciate the urgency, but disagree air transport has a significant advantage over ground in the senario as stated.
rock_shoes Posted December 20, 2009 Posted December 20, 2009 Rock shoes, you are very close. Helium does in fact have a very high level of thermal conductivity. In addition, gas inhaled from a tank will be quite cold at the depths mentioned. This changes with rebreather diving; however, this patient was in fact breathing open circuit. Take care, chbare. When you breathe in a substance you are essentially taking it directly into your core. If you take something that is significantly colder than body temperature and highly conductive into direct contact with your core the potential rate of cooling spikes significantly. It would be somewhat like putting a giant ice-cube in your stomach then swapping it out frequently. There is no way your body can keep up in terms of heat production. Close proximity of your lungs to major blood vessels would only accelerate the process further. I’m not sure what else I’m missing to be honest.
fireflymedic Posted December 20, 2009 Posted December 20, 2009 So are we completely ignoring the fact that on average it takes 20 min to get a helicopter in the air, get to scene, land, load the patient, and back in the air at a minimum? Then you still have the 7 minutes to the hospital - sounds like you've already ate up most of your thirty minutes there. I think the discussion of ground vs air transport is very valid. Anything 30 min or under really doesn't warrant air transport because you are looking at equal time almost. sometimes it's even faster. I know there are more than a few times someone from ground has gotten to the hospital before the helicopter. It's not as uncommon as one might think. Plus add in the variability of causing additional issues with air transport. If time is your largest concern - then you are actually eating up time that the patient could (and most likely would) have already been at the hospital. You are going to have more room to work in the back of the majority of ambulances than in the air. I think I'm going to favor ground transport which is a very valid point here. Did we ever stop to think the air is colder with height? It may be comfortable to us, but if your not CAMTS like some, there's not heat or AC - something to consider. What was the temp of water he was in? What's the ambient temp? It may be 80 degrees outside and we want AC and he's gonna require heat. What if you don't have it? If you're flying with some providers you don't have it and well blankies only do so much. Warm fluids? What's your proposed method of rewarming in that environment? I dare say if he's still shivering and with helo transport you're risking greater complications than if you just take him by ground.... 1
chbare Posted December 20, 2009 Author Posted December 20, 2009 I understand the transport concern and going by ground may in fact be faster depending on details I did not specify. Obviously, I can fill in the blanks and force the situation to go any way I want; however, the scenario required you to transport the patient regardless. As I stated earlier, I neglect some aspects to emphasize others and sometimes you have to have suspension of reality. For example, giving you the ability to interrogate dive computers and find out that heliox at 90/10 was mixed instead of trimix. I do not know how to interrogate the computer of a mk 15.5 rebreather, but I give out the information to emphasize teaching points. This is no different from letting you guys do CT scans in your ambulance. I absolutely appreciate a conversation about transport considerations, time, and safety; however, these were not concepts that I integrated into the original scenario. Sorry if you are dissapointed, I realize I cannot make everybody happy. If it will help, you could simply look at this as a straight ground transport scenario as the way to get the patient was less important than the investigation of the pathophysiology of the patients condition in this specific scenario. I try very hard to present challenging scenarios and I often emphasize points. Most of my case studies are presented in such a way. Rock shoes, you are correct. Take care, chbare.
Richard B the EMT Posted December 20, 2009 Posted December 20, 2009 Yes, there exists a small difference between fresh water and seawater, and even a difference between different areas of the ocean and the oceans and seas themselves. OK, so does any of this come into the equasion when figuring out Feet under Sea Water, even before figuring in "Bottom Time?" Or, is that just a distraction for folks like me who never had a Bends patient, or a mixed gas diver poisioning case, again, like me.
chbare Posted December 20, 2009 Author Posted December 20, 2009 (edited) OK, so does any of this come into the equasion when figuring out Feet under Sea Water, even before figuring in "Bottom Time?" Or, is that just a distraction for folks like me who never had a Bends patient, or a mixed gas diver poisioning case, again, like me. From what I understand, yes it does. I use the term FSW as if the diver were actually under X feet of water; however, diving gauges and decompression times are calculated based on pressure. So, depending on salt concentration, altitude, and even temperature, the pressure experienced may be different than the actual depth. When I use FSW in this scenario, it is more of a broad and nebulous concept. However, the real application is how much pressure was the diver experiencing? If the pressure = 300 FSW, then I simply say 300 FSW regardless of the actual depth the diver since I am primarily talking about Henry's law of solubility, the term FSW is the pressure that the diver experienced and not necessarily the actual depth. However, for the sake of simplicity I made both concepts equal in this scenario. A great question however. If you like math, the following link actually take you through calculating the difference. http://www.mindspring.com/~divegeek/altitude.htm In the real world, I think it is more important to obtain a good history if possible and transport the divers equipment and gas mixes and take people who were involved in the dive to the receiving facility because this will be a primary source of information for the said facility. As I stated, unless told you may not even know how deep the patient went as I would not even mess with diving equipment and would not advise people mess with the equipment. So, I would ask about; rate of descent, bottom time, deepest depth, gas mixes utilised, equipment utilised, ascent and adherence to decompression stops and times and any complications encountered in addition to the typical questions you should ask of every patient, then let the hyperbaric gurus figure out the details. Like you, my experience with diving related emergencies is limited. I have only one experience, and a strange one at that. I had a Spanish guy present to my remote clinic near Kabul. He had rather unimpressive signs and symptoms; headache, generalised myalgia, and sinus congestion. I tend to take very detailed histories and only found out about his hobby of technical diving when interrogating him about his social and personal habits. He had just returned to Afghanistan from a month of leave, during that time he did a 75 meter mixed gas technical dive simply for the fun. It had nothing to do with his current complaints; however, I must have asked him a hundred questions. Hope this helps. Take care, chbare. Edit: I have added a short video that does a down and dirty explanation of the gas mixes and even has an animation. This is a video about Nuno Gomex, a South African who holds the current technical dive open circuit record of just under 1,000 feet. Edited December 20, 2009 by chbare
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